electric flight uk - British Electric Flight Association - Jan Bassett's
electric flight uk - British Electric Flight Association - Jan Bassett's
electric flight uk - British Electric Flight Association - Jan Bassett's
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ELECTRIC FLIGHT U.K.<br />
ISSUE No. 83 WINTER 2005<br />
THE MAGAZINE OF THE<br />
BRITISH ELECTRIC<br />
FLIGHT ASSOCIATION<br />
This PDF sample ELECTRIC FLIGHT U.K. is representative of the typical<br />
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<strong>Electric</strong> <strong>Flight</strong> - U.K. Issue 83 - Winter 2005<br />
"To Encourage and Further all Aspects of <strong>Electric</strong> Model <strong>Flight</strong> in<br />
the <strong>British</strong> Isles and Elsewhere" - B.E.F.A. Constitution<br />
BEFA Committee 2005/6 ........................... 4<br />
Chairman's Chatter .................................. 5<br />
Current Lines ........................................... 5<br />
BEFA AGM 2006 ...................................... 6<br />
Letter to the Editor .................................... 9<br />
New-2-U ..................................................25<br />
TLC from your TLO ................................. 31<br />
Readers’ Models ....................................... 37<br />
The Electrifly PolyCharge4 ....................... 42<br />
Fixing Günther Propellers ........................44<br />
CONTENTS<br />
Cover Photo: The cover photo is the Editor’s Scorpio threedee. It is powered by<br />
a Typhoon 15 brushless motor, a Hacker Master 30-3P brushless controller and<br />
3S1P Kokam 15C 2000mAh cells. It is fitted with a Ramoser Technik & Design<br />
VarioPROP 2-blade hub with 9.7" Scale-Optic blades, set at approx. 5" pitch. This<br />
setup gives a static power to weight ratio of almost 1.5:1 so vertical climbs are<br />
effortless, even after a 10 minutes of aerobatics.<br />
NEXT ISSUE. The copy date for the Spring 2006 issue is 28 February 2006, with<br />
the magazine due for publication by 31 March 2006.<br />
DISCLAIMER<br />
Wings & Wheels Model Spectacular .......... 47<br />
NEAT Fair 2005 ......................................48<br />
Perkins ARTF Tiger Moth ........................57<br />
A Smarter Dart ....................................... 61<br />
Intermodellbau 2005 ................................67<br />
Event Calendar ....................................... 72<br />
For Sale / Wanted ....................................75<br />
New to <strong>Electric</strong> <strong>Flight</strong>? Start Here ............77<br />
BEFA Sales ............................................. 78<br />
Advertisers Index .....................................78<br />
B.E.F.A. and <strong>Electric</strong> <strong>Flight</strong> U.K. wish to point out that the content, techniques and opinions<br />
expressed in this magazine are those of the individual authors and do not necessarily represent the<br />
views of either the Editor of this magazine or B.E.F.A. and its committee.<br />
© All information in this magazine is copyright of the authors. Any request to use information<br />
from this magazine is to be made to the editor (contact details overleaf).<br />
All reasonable care is taken in the preparation and compilation of the magazine, but B.E.F.A. and<br />
its committee cannot be held liable for any error or omission in the content of this magazine or any<br />
subsequent damage or loss arising howsoever caused.<br />
To allow proper appreciation of the photographs used, colour copies of them will be posted on the<br />
B.E.F.A. website after publication of this magazine. If you can, check them out at www.befa.org.<strong>uk</strong><br />
E.F.-U.K. 3
BEFA Committee 2005/6<br />
Chairman Robert Mahoney<br />
123 Lane End Road, High Wycombe, Bucks. HP12 4HF<br />
EMail: befa@rlmahoney.co.<strong>uk</strong><br />
Secretary Peter Turner<br />
37 Church Street, Horsley, Derbyshire. DE21 5BQ<br />
Tel: 01332 881 265, Email: peter@alport.fsnet.co.<strong>uk</strong><br />
Membership Secretary Bob Smith<br />
1 Lynwood Avenue, Tollesby, Middlesborough, Cleveland. TS5 7PD<br />
Email: bob.smith007@ntlworld.com<br />
Treasurer Bob Smith, details as Membership Secretary<br />
EF-UK Editor <strong>Jan</strong> Bassett<br />
111 Plantagenet Chase, Yeovil, Somerset. BA20 2PR<br />
Tel. 01935 472743, E-mail: editor@befa.org.<strong>uk</strong><br />
Events Co-ordinator Terry Stuckey<br />
31 Dysart Avenue, Kingston-upon-Thames, Surrey. KT2 5QZ<br />
Email: terrystuckey@blueyonder.co.<strong>uk</strong><br />
Competition Secretary Bob West<br />
51 Haweswater, Huntingdon, Cambs., PE29 6TW<br />
Tel. 07970 238 704, Email: robertj.west@tesco.net<br />
Midlands Representative Roger Winsor<br />
14 Butler Gardens, Market Harborough, Leics. LE16 9LY<br />
Email: Rogerwinsor7@aol.com<br />
Northern Representative Bob Smith, details as Membership Secretary<br />
Southern Representative Dave Chinery<br />
251 Station Road, Hayes, Middx. UB3 4JD<br />
Email: DavidDchinery@aol.com<br />
South West Representative <strong>Jan</strong> Bassett, details as Editor EF-UK<br />
Indoor & Free-<strong>Flight</strong> Rep. Gordon Tarling<br />
87 Cowley Mill Road, Uxbridge, Middx. UB8 2QD<br />
Email: gordon.tarling@ntlworld.com<br />
Technical Liaison Officer Alan Bedingham<br />
17 Highcliffe Close, Wickford, Essex. SS11 8JZ<br />
Email: bbba18333@blueyonder.co.<strong>uk</strong><br />
Public Relations Officer John Thompson<br />
19 Park Avenue, Liversedge, West Yorks, WF15 7EQ<br />
Tel. 01924 515 595, Email: johnty99@ntlworld.com<br />
Webmaster <strong>Jan</strong> Bassett, details as Editor EF-UK - (www.befa.org.<strong>uk</strong>)<br />
Safety Adviser David Beacor<br />
34 Chestnut Close, Brampton, Huntingdon, Cambs., PE28 4TP.<br />
Please enclose an SAE with all correspondence to the committee.<br />
4 E.F.-U.K.
Dear members,<br />
Chairman’s Chatter<br />
Welcome to autumn 2005 issue of your association's quarterly magazine.<br />
For once I can give you some good news! Lieutenant Colonel (Retired) R J Thayer<br />
has graciously given his consent for us to hold our annual Middle Wallop event<br />
with the normal conditions regarding the operations of our model aircraft.<br />
So open your diary at the 1st & 2nd of July 2006 and reserve that weekend for the<br />
BEFA Middle Wallop <strong>Electric</strong> weekend.<br />
If you or your club is going to hold an <strong>electric</strong> <strong>flight</strong> event please let <strong>Jan</strong> Bassett<br />
and myself have the information to put in this magazine and on the websites! I<br />
can see the 2006 being very busy with <strong>electric</strong> <strong>flight</strong> events. It will pay to get your<br />
dates in quickly to ensure you are first on any given day.<br />
In would like to wish you all seasons greetings and a prosperous New Year<br />
KEEP THE WATTS UP!<br />
Robert Mahoney<br />
Current Lines<br />
from the Editor<br />
Thanks again to all the contributors to this issue, you really make my life easier.<br />
I do request that articles are sent electronically if at all possible as it saves me<br />
retyping something that has normally been type once before.<br />
Unusually I managed to hold a couple of articles over to the next issue, but that<br />
still leaves most of the magazine to fill. My plea for articles and model information<br />
is therefore just as urgent, please submit something.<br />
This is my penultimate issue as Editor. We have a volunteer to take over the<br />
magazine who is suitably experienced and keen. However, I may not<br />
disappear completely from the pages of this publication as some fear<br />
(or was it cheer!). I will offer my services to the new Editor in<br />
commenting on articles if my services are a benefit.<br />
I also plan to spend some of my freed time in building a number of<br />
models that have been part started, sit in boxes on the top of<br />
cupboards or are just in my mind. I will be submitting articles<br />
on these projects, why don’t you do the same.<br />
All the best for the festive period and 2006.<br />
Regards<br />
<strong>Jan</strong><br />
E.F.-U.K. 5
2006 Annual General Meeting<br />
to be held at 2.00 pm on<br />
6th March 2006<br />
at the<br />
Royal Spa Centre, Royal Leamington Spa, Warks.<br />
with Traders’ Fair from 9:30am<br />
Access will be allowed for the depositing of items for the Bring & Buy stand from<br />
9.00 am. It is requested that anyone bringing items to sell on the Bring & Buy<br />
stand complete the form (or a copy of it) overleaf before arriving. The is also<br />
available from the event page of the BEFA website (www.befa.org.<strong>uk</strong>). It is<br />
essential that all items are listed on the form and that all items are labelled with<br />
a minimum of the sellers’ name and the price asked. The Bring & Buy stand will<br />
stop trading at 1.00 pm to allow things to be cleared up before the AGM starts.<br />
The main doors will open for access to the Bring & Buy and Traders’ Fair at 9.30<br />
am. An admission fee of £3 will be charged for access to the Bring & Buy and<br />
Traders’ Fair, being payable on the door.<br />
Free access will be allowed to members after 1.30 pm so they can attend the<br />
Annual General Meeting, which will commence at 2.00 pm in the Lecture Theatre<br />
AGM Agenda<br />
Minutes of the last AGM<br />
Matters arising.<br />
Annual Reports from the Chairman, Secretary & Membership Secretary.<br />
Treasurers statements and review of the Statement of Funds<br />
Agree the Annual Subscription for 2005/6<br />
Appoint the Financial Auditor for 2005/6<br />
Election of Committee Officers -<br />
Secretary<br />
Membership Secretary<br />
Editor<br />
Events Co-ordinator<br />
Free <strong>Flight</strong> and Indoor Representative<br />
Proposals: The Committee has proposed one resolutions (see facing page).<br />
Nominations for the Committee positions due for re-election must be received in<br />
writing by the Secretary (see page 4 for address) at least 15 days before the AGM.<br />
6 E.F.-U.K.
The following change to the BEFA Constitution is proposed by the<br />
Committee for acceptance at the 2006 A.G.M.<br />
Clause 7 – Existing wording<br />
7) Election of the Committee.<br />
The officers of the Committee will be elected at the Annual General Meeting<br />
of the <strong>Association</strong>. Persons nominated for election must confirm in writing<br />
that they are prepared to serve if elected and must be proposed and seconded<br />
by paid up members. Nominations must be received by the Secretary at<br />
least fifteen days before the date of the A.G.M. In the event of insufficient<br />
nominations being received to fill all positions on the Committee, the elected<br />
members of the Committee will have the power to co-opt any eligible member<br />
who is prepared to serve.<br />
The problem with this system is that it is very cumbersome and tends to discourage<br />
nominations. This is particularly true in that we cannot accept nominations from<br />
the floor at our AGM which is the one occasion when we might expect to find<br />
volunteers. Under our present rules we can only co-opt such volunteers for a year<br />
prior to their nomination at the following AGM which also puts their election out<br />
of phase with our biannual pattern.<br />
We would like to simplify this procedure such that we can also accept nominations<br />
from the floor of the AGM to fill vacancies (supported by a proposer and seconder)<br />
and that if successful, such nominees could begin to serve on the committee<br />
immediately.<br />
The Committee therefore proposes that clause 7) be modified as follows:-<br />
7) Election of the Committee.<br />
The officers of the Committee will be elected at the Annual General Meeting<br />
of the <strong>Association</strong>. The Secretary should normally receive nominations at<br />
least fifteen days before the date of the A.G.M. Persons nominated for<br />
election in this way must confirm in writing that they are prepared to serve<br />
if elected and must be proposed and seconded by paid up members.<br />
In the event of insufficient advance nominations being received to fill all<br />
positions on the Committee, the committee may appeal for nominations for<br />
these unfilled positions from the floor. Provided such nominees are proposed<br />
and seconded by paid-up members, and are present at the meeting to accept<br />
nomination, then they may also be elected by majority vote of the members<br />
present.<br />
Should this procedure still fail to fill the vacancies the elected members of<br />
the Committee will have the power to co-opt any eligible member who is<br />
prepared to serve.<br />
E.F.-U.K. 7
8 E.F.-U.K.
Letters to the Editor<br />
Firstly a letter from John Bunting (aj.bunting@btopenworld.com) about Scale<br />
Speed, following on from my comments to last issues TLC from your TLO article.<br />
I'd like to discuss scale speed, and in particular Bob Boucher's article on the<br />
Astro<strong>flight</strong> website, to which you refer in EF-UK 82. I'm perfectly happy to<br />
be shot down if I'm wrong, but I'm not convinced by the idea that the model<br />
speed should be derived by multiplying the full-size speed by the square root<br />
of the scale.<br />
Let's take a one-ninth scale Spitfire as an example. The full-size span is 36<br />
feet, and typical speed 300 mph. The square root of one-ninth is one-third, so<br />
the speed of the 4-foot span model, according to Bob, should be 100 mph. At<br />
this point I begin to have doubts, which grow stronger when he talks about<br />
'Scale Time', and says in the section headed 'Scale Size Loops' that the square<br />
root factor applies here as well, so the model should do a loop in one third of<br />
the time taken by the real aircraft.<br />
Now, suppose you have a video of a real Spitfire doing aerobatics. You watch<br />
it several times, and you have a good idea, possibly assisted by a clock display<br />
in the corner of the screen, of how long it takes for the machine to do various<br />
manoeuvres. For instance, you may notice that it typically takes about ten<br />
seconds to do a loop.<br />
Then someone shows you another video, also of a Spitfire. For the first few<br />
seconds the machine is in steady <strong>flight</strong>, with a clear sky background, and you<br />
might easily think it's a real aircraft. But then it starts doing aerobatics, and<br />
the illusion is shattered, because it does a loop, not in ten seconds, but in<br />
about three seconds, so you know immediately that it must be a model. So<br />
much for realism.<br />
To crown it all, Bob tells us, "These very high power military aircraft are very<br />
difficult to model at scale speed". Well, I'm not surprised, if you think the<br />
scale speed for a one-tenth scale P-51 should be 135 mph.<br />
My conclusion is that this square-root-of-the-scale idea is misconceived. For<br />
realism in <strong>flight</strong>, I think the speed should vary directly as the scale. In other<br />
words, the real aircraft and the model should each take the same time to<br />
cover a distance equal to their own length; in which case our one-ninth scale<br />
Spitfire would fly at about 33 mph, and would do a loop in ten seconds. Not<br />
always easy to achieve in practice perhaps, but that's another matter.<br />
John raises a very interesting point in his letter and I’m sure it has merit. However,<br />
I’d like to consider the issue in more detail. I’m not sure about the 300 mph speed<br />
that John gives as typical. For completeness I’m going to compare the figures for<br />
stall, manoeuvre and maximum speeds (in mph) for a Spitfire.<br />
E.F.-U.K. 9
Spitfire IX Boucher (1/3) Bunting (1/9)<br />
Stall Speed 70 23.3 7.8<br />
Manoeuvre Speed 215 71.7 23.9<br />
Maximum Speed 408 136.0 45.3<br />
The Balsacraft Spitfire Mk IX is 1/9th scale and will be used to test the figures<br />
above. A typically flying weight for the Balsacraft Spitfire with a Graupner Speed<br />
600 Race 8.4v motor and 8 RC-2400 cells is 1.6 kg (3lb. 8oz.). This is a 14 oz.<br />
below the Bob Boucher weight of 4 lb. 6 oz.<br />
For this weight ElectriCalc estimates a stall speed of 17 mph. The Bob Boucher<br />
figure is reasonably close and will be achieved. The figure using the scheme that<br />
John proposes (7.8 mph) is not achievable unless the model weighs only about<br />
300g (~11 oz.). Even if this low speed could be achieved, I don’t think that a<br />
Spitfire would look credible at only twice walking pace. Certainly when it comes<br />
to stall speed, I have to side with Bob Boucher.<br />
It must be remembered that Bob Boucher says that the weight and power should<br />
be reduced to one half of the calculated values for high power aircraft. This reduction<br />
in power will inevitably mean that scale speeds will not be achieved. The 50% loss<br />
of power will mean a speed reduction of around 25% at maximum power.<br />
Another important factor at the upper speeds is that it is extremely rare for a<br />
model to have a variable pitch propeller. This means we have to compromise on<br />
propeller selection to get acceptable performance for take-off and climb out.<br />
Applying the 25% reduction to the maximum speed from Bob Boucher’s system<br />
gives a speed of 102 mph. This speed is still excessive and couldn’t be achieved<br />
with the 266W (at the propeller) available at half scale power. Using this power,<br />
it is probably realistic to expect 65 mph allowing for the scale lines.<br />
I am fortunate to see the Royal Navy Historic <strong>Flight</strong> Hawker Sea Fury FB11 fly<br />
regularly at RNAS Yeovilton. When you see this superb war bird hammer across<br />
the sky at around 450 mph it is an amazing sight (and sound). It is surprising<br />
how much sky an aircraft covers at these speeds, at a scale distance you could get<br />
whiplash. Because of that I think that John’s maximum speed of 45 mph is just<br />
too low, the model would appear very slow.<br />
I have to agree with John about the times to complete aerobatic manoeuvres, but<br />
it is a tricky problem. I think it important that the Manoeuvre Speed is considered<br />
here as this is typically the limiting speed for such antics. The Manoeuvre Speed<br />
using John’s recommendation is 23.9 mph, which would make it almost impossible<br />
to complete a loop. Again Bob Boucher’s speed is unreasonably high and would not<br />
be achievable.<br />
The solution is probably to fly at an intermediate speed and to enlarge the diameter<br />
of the loop slightly. You may not get to 10 seconds, but it will look better.<br />
10 E.F.-U.K.
Next is a series of letters / emails from Peter Vivian following on from his article<br />
“Some LiPo Experiments” in the last issue. I’m sure there are a lot of readers that<br />
are unsure about LiPo cells and balancers, so it is worth printing the whole history.<br />
I was interested to see that you published my LiPo experiments - as you say,<br />
you are short of offers!<br />
Seriously, one of the most important aspects of your efforts and contributions<br />
to the BEFA is that you make comments upon articles you publish, comments<br />
based upon knowledge and, more importantly, experience. This is important<br />
because it encourages articles which might seem pretty basic to some but can<br />
have serious input to even the "experts" when your comments are added. So<br />
I am afraid your plan to retire is not welcome.<br />
To get to my article, firstly I may have given a slightly incorrect impression<br />
- I am not totally new to <strong>electric</strong>s, just <strong>electric</strong> <strong>flight</strong>. In fact I am (or was) an<br />
electro-chemist and at one time I actually designed and made batteries! Seawater<br />
activated, ever heard of them? Think of the problems of series-connected<br />
open cells in a common electrolyte, the sea! So Ohms Law etc are not exactly<br />
egghead science to me.<br />
But to your comments in that article. Firstly, no I did not actually charge at<br />
1C. I gave the charger, a Mercury EX as I said, all the details it requested -<br />
type of cell, capacity, charge rate (1C) etc and the charger decided what to<br />
actually do when I switched it in. It started quite quickly to charge at 1C but<br />
then the current dropped off pretty rapidly towards about half that figure<br />
and carried on down. So recharging was in fact a long process. Now either<br />
I could assume the charger knows best or override the charger or buy a new<br />
charger. You imply the latter, I prefer the former because then I do not blow<br />
batteries up but others do! But if you know of a safe charger which will give a<br />
fairly level charge rate to a LiPo cell, much as my EX does to a NiMH or<br />
NiCd, please tell me.<br />
As for balancing leads, firstly my LiPo do not have them, I had to do that.<br />
But then, connection to a connector is space & weight when you think of the<br />
current-carrying capacity needed by wires and connector. And I am suspicious<br />
of "balancing chargers". How many people actually bother to do what I did -<br />
after some use and final charge disconnect all cells and check the after-charge<br />
voltage of each individual cell. I think most people believe what they are told.<br />
If they checked they may be a bit disenchanted - or wreck the battery!<br />
Finally, you compare 5S2P Kokam with 18S GP3700. Surely more exactly<br />
this should be 6S2P Kokam? (6 x 4.1 = 24.6, 18 x 1.35 = 24.3 OR 6 x 3.7 =<br />
22.2, 18 x 1.2 = 21.6) But anyway, is there a charger which can charge at that<br />
voltage? You also say that LiPo will charge in 90 minutes. Well, that was a<br />
major point of my article, I found that they will not equally charge in that<br />
time (or any other time) if connected up in series. The same amount of<br />
E.F.-U.K. 11
current passes through each (Kirchoffs Law) but because the voltage drop is<br />
different across each cell the wattage per cell is different. Yes, in parallel<br />
probably but my results show that 5S (or 6S) charging is not acceptable after<br />
a time, the cells go too far out of balance. And they do so for exactly the<br />
reason you say, different internal resistances which are exacerbated by repeated<br />
charging. So, LiPo or NiMH? High cost, low weight, long charge time (in<br />
reality) versus lower cost, higher weight, shorter charge time. I have the<br />
impression that you favour LiPo - or have I got that wrong?<br />
Anyway, please keep up the good work. And incidentally, another of your<br />
contributors to the same issue, Nick Fitton, rang me and we met up at a<br />
suitable hostelry. We had a very interesting couple of hours during which he<br />
strongly advocated Motocalc when trying to convert an IC to <strong>electric</strong>. I have<br />
downloaded it but I am not too sure yet - but of course not sufficiently<br />
experienced with it probably. Any comments?<br />
Do I have any comments, it would be surprising if I didn’t<br />
I thought your article was extremely useful as it allowed the explanation of a<br />
number of issues.<br />
I appreciate what you say about the worth of my comments, but I've spent<br />
thousands of hours doing the magazine over the last 5 years and now I want to<br />
do some more hands-on modelling. I've a number of projects I want to do but<br />
can't find the time whilst editing the magazine and working full time. I am<br />
not adverse to helping out the new editor and may still be making comments<br />
once the new editor has taken up post.<br />
I know a little about immersion batteries, salt and fresh water - they are used<br />
in a number of military projects that I am, and have been, involved in. It is<br />
always difficult to know at what level to pitch information, but there is always<br />
someone out there without the basic knowledge.<br />
From what you say it seems that the Mercury charger is extremely cautious<br />
in charging LiPo cells. My Schulze chamelëon isl6-330d & isl6-430d chargers<br />
will both complete a 1C charge in around 90 minutes, whilst still following the<br />
charge guidelines.<br />
My isl6-430d charger also<br />
has a RS-232 output,<br />
which allows connection<br />
to a PC to monitor or plot<br />
the (dis)charge. I've<br />
attached the graph from<br />
a charge conducted today<br />
on my Kokam 2000mAh<br />
15C 3S pack, which is<br />
starting to loose capacity.<br />
12 E.F.-U.K.
Both these Schulze chargers can charge up to 11 LiPo cells and at currents up<br />
to 5A where the pack allows. I am rapidly starting to think that a balancer or<br />
balancing charger is advisable for every charge. These limit the voltage across<br />
each cell to a maximum of 4.2V. The excess power is dumped by the balancer<br />
circuit so that the cell itself isn't passing the full charging current. Thereby<br />
each cell can charge to full capacity unaffected by the other cells. With external<br />
balancers connected I would have no qualms about charging an 11S pack with<br />
the Schulze chargers.<br />
I am looking around at different balancers and balancing chargers and may<br />
well put an article in the next issue on them. To use a balancing charger no<br />
disconnection of cells is required provide the pack was wired for balancing in<br />
the 1st place. All recent packs seem to have balancing leads, which means the<br />
cells must be paralleled and then connected in series. Unfortunately there is<br />
no standard balancing connector, which means that adapter lead need to be<br />
used for most packs.<br />
You are quite correct, I must have hit a 5 instead of a 6 and the spell checker<br />
wont spot that.<br />
I tend to prefer ElectriCalc to MotoCalc as the results are immediate. By<br />
changing the equipment or settings you can see the effects immediately. I do<br />
also use MotoCalc, but it takes a little more getting used to and I find it more<br />
time consuming.<br />
Peter Vivian the responded with a follow-up message:<br />
Thank you, that charging graph is interesting and I shall draw up a<br />
comparison with my Mercury charger. Long hand of course, no PC connection!<br />
And most interesting is your input on chargers generally, I shall have to look<br />
into it and see what I can afford.<br />
I would look forward to an article on balancing please - I still have doubts<br />
and I am sure that some people are being fooled. You say all recent packs<br />
have balancing leads. Really? From what little have seen I fail to understand<br />
the logic, some people seem to think that because you can see cell<br />
interconnection leads and the battery has a connector on the end of 2 wires<br />
this is a balancing system. You will know this is rubbish, but much more<br />
basic technical data is needed - right down to basics.<br />
Personally I fail to see, at the moment, how any series connection can be<br />
balanced without breaking/making connections. Kirchoff's Law, "the current<br />
through components in series is equal in all parts of the circuit" means that<br />
irrespective of the state of charge all series cells will have the same current<br />
passing through them. Parallel cells will of course have different currents<br />
passing through depending upon their internal resistance - and state of charge<br />
- and so will eventually balance.<br />
E.F.-U.K. 13
So a "basics" article would be most welcome, to very many people I think and<br />
not just to me - but perhaps less so to battery dealers!<br />
Best regards and many thanks. You will be missed but when work gets in the<br />
way of other interests it is always a problem - one I no longer have!<br />
Before I had chance to respond, Peter sent anther email:<br />
I attach a graphic representation which is designed to show my concerns<br />
about charger "balancing" and your comments would be appreciated.<br />
Assume that I have 6 LiPo cells each of 2500 mAh, part discharged.<br />
Now, I have named these cells cell 1, cell 2 etc and connected them up in<br />
parallel pairs to make 3 off 1S2P batteries, labelled Battery 1, 2 and 3. The<br />
"ohmic impedance" of each cell has been measured, commonly referred to as<br />
internal resistance but that is not really the correct term.<br />
Internal resistance is more exactly a fixed manufacturing condition whereas<br />
the total impedance depends not only on that but the stage of charge, the<br />
temperature, electrolyte and electrode conditions, contact resistance etc. etc.<br />
However, the effect is much the same at the start of charging.<br />
Then I show these batteries connected up in series and you will see from the<br />
diagram that if charging commences at 5 amps (1C) then 13 volts is the<br />
applied voltage. Using maths you can see the effective resistance of each 2cell<br />
battery and hence the voltage applied over that battery, the current passing<br />
through the total 3S2P battery and the current passing through each cell.<br />
Same current through each battery, different through each cell of course.<br />
14 E.F.-U.K.
Now, the parallel pairs will eventually balance. Take Cell 1 and Cell 2, after<br />
a time the different current passing through will charge the lower one to<br />
catch up with the higher - they essentially have to reach the same voltage<br />
because the higher-voltage cell is "charging" the lower one until voltages are<br />
equal. Until that happens the cell at the higher voltage will be constantly<br />
trying to input into the lower, so voltage balance is unavoidable.<br />
However, since equalisation of impedance would depend simply on luck there<br />
is little chance of the cells having equal capacities. Provide they are used in<br />
parallel that is of little problem because, as with charging, they will "correct"<br />
each other as they discharge. Well, they should but I have so far failed to<br />
confirm that.<br />
However, if we look at the other pairs of cells, the other batteries numbers 2<br />
and 3, they can never achieve the same voltage. Each of the series-connected<br />
2-cell batteries will receive the same amount of current for the whole of the<br />
time they are on charge (unlike those connected in parallel) and because of<br />
the different impedances, to say nothing of capacities, they will have different<br />
final voltages. If charging ends when, say, the total voltage of the 3S2P<br />
battery is 12.3 volts then each 2-cell battery may differ substantially - could<br />
easily be (as I know) 1 at 3.9 volts, 1 at 4.1 volts and 1 at 4.3 volts, a difference<br />
of 9% between highest and lowest. Not the way for a long life. The only way<br />
they can match is for each 2-cell battery to be charged up separately to the<br />
same final voltage. But it is claimed that a "balancing" charger can compensate<br />
in some way, can "bleed off" the overcharge being offered to the better battery<br />
and concentrate on boosting the lesser charged ones.<br />
OK if that is true why can no-one explain to me what the connections are,<br />
how it works. I have been told that it works by "rewiring" the cells and<br />
connecting them all up in both parallel and series/parallel. Oh yeah? It<br />
would be possible to have a connector panel (high current capacity PC board?<br />
Difficult) such that cells are connected to one set of terminals in series/parallel<br />
and another set in parallel only. Then applying charger leads to the parallel<br />
set only would charge all cells up to equal voltage. Then connecting to the<br />
series/parallel set for discharge would give you the required output voltage.<br />
True, but in this simple little case 6 cells of 2500 mAh would need to charge<br />
at 15 amps for 1C charging. Now imagine a 6S2P battery, 12 cells each of say<br />
2500 mAh. All magically connected in parallel, charge at 30amps and hope to<br />
finish in 90 minutes. 400+ watts and a sick car battery! Or 5 amps for 9<br />
hours. Or 10 minutes flying time and go home. Or take out a second mortgage<br />
for a bag of power packs.<br />
Or am I badly wrong somewhere?<br />
I have not put in all this information in the belief that I am teaching you<br />
anything or telling you anything you do not already know, but simply to<br />
show exactly where I am coming from so that you can teach me - and others!<br />
E.F.-U.K. 15
Not wanting to write an article on this (I have far too much to do and too little time<br />
already), I decided to respond to Peter directly and include the text in the ‘Letters<br />
to the Editor’ feature.<br />
I appreciate your concerns, but they are unfounded when using a balancing<br />
charger or external balancer. There is no need to perform any soldering or<br />
change pack connections to achieve balanced charging. Hopefully the following<br />
will explain it properly.<br />
Firstly, the limiting voltage for a 3S pack should be 12.6V (4.2V/cell) and<br />
therefore 13V should never be seen. If a LiPo charger is at 13V when set for 3S<br />
there is a serious safety fault with it and it should not be used.<br />
I have modified your spreadsheet to show the action of the balancer circuits.<br />
Charging at 5A with balancers connected<br />
Each balancer is a variable resistance provided by a FET, which dissipates the<br />
unwanted current as heat. Typically they start to operate at 4.21V and limit<br />
individual cell groups to 4.25V. This is so that they don't interfere with the<br />
function of the charger. As the pack nears fully charged, the pack voltage<br />
rises to 12.6V and the charger will limit it to that.<br />
If one group on a 3S pack is extremely low it could be at 4.1V, with the others<br />
at 4.25V. As the voltage on this group increases above 4.1V, the voltages<br />
across the other packs will drop, maintaining the 12.6V overall.<br />
You will notice on your diagram that cells 4 and 5 are exceeding the 1C charge<br />
current of 2.5A. I produced another chart at 4.5A (0.9C), but cell 5 still exceeds<br />
the 1C cell rate at a pack rate of 0.8C. Reducing the current further to 4A<br />
(0.8C) drops the current to an acceptable level. For this last diagram I had to<br />
16 E.F.-U.K.
Charging at 4.5A with balancers connected<br />
increase the resistance of each cell otherwise the voltages were all below 4.2V<br />
and the balancer would have been doing nothing.<br />
This is one of the reasons why we recommend a maximum rate of 0.75C when<br />
charging packs connected in parallel. This reduces current means that the<br />
cells should stay in the safe zone even when considerable imbalance is present.<br />
In most case the negative of cells 1 & 2 and positive terminals of cells 3 & 4<br />
share a single pin on the balancing connector. Thus a 4-pin balancing connector<br />
is all that is required for a 3S pack. Most LiPo balancers have an LED that<br />
Charging at 4A with balancers connected<br />
E.F.-U.K. 17
shows when 4.2V is reached on each paralleled group (e.g. R1 + R2).<br />
The critical point is that each of the paralleled groups must be connected to a<br />
balancer otherwise the voltage on those cells is completely uncontrolled and<br />
could rise to dangerous levels.<br />
Hopefully this and the spreadsheet all make sense, if not please ask for<br />
clarification.<br />
Peter responded with a long letter:<br />
Thank you for your e-mail of the 10th Nov. Now all is clear, I had never<br />
considered the use of a FET for “switching off” the charger, in fact I just did<br />
not realise how cheap they are today and such a means would never have<br />
crossed my mind. That said, I still have a problem. This may be because I<br />
am “out of date” with FETs or may be because you are simplifying things for<br />
general consumption.<br />
Firstly, a FET has 3 terminations in my world, Source, Drain and Gate, but<br />
in your diagram you show only two so I am not clear on your connections.<br />
Next, so far as I know, and I am an Electro-Chemist not a Physicist or<br />
Electronics man, a FET works by conducting a signal down a “channel” from<br />
Source to Drain unless a positive charge is applied to the Gate. Such a<br />
charge, as it increases, reduces the Drain effect (reduces the current flow) by<br />
increasing the resistance of the channel. This resistance increase carries on<br />
as the Gate charge voltage rises until the channel is totally “blocked”, no<br />
more current can pass.<br />
The voltage at which this total blockage occurs depends upon the design of<br />
the FET, for use on LiPo balancing a FET would be selected which “switches”<br />
at 4.2 volts. And it should be noted that at this point current flow ceases, it<br />
is not dissipated as heat. Such an action is not possible, current flows from a<br />
higher Potential Difference to a lower but it cannot be dissipated (Kirchoff’s<br />
Law). The effect of that, again so far as I understand, is illustrated in my<br />
attached Method 1 schematic and explanation. When a cell is fully charged<br />
then the charged Gate stops an current flow, throughout a total circuit of<br />
series connections.<br />
However, you appear to show the FETs connected in parallel with the cells<br />
and if this is correct it demonstrates a technology and FET property of which<br />
I have no knowledge - it would need in effect FET to be normal resistive in the<br />
Source to Drain channel, not conductive, until a charge is applied to the<br />
Gate. By this means, as the cell charges up so the Gate charge would increase<br />
and the channel would open, and at 4.2v (for a LiPo) the channel would be<br />
totally conductive.<br />
All the current would cease to flow through the cell, it would bypass the cell<br />
and go down the channel to the next cell. This would have the advantage of<br />
maintaining current flow through the 3S system even when one cell was<br />
18 E.F.-U.K.
Method 1<br />
Three FET devices are connected in series with 3 LiPo cells as shown below.<br />
Note the 3 FET leads, SOURCE, DRAIN and GATE. The Charger is connected<br />
negative to Lead 1, positive to Lead 4 and set up to charge 3 LiPo cells at 1C.<br />
The Red part of the FET is totally resistive at all times so does not conduct<br />
but the Black “conductor channel” conducts, so current (the same current)<br />
passes right through the FETs and charges up the cells. However, as a cell<br />
charges up its +ve voltage becomes greater of course and something called a<br />
“field effect” puts a +ve charge on the Gate.<br />
Now this increase in the “positiveness” of the Gate effectively “squeezes up” the<br />
“conductor channel” and when the +ve reaches its “switching” limit (4.2 volts<br />
for LiPo cells) the conductor channel actually becomes effectively “blocked”<br />
and hence a total resistor and so it stops any more current flowing-hence<br />
there is no more charging of anything.<br />
So when the first cell to reach full charge “blocks” the conductor it blocks all<br />
current flow so all charging ceases. No cell can become over-charged, but of<br />
course two cells will remain under-charged. Probably not by much, but not<br />
acceptable. The charger should indicate which cell is fully charged, and let us<br />
say it is Cell 2. So now we have to “top up” Cells 1 &3.<br />
So we firstly put the charger negative to Lead 1 and positive to Lead 2 and set<br />
the charger to charge 1 LiPo cell at 1C. Again, when the +ve of Cell 1 reaches<br />
4.2v the field effect from the positive of Cell 1 puts 4.2v on Gate 1 and FET 1<br />
stops conducting. So Cell 1 is now fully charged but Cell 3 still needs a bit<br />
more so we repeat as before, put the charger –ve to Lead 3 and positive to<br />
Lead 4 and set the charger for 1 cell 1C. These “topping up” operations should<br />
only take a few minutes but if it takes much longer it means that cell was very<br />
out of balance and it is just as well you discovered it!<br />
charged, and it would continue for the remaining 2 cells and then finally the<br />
remaining 1 cell. There would be no need to “top-up” any cells separately as<br />
would be needed with my Method 1. I show all this graphically in my Method<br />
2 schematic, but I must emphasise that although I am conversant with FETs<br />
of Method 1 I have no actual knowledge of Method 2 and all that I have<br />
written is pure speculation. Be good if it was correct!<br />
E.F.-U.K. 19
Method 2<br />
Three FET devices are connected in parallel with 3 LiPo cells as below. Note<br />
the 3 FET leads, SOURCE, DRAIN and GATE.<br />
The Charger positive is connected to Lead 1, negative to Lead 2 and set up to<br />
charge 3 LiPo cells at 1C.<br />
The Red part of the FET is totally resistive at all times and at the start so is<br />
the Black “conductor channel” which can conduct under certain conditions -<br />
see later - but which is a total resistor at the start.<br />
So current (the same current) passes right through the cells and charges them<br />
up. However, as a cell charges up its -ve voltage becomes greater of course and<br />
something called a “field effect” puts a -ve charge on the Gate.<br />
Now this Increases the “negativeness” of the Gate which effectively “opens up”<br />
the “conductor channel” and when the –ve reaches its “switching” limit (4.2volts<br />
for LiPo cells) the conductor channel actually becomes effectively “open” and<br />
hence a total conductor of no resistance. So the current by-passes the fully<br />
charged cell and so the cell does not overcharge.<br />
Because there is now less resistance in circuit the charge current drops but<br />
the remaining two cells continue to charge up.<br />
The next highest charged cell will then “shutdown” as it fully charges, followed<br />
by the third one.<br />
However, what this means is that for Method 1 the cell manufacturers would<br />
need to supply flying leads. For a 2S there would be 1 positive and 2 negatives<br />
(one to each cell) or for a 3S 1 plus 3 and so on. I can find no evidence of<br />
Kokam or any manufacturer doing this except PolyCell - ignoring simple 2S<br />
systems with centre pole connection. But I am sure you know better so please<br />
let me know, I am sick of soldering and unsoldering LiPo cells, I have wrecked<br />
2 so far and I am supposed to know what I am doing! As to packs with<br />
balancing FETs fitted, sounds good but for me only if connections are visible<br />
and can be reached with meter or clip contacts. I would prefer to be able to<br />
20 E.F.-U.K.
uy a PC board with assembled FETs, say for a 2S or a 3S or a 4S (or<br />
whatever the limiting series charging is today) and plug/unplug this to/<br />
from the factory-installed battery flying leads. Or, how do I specify and<br />
where do I buy such FETs, to make my own balancer?<br />
Finally, how can any model shop claim to sell a “balancing charger” to plug<br />
into a battery? I cannot visualise any such thing. In spite of you saying there<br />
is no need for a soldering iron I remain certain that connection to each cell is<br />
essential and if not factory supplied we must do it ourselves. Yes, if my Method<br />
2 works you would be able just to connect up a FET-fitted battery to a suitable<br />
charger - but such a charger would simply have a limiting capability not any<br />
balancing capability and should not be so described.<br />
But again, if I’ve got it wrong I would be delighted to be told.<br />
OK, a lot to cover, so here goes.<br />
In my last response I did simplify things in an attempt to make it easier to<br />
understand the principle. I also erred slightly, what I should have said is that<br />
each balancer circuit contains a FET. Peter is correct that FETs have 3 leads<br />
as identified. However, FETs are available in a number of different varieties<br />
with very different characteristics. The majority of FETs available do not<br />
conduct when the Gate voltage = Drain voltage, which means they are “off”<br />
when power is initially applied.<br />
Over the past few years the “on” resistance has reduced markedly, with surface<br />
mount FETs available as low as 6mÙ for a single FET. This ultra low resistance<br />
means very low loses and that these small packages can handle higher currents<br />
than their predecessors. This is one of the main reasons for the reduction in<br />
cost and size of speed controllers as less FETs are required. For brushless<br />
controllers this is a major advantage when 6 banks of FETs are required.<br />
Peter’s Method 1 could be used, but if that was to chosen method it would be<br />
better incorporated in the charger. Provided the voltage across each cell can<br />
be maintained it would work. I consider that this method is unnecessarily<br />
complicated and would not be cost effective.<br />
Method 2 is along the lines used by commercial balancers, although you can<br />
do it as simply as this. I’ll describe how a typical LiPo balancer circuit works<br />
in the following paragraphs and hopefully everything will become clear.<br />
A LiPo balancer typically contains a precision voltage reference, a voltage<br />
comparator, a number of discharge resistors, a pulse-width modulator (PWM),<br />
and a FET. The voltage reference is used by the comparator to produce an<br />
error signal. This error signal controls the PWM, which turns the FET on<br />
and off. As the voltage rises above 4.21v, the PWM starts with short pulses,<br />
which increase in width until, the FET is always on at 4.25v.<br />
Typically they also have a LED on the board, which indicates what the balancer<br />
E.F.-U.K. 21
is doing. If the LED is off the battery voltage is below 4.21v. The LED lights<br />
once the PWM circuit starts to operate and effectively indicates the pulse length<br />
being produce (although at a much slower, visible, rate). If an LED is constantly<br />
lit, the balancer is at maximum load and the voltage could be above 4.25v. To<br />
ensure that no damage is done the charging current needs to be immediately<br />
reduced to a level that all the LEDs are flashing or off. As the charging cycles<br />
nears completion the LEDs will extinguish as all the cells are below 4.21v.<br />
Some balancers are designed to be permanently connect across the cells, whilst<br />
others are connected only when charging. Those permanently connected have<br />
some advantages as they can’t be forgotten, however, you will need a balancer<br />
for every series cell in your packs. To explain, a 3S1P pack would require 3<br />
balancers, a 3S2P pack requires 3 balancers and a 5S4P packs requires 5<br />
balancers. As you can imagine this will be expensive if you have a lot of packs.<br />
Balancers that plugged in to external connections offer a method of balancing<br />
all your cells, whilst keeping the costs down. I said it before, but I’ll repeat it<br />
again here - it is essential that every series cell in a pack on charge is<br />
connected to a balancer.<br />
Balancers have a limit to the current that they can sink. Cells can be charged<br />
at currents considerably above the balancer rating provided they are sufficiently<br />
well matched. In the example I gave in one of the earlier responses, the balancer<br />
was required to sink 514mA to limit the voltage at a 5A charge current. If the<br />
balancer could only sink 250mA it would not be able to control the voltage,<br />
which would rise to approx. 4.50v - extremely unsafe.<br />
Please bear in mind that the above is typical, but wont be the case for all<br />
balancer designs. Please read, understand and follow the instructions supplied<br />
with the balancer you are using.<br />
I’ve hunted around to find balancing chargers and balancers to provide the<br />
best list I can of those currently available. The list is not exhaustive and I’d be<br />
interested in details of any others that are known.<br />
Balancing Chargers<br />
Make + Model Cells LiIo LiPo Max I Comments<br />
Schulze LiPoCard 1-4 Y Y 3.85A PC Interface, Auto setup<br />
The Schulze LiPoCard in use on a 3S1P Kokam 2000 pack<br />
22 E.F.-U.K.
Cell Balancers<br />
Make + Model Cells LiIo LiPo Max I Comments<br />
Astro<strong>flight</strong> Blinky 1-6 N Y 200mA<br />
CSM LiPo Balancer 1 N Y 335mA Designed for permanent fit<br />
DualSky Balancer 3 N Y unknown<br />
<strong>Flight</strong>Power Duralite 3 N Y unknown<br />
<strong>Flight</strong>Power Duralite 2-6 N Y unknown<br />
Graupner Micro Bal 1-5 N Y 100mA<br />
Hyperion EOS LBA6 2-5 N Y 6A charge Charge & discharge control<br />
MGM Compro BLCR-4 2-4 N Y unknown<br />
Orbit LiPo-Checker 1 N Y 550mA Supplied as a block of 5 units<br />
Pro LiPo Balancer 1-6 N Y 350mA<br />
Schulze LiPoBal08 1-8 Y Y 1.0A PC Interface, Auto setup<br />
Schulze LiPoBal14 1-14 Y Y 1.0A PC Interface, Auto setup<br />
Sky-Holic H021 2.4 N Y 300mA<br />
Thunder Power 2-5 N Y 420mA Linkable to some TP chargers<br />
The only unit I have experience of is the Orbit LiPo Checker, which is available<br />
with (•58.60) or without (•44.60) BEC type leads from http://orbitronic.de. These<br />
units are used by Jean-Paul Schlosser (JéPé) and I found these units very good<br />
and wont charge 2S+ packs without them connected.<br />
Astro Blinky<br />
5 Orbit LiPo Checkers<br />
Sky-Holic H021 Balancer<br />
Schulze LiPoBal 14<br />
E.F.-U.K. 23
If your packs do not have balancing leads fitted it is relatively simple to fit them to<br />
your packs. To fit a lead all that is needed is a suitable connector, some heatshrink<br />
tubing, a soldering iron and a little solder.<br />
The connector can be of any type to suit the balancer you intend to use but 0.1”<br />
pitch Molex connectors are a good choice. If using the Orbit LiPo Checker with<br />
the supplied BEC leads, use these connectors for the balancing leads.<br />
Firstly carefully remove the heatshrink sleeve from the pack and expose the soldered<br />
connections to the cells. You may find that hot glue has been used to stop the thin<br />
electrodes from moving about, this will need to be removed from the soldering<br />
area.<br />
It is easiest to solder to the<br />
electrodes where they are<br />
already covered in solder from<br />
the original connections.<br />
Carefully solder the leads to<br />
the terminals, as shown in the<br />
photograph and diagrams<br />
below, minimising the heat<br />
applied to the electrodes.<br />
Reapply hot glue or epoxy to<br />
protect the electrodes from<br />
flexing and re-cover the pack<br />
with heatshrink.<br />
24 E.F.-U.K.<br />
A 3S pack of 15C Kokam 2000 mAh cells with<br />
balancer lead retrofitted.
New-2-U<br />
A Brief Round-up of New Items of Interest.<br />
If you are a manufacturer or retailer that has something new they want to<br />
share with the readers, please send details to the Editor (addresses on page 4).<br />
Whilst this first item has been released for a while, it has not been seen in other<br />
press or at any of the fly-ins I’ve attended. The Rödelmodell Kobra “Revival” is a<br />
90cm (35½”) span, 79cm (31”) long sleek, moulded, twin boom, ARTF sports model.<br />
The original Kobra was a<br />
1980s model designed for<br />
2cc glow motors, but this<br />
latest version is solely for<br />
<strong>electric</strong> power.<br />
The flying weight is<br />
intended to be around<br />
950g (33½ oz.). Power is<br />
an AXi 2820/10 on a 3S<br />
pack of 15C 2000mAh<br />
LiPo cells or similar,<br />
giving unlimited vertical<br />
performance and 10 to 12<br />
minute <strong>flight</strong>s.<br />
The low weight and reasonable wing area also<br />
give excellent slow speed handling.<br />
As can be seen left, the wing and fuselage are<br />
supplied as a single piece with tail boom<br />
mounts, giving excellent strength for high<br />
speed manoeuvring. The transparent or carbon<br />
fibre canopy gives good access to the battery.<br />
The Kobra is supplied with hardware and<br />
decals (I’m not sure about the P-38 markings).<br />
A power set containing the AXi motor, speed controller, battery pack, folding<br />
propeller and hardware is also available.<br />
It is available from the Rödelmodell online<br />
shop at www.roedelmodell.de or contact<br />
them on +49 82 68 713, by email at<br />
info@roedelmodell.de or by mail to<br />
Rödelmodell GbR, Bernd & Petra Dörfler,<br />
Lausangerweg 4, 86874 Mattsies,<br />
Germany<br />
E.F.-U.K. 25
Hyperion have recently released a new<br />
range of outrunner motors, the Z-40<br />
series. They have a 45mm diameter<br />
stator, and is available in 3 different<br />
lengths 25mm, 35mm and 45mm.<br />
The magnets are specially made for<br />
these motors and are curved on both<br />
bell and stator sides. This maximises<br />
heat transfer and improves the<br />
magnetic flux.<br />
They also feature shielded stainless<br />
bearings. The motors also feature a large<br />
ring bearing at the at the front of the<br />
motor to prevent deformation of the bell<br />
at high rpm. The motors can be back<br />
mounted directly to a bulkhead or via the<br />
mounting kit. They can also be mounted<br />
using the rigid front mount, which can<br />
be adjusted over a wide range of lengths.<br />
Model Max Eff. I<br />
(A)<br />
Max. I<br />
(A)<br />
IO (A)<br />
KV (rpm/v)<br />
Ri (mÙ)<br />
Weight<br />
(g)<br />
Power<br />
(W)<br />
Z4025-10 40-60 80 2.96 560 16.2 356 600-1100<br />
Z4025-12 35-50 65 2.38 486 21.8 356 600-1100<br />
Z4025-16 30-40 50 1.85 368 37.2 356 600-1100<br />
Z4035-10 40-60 78 2.38 405 18.7 446 800-1400<br />
Z4035-12 36-53 65 1.98 343 26.1 446 800-1400<br />
Z4035-14 33-44 57 1.80 299 34.5 446 800-1400<br />
Z4045-10 40-60 77 2.05 320 22.1 553 900-1800<br />
Z4045-12 35-50 63 1.63 275 31.3 553 900-1800<br />
Z4045-14 31-40 48 1.50 236 40.9 553 900-1800<br />
A typical application is a 1/4 scale Ryan STA, 82” span, Hyperion Z4045-10 with<br />
Hyperion Titan-90HV and 8S Hyperion 3700mAh 20C LiPo and APC 16” x 8” thin<br />
<strong>electric</strong> propeller. This gives a flying weight of 12 lb. 4 oz. and draws 56A static<br />
current at 27.9v, giving 1560W and 5790 rpm. After <strong>flight</strong> the calculated average<br />
current was under 35A, motor was 51°C, the battery 36°C and controller 38°C.<br />
The Hyperion Z-40 motors and back mounts are available online from Robotbirds<br />
at http://robotbirds.com or contact them on 0208 841 7873.<br />
26 E.F.-U.K.
Another recently introduced item by<br />
Robotbirds is the nifty PJS 550R Double<br />
Contra rotating brushless outrunner.<br />
Stock is limited and they may have gone<br />
by the time this is published, however,<br />
contact them as they may get more.<br />
The PJS 550R is designed for scale<br />
models that need contra-rotating props,<br />
in other words one propeller rotating left<br />
& the other to the right. It has a<br />
diameter of 32mm and an overall length<br />
of 117mm and the weight is 139g.<br />
The motors have a Kv value of 1300 rpm/v and are 100mÙ each. The suggested<br />
propeller is 8” x 6” and you need one normal propeller and one with reverse pitch<br />
(commonly called Left hand). The battery is 2 to 3 cell Lithium and the maximum<br />
current is given as 21.7A per motor.<br />
The price is a very good £69.95 +P&P. Contact details for Robotbirds on page 26.<br />
Robotbirds have also just<br />
introduced the Smart Charger<br />
2020 (left), a 1 - 3 cell Lithium<br />
Polymer charger with output<br />
currents of 110mA, 250mA,<br />
500mA, 750mA and 1200mA. It<br />
is reverse polarity & short circuit<br />
protected and measures only<br />
90mm x 48mm x 11mm.<br />
The input voltage range is 10.5v to 15v. It features power on LED, error LED,<br />
charge complete LED and an LED for each cell connected. The settings are all<br />
manual using jumpers on the right hand side. Price only £17.95 +P&P.<br />
The final items included from<br />
Robotbirds are 3 new carbon<br />
undercarriage legs. They don’t state<br />
the weight of the legs, but the following<br />
information is available (all<br />
dimensions in mm)<br />
W H L Model Price<br />
190 100 25 700g £ 8<br />
245 120 28 1000g £ 9<br />
290 145 35 1300g £ 13<br />
E.F.-U.K. 27
Here we have a new EDF jet model from<br />
Schübeler Jets called the Vector II. The<br />
most striking thing about this jet is the<br />
leading edge slats allowing the profile<br />
geometry to be adjusted during <strong>flight</strong>.<br />
Due to the leading edge flaps the stall<br />
speed is reduced and it enables a high<br />
thrust-weight ratio (up to 1.2:1 with<br />
LiPo cells) jet-like acrobatics.<br />
At the EDF-Meeting in Gronau<br />
measurements showed the very good<br />
slow flying characteristics of Vector II.<br />
They also recorded a top speed of 183 mph (295 km/h)<br />
when using the DS-51-DIA (3 ph) moulded carbon fan<br />
and a brushless motor running on 20 Sanyo RC-2400<br />
NiCds. When using LiPo a much higher thrust to<br />
weight can be achieved.<br />
The fuselage and wing roots are hand moulded as a<br />
single piece<br />
from CRP, GRP & ARP, with balsa<br />
covered foam outer panels. The winglets<br />
are CNC milled and are screwed onto<br />
the wing to allow removal.<br />
The model is supplied with seamless<br />
ducts for the DS-51-DIA (3 ph) fan, which<br />
are almost “plug & fly”.<br />
The wing span is 1158mm (45½”), the<br />
length 1103mm (43½”). The flying<br />
weight is given as 2.75kg (6 lb.) (20 RC-<br />
2400 cells) or 2.25kg (5 lb.) (LiPo).<br />
Schübeler Jets products are imported<br />
into the UK by Al’s Hobbies, but as yet<br />
do not appear in their website<br />
(www.alshobbies.com). For more<br />
details email info@alshobbies.com or<br />
call 0208 500 8884. The kit price is £350<br />
plus £180 for a DS-51-DIA (3 ph) fan.<br />
28 E.F.-U.K.<br />
More info and other worldwide dealers<br />
can be found on the Schübeler Jets<br />
website at www.schuebeler-jets.de
Two models from Graupner on this page.<br />
Firstly an unusual model that is boat and<br />
plane - the HYDROPLANE 3D.<br />
The model resembles a typical fast racing<br />
hydroplane design, but has 2 sets of<br />
elevons at the tail (stern?) that are<br />
interconnected. It also features twin air<br />
rudders. Manoeuvrability on water is<br />
unlikely to be brilliant, but this is a very<br />
different model..<br />
The Hydroplane 3D is 79cm<br />
(31”) long, 55cm (21½”) wide<br />
and 22cm (8½”) high. The<br />
flying weight is around 235g<br />
(8¼ oz.) giving a wing loading<br />
of only 11.9g/dm 2 (3.9 oz./sq.ft.)<br />
It is quick and easy to assemble from vacuum-moulded and laser-cut Depron ®<br />
components. The reinforcing struts are lightweight, high-strength CRP profiled<br />
strips, ensuring a low all-up weight. To complete the model you’ll want a 280<br />
class brushless motor, a suitable 10A controller, propeller, a 3s LiPo pack between<br />
350mA and 650mA and 3 mini-servos.<br />
The Hydroplane 3D should be available through your local model shop or any of<br />
the internet model shops. The cost of the kit should be around £60.<br />
The second model is the Graupner<br />
SPEED CAT. The Speed Cat is a pylon<br />
racer of all-GRP construction. All the<br />
model´s components, i.e. fuselage, onepiece<br />
wing, tailplane & wheel fairings,<br />
are supplied ready-made moulded items,<br />
high-gloss , painted in the mould.<br />
The key features of the Speed Cat are<br />
its beautifully, harmonious, lines and distinctive “apple cheeks”, which give the<br />
model an interesting semi-scale appearance. The model is capable of very high<br />
airspeeds, especially <strong>electric</strong> powered. The aerodynamic layout of the Speed Cat<br />
gives the model pleasantly stable flying characteristics, and any RC pilot with<br />
average flying skills will not find it difficult to control.<br />
It features aileron, elevator and throttle control, has a span of 101cm (39¾”) and a<br />
wing area of 18.8 dm<br />
E.F.-U.K. 29<br />
2 (290 sq.in.). The target flying weight is 1.2kg (2 lb. 10 oz.)<br />
using a 500 size brushless motor and 3s LiPo with 40A ESC. Also included are the<br />
pre-formed aluminium undercarriage, 2 foam wheels, plastic spinner, small items,<br />
decal sheet & linkage pack. Price around £150 from local model shops/internet.
Want a small and<br />
inexpensive brushless<br />
motor and controller,<br />
then maybe the new<br />
budget items from All<br />
<strong>Electric</strong> RC are for you.<br />
The motor is equivalent to a Speed 400 motor and<br />
costs only £9.99. The controller is £15.99, rated at<br />
10A, weighs only 10g (0.35 oz.), is a simple plug & play design and has a jumper to<br />
select between 2s and 3s LiPo. Even better, buy the two together for only £19.99.<br />
Check out the All <strong>Electric</strong> RC website at www.all<strong>electric</strong>rc.co.<strong>uk</strong> for the complete<br />
range of products. Call them on 01782 788 778 to order or for more details.<br />
Another recent product that you might have<br />
missed are the Saphion Lithium Phosphate cells<br />
available from Overlander. Lithium Phosphate<br />
(LiPh) cells are much safer than Lithium Polymer<br />
(LiPo) & Lithium Ion (LiIo). They are only<br />
dangerous when short circuited or put in a fire,<br />
much the same as with NiCd or NiMH.<br />
The only capacity available at present are 1200mAh<br />
cells, which are rated at 15C, which is an 18A<br />
discharge rate. According to the data, they can<br />
withstand burst at 25C (30A). They also have the<br />
benefit of being chargeable at 2C (2.4A) so recharging in the field is more practical.<br />
LiPh cells have a lower terminal voltage at 3.2v/cell. Despite this difference,<br />
Overlander stated that they can be charged using a LiIo or LiPo charger (3.6v or<br />
3.7v per cell). They can be discharged down to 2v/cell without harming the cell.<br />
Each cell weighs 42g, broadly the same as similar capacity and discharge rated<br />
LiPo cells, however, the Watt-Hours are lower<br />
due to the lower voltage.<br />
Packs are available as 2S1P (6.4v) £16.99, 3S1P<br />
(9.6v) £24.99, 4S1P (12.8v) £32.99 or 5S1P (16.0v)<br />
£41.99. Packs can be parallelled (as LiIo and<br />
LiPo) to increase capacity or discharge rating.<br />
30 E.F.-U.K.<br />
Saphion cells should be available from your local<br />
model shop, or direct from Overlander. Check<br />
out their website at www.overlander.co.<strong>uk</strong> or<br />
contact them by phone on 0870 750 6411 or email<br />
at john@overlander.co.<strong>uk</strong>
TLC from your TLO<br />
By Alan Bedingham<br />
It all started when I bought a glider fuselage for my 2.5m <strong>electric</strong> Silent Dream. A<br />
few twangs off the bungee later, I was surprised how easy it was to get away in<br />
light lift with the glider versus the <strong>electric</strong> version. I don’t know about you, but to<br />
me, an <strong>electric</strong> glider is for just plain enjoying the day rather than competitions.<br />
No hassle with laying out bungees or trying to find the blasted parachute when it<br />
drops in the long grass. The sheer pleasure of working a little bit of lift low down<br />
and a long way off that you wouldn’t dream of trying for if you didn’t have the<br />
<strong>electric</strong> thermal to fall back on. Competing against myself I suppose.<br />
One guilty pleasure is deliberately circling in sink with the power on waiting for<br />
other gliders to join me and watching them drop like stones. Tee hee! So why is<br />
the glider version better in light lift than the <strong>electric</strong> version? Well, the obvious<br />
answer is that it is quite a bit lighter, over 19 oz. lighter in fact. The wing loading<br />
of the glider is 10.6 oz/sq.ft., the <strong>electric</strong> is 14.9 oz/sq.ft., some 40% higher – blimey!<br />
The next question was - how can I get the weight down?<br />
The setup I’m using is an Irvine 05/07 Cobalt with a 3:1 gearbox driving a 14” x<br />
10” folder on 8 RC-2400 cells. I had an 8 cell pack of CP-1600s that was 4oz.<br />
lighter than the RC-2400s, let’s try them. Much to my surprise, the climb (always<br />
pretty brisk) resembled a homesick angel and I needed a bit more down trim<br />
mixed in.<br />
Hmm – let’s try a smaller propeller. I had a 12.5” x 10” folder in stock, so I gave<br />
it a try. The climb was pretty good but it was obvious that saving 4oz wasn’t going<br />
E.F.-U.K. 31
to be enough to get the glide performance I was looking for.<br />
Changing to the smaller propeller had dropped the current from 31A to 20A, maybe<br />
I should be looking at LiPo batteries? I’ve been using a 3S pack of 1500mAh<br />
batteries in a Speed 400 powered Hawk for a while, but they wouldn’t give 20A,<br />
more like 12A. Then the penny dropped – buy another 3S 1500mAh pack and run<br />
the two in parallel.<br />
I made up a balsa crate to fit them in the space where the NiCds used to go and<br />
made up a couple of Y leads. Luckily, the NiCds were on the CG, so the LiPo pack<br />
had no effect on the overall CG of the ‘plane. Weight saved so far – 10 oz, dropping<br />
the wing loading to 12.7 oz./sq.ft., still some 20% more than the glider version.<br />
Flying it was a revelation, the climb is back to homesick angel levels and light lift<br />
scratching is much easier than before. Not only that but I had more battery<br />
capacity (3Ah instead of 2.4Ah) and nearly double the power on time because of the<br />
lower current draw! Roll on the next All Up Last Down competition!<br />
My best <strong>flight</strong> in one of those was nearly an hour and three quarters with the old<br />
setup, what’s possible with the new one?<br />
It’s difficult to see where I could lose that last 9oz., maybe an outrunner would<br />
save me about 4 of them (at a cost) and if I could find one that will swing a big<br />
32 E.F.-U.K.
propeller on 3S LiPo and only pull 20A or so. I think I’ll leave things as they are<br />
for now and enjoy flying a ‘plane that’s much lighter than it was.<br />
Lessons Learned<br />
I was surprised at the difference relatively small reductions in all up weight can<br />
make to climb performance.<br />
Changing an existing ‘plane to LiPo saves so much weight that you can think<br />
about cutting the current by using smaller propellers and still have the same<br />
performance.<br />
Cutting the current means that you can use lower capacity LiPo packs or get<br />
more power on time.<br />
Next Steps<br />
I was at the Southern Model Air Show and spotted on the RCM Direct stand a 3s<br />
10C capable pack of 3600mAh LiPos for a very reasonable £48. Wonder if they’ll<br />
go into my Vermont Belle? This is fitted with an AXi 2820/10 (when will<br />
manufacturers stop using these gibberish names?) running a 12” x 6” propeller on<br />
an 8 cell pack of RC-2400 at around 38A.<br />
Performance is good with enough vertical for big loops and even vertical eights.<br />
It’s only problem is that I have to limit myself to six minutes to make sure I have<br />
enough grunt left for a go around if I need one. Still haven’t quite got the hang of<br />
this landing lark after all these years!<br />
E.F.-U.K. 33
The LiPo is wider than the NiCd pack so a bit of hacking and carving was need to<br />
get it to fit. Weight saved is just over 8oz., some 15% lighter overall. I tried<br />
different propellers with an eagle eye on the Whattmeter and settled on a 10” x 7”<br />
that pulled 36A. Note the big change in propeller size, don’t forget a LiPo is worth<br />
around 3 NiCds so I was effectively fitting a 9 cell pack and I also wanted to cut the<br />
current a bit. It flew very well, the vertical is better than before and the duration<br />
is working up to 10 minutes.<br />
Perhaps I should explain that remark. I don’t have a single LiPo capable speed<br />
controller, so what I do is start at a conservative <strong>flight</strong> time, like six minutes,<br />
recharge the battery after each <strong>flight</strong> and gradually increase the <strong>flight</strong> time until<br />
I’m putting back about 70% of the capacity.<br />
My transmitter has separate count down timer settings for each memory which<br />
makes this easy to do. The only problem is hearing the beeps over the noisy oily<br />
fans! It’s a conservative approach that leaves a bit of leeway for windy days (you<br />
always use more power on windy days, have you noticed?) and that keeps me on a<br />
relatively level part of the discharge curve and well away from the LiPo 3V limit.<br />
My aim with this <strong>electric</strong> lark has always been to equal or better the oily fan<br />
‘planes. I’m there in terms of performance, in fact, when I took over a learner’s<br />
glow model to show him how to do a proper circuit for his ‘A’ test, I was surprised<br />
how under powered it felt compared to my <strong>electric</strong> models. Duration has always<br />
been the bugbear, until now.<br />
34 E.F.-U.K.
I was flying the Vermont Belle, trying out aerobatics, when I heard a glow model<br />
start up behind me. Both of us shared the pattern until he called ‘landing’ and<br />
brought his ‘plane in. I was still in the air! First time that has happened to me.<br />
Flushed with success, I started looking at some other models that hadn’t been<br />
flown for a while. My gaze lighted upon the venerable Fiasco. This had been<br />
designed to fit in the trunk of the Fiesta I owned at the time (always known to us<br />
Fordies as the Fiasco – just black humour - you don’t want to know what we called<br />
the Focus) lengthways with the rear seats folded, so it is 50” wide and 50” long.<br />
Designed as a knockabout fun model, with a symmetrical wing section, it flies just<br />
as well inverted as the right way up. My trademark of rolling inverted just as the<br />
wheels left the ground once attracted a ‘had a glitch did you?’ comment from one of<br />
our members. Isn’t it nice to know your engine isn’t going to misfire or stop?<br />
It was fitted with an Astro 25 geared swinging a 12” x 8” on 14 cells and weighed<br />
70oz. all up. It has served me well, doing plenty of flying and surviving a few<br />
crashes over the years. Have you noticed how long <strong>electric</strong> planes live for if you<br />
manage to keep them away from terra firma? I reckon it’s the lack of vibration<br />
E.F.-U.K. 35
and oil that does it. The oil because it makes them easy to repair!<br />
It had been put on the backburner because you don’t get many charges of a 14 cell<br />
pack from a car battery in a day and it had a distressing tendency to bend the<br />
undercarriage if a landing wasn’t absolutely perfect. I tend to average one out of<br />
ten landings perfect, six out of ten acceptable and the rest I don’t want to mention.<br />
There followed a feverish session on ElectriCalc assessing the possibilities. I ended<br />
up with the 3s 3600mAh LiPo pack and an Astro 05 geared swinging an 11” x 7”,<br />
the Astro simply because I had one in stock. This doesn’t seem possible until you<br />
look at one of the useful numbers ElectriCalc works out – W/lb.<br />
The 14 cell version is 89 W/lb., the LiPo version is 103 W/lb. The drop from 410W<br />
to 310W is more than made up for by the massive weight saving. Have a look at<br />
the pictures, the 14 cell powertrain weighs 44½oz. including a receiver battery,<br />
the LiPo 18½oz. (no receiver battery required), a reduction of 26oz.<br />
The whole ‘plane is 35% lighter! Looking at the ‘plane pictures you can see how<br />
eerily empty it appears with the LiPo setup.<br />
Off to the flying field to give it a go. This can’t work, can it? It can! Just as lively<br />
and aerobatic as before and with a lighter feel, more like the Vermont Belle. The<br />
landings were like a butterfly on thistledown.<br />
Well, you know what I mean, it’s always easier to make a landing look good with<br />
a light ‘plane than a heavy one. So it flies just as well for longer and I can get more<br />
<strong>flight</strong>s in a day since charging the LiPo hardly dents the capacity of the car battery.<br />
As the Americans say, ‘a win-win situation’.<br />
Lessons Learned 2<br />
LiPo conversions aren’t necessarily just a simple substitution of one battery for<br />
another, you really need to think about the whole power train before and after.<br />
You may be surprised at how much weight you can save.<br />
Anyone 36 want to buy a pile of NiCds? E.F.-U.K. Velly cheap!
Readers’ Models<br />
Your chance to show the members your model(s).<br />
Above is the “Donald 4” flying boat of Rich Flichbaugh, South Dennis, MA. It has<br />
a Mega ACn 22/10/6 motor, Castle Creations Phoenix 35 controller and a 10-cell<br />
Sanyo 1300mAh battery pack. This gives ample power for up to 10 minute <strong>flight</strong>s.<br />
Below is Rich Flichbaugh with his Great Planes Piper J3 Cub float plane taken at<br />
Scargo Lake, Florida. It features scale early design Edo “flat top” floats. A Mega<br />
ACn 600/20/5 motor with the same equipment as above give 8 - 10 minutes. The<br />
weight is 51 oz. (1.45kg), giving a wing loading of 15.6 oz./sq.ft. (47.6g/dm 2 ).<br />
E.F.-U.K. 37
These pages feature the 'Interceptor' of Mike Pirie, built from Gordon Whitehead's<br />
plan. It certainly does! What's more it then gives a 20 minute aerobatic <strong>flight</strong>.<br />
The original Frog ‘Interceptor’ with Mike Pirie’s model<br />
The original 'FROG' Interceptor was produced in the 1930s and was probably one<br />
of the world's first ARTFs. With a span of 11” it came in a small cardboard box<br />
and comprised a fuselage, two plug-in wings, removable undercarriage and a<br />
gearbox/propeller unit with a rubber motor. After assembly, it was wound up by<br />
placing the fuselage in its cradle in the bottom half of the box so that the propeller<br />
engaged with a ratchet mechanism at the front of the box, then a small handle<br />
was inserted into the box from the outside and turned the required number of<br />
times. With sufficient winds the model would then rise off a smooth surface to fly<br />
for a short time - probably only for a few seconds.<br />
Mike’s model in <strong>flight</strong><br />
38 E.F.-U.K.
On Finals, very graceful<br />
Gordon's stylish model is a four times scaled up version of the original, and spans<br />
118cm (46½”). Things have moved on a bit since the time of Gordon's plan (at<br />
least a decade ago) and by the elimination of gearbox, receiver battery and heavy<br />
radio gear, I succeeded in reducing the a.u.w. by a respectable 100g to 1230g<br />
(43 oz), giving a wing loading of 54 g/dm² (18 oz/ft²).<br />
On my model, a Fanfare Powermax 40T up front, turns a 10” x 5” APC propeller<br />
direct drive, the energy coming from a 3s2p pack of Kokam 2000s. The motor<br />
draws 25A (static) so I guess the power loading must be in the region of 250 W/kg<br />
or 90 W/lb - this could explain the stunning performance!<br />
The colour scheme is as per the original FROG model, the silver fuselage being<br />
replicated by the use of chrome Fibafilm. The 'FROG' logo was found on the<br />
internet and transferred on to transparent inkjet vinyl (from Overlander).<br />
The plane is a shear delight to fly, and performs aerobatics (limited in my case)<br />
with ease. It is difficult to avoid a bounce on the landing however, and<br />
disappointingly it is not very willing to taxi in a straight line (it needs a steerable<br />
tail wheel).<br />
The only deviation from the<br />
plan was for the battery<br />
access which is now by<br />
removal of the wings (one bolt<br />
to unscrew) rather than<br />
having an unsightly hatch on<br />
the lower fuselage.<br />
I also added a fibre-glass<br />
bandage at the wing joint as<br />
I didn't like the idea of a butt<br />
join. And oh yes . . . I added<br />
a pilot!<br />
E.F.-U.K. 39
I thought that you might like to see the following photos of my fellow Guildford<br />
Model Flying Group members’, Dave Dyer (above) and Tony Skilton (top right),<br />
Lancasters, and maybe include them in a future edition of <strong>Electric</strong> <strong>Flight</strong> U.K.<br />
Both models were built from the Priory Models kit using standard 6v Speed 400<br />
motors, and 8 x 3300mAh cells - either GP 3300’s or Puffin Hi-Flow 3300’s. Tony’s<br />
Lancaster weighs 5lbs 4ozs, Dave’s weighs a little more as he has fitted working<br />
rudders to his model. The wing span is 6ft. Both get between 8 - 10 minutes flying<br />
time on the 8 cell packs. Unfortunately, the only time we managed to get both of<br />
these Lancasters in the air together, we had no camera around !!<br />
40 E.F.-U.K.
E.F.-U.K. 41
The Electrifly PolyCharge4<br />
by John Stennard<br />
Every now and then modelling items appear that answer a particular need and<br />
this charger is certainly one of them. I saw this charger advertised in American<br />
model magazine and quickly found that not only did Tower Hobbies have them in<br />
stock but they were at a ‘special deal’ rate. Following a phone call to a helpful lady<br />
at Tower one of these chargers was on its way to me.<br />
Why was I particularly excited about this charger? In common with virtually all<br />
the flyers at our indoor sessions I never charge in the sports hall as I now have<br />
enough cell packs to keep me flying all evening. Of course the problems start<br />
when I get home and have about ten packs to charge.<br />
There is no question of leaving LiPo packs connected and charging overnight so it<br />
is a long process the next day charging all the cells. The Polycharge4 is unique as<br />
it is actually four chargers combined in one unit. Each charger can charge 1 – 4<br />
cells at rates from 300mAh to 3000mAh. A built in fan keeps the charger cool and<br />
the unit is fused. The unit is packed with ‘features’ and mine works perfectly.<br />
The charger requires a 12- 15v power source and of course if running all the<br />
outputs at the maximum current at least a 12A required. A mains regulated unit<br />
is obviously preferred rather than a Leisure battery to supply the charger.<br />
42 E.F.-U.K.
Two A4 sheets of instructions cover the handling and use of the charger. Basically<br />
it is extremely simple and as usual the only likely cause of an error would be if you<br />
set an incorrect charge rate. After connecting the pack and setting the correct<br />
charge rate, normally 1C, the black button is pressed. The system uses a tricolour<br />
LED to indicate certain conditions starting with the automatic cell count.<br />
Initially a solid green LED indicates that the cell count is being checked. When<br />
this has been done, the LED flashes according to the number of cells that the<br />
charger has read as being present. This is a first indicator that the pack is in good<br />
condition. Obviously an incorrect count means that a cell is malfunctioning.<br />
When the pack is fully charged the LED flashes red and an audible tone sounds.<br />
Again the red LED flashes according to the cell count so this is a further check on<br />
the state of the pack. If for any reason the pack does not charge within a threehour<br />
period the charger switches off automatically and the LED flashes orange.<br />
Included in the instructions are ‘Important Precautions’ that deal with the correct<br />
handling of LiPo cells. These instructions are very clear and explicit and are<br />
worth reading even if you are experienced in handling LiPo cells.<br />
I hope this charger will soon be available in the UK from the GreatPlanes distributor<br />
as it has certainly been one of my ‘best buys’.<br />
E.F.-U.K. 43
Fixing Günther Propellers<br />
by Nick Fitton<br />
My first encounter with 2.3mm shafts was via the TwinJet. I was sceptical about<br />
the recommended method of propeller attachment (push it on) so I phoned a highly<br />
experienced EF guru, who shall remain nameless. He told me that a bit of spit on<br />
the shaft and a good push was all that was needed. Indeed, he told me that he had<br />
never had a Günther propeller come off, saying that he must have spit like epoxy!<br />
Thus assured I flew my TwinJet with delight until one day a propeller came off at<br />
exactly the wrong moment, i.e. the instant it left my hand at launch. I couldn't<br />
hold the resultant asymmetric thrust and the clutching hand which is gravity<br />
took over. Not much damage but a lot of annoyance.<br />
I wanted to be convinced that pushing propellers on was sound practice, but my<br />
fathers oft repeated dictum "A man convinced against his will remaineth<br />
unconvinced still" was never far from my mind. I tried bonding the propeller on<br />
using thin cyano, being careful to remove all traces of oil from the shaft and not to<br />
bond the shaft to the motors front bearing. But still propellers flew off occasionally,<br />
fortunately at non-critical times.<br />
My next cunning plan was to drill a pin hole right through the black plastic insert<br />
and allow a blob of gap filling cyano to flow into the insert before pushing it on to<br />
the shaft - you have to do this quickly otherwise the cyano starts curing before the<br />
propeller is fully home. I was convinced this would solve the problem, but there<br />
was no improvement.<br />
I tried the same with epoxy, poking it into the insert with a match, but whilst this<br />
seemed better than cyano, it was only better in the sense that the propeller stayed<br />
on longer before letting go.<br />
As a last resort I tried high shear strength adhesive, one of those specifically<br />
designed for fixing pinions to shafts in geared applications - and I have never had<br />
a failure in this application. Again I was unsuccessful. Presumably these adhesives<br />
are not designed for metal/plastic bonding, which comes as no surprise.<br />
I persevered, but I knew in my heart that gluing propellers on was not the right<br />
path - as Taoists would put it, it was a "path without a heart", thus one to be<br />
abandoned. It takes a lot of pressure to force a Günther propeller on to the shaft.<br />
I was sure that what was happening was that the black plastic sleeve was relaxing<br />
over time, weakening its grip on the shaft.<br />
In addition, propeller acceleration/deceleration forces would constantly test the<br />
integrity of the bond line, as would the occasional ground contact. Cyclic thermal<br />
stresses may play a malign part too.<br />
Thus I was forced to conclude that all glued methods must eventually fail, and I<br />
moved to mechanical type adapters. Here are my findings:<br />
44 E.F.-U.K.
The Collet type<br />
These exert an enormous clamping force on the motor shaft, and are self centring.<br />
The ones I bought had, however, a number of disadvantages. Firstly, the relatively<br />
large back plate fouled the back of the Günther propeller, and I don't like hacking<br />
away at any propeller, especially one turning at 14000 rpm, even if it is very light.<br />
Secondly, the collet was relatively massive, with a centre of gyration some distance<br />
from the shaft axis. Any inherent vibration in the system will be amplified by<br />
these factors, as will mounting the collet near the end of the shaft. The Speed 400<br />
shaft is long, thin and 'whippy'.<br />
A big advantage was that one could achieve a very small gap between nose and the<br />
back of the spinner, which is aesthetically pleasing, but fitting the spun blue foam<br />
spinners I use proved impossible. Sometimes collets can be difficult to remove,<br />
such is their massive hold on the shaft.<br />
The Grub Screw type<br />
To all intents and purposes these too have a virtually unbreakable hold on the<br />
motor shaft, and certainly so in the case of Speed 400 motors. Those with two<br />
grub screws (Graupner do a lovely one) are to be preferred, if only for their<br />
engineering excellence, more on these later.<br />
A major disadvantage is that it is difficult to produce an aesthetically pleasing<br />
fuselage / spinner gap. The way round this is to glue a balsa ring to the nose to fill<br />
this gap: one might also mount the motor some distance back from the bulkhead<br />
but this would introduce problems of lack of rigidity and high localised forces on<br />
the mounting plate.<br />
The Graupner propeller adapter is beautifully produced (see below), is light and<br />
thus has low rotational inertia. It also has a bullet type nut, this feature giving us<br />
something to which a spinner can be attached.<br />
The spinner is spun blue foam. I make a 1/16” ply disc of the required diameter<br />
and using double sided tape, fix a block of blue foam to it. Spin it (in a power drill<br />
in a vice) to the desired shape and length and separate it from the ply former. This<br />
is not needed any more, but is retained for future use.<br />
E.F.-U.K. 45
As accurately as possible, carve the foam to receive the Günther propeller so that<br />
the back of the propeller is flush with the back of the spinner. Using the cone<br />
shaped rotary stone attachment for the Dremel, lightly bore into the foam, keeping<br />
everything as central as possible.<br />
Now the clever bit. Cover the Graupner spinner with double sided tape and simply<br />
press the foam spinner on, using the model's nose former as a square, flat guide.<br />
You'll probably have to experiment a bit to get it right.<br />
A small degree of eccentricity is not noticed in practice. There is no <strong>flight</strong> load on<br />
it, the only force being the airstream pushing it on, which is to our advantage, and<br />
the rotating mass is so low that there is no vibration, even at 13000 rpm.<br />
One of the features of using the Günther propeller is that spinners tend look too<br />
large in relation to the propeller, blocking out a seemingly high percentage of the<br />
swept area. The small Günther propeller has a diameter of 125mm. Even if a<br />
spinner were half that at 62.5mm, which is unlikely, it would blank out only 25%<br />
of the swept area. Actual spinners required are typically less than 40mm, blocking<br />
out less than 10% of the disc area.<br />
More important is the effect a large nose diameter has on the airflow leaving the<br />
back of the propeller, so it makes sense to reduce the nose diameter to the minimum<br />
practicable. This can be achieved by utilising the full length of the Speed 400<br />
shaft. About 30mm diameter spinners can then be fitted. These have a mere 6%<br />
blanking effect. It is always good practice on an aeroplane, full size or model, to<br />
reduce everything to the minimum that will do the job.<br />
My Speed 400 Tucano incorporating all the above best practices, built light and<br />
with an 8 cell KAN pack has a flying weight of just over 18 ozs. It goes like stink,<br />
has good duration and amazes the IC mob. What price now brushless / LiPo !<br />
So far going the 'grub screw adapter' route has proved completely satisfactory. I<br />
keep two spare complete propeller/spinner assemblies in my <strong>flight</strong> box just in case.<br />
Propellers can be quickly and easily changed in the field should one experience a<br />
less-than-ideal landing, not that this has ever happened to me (honest).<br />
46 E.F.-U.K.
Wing & Wheels Model Spectacular is delighted to be able to remind Modellers that<br />
24th and 25th June 2006 represents the 20th Anniversary of the show.<br />
First held at North Weald Airfield in<br />
1986, the show has evolved into one of<br />
the most respected and popular model<br />
shows in the UK and has featured some<br />
of the very best models and pilots from<br />
the UK and Europe. With its fabulous<br />
runway facilities, excellent crowd<br />
proximity capability and massive trade<br />
support, Wings & Wheels has always<br />
been able to put on a show that<br />
spectators return to year after year.<br />
A large part of our success has been due<br />
to the support and participation of the<br />
Show Pilots, helpers and their models,<br />
the loyalty of our Traders, as well as<br />
the many other supporting attractions<br />
such as Modellers’ Bring & Buy, Indoor<br />
Flying Displays, Large Model Boat Pool,<br />
Model Car Displays and huge Saturday<br />
Market adjacent to the Show.<br />
Whether you are a participant of one of the above attractions or a visitor we<br />
would be delighted if you would come to next year’s show to celebrate 20 years of<br />
Wings & Wheels<br />
See more about us at: www.wingsnwheelsspectacular.com<br />
or contact the Show Organiser<br />
Designaction Limited, PO Box 284, Huntingdon, Cambs PE28 9WT, UK.<br />
Tel/fax: 01480 462 265. Mobile: 07836 297 168<br />
email: wingsnwheels@dial.pipex.com<br />
E.F.-U.K. 47
NEAT Fair<br />
16-18 September 2005<br />
by John Anderson<br />
Downsville, NY, is now firmly established as the place to be for <strong>electric</strong> flyers in<br />
North East America on the third weekend in September. A few make long journeys<br />
to be there, a thousand miles or so!<br />
At this point I have to confess that some of my notes cannot be found now that I<br />
am back at home. Accordingly not all the photos have full captions and some have<br />
only what I can remember or given to me on a piece of paper by the modeller.<br />
Own design sailplane by Joseph Dellutris named Rita. 4m span powered by AXI 2826-10<br />
with 14” x 7” propeller and 2S2P 2000 mAh<br />
48 E.F.-U.K.
Last year the meeting was washed out by 14 inches of rain in 24 hours. This year<br />
the weather was much kinder. Most of the time it was sunshine and varying<br />
amounts of cloud. The site opens on the Thursday for traders but also many<br />
modellers arrive to claim a good position to pitch their canopies including my<br />
friends from Syracuse who provide cover and seats for me.<br />
As the weekend wore on the sun increased and by Saturday lunchtime the crowd<br />
was four or five deep to watch the lunch time demo <strong>flight</strong>s. Generally the wind<br />
was light but being in a valley occasionally a gust would funnel through.<br />
Each year I try to take out a model that is produced in U K. My selection is<br />
limited to a model that can be transported easily. This year I had been playing<br />
with a P-51D from Electro <strong>Flight</strong>.<br />
This is basically a Depron model with a printed paper overlay. I selected the<br />
Spitfire from the range and undertook the pasting of the printed paper to the<br />
Depron at home. This enabled me to transport it in my checked suitcase sandwiched<br />
between my unmentionables<br />
Assembling the model and installing the motor, ESC, servos and links was<br />
undertaken at my daughter’s home in upstate New York. Range checks and test<br />
<strong>flight</strong>s took place nearby and attracted most of the children (and some dads) from<br />
the nearby houses. With the test <strong>flight</strong>s completed it was off to the Fair.<br />
A Spruce Goose from Laddie Mikulasko, span 86” and powered by 8x Speed 400 motors<br />
each powered from 8 cells in a combination of series and parallel. Weight around 9lbs.<br />
E.F.-U.K. 49
So what was new. Nothing I saw could<br />
be described as revolutionary. The<br />
charging of LiPos is where safety is being<br />
given priority. “Astro” Bob Boucher has<br />
developed the ‘Blinky’ cell balancer (see<br />
page 23) and Kokam are charging each<br />
cell in a series pack individually.<br />
These two are tackling the problem from different angles although both require<br />
each cell to have a tap to a terminal. Astro <strong>Flight</strong> Balancer is used with a charger<br />
connected in the usual way and the balancer connected to a tap from each cell.<br />
The circuitry looks continually at the voltage of each cell to three decimal points<br />
and discharges the higher voltage cell(s) to reach equilibrium. Only a small number<br />
have been made for test purposes but they should be available later this year.<br />
With Kokam it is simply each cell being individually charged by a special charger.<br />
The Kokam Balance Charger comes for 2 series and 3 series cells and detects<br />
when each cell is full and shuts down the charge to an individual cell as it peaks.<br />
A different charger is needed for 2S packs and 3S packs which makes the set up<br />
rather expensive as they may not be suitable for other brands of LiPos. Personally<br />
I am drawn towards the Astro gismo but before I can consider this I need to get my<br />
3S LiPos tapped. Is this a job for a modeller or should it only be trusted to a<br />
specialist? I look for guidance. (Editor: see my notes on page 24)<br />
50 E.F.-U.K.<br />
Beautifully built Antoinette about 6ft span.<br />
Only a few seconds in the air before stalling
Hobby Lobby B-25 Mitchell. 19lbs 2x AXI 4130 driving 15” x 8” propellers on 6S3P<br />
Some new models were on show, the most noteworthy from a commercial concern<br />
being the B-25 Mitchell from Hobby Lobby. A kit should be available towards the<br />
end of the year with pricing in the region of $500.<br />
An exceptional model of an Antoinette was on a stand by the truck of Don Bosquet<br />
although I am not sure that he had built it although it was in his style. Dave<br />
Barron, the regular B-17 pilot, was recruited to test fly the model. But as you will<br />
see from the photos the angle of climb shortly after take off was too steep and a<br />
second or so after the photo it stalled. Repairable in the workshop where no doubt<br />
the C of G will be examined.<br />
The Hobby Lobby stand was decked out with about 20 models from their range,<br />
although they had taken the decision not to sell direct. Every one who has visited<br />
the USA will know that the price on the ticket will have sales tax added at the till.<br />
This varies from state to state but is not applicable to sales made and shipped to<br />
residents of other states or exports.<br />
Hobby Lobby had taken the view that by selling at the NEAT Fair they may<br />
become caught by the New York tax system and this would mean all sales to NY<br />
residents would be taxed, instead of tax free coming from their home state of<br />
Tennessee. They have been supporters of the Fair since inception and this year<br />
provided raffle prizes for the draws on each of the three days. The star was the<br />
Gee Bee complete outfit which had been flown regularly in the hours leading up to<br />
the raffle. A very generous gesture as its value must be at least $1000.<br />
There is a down side to this well attended meeting, over 250 pilots registered this<br />
year. It is the lack of accommodation in the area. Most motels within 20 miles are<br />
E.F.-U.K. 51
Also from Laddie this Blohm und Voss, span 50”, weight 4¼lbs, 2x S400 with 2:1 boxes<br />
small, not more than 15 or so rooms, and are often booked up months before.<br />
Camping is popular and there is plenty of room on the site for mobile homes and<br />
tents. Caterers provide a good selection of food from early morning to evening.<br />
The campers using tents can rely on sustenance without having to leave the site.<br />
I shall go again next year, God willing, as I get 3 days away from my grandchildren!<br />
Spectator line for the Saturday demo hour.<br />
52 E.F.-U.K.
Balsacraft fan Edward Brimo brought three models to the Fair. Sea Fury powered by<br />
AXI 2820-10 with 10.5” x 6” propeller and Kokam 3S1P 2100 mAh. Spitfire powered by<br />
Phasor 30/3 and 10” x 7” propeller and Thunder Power 3S7P 3200 mAh. Bearcat<br />
powered by AXI 2820-12 with 10” x 7” propeller and Thunder Power 4S2P 4200 mAh<br />
This autogyro is built by Dave Ramsey based on a design of Mickey Knowles. Uses a<br />
helicopter linkage to the rotor (kit bashed 2 sets to make up head) and set the head in<br />
GWS gearbox. Flew nicely in the calm conditions<br />
E.F.-U.K. 53
Here is Dave Barron with the Joe Bashir B-17 making final preparation for yet another<br />
<strong>flight</strong> with this impressive model.<br />
Ric Vaughn drove from Atlanta with his workshop trailer housing this enormous model.<br />
Don’t have details but it has a floodlight system making night flying a piece of cake<br />
54 E.F.-U.K.
Apologies to David ? This 10 year old flew a superb slot in the lunch time demo. Sorry<br />
no details of this pattern ship but I remember that 800W was available at full throttle.<br />
Flown by Hobby Lobby was this Funtana. Power was Hacker C50XL with 6:1 gearbox.<br />
10S3P Tanic cells gave urge to this 9lb model<br />
E.F.-U.K. 55
The writer’s Electro <strong>Flight</strong> Spitfire. Tweety Torque motor with Jeti 8-3P controller and<br />
Kokam 3S1P 640mAh pack turning GWS 7” x 4.3” propeller<br />
56 E.F.-U.K.
Perkins ARTF Tiger Moth<br />
by John Thompson<br />
This kit is by Green R/C Model Airplane Co Ltd made for J. Perkins, spans 50”<br />
(128cm), and is designed for a .30 cu. in. (5cc) 4-stroke glow motor. Mine was<br />
bought part assembled from my local model shop, where it had been in this state<br />
for some months. The assembly appears straight forward as all the main parts<br />
are supplied covered, even the decals fixed in place.<br />
The tail unit is attached with two bolts from below, and here was one of the changes<br />
I made. The kit includes a tail wheel, and I have never seen a Tiggy with one of<br />
those, so a steerable skid was made, much better for our grass runways.<br />
The rudder servo is coupled to an idler that protrudes through the fuselage sides to<br />
take the closed loop wires in scale fashion. This idler is supplied made from CNC<br />
cut plywood that did not seem very good to me, so a replacement was made out of<br />
fibreglass circuit board (see below).<br />
Beside the rudder servo is the elevator one and this also has closed loop connections.<br />
I was concerned that these actually twist through 90° so a simple addition to the<br />
tray turned the servo to be in the same plane as the elevator hinges. Both these<br />
controls now worked in a smooth fashion and gave accurate neutrals.<br />
The ailerons use separate servos with short rods, so were no problems here. Perkins<br />
had included some of their own items in the contents of the kit, with an addendum<br />
to the instructions.<br />
E.F.-U.K. 57
These included metal quick-links with springs to secure them. I found these links<br />
rather tight on the threaded connectors, and had one strip. The landing and<br />
flying wires also use these links which fit into alloy angle brackets, and these<br />
went together quite well. One thing would improve it, a moulded corrugated cover<br />
for the centre section tank.<br />
The <strong>electric</strong> conversion was not difficult as the deep cowling gave space under the<br />
motor for a battery pack. This cowling is a superb light, fibreglass moulding but<br />
there was no indication as to exactly where or how it should fit. I installed it as far<br />
back as possible using a hardwood block below and an alloy bracket above to take<br />
self-tapping screws. My first choice of motor was an AXi 2820/10 that I had spare,<br />
and it was installed in a simple plywood mount with speed controller behind.<br />
Under it a ply box was fitted tailored to fit a 3s2p 2600 LiPo battery. Access to this<br />
is a removable panel between the undercarriage ()shown below) and the firewall<br />
that has two Balsa rails to stop the cells from moving backwards. Scale air intakes<br />
are used and the floor of the front cockpit was removed to allow the cooling air to<br />
exit. With this layout the CG was too far back, so against my usual principles<br />
lead was added to the battery box.<br />
The motor was pulling 20A on an 11” x 7” propeller so it should fly. However the<br />
first <strong>flight</strong> showed that more lead was needed. The model showed promise, although<br />
full throttle was required most of the time. In true Tiggy fashion a dive preceded<br />
any attempt at manoeuvres, and <strong>flight</strong>s of six minutes were easily accomplished.<br />
58 E.F.-U.K.
Later one of the new 18/15 outrunners from Plettenberg was tried, and this was a<br />
little better, but pulled more amps. A new pack of 2200 LiPo from <strong>Flight</strong>Power<br />
proved to be much lighter so needed even more weight. In the meantime I had had<br />
the lucky escape with my Diablotin (see the last magazine) so was even more<br />
careful with LiPo.<br />
Looking through the specifications a new AXi was chosen to give more power and<br />
reduce the deadweight a bit. The 2826/12 happily swings a 12” x 7” propeller and<br />
improves the <strong>flight</strong> performance noticeably. It is now possible to throttle back and<br />
have power to spare, and the<br />
controls are well synchronised.<br />
Then my local shop had some of<br />
the new Saphion cells in from<br />
Overlander. These are Lithium<br />
Phospate (LiPh) cells which<br />
promise improved safety (again<br />
harking back to the Diablotin).<br />
Two 4-cell 1200mAh packs were<br />
bought. Saphion cells are only<br />
3.2v/cell, lower than LiPo, but the<br />
4s pack gives extra volts which<br />
E.F.-U.K. 59
should also help. The 2p configuration and 15C continuous rating, gives 36A<br />
maximum. Interestingly they also quote a 2C charge rate, which makes field<br />
charging the cells more practical than LiPo.<br />
These packs are almost twice the weight but better that than lead. A small battery<br />
box mod and they fitted snugly. So that I could use the individual packs in smaller<br />
models 2mm gold connectors were fitted, and 4mm parallelling adaptors made.<br />
The CG came out dead on without the lead, and the Tiggy will now leap into the<br />
air and do consecutive loops with ease. This means scale speed is now half throttle,<br />
and ten minute <strong>flight</strong>s with power left to taxi back. I could still experiment with<br />
different propellers but it all works fine so what’s the point if the model flies well?<br />
It is now a pussy cat to fly and has the presence of the full size as long as you do not<br />
open the taps.<br />
My model weighs 3lb. 10oz. (1.64kg) without batteries, about the same as the IC<br />
version without fuel. Batteries-<br />
R/C Smart LiPo 2600 3s1p 6.2 oz. (174g)<br />
<strong>Flight</strong>Power LiPo 2200 3s1p 5.0 oz. (141g)<br />
Saphion LiPh 1200 4s2p 12.3 oz. (348g)<br />
So Saphions are heavier than LiPo, but safer, lighter than NiMH - time will tell.<br />
60 E.F.-U.K.
A Smarter Dart<br />
by John Stennard<br />
I’m going to begin with some background information before launching the Smarter<br />
Dart. I am a committed <strong>electric</strong> flier with a particular interest in indoor flying<br />
and as a result also organise the indoor flying sessions for our club. As part of my<br />
indoor interest I write monthly features for two model magazines and this combined<br />
with my club involvement, has resulted in a constant search for a model that can<br />
be flown as an indoor trainer but also be enjoyed by flyers with more experience.<br />
I regularly fly in different sized venues that vary from a one basketball court gym<br />
to a five badminton court sports hall. At last believe I have found a model that can<br />
be flown comfortably in the smallest to the largest hall and put a smile on any<br />
flier’s face. Before going into details I think it is worth spending a short time<br />
looking at the requirements of an ‘indoor’ trainer.<br />
Firstly it needs to be easy to fly and relatively impact proof. Outdoors the ‘impact<br />
proof’ requirement does not rate the same importance as indoors where floor/wall/<br />
ceiling impacts (plus the occasional mid-air!) are a constant hazard. A light wing<br />
loading is essential to enable the model to be flown slowly plus enough power to get<br />
out of trouble. A suitable model combined with a good power system should benefit<br />
from a high power/weight ratio. A ratio of 2:1 is easy to achieve using the correct<br />
motor/battery combination and will provide a high degree of agility.<br />
Agility is extremely important when flying in smaller spaces and can frequently<br />
save models from collision damage. A reasonable duration is need never a problem<br />
and anywhere between 5-10 minutes is easily obtained and perfectly adequate. In<br />
fact in crowded venues you might be unpopular if you stayed aloft for much longer.<br />
Most <strong>electric</strong> enthusiasts now accept that while many models perform perfectly<br />
well, or are even particularly suited to brushed motors and NiCd/NiMH cells,<br />
indoor models are at their best when combined with brushless motors and Lithium<br />
cells. The model I am writing about in this feature is powered by a low cost,<br />
brushless motor and flies extremely well using a 2s1p LiPo pack. The GWS IPS<br />
system is suggested as an alternative but I’m personally only interested in fitting<br />
the optimum power system.<br />
Now let’s take a look at the model. Paul Cook produces a number of excellent<br />
plans for <strong>electric</strong> enthusiasts. These are all small high performance <strong>electric</strong> powered<br />
models, and the plans are extremely well drawn and printed. Paul’s plans are<br />
available direct from him at <strong>flight</strong>line@hotmail.co.<strong>uk</strong><br />
One of Paul’s plans is for an enlarged RC version of the rubber powered BMFA<br />
Smart Dart and is called the Smart Dart ‘XS’. His model has a 560mm (22”)<br />
wingspan and weighs around 125g (4.4oz.). Paul’s first version of this model has<br />
a 3mm (1/8”) balsa fuselage and built up wings, tailplane and fin using different<br />
widths of 3mm strip balsa. The flying surfaces are covered in lightweight film<br />
E.F.-U.K. 61
and the model uses rudder and elevator<br />
control. I was quite surprised when Paul<br />
told me that his model hovers well but this<br />
was confirmed by a photo of him and his<br />
model and I’ve since proved it very<br />
convincingly for myself.<br />
The arrival of our indoor season coincided<br />
with a gap in my ‘model reviewing’ schedule<br />
so I decided to build a Smart Dart ‘XS’<br />
myself. Anticipating that I would build<br />
this model I had already purchased one of<br />
Paul’s ‘Aircraft-World’ type CD-ROM<br />
conversion motors (right).<br />
Paul’s motors are ready to run and at the time of writing cost just £16. Searching<br />
in my building material storage boxes soon revealed a deficit of 3mm balsa but a<br />
surplus of 3mm Depron foam.<br />
I was about to abandon the project until I had a chance to restock with balsa when<br />
I realized that I could substitute Depron for balsa on the flying surfaces. Without<br />
the natural rigidity of the balsa framework I would have to use some CF strip for<br />
strengthening but otherwise there seemed to be no problems. Using foam allowed<br />
me to build the model in a couple of hours.<br />
The fuselage was built exactly as per the plan complete with undercarriage and<br />
motor and 3mm Depron used for the wings, fin, rudder, tailplane and elevator.<br />
The only modification I made was to use a straight trailing edge on the elevator to<br />
keep this parallel with the front edge and give some additional strength.<br />
The wing leading edges required stiffening and I used a very convenient 3mm half<br />
round section strip of CF rod obtained from Woolmer Forest Composites. Flat<br />
3mm CF strip or even 3mm square balsa or spruce could be used. The half round<br />
CF on the leading edges did affect the C of G but I’ll come back to this later.<br />
Apart from the wing leading edges the only other strengthening was a length of<br />
3mm CF strip on the rear edge of the fin and on the front edge of the elevator. 3M<br />
Blenderm tape (left)<br />
hinged the control surfaces,<br />
coming from OnlyRC. This<br />
firm sells this excellent tape<br />
at a price much lower than<br />
you will pay in the chemists<br />
and in three different<br />
widths. The wings were<br />
joined with epoxy and no<br />
dihedral braces were used.<br />
62 E.F.-U.K.
With the model assembled I soon found that I would have to move the servos from<br />
the position shown on the plan to achieve the correct C of G. The foam wing with<br />
the CF on the leading edges had made the model nose heavy. However it was quite<br />
easy to move the 4.4g Titch servos from Perkins rearward to enable the correct<br />
CofG to be achieved. A bonus here was that the control rods would be very short.<br />
The length of the lead from the controller, a Phoenix 10 from Castle Creations,<br />
and the length of the servo leads established<br />
the position of the RX, this was then held in<br />
place with Velcro. The battery location,<br />
again using Velcro was established near the<br />
CofG as this allows different weights of pack<br />
to be used with having to move the battery<br />
pack too much in either direction.<br />
I was delighted to find that the Smart Dart<br />
weighed just 100g (3.5 oz.) without a battery<br />
pack. I had three sizes of 2s1p LiPo packs<br />
available to try and these were a 310 mAh<br />
pack from WES-Technik, a 350 mAh Kokam<br />
pack from Robotbirds and a 450 mAh E-Tec<br />
pack from Puffin Models. These weighed<br />
19g (0.67 oz.), 22g (0.78 oz.) and 25g (0.89 oz.)<br />
respectively.<br />
E.F.-U.K. 63
So with my lightest pack my depron<br />
Dart had an AUW of 119g (4.25 oz.)<br />
and with the heaviest 125g (4.5 oz.).<br />
Initial <strong>flight</strong>s were made using a<br />
GWS 7” x 5” propeller but I later<br />
changed to the APC 8” x 3.8”<br />
propeller recommended by Paul for<br />
this particular motor.<br />
I very quickly found that the Smart<br />
Dart ‘XS’ is a delightful model to fly<br />
and our one basketball court gym<br />
provided plenty of space. It can be<br />
flown safely in different ways, slow<br />
or fast level <strong>flight</strong>, slower <strong>flight</strong> with<br />
medium alpha attitude or very slow<br />
extremely high alpha ‘hovering’ <strong>flight</strong>. The design of the model with its ample<br />
dihedral makes it very stable and with Paul’s motor and a 2s1p pack it will hover<br />
easily and perform loops from level <strong>flight</strong>.<br />
In fact it is one of the easiest models I have flown in hovering <strong>flight</strong>. It will roll,<br />
somewhat reluctantly, but rolls off the top of a loop more easily. Considering its<br />
‘specs’ I think that the Smart Dart ‘XS’ has an absolutely amazing performance.<br />
64 E.F.-U.K.
With some expo and reduced movements on the control surfaces I think this model<br />
would make an ideal trainer. However well past that stage you might be it’s still<br />
great fun to fly and ideal for multi plane flying where you might not want to risk<br />
your best 3D model.<br />
My opinion was shared by the other regular club indoor flyers especially those on<br />
the same mode who had a go on the sticks. The enthusiasm shown was such that<br />
this model is likely to become the recommended model for anyone who wants to fly<br />
in our rather restrictive one basketball court flying space. A ‘standard’ model like<br />
this would be perfect for fun events like Limbo and I know the Smart Dart ‘XS’<br />
population in our club is about to increase rapidly.<br />
I found that while the 310 mAh battery pack was perfectly adequate for general<br />
flying and offered the lowest weight. The 350 mAh or 450 mAh packs are preferable<br />
if you want to spend a lot of time looping and hovering. The 450 mAh pack gives<br />
a 20 minute plus duration.<br />
Personally I like to decorate even functional models, particularly if they are made<br />
from white foam, so I applied some simple but eye-catching colour to my Smart<br />
Dart ‘XS’. I used felt pens for the layout and acrylic paint for filling in.<br />
E.F.-U.K. 65
Contacts<br />
Paul Cook<br />
<strong>flight</strong>line@hotmail.co.<strong>uk</strong><br />
<strong>Flight</strong> Line Plans, Bourne<br />
Court, Ragged Appleshaw,<br />
Andover, Hants, SP11 9HX<br />
Puffin Models<br />
www.puffinmodels.com<br />
Tel 01454 228 254<br />
Robotbirds<br />
www.robotbirds.com<br />
Tel 0208 841 7873<br />
OnlyRC<br />
www.onlyrc.com<br />
Tel 01702 477 626<br />
Woolmer Forest Composites<br />
www.woolmer.co.<strong>uk</strong><br />
Tel 01428 712 126<br />
66 E.F.-U.K.<br />
Delighted with my foam<br />
version I got in touch with<br />
Paul to praise his design<br />
and found out from him<br />
that a plan for a foam<br />
version was now<br />
available.<br />
After seeing how well my<br />
foam Smart Dart ‘XS’ flies<br />
I am going to now build<br />
the balsa version. If<br />
covered with translucent<br />
film I think it will look<br />
particularly attractive in<br />
the air when the open<br />
framework will be visible.<br />
If you are looking for a<br />
cheap, multi-role, indoor<br />
model with a sparkling<br />
performance look no<br />
further than Paul Cook’s<br />
Smart Dart ‘XS’.
Intermodellbau 2005<br />
by Dave Chinery<br />
As models shows go, the Americans have the quaint impression that their Toledo<br />
model exhibition is the biggest. In fact the annual Intermodellbau show at<br />
Dortmund in Germany is much bigger, with just the aeroplane hall, by itself,<br />
outsizing the Yanks!<br />
This year’s show was open from the 13th – 18th April, and was attended by a large<br />
number of <strong>British</strong> modellers. Although the state of the German economy and the<br />
Euro means the knock-down prices of a few years ago are no more, the show’s well<br />
worth attending for the huge variety of models and accessories, either new, or<br />
never seen in the UK.<br />
The show is even easier to get to now! We used to drive over – it’s about 400 miles<br />
from West London via the Tunnel, and the BMFA have organised coach/hotel<br />
packages for those who won’t drive. However, from this year EasyJet have a<br />
twice-daily service from Luton direct to Dortmund Airport, just a bus ride from<br />
your hotel, and this year’s fare was only £31 return, booked well in advance!<br />
Marble halls!<br />
The huge exhibition complex is right next to the stadium of the famous Borussia<br />
Dortmund football club, and hotels are within easy walking distance of the doors.<br />
As usual, this year’s show occupied eight halls, the largest of which, Hall 4, is<br />
dedicated to flying models of all types. The smallest hall, 2N, is still big enough<br />
for the indoor flying demonstrations, with Shock Fliers doing rolling loops through<br />
the roof girders!<br />
Of the rest of the site, Hall 1, the original Westfalenhalle, is full of model boats,<br />
Hall 2 is mainly model cars and fire engines, and Hall 3 contains a big indoor R/C<br />
car race-track and spectators bleachers.<br />
This year, a new Hall 3N contained a separate Computer and Games exhibition,<br />
with free entry from the Modellbau. Halls 5 and 6 are mainly devoted to R/C cars<br />
E.F.-U.K. 67
and trucks, with a big arena full of 6ft-long artics and scale model contractor’s<br />
plant, the latter shifting piles of dirt from A to B then back to A again – whatever<br />
turns them on! The Germans are into this in a big way, with many models<br />
featuring miniaturised real hydraulic systems.<br />
Hall 5 also contains the Conrads stand – a magnet for modellers and electronics<br />
buffs of all types. Conrads is the German equivalent to Maplins, except that it<br />
carries an extensive range of model products as well. The stand is set up like a<br />
supermarket, through which a densely-packed line of customers shuffle. The bins<br />
of goods contain a vast range of items, from solder to epoxy to assorted model<br />
wheels, and usually cheap servos. This year, I bought good quality standard<br />
servos with accessories, for a mere • 4 each!<br />
Halls 7 and 8 are for railway fans, and the latter is filled with enormous layouts<br />
from societies all over Europe. They even lay on little “play” layouts for the younger<br />
visitors to have a go! Another branch of the hobby, which I saw for the first time<br />
this year, was a stand selling a construction system for design-your-own miniature<br />
roller-coasters. Loops, spirals and “stall turns” can all be included in your own<br />
table-top “white knuckle” ride! Helps to cover the ups and down of the German<br />
economy, I suppose!<br />
Plane speaking!<br />
Hall 4 is the one I spent most time in, looking at the myriad models and accessories<br />
on sale from all over Europe. As usual, most of the models, kits, ARTFs and<br />
accessories on offer are seldom seen in the UK. With the German economy in<br />
decline, the “good old days” of super-cheap prices have gone, along with traders<br />
like Langnickel, and many smaller vendors like WeMoTec can no long afford to<br />
have stands at the show, but their wares are available from some of the retailers<br />
still at the show. All the major manufacturers like Graupner, Robbe, Simprop,<br />
Aeronaut and Jamara had display stands at the show, but there were no real eyecatchers<br />
in the way of revolutionary new models, except for the latter (see below).<br />
Simprop were showing their “TurnLeft” pylon-racers, which suit the new F5D<br />
rules, together with their existing trainer pair of Pilatus PC-9 and Harvard 1.<br />
Dortmund 2005 Hall 4<br />
68 E.F.-U.K.
The colourful Hollein stand had its usual<br />
selection of kit-build models, and this<br />
year showed an all-moulded Speed-400size<br />
pylon racer, the Voodoo.<br />
Among the smaller manufacturers,<br />
PAF Modell has its usual range of ARTF<br />
models, ranging from big gliders to<br />
<strong>electric</strong> scale types. These included a<br />
nice Grumman Albatross and two sizes<br />
of PBY Catalina seaplanes. Franken<br />
Modellbau have been previously<br />
associated with sport and scale type<br />
models. My big P-47 Thunderbolt came<br />
from the range, but this year their stand<br />
was almost monopolised by <strong>electric</strong> and<br />
conventional soarers.<br />
FVK Modell occupied their customary<br />
place in a corner of the hall, and, in<br />
addition to their well-known range of<br />
high-tech soarers like the “Simply the<br />
Best”, “Organic”, etc, offered a new<br />
They also showed a badge-engineered<br />
version of the SuperNova charger with,<br />
according to them, more advanced<br />
features including Lithium programs.<br />
Graupner showed a range of new models,<br />
smallest but not least was a tiny Junkers<br />
52 trimotor park-flyer. It looks the<br />
picture for those able to combine a calm<br />
day with short grass, although the little<br />
model could obviously be hand-launched.<br />
<strong>electric</strong> sportster, the ROCCO-M. With<br />
a sleek moulded fuselage and plug-on<br />
wings, it really looked the part of a light<br />
yet manoeuvrable Sunday flyer. This<br />
model was right up my street, but I<br />
resisted as I already have too many<br />
airframes (wanna buy a Brabazon?).<br />
However, clubmate Tom Lambert<br />
succumbed (see photo left) and his was<br />
completed in record time and flies a<br />
treat! Another model I did like was a<br />
E.F.-U.K. 69
large (about 70” or 1.7metres) Zlin<br />
Acrobat, reminiscent of my own-design<br />
“Czech-mate” but bigger. This was seen<br />
on the Jamara stand, but this was a nonretail<br />
display and I couldn’t find one<br />
among the retail sites.<br />
Elsewhere in the hall, the legendary<br />
Batt-Mann was doing his usual roaring<br />
trade, with customers scrumming five<br />
deep to get to his counters (photo taken<br />
moments after the doors opened).<br />
I have been used to seeing the Ramoser<br />
VarioPROP stand (right) at successive<br />
Dortmund shows, but have never<br />
previously been tempted to buy one.<br />
However, this time, I bought a 3-bladed<br />
unit with the “Harvard 2” in mind. It’s<br />
difficult to match motor load and model<br />
performance when changing from a 2bladed<br />
propeller to a 3- or 4-bladed, so<br />
the adjustable pitch feature of these<br />
ingenious propellers would give me a<br />
considerable “fudge factor” to play with.<br />
70 E.F.-U.K.<br />
I found some of the excellent new<br />
GP1100 cells, which will be essential<br />
this year for me to remain competitive<br />
in the E-400 competition. The same size<br />
as the old Sanyo 500ARs, these new cells<br />
pack over twice the capacity while<br />
having a much lower internal resistance<br />
than the KAN1050s I bought last year.<br />
(Since using these new cells, the climb<br />
rate of my model has been transformed<br />
– but I don’t know how long the “hot”<br />
4.8V Speed 400 Race motor will last!)<br />
Ramoser produce propellers in various<br />
size ranges and with from two to five<br />
blades! They even produce forked metal<br />
roots to take standard 8mm folding<br />
propeller blades, allowing a very wide<br />
range of sizes to be assembled. Adapters<br />
are also available for standard spinners.
Making an exhibition!<br />
This year’s Dortmund show was<br />
technically very interesting even if the<br />
prices were no great shakes. It was easy<br />
to see that the German economy is no<br />
longer buoyant, which was reflected in<br />
the smaller number of stands (Editor:<br />
and the comments of the traders).<br />
This saved a day travelling and also<br />
saved a night in the hotel. (Editor: Dave<br />
didn’t mention that the cost was less<br />
than the fuel and fery or tunnel costs.<br />
The only restriction is you are limited<br />
in what you can bring back and you<br />
can’t stop at Aucan or the Wine<br />
Merchant’s before the return crossing.)<br />
I’m definitely going again next year!<br />
(Editor: Me too!)<br />
As usual, about 30% of the hall was<br />
taken up with models on display, ranging<br />
from huge model airliners and rare<br />
military types, to daringly-decorated<br />
“Funky Chicken” models. In contrast<br />
with the up-to-date stuff, there was an<br />
extensive display of vintage & veteran<br />
models with gliders, rubber models,<br />
compressed-air, and i.c. types. The<br />
usual selection of “wacky” models with<br />
7 wings and 3 undercarts were there too.<br />
Notable absentees were Oliver<br />
Wennmacher’s WeMoTec and Airworld,<br />
however, product from both these<br />
sources were available elsewhere in the<br />
hall. Unfortunately the exhibition is not<br />
improving with time, we’ll have to see<br />
how things fair.<br />
However, using the EasyJet route makes<br />
it much more accessible than hitherto.<br />
E.F.-U.K. 71
<strong>Electric</strong> <strong>Flight</strong> Calendar<br />
If you would like details of your event to appear in these pages please send full<br />
details to the Editor EF-UK, contact details on page 4. Please bear in mind that<br />
this magazine is quarterly so ensure that the details are sent in good time.<br />
For last minute information on events please check out the events list on the<br />
BEFA website (www.befa.org.<strong>uk</strong>). Dates, times and, even, locations of events<br />
can change at the last minute. You are strongly advised to check on events with<br />
the given contacts before setting out on your journey to any event.<br />
All BEFA flying events require proof of BMFA (or equivalent) insurance<br />
and an ‘A’ Certificate to fly. For fixed wing models, any of the fixed wing ‘A’<br />
certificates are acceptable. For helicopters, a helicopter ‘A’ certificate is required.<br />
All flying models must have been satisfactorily flown at least twice<br />
since build or repair before flying at a BEFA event.<br />
NO TEST FLIGHTS ON THE DAY<br />
<strong>Jan</strong>uary 2006<br />
1st The Brighouse Vintage MAC have been using the small airfield at<br />
Tockwith, near Wetherby, Yorkshire for several years, but have<br />
recently had noise problems. The field is now all <strong>electric</strong> and any<br />
BMFA Member is invited to fly there on the First Sunday in each<br />
month from 10 to 5pm for a small fee. Do not be put off by the 'Vintage'<br />
part they fly anything! There is a concrete runway available and<br />
details of the site can be had from Derek Haviour on 01422 204 472.<br />
14th BMFA Northern Area Indoor RC Flying at the Garforth Squash<br />
& Leisure Centre, Ninelands Lane, Leeds, LS25 - off the A63, Leeds-<br />
Selby Road. Flying from 2pm to 5 pm. Separate slots for Slowfly,<br />
Aerobatic, Scale and Helicopters. Sub 350 and equivalent brushless<br />
motors only. Any legal frequency. Proof of BMFA membership<br />
essential. No free <strong>flight</strong> or IC. Spectators £1 on balcony, Pilots £5.00<br />
(Juniors £2.00). Contact John Thompson on 01924 515 595, or email<br />
him at johnty99@ntlworld.com<br />
14th North London MFC Indoor R/C Meeting. Fixed Wing 225g max,<br />
Heli 400g max. 6pm to 10pm. Furzefield Sports Centre, Potters Bar.<br />
(J24, M25). Contact Peter Elliott on 01707 336 982.<br />
14th Waltham Chase Aeromodellers Indoor RC Meeting. 7 to 10pm.<br />
Havant Leisure Centre, Havant, Hants. Call Alan Wallington on<br />
01489 573 141 or Chris Carr on 0238 043 7805 or check out<br />
www.wcaero.fsnet.co.<strong>uk</strong><br />
72 E.F.-U.K.
22nd Black Lion Indoor Fun Fly. 10am to 5pm. Black Lion Leisure<br />
Centre, Gillingham, Kent. Contact Brian Millgate on 01634 570809<br />
or Neville Legg on 01795 877 918 or at nevlegg@aol.com or see<br />
www.medwaymfc.co.<strong>uk</strong><br />
February 2006<br />
5th The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details.<br />
11th North London MFC Indoor R/C Meeting. See 14th <strong>Jan</strong>uary.<br />
18th BMFA Northern Area Indoor RC Flying at the Garforth Squash<br />
& Leisure Centre. See 14th <strong>Jan</strong>uary<br />
18th Waltham Chase Aeromodellers Indoor RC Meeting, see event<br />
on 14th <strong>Jan</strong>uary for details.<br />
22nd Black Lion Indoor Fun Fly. See 22nd <strong>Jan</strong>uary for information.<br />
March 2006<br />
5th BEFA 2006 Annual General Meeting & Traders’ Fair at the Royal<br />
Spa Centre, Leamington Spa. See page 6 for more information.<br />
5th The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details<br />
11th North London MFC Indoor R/C Meeting. See 14th <strong>Jan</strong>uary.<br />
18th BMFA Northern Area Indoor RC Flying at the Garforth Squash<br />
& Leisure Centre. See 14th <strong>Jan</strong>uary<br />
18th Waltham Chase Aeromodellers Indoor RC Meeting, see event<br />
on 14th <strong>Jan</strong>uary for details.<br />
19th Impington Village College Indoor Meeting. 9am to 5pm – Fly<br />
All Day. Including Bostonian Comp and Separate RTP Hall. Impington,<br />
Nr Cambridge. Contact Chris Strachan on 01223 860 498 or at<br />
chris.strachan@btinternet.com<br />
April 2006<br />
2nd The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details<br />
8th North London MFC Indoor R/C Meeting. See 14th <strong>Jan</strong>uary.<br />
May 2006<br />
7th The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details<br />
June 2006<br />
4th Hayes & DMAC West London Fly-in at Cranford Park, Hayes.<br />
More details to follow.<br />
E.F.-U.K. 73
4th The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details<br />
24th - 25th Wings & Wheels at North Weald Airfield, Nr Epping, Essex, CM16<br />
6AA. Email wingsnwheels@dial.pipex.com<br />
July 2006<br />
1st - 2nd BEFA Middle Wallop Fly-In. Possibly the largest <strong>electric</strong> event in<br />
the UK. The Saturday is shared with the League event. Only even<br />
35MHz frequencies can be guaranteed as available, but it is planned<br />
that the odd frequencies not in use by the league event will be also<br />
available. On the Sunday all 35MHz frequencies will be available.<br />
More details to follow.<br />
2nd Ebor Silent <strong>Flight</strong> meeting on the York Racecourse.<br />
2nd The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details<br />
9th Chester "Roodee" <strong>Electric</strong> Fly-In.<br />
August 2006<br />
6th The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details<br />
18th - 26th 2006 FAI World <strong>Electric</strong> <strong>Flight</strong> Aeromodelling Championships<br />
for classes F5B and F5D in Pitesti, Romania. For more details contact<br />
Mihail Zanciu at mzanciu@modelism.mcit.ro or Marius Conu<br />
mconu@modelism.mcit.ro<br />
September 2006<br />
3rd The Brighouse Vintage MAC - see the event details on the listing<br />
on 1st <strong>Jan</strong>uary.<br />
October 2006<br />
1st The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details<br />
November 2006<br />
5th BEFA 2006 Technical Workshop & Traders’ Fair (provisional<br />
date) at the Royal Spa Centre, Leamington Spa, Warks. All the<br />
usual fun of the fair.<br />
5th The Brighouse Vintage MAC - full details of this regular event on<br />
the 1st <strong>Jan</strong>uary listing.<br />
December 2006<br />
3rd The Brighouse Vintage MAC - see 1st <strong>Jan</strong>uary for details<br />
74 E.F.-U.K.
FOR SALE / WANTED<br />
Member's Sales & Wants<br />
The items below are for sale by Trevor Wain, contact at trevorwain@tiscali.co.<strong>uk</strong><br />
or on 01332 792 508.<br />
• Puffin Models Elegant, 2.6m glider / <strong>electric</strong> glider. Flown twice, but<br />
other interests took over - no equipment fitted. Offers around £100.<br />
• Kontronik Smile 40-6-18 opto, brushless, speed controller, 40A 6-<br />
24V with Kontronik 4mm silver connectors on the output and Schulze 3.5mm<br />
connectors on the input and has been used twice. He would like to exchange<br />
for the same or very similar with BEC or sell for £65.<br />
Neil Stainton is selling the following items. All are plus postage or can be picked<br />
up from Leamington Spa. Contact Neil Stainton on 01926 314 011 or email him at<br />
Neil@ITpartnership.com<br />
• Schulze 6-636+ 8A charger for 1-36 NiCd / NiMH cells & 1-11 LiPo cells.<br />
V8 software: £179<br />
• New Blade Runner indoor helicopter, including 27Mhz R/C, LiPo<br />
battery & charger: £49<br />
• Hornet Helicopter FP VGC, with carbon blades: £35<br />
• GWS PG03 gyro: £19<br />
• Blue Arrow 4.3g servos, new, boxed £8.95 each<br />
• Blue Bird 3.4g quality micro servos with coreless motor £11.95 each<br />
Jim Horne has a WeMoTec Midi-fan with Aveox 36/24/2 sensorless brushless<br />
motor for sale - £70. Email Jim at HORNEGb@aol.com or phone 01388 819 638<br />
For Sale by Martin Collins. Contact Martin by email or telephone on 01908 583<br />
545 (Milton Keynes). Can be picked up from me in Milton Keynes<br />
• KYOSHO T-33 in Thunderbirds aerobatic colours. Comes with the motor<br />
& fan unit installed (I was told it was a WeMoTec fan but I cannot confirm<br />
that). Good condition apart from a couple of the decals missing. Price is £60<br />
(no offers).<br />
• RIPMAX ARTF SPITFIRE fitted with AXi 28/20/10 and model motors<br />
brushless controller. The Spitfire has 2 mini servos in it (aileron/elevator) and<br />
comes with an 8 cell 2400 Sanyo pack and 11" x 7" propeller. Just fit your<br />
receiver to make it a flyer, selling due to house move and other projects it has<br />
only 6 <strong>flight</strong>s from new on it, price is £200<br />
E.F.-U.K. 75
Neil Stainton wants a Highlight <strong>Electric</strong> Fuselage, any condition. Contact Neil<br />
at Neil@ITpartnership.com or on 01926 314 011<br />
Peter Vivian would like to contact any others in his approximate area (Camberley,<br />
Surrey) who are also new to <strong>Electric</strong> Flying, with a view to mutual assistance and<br />
support. Peter returned to model aircraft fairly recently after a 55-year break,<br />
with an interest mainly in building and experimenting (definitely NOT ARTF!).<br />
He would like to meet up with others having similar interests. Contact Peter by<br />
email at PGLV@aol.com or on 01276 21 304<br />
Wanted by the Editor, any of the following (see page 4 for contact details):<br />
• General / Technical Articles.<br />
• Hints & Tips.<br />
• Product Reviews.<br />
• New Product notifications.<br />
• <strong>Electric</strong> <strong>Flight</strong> Event Reports.<br />
• Photographs of your models.<br />
• Other items of interest.<br />
Please send colour Digital photos or photographic (6” x 4” or bigger) prints to<br />
the editor. Please do not send inkjet prints as too much quality is lost during<br />
the printing and scanning process. If you have no way to write the files to a<br />
CD, contact the Editor for other options.<br />
Photographic prints supplied will be returned, unless specified otherwise (as<br />
long as you give a return address).<br />
Digital photos should be sent at the highest resolution possible, in colour, and<br />
preferably uncompressed. Where compression is unavoidable the camera should<br />
be set to the lowest compression possible. Photographs can be emailed to the<br />
Editor at editor@befa.org.<strong>uk</strong><br />
Readers want to know what equipment is fitted to models so they know what<br />
combinations work well. Therefore please include as many details of the models<br />
in the photographs as possible, but ideallt at least span, power train, battery<br />
used & <strong>flight</strong> performance.<br />
Where articles are produced on a wordprocessor package, please include an<br />
electronic copy - it make the Editors job much easier and quicker. Ideal formats<br />
are Microsoft Word (any version), Works wordprocessor, WordPad or Notepad.<br />
Other formats can be accommodated, but please contact the Editor first.<br />
76 E.F.-U.K.
New to ELECTRIC FLIGHT?<br />
START HERE . . . . .<br />
You may be taking up <strong>Electric</strong> <strong>Flight</strong> for the first time or you may be converting<br />
from another discipline. Whatever your situation, help and advice is available.<br />
BEFA has prepared an information sheet which details further sources of<br />
information which you may find useful when just joining the hobby. To receive a<br />
copy, please send a Stamped Addressed Envelope (S.A.E.) to Robert Mahoney,<br />
address on page 4.<br />
BEGINNER'S GUIDE<br />
A Beginner’s Guide to <strong>Electric</strong> <strong>Flight</strong> is available, which explains many of the<br />
‘Mysteries' of <strong>Electric</strong>s’ and will, hopefully, set you off on the right foot. Please<br />
send £3.00 per copy required to The Editor of EF-UK at the address on page 4.<br />
Please add £1.00 extra for overseas postage and remit in Sterling. Cheques should<br />
be made payable to BEFA.<br />
TECHNICAL HELP SERVICE<br />
Technical help is now available again for the use of all members. We regret that<br />
no telephone service is available, but all questions in writing (or email) will be<br />
answered by our Technical Liaison Officer (TLO). Please refer your queries to our<br />
TLO, to the postal or email address on page 4. If sent by post, please ensure that<br />
you include an S.A.E. for a reply.<br />
CONNECTIONS SERVICE<br />
Requests are frequently received from members who wish to be put in contact<br />
with other members living in the same area. The easiest method of doing this is<br />
to place a free 'wanted' advert in the classified section of this magazine.<br />
Alternatively, a request may be made IN WRITING to the Membership Secretary<br />
who is allowed to divulge such information to members ONLY. Please supply as<br />
much information about your location as possible and please remember to include<br />
an S.A.E. for your reply.<br />
B.E.F.A. MEMBERSHIP<br />
Membership of the <strong>Association</strong> is open to all. Those who are not members of<br />
BMFA (our national controlling body) will have a subscription to EF-UK membership<br />
with none of the other benefits. Overseas members are very welcome and will be<br />
classed as full members if they belong to their own national controlling body.<br />
CONTACT<br />
For full details, please send an S.A.E. to the Membership Secretary (address on<br />
page 4) requesting a membership application form. Those with Internet access<br />
may visit the B.E.F.A. website at www.befa.org.<strong>uk</strong> where you will find all the<br />
membership information you should require and a application form.<br />
E.F.-U.K. 77
78 E.F.-U.K.<br />
B.E.F.A. Sales<br />
BEFA Round, Coloured Rub-down Decals - Ultra-thin & light - 50p each<br />
EF-UK Back Issues - Issues 71 to 73 and 75 to 81 are available to BEFA members<br />
at £3.00 each, or £5.00 each to non-members. These prices include UK P&P,<br />
overseas rates on application. Reprints of earlier issues may be available to special<br />
order at slightly higher cost, contact the Editor for details (see page 4).<br />
EF-UK Index. A comprehensive index of EF-UK, from issue 28 to date, is available<br />
by sending a £1 coin to cover copying and postage cost.<br />
Binders:- are available to hold 8 to 12 issues of <strong>Electric</strong> <strong>Flight</strong> U.K. Produced in<br />
dark blue with gold lettering on the spine, these cost £4.50 each including U.K.<br />
postage. Please add £1 for European postage and £2 for Worldwide postage.<br />
Please send all orders to The Editor of EF-UK at the address on page 4.<br />
Sweat Shirts & Tee-Shirts: Stock of these is now almost all gone - please<br />
contact Robert Mahoney regarding remaining stock, sizes and prices.<br />
PLEASE REMIT IN STERLING ONLY,<br />
WITH ALL CHEQUES MADE PAYABLE TO B.E.F.A.<br />
Advertisers Index<br />
BEFA Sales................................................................. 78<br />
Fanfare.............................................. Inside Back Cover<br />
For Sale / Wanted ....................................................... 75<br />
New-2-U ............................................................. 25 to 30<br />
RC Groups / E-Zone ......................... Inside Front Cover<br />
Traplet ............................................Outside Back Cover<br />
Wings & Wheels Model Spectacular .......................... 47<br />
EF-UK advertising rates are £25 per inside or outside cover page,<br />
£20 per full page, £10 per half page, all per issue.<br />
Contact the EF-UK Editor for more details (see page 4).
FANS<br />
Morley ‘Jet Elec’ Fan .............................. £15.00<br />
WeMoTec Micro-Fan (280/300/330) ..... £14.00<br />
WeMoTec Mini-Fan (400/480) ............... £28.00<br />
WeMoTec Midi-Fan (540/ 600/930) ....... £38.00<br />
MOTORS<br />
MPJet Brushless motors; 9 motors; outrunners,<br />
inrunners & geared; 280 to 700 .... £37.00 to £58.00<br />
WEP Turbo 10 ....................................... £55.00<br />
Fanfare Silver 16T & 20T ...................... £34.00<br />
Fanfare Powermax 40T ........................ £38.00<br />
Speed 600 8.4v BB SP .......................... £17.00<br />
Speed 600 8.4v Race ............................ £22.00<br />
RE 380 / Rocket 400 ................................ £5.00<br />
Speed 480 BB ........................................ £21.00<br />
Pro 400 .................................................... £5.00<br />
Pro 480 HS ............................................... £6.00<br />
Pro 480 HS BB ......................................... £8.00<br />
MAXCIM BRUSHLESS<br />
Max Neo 13Y 1430 rpm/v ................... £160.00<br />
Max Neo 13D 2470 rpm/v .................... £160.00<br />
Maxu 35D, 21 Cell Controller ............... £140.00<br />
Maxu 35C, 25 Cell Controller ............... £180.00<br />
Superbox 1.6 to 4.28:1 ......................... £50.00<br />
Monsterbox 4 to 6.8:1 .......................... £60.00<br />
Motor Mount ........................................... £12.00<br />
CHARGERS<br />
Speed 1 Pulse / Pk<br />
Det 4-8 cells ........................................... £27.00<br />
Speed Ex Digital<br />
as above with discharge ...................... £55.00<br />
Simprop 25 cell .................................... £100.00<br />
Wheels, Wire, Servos, Fuses, Caps,<br />
Powerpole, 4mm & 2mm gold conns.<br />
– MAIL ORDER –<br />
SPORTS ELECTRIC FLIGHT<br />
FANS AND GEARBOXES<br />
www.fanfare.f9.co.<strong>uk</strong><br />
GEARBOXES<br />
Master Airscrew - 2.5, 3, 3.5:1 ............................. £18.00<br />
MP Jet Planetary - 3.33 & 3.8:1 - 400 / Pro 480 ...... £28.00<br />
MP Jet Planetary - 3.33 & 3.8:1 - Speed 480 ........ £28.00<br />
MP Jet Planetary - 3.33 & 3.8:1 - 540 / 600 ............ £28.00<br />
MP Jet Plastic BB - 4 & 5:1 - 280 / 300 ...................... £8.00<br />
MP Jet Plastic BB - 3, 3.5 & 4:1 - 400 / Pro 480 ......... £8.00<br />
MP Jet Plastic BB - 2.33, 3.5 & 4:1 - Speed 480 ..... £10.00<br />
MP Jet Plastic BB - 1.75, 2.33 & 2.8:1 - 540 / 600 .. £15.00<br />
Mini Olympus ............................................ £8.00<br />
Olympus ................................................. £12.00<br />
MOTORS / GEARBOXES<br />
Speed 400 FG3 ..................................... £17.00<br />
SpeedGear 400 4:1 Inline ...................... £38.00<br />
SpeedGear 480 3.45:1 .......................... £55.00<br />
SpeedGear 600 2.8:1 ............................ £52.00<br />
SpeedGear 700 2.7:1 9.6v .................... £70.00<br />
SpeedGear 700 Neo .............................. £92.00<br />
Mini-Olympus & RE380 .......................... £12.00<br />
Olympus & 540 ...................................... £19.00<br />
Jamara 600 2.9:1 ................................... £24.00<br />
Jamara 650 2.9:1 ................................... £26.00<br />
PROPS<br />
M.A. Folding 12x8 ................ £14.00<br />
15x12 .............. £15.25<br />
M.A. Wood <strong>Electric</strong> 10x6/10x8 ......... £4.00<br />
11x7/11x9 ......... £4.25<br />
12x8/12x10 ....... £4.50<br />
13x8/13x10 ....... £5.00<br />
Carbon Folders 7x4 .................... £6.00<br />
(Perkins) 8x4 .................... £6.00<br />
11x8 .................. £9.00<br />
Slimprops 8x4, 8x6, 9x6 .... £3.50<br />
APC <strong>Electric</strong> 5½” - 12” dia . £3 to £4<br />
(full range available) 13 ” - 20” dia.£5 to £15<br />
Selection of Graupner & Aeronaut<br />
folding & fixed props.<br />
FANFARE • 18 HILLSIDE ROAD • TANKERTON • WHITSTABLE • KENT • CT5 3EX<br />
‘Sports <strong>Electric</strong>’ Helpline - Phone / Fax: (01227) 771331 - E-mail: john.swain1@virgin.net<br />
Now online at - www.fanfare.f9.co.<strong>uk</strong>