ALL WEATHER - Radio Race Car International Magazine

MCD RALLY 

Anew racing breed has 

emerged from the King 

Cobra stables, developed 

over time with feedback from 

drivers and test sessions alike. 

Inspiration came from the 

company owner and 

designer of 

the 

by Trevor Tennant 

MCD car, 

Sinan Sunali 

from Istanbul, who is an 

avid rally car fanatic and knowledgeable 

enough to qualify as 

a scrutineer for the WRC 

series. Rest assured he 

knows his mechanics, what 

works and what doesn’t and 

he has put all his real world 

experience into the design 

of the MCD Rally car 

which will ensure not 

only realistic performance 

and handling but 

reliability and ease of 

maintenance too! 

What Sinan has 

come up with is a 

very clever design 

that most importantly 

is a car 

which is a practical 

racing 

machine. Sure, 

people will 

want to 

upgrade 

Keeping the power on and drifting large scale proved remarkably consistent at Tibshelf, wet or dry 

Getting the gas on to kick the rear out made dry cornering faster 

the looks and performance, it’s 

only natural, and the rules for 

the MCD race series allow certain 

parts to be replaced but 

they must be freely available on 

the open market. The ultimate 

goal of the series is for the best 

driver to conquer regardless of 

budget and to that end a control 

tyre is specified that has 

acceptable traction, excellent 

wear and moderate cost. 

ALL WEATHER 

Work on improving the control 

tyre is an on going project as 

Sinan moulds his own tyres and 

can react very quickly to driver 

requests as proved at the recent 

24 hour race in Turkey for the 

MCDs where the weather 

changed four times in one day, 

so Sinan moulded 400 tyres for 

the event specially, and 

remoulded the entire batch 

when the weather forecast 

proved incorrect! Why? So that 

everyone had the same tyre 

choices and the level playing 

field was maintained. 

When I was offered the opportunity 

to be able to run this car 

as an RRCi project I was 

intrigued to say the least. The 

majority of large-scale cars in 

the past have been two wheel 

drive and as a result not the 

easiest of machines to drive and 

Thanks to Pro Drive we have a unique and realistic race paint job 

from TelsShells, based on a Slovenian Champion’s Subaru 

heavy on rear tyre wear. What 

impresses me about the whole 

concept of this car is the simple 

design. Many large-scale cars 

appear to be overweight devices 

but the MCD does not give that 

impression. 

Some careful thought has 

gone into making the car as light 

as possible without losing structural 

integrity. Another really 

practical feature which is to be 

applauded is the common use of 

many of the components. So you 

do not need a great deal of 

spares to cover the inevitable 

crash damage. 

All four corners use a lot of 

common parts. The side guards 

are also reversible. 

Radio tray fitted with awesome Multiplex Rhino digital servos for 

maximum performance and reliability. Wiring requires careful 

routing to avoid driveline components 

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Equi-spaced Intermediate gear train, gives a choice of 12 ratios 

A rubber gasket keeps the lid sealed to the radio box 

MCD wheels feature steel insert hex drive 

King Cobra modified Zenoah G260RC 26 cc engine suits MCD cars 

Toe out at the front and toe in at the rear gives stability with keen 

steering responses 

Well we couldn’t do it blue could we. The MCD dwarfs a 1/18th 

version 

GET A GRIP 

The car is supplied ready 

assembled with only the engine 

and radio fitment required. The 

tyres are fitted but you will have 

to adhere the tyres to the rims 

with a slow drying Cyno adhesive. 

Owing to the weight of the 

car the tyre/rim joints take a lot 

of stick so the preparation and 

gluing method is crucial to long 

tyre life and good performance 

by getting it properly seated and 

perfectly concentric. 

I used a sanding drum in a 

Dremel to scuff up the edges of 

the tyre at the glue joints. A 

large hose clip is a great help to 

squeeze the tyre lip firmly onto 

the hub. To do a decent job here 

is quite time consuming but well 

worth all the hassle. Use a good 

quality thick CA like the Pro-Line 

series or the new Slow Cure CA 

from Weston UK to get a really 

professional finish. 

STAY IN CONTROL 

As the MCD is quite a good 

heavier than even a 1/8th scale 

Monster Truck some seriously 

powerful servos are in order. 

Thanks to Multiplex we have 

been able to fit 3 of their superb 

Rhino DIGI 4 servos. The specification 

is very high and the cost 

per unit represents excellent 

value for money. 

The servos come with strong 

nylon operating horns which we 

have used on our model, but 

optional alloy servo horns are 

also available for extreme 

strength with a little bling factor. 

It was decided to use the rubber 

THE RHINO DIGI 4 NO 

65128 SPECIFICATION 

Metal Geared 

3 ball races on output shafts 

Size 59 mm x 29 mm x 55 mm 

Weight 175 grams (6.1 oz) 

Torque at 6 Volts = 250 Ncm 

Holding power at 6 Volts = 

225 Ncm 

Transit speed at 6 Volts = 

0.10 (40°) 

The front and rear differential gear sets utilise a helical tooth 

form for better wear properties 

grommets to isolate the servo 

cases from the radio plate to 

improve vibration resistance and 

help a little with shock 

absorbency/isolation. Thankfully 

Multiplex servos all come with 

the Universal fitment plug these 

days so they fitted to our 

receiver straight out of the box. 

Fitting the servos was quite 

straight forward making very 

certain that the two steering 

servo horns were alighted precisely. 

This is a vital aspect 

because you do not want the 

two servos fighting one another. 

I was advised to use the larger 

Rhino servo on the 

throttle/brake system but you 

can via the supplied adaptor 

pieces install a medium size 

servo to save some weight. 

Routing the servo leads requires 

some thought to avoid the central 

driveshaft and gears to 

avoid any premature failures so 

take your time and keep it tidy. 

The radio box will hold up to 

five sub-C size cells and the 

receiver. On our car I have used 

GP 3300 cells and the configuration 

is such that unless you 

purchase the MCD specified 

receiver pack you will have to 

custom build your own. 

The switch unit includes a 

flashing LED that operates when 

the radio is turned on. With the 

BRCA allowing Spektrum 2.4 

GHz to be used by finally being 

voted in at the latest AGM, the 

choice of receiver was obvious. 

Similarly an AMB personal 

transponder is essential racing 

kit and once you’ve raced with 

2.4 GHz and a PT there really is 

no going back to the ‘Dark Old 

Days’. 

5 mm damper shafts compliment the heavy-duty shocks 

IT’S NOT ALL ABOUT 

POWER 

The one fundamental issue 

with large scale is the typical 

two-stroke engine which in the 

beginning were designed to be 

used in the harsh world of industrial 

and domestic gardening. 

User-friendly chassis characteristics 

are considered more 

important than trying to construct 

a lightweight chassis with 

the ultimate power output, so 

starting the machine easily and 

reliably is the number one priority. 

As a result the engines are 

built to take some serious abuse 

without falling apart which is 

great for racing but means they 

are usually over engineered. 

The featured class allows any 

suitable engine to be used. They 

range in capacity from 23 to 29 

cc and they can be tuned if 

desired, bearing in mind however 

that the tyre rules effectively 

restrict the traction available, so 

it may not be such a good idea 

to have the engine tuned so 

much that the car spins all four 

wheels excessively. Good driving 

technique is the route to track 

success. The Americans are 

always going on with a great 

degree of conviction about driving 

slow to go fast; the great Joel 

Johnson being an excellent 

example of the breed. 

This is the method where you 

do not mash the throttle and 

saw at the steering. His ideas are 

you should restrict the steering 

throw and place the car in the 

correct place on the track whenever 

possible and I know it 

works. 

Watch the really great drivers 

and their main weapon is 

smoothness allied to great race 

awareness. 

Returning to the engine issue 

you are allowed to use any 

Zenoah or similar in any capacity 

between 23 and 29 cc. I 

understand that surprisingly the 

difference in performance is not 

that pronounced between any of 

them. Our MCD is using the 

Zenoah 26 cc G260RC unit in 

standard tune. 

Because of the freely available 

replacement parts buying a used 

Solid dependable front suspension arrangement is fully 

adjustable 

engine can be an economical 

proposition. You must make certain 

it includes the standard 

centrifugal clutch hub and shoes 

along with the relevant mounting 

casting. 

One thing that has to be done 

to the engine is that the bottom 

of the crankcase has to be 

relieved to allow the central driveshaft 

to pass through the 

engine. Any engine supplied for 

MCD application will come 

already machined, but King 

Cobra will machine your existing 

engines for a sum of £25.00 

which would be a wise investment 

as you don’t want to wreck 

your engine using an angle 

grinder do you? (It has happened 

I gather at a meeting where the 

resident club ‘expert’ trashed 

someone’s engine – oops!) 

THE BODY BEAUTIFUL 

The TelsShels paint job is just 

excellent, replicating a Slovenian 

Rally Champion’s Subaru Impreza 

WRC which was tracked down 

with help from Pro Drive who 

were only too glad to help us find 

a unique and striking yet realistic 

Subaru colour scheme. Well we 

just couldn’t do another Blue one 

could we, far too easy! 

The front bumper foam block 

comes ready to trim to fit snugly 

inside any of the bodyshells 

available for this scale, so take 

your time and go steady, a close 

fit will keep your bodyshell looking 

great for much longer, but 

leave it too big and you’ll stress 

the bodyshell against the body 

mounting posts, cut it too small 

and your front end will flap in the 

wind and flex during crashes, 

increasing the chances of a split 

developing in the thick Lexan. 

The engine requires premix 

lubrication, but don’t go slapping 

any old oil in the petrol that you 

find on the shelf at the petrol station. 

King Cobra has tried numerous 

oils over a period of several 

years and has been instrumental 

in developing a specific racing oil 

for large scale models with the 

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Buried inside the gear train are the cam operated triple brake 

discs 

Primary drive from the gearbox output is via a bevel gear on the 

propshaft centre mount 

Racing Venom was developed 

by Rock Oil for King Cobra to 

suit large scale R/C applications 

Rock Oil company, and are now 

the sole source of the unique oils 

designed for these small fan 

assisted, air cooled engines. 

‘Racing Venom’ is the result of 

many racing seasons and driver 

feedback, and comes highly recommended. 

DON’T GET YOUR LINES 

TWISTED 

The fuel tank has a feed and 

return line to the carburettor, so 

when fitting the engine for the 

first time or if you ever service the 

car and remove the tubing be 

sure and get them back in the 

right locations or the engine will 

not start. The clear fuel line is the 

return, while the black line is the 

feed. The engine has a fuel-priming 

bulb to draw fuel up to get you 

going but once running the carb is 

self feeding. 

The main propeller shaft passes right through the petrol tank 

Rear suspension is well braced! 

The transmission design of this 

car is quite interesting, and the 

one thing that was immediately 

noticeable was that the whole 

drive train freed up significantly 

after a few minutes running. 

The engine came with the 

standard two shoe centrifugal 

clutch. It engages into a plain 

clutch bell that is shaft mounted 

via a pair of ball races on the 

outrigger gear set mounting. 

This transfers power through a 

gear driven hub that is held to 

the shaft by enormous grub 

screws against machined flats 

for a secure mounting. 

A nylon pinion has straight cut 

teeth and is fitted on the hub, 

retained by a nyloc nut. The pinion 

meshes with another pair of 

straight cut nylon gears that 

mesh with the gear mounted on 

the output shaft. The design is 

such that the gear pairs use 

identical shaft spacing to allow 

you to swap the gears around in 

various combinations and obtain 

a range of final drive ratios, to 

suit the track conditions. Pure 

genius! 

The output shaft has the brake 

discs mounted on it and it terminates 

in a spiral cut bevel gear. 

That gear meshes with a compatible 

gear that is mounted on 

a fully ball raced support housing. 

A pair of heavy section Dog 

Bone propshafts transfer the 

drive to the differentials front 

and rear while output shafts 

drive very sturdy CVA joints at 

the front and Dog Bone shafts at 

the rear. 

The differential assemblies 

once again use helical gears, 

where the action is shared over 

more than one gear tooth for 

better reliability and efficiency; a 

system used with great success 

for many years on full size motor 

vehicles. The servicing of the 

differential cases requires great 

care in reassembly. It is easy to 

get the main drive gear on 

crooked but I found the solution 

was to turn the output shaft and 

gently tap the outside face of 

the gear as the two clamping 

screws were tightened. 

Differential resistance can be 

adjusted by using a variety of 

lubrication media, altering the 

weight of the grease in the diff 

will change the way the car turns 

and the overall balance of grip 

Front suspension and twin post, double servo saver installation 

front to rear and once set up 

correctly the ability to throw this 

large car around like a 1/10th 

scale car was astonishing. 

THE PLAN 

In the first place the plan was to 

race the car at a winter series as a 

precursor to the TOPSA National 

series in 2007. 

Initial runs were done with the 

bodyshell removed to allow the 

engine extra cooling air while we 

checked the chassis build integrity, 

but are glad to reveal that 

everything is assembled perfectly 

and nothing shook loose in our 

initial trials. 

It is recommended that you run 

the highest octane rating fuel that 

you can get at a normal service 

station in these cars. I used Total 

97 but would prefer the Shell V 

Power if it was available closer to 

home. 

We took the MCD to the famous 

Tibshelf track to give the car a 

good workout on a high-speed 

yet very demanding circuit with 

plenty of corner variation and 

camber changes. On arrival we 

were lucky to find a bone-dry 

track so after a few easy laps to 

get acquainted to the track layout 

and bed the tyres into the surface 

we finally gave it full throttle and 

finally got to stretch its legs. 

One thing we changed was the 

gear ratio; from the base setting 

to the highest ratio possible to 

suit the wide-open sweepers of 

the Tibshelf circuit. This greatly 

improved the speed but made the 

engine run a little hotter so a 

small adjustment of the fuel mixture 

screw was required. A word 

here to those of you only used to 

running nitro engines, you will 

have to be far more precise with 

mixture adjustments when running 

a petrol running engine. After 

around 20 minutes running intermitted 

by several changes to the 

suspension setting the driver was 

able to get the car from 22 second 

laps down to a best of 18.6 

seconds which is right on the pace 

of the regular drivers so we were 

more than pleased with both the 

MCDs out of the box geometry 

and Stuarts braver on the sticks. 

Then down came the rain hard 

and we were pleased to find the 

control tyres gave a surprising 

amount of traction and when provoked 

the car could be thrown 

about with a reassuring degree of 

control. 

After approximately an hours 

running, proceedings were 

brought to a halt caused by the 

receiver battery going flat, which 

showed itself first as a reduction 

of braking effort. 

RACE DAY 

After such an encouraging start 

a visit to Halifax for a winter club 

racing series meeting was undertaken 

and through the course of 

the day several changes were 

made to the set up: 

FRONT SHOCKS 

Hard grade springs, FG 1000 

grade silicone oil, variable piston 

was adjusted to 2 holes open. 

REAR SHOCKS 

FG 500 grade oil, variable piston 

was adjusted to 2 holes open. 

The front steering arms were 

relocated above the steering drop 

arms to change the bump steer 

characteristics, and all the drive 

joints were liberally dosed in chain 

lube spray grease. The access 

holes in the Lexan body were 

increased to allow more air to flow 

through the body, and I fitted a 

ventilator pipe to the petrol tank 

to let it breath more easily. 

Arriving at the circuit quite early 

saw the racing surface still wet 

from all the rain that fell the day 

before. With little wind the track 

remained damp and greasy for 

the first 2 rounds of heats. 

Our MCD was joined by 2006 

TOPSA Champion Trevor Kersey 

who was using alternatively his 2 

wheel drive car and an MCD. 

Round one saw the two wheel 

drive cars really struggle at the 

end of 10 minutes Trevor was first 

with his two wheel driver and 

Stuart a good second commenting 

that traction even with 4WD 

was very difficult. 

Round 2 and the wind had come 

up and the track was beginning to 

dry out but still very greasy. This 

time Trevor used his MCD with 

some wet weather tyres and beat 

Stuart into second place again. 

Round 3 saw the track almost dry 

but a bottom suspension screw 

worked itself out wreaking any 

chance of improvement. 

Many of the 2WD entries 

improved this time and as a result 

Stuart started 4th on the grid for 

the final. The weather meanwhile 

had taken a turn for the worst 

with the rain coming down quite 

hard. At the hooter Stuart rapidly 

got up to second but as the rain 

came down harder the MCD tyres 

were not in the same league as 

the cars using discrete rain tyres. 

After much off roading the driver 

finished in 6th spot finding things 

a real struggle in the conditions. 

FEEDBACK 

Apart from the issue with the 

screw dropping out the car had 

been very reliable after quite a 

few contacts with others cars. We 

found that what the car needs to 

be truly competitive is a tuned 

pipe for the engine. The standard 

silencer gives away far too much 

power and the driver did very well 

with so little power. I understand 

that lightening the clutch shoes 

will improve the pick up from corners. 

The optional multi weather 

air filter set is a very good idea as 

is the rear suspension control rod 

sets. 

After the meeting the car was 

so dirty as to be a real job to get 

clean. I totally stripped the car 

down and jobs such as stripping 

out the gearboxes and replacing 

the kit grease with some CVA 

grease in the rear and some FG 

thick differential silicone grease 

in the front. I have now added 

some alloy nipples that allow you 

to spray chain lube into the gearbox 

cases. The brake discs were 

flattened along with the brake 

calliper plates with fine emery 

paper. 

CLASS: 1/5th 4WD Rally Car 

TYPE: Pre-assembled chassis kit with 

trimmed clear shell 

MANUFACTURER: MCD 

PRICE: £875 RRP 

REQUIRED AND RECOMMENDED 

ENGINE: Zenoah G260RC 

RADIO: JR R1 with Spektrum 2.4 GHz 

SERVOS: Rhino Multiplex DIGI 4 

Digital 

FUEL: Unleaded 95 RON 

PRE MIX OIL: Rock Oil ‘Racing 

Venom’ 

RECEIVER BATTERY: GP 3300 mAh 

5-cell, 6 V 

DISLIKES 

Side exit exhaust means cutting more 

windows out 

LIKES 

Drivability, in all weathers 

Spares back up 

Standard race formula with minimal 

mods 

Ratio options via interchangeable gears 

Sturdy and yet compact design 

Fully adjustable suspension 

CONTACT 

For more info contact the UK MCD 

importer, King Cobra Distribution Ltd 

on 01706 260502 or visit 

www.kingcobra.co.uk 

I understand that some new 

‘Thermal’ tyres will be available by 

the time you read this piece which 

have a wider temperature range, 

yet wear rate is lower than the 

earlier types. We can’t wait to try 

them! 

The intention is to race in the 

TOPSA series and update the car 

as and when required, so keep 

your eye on RRCi for all the news 

through the season as the MCD 

battles the best large-scale drivers 

around the country. If our initial 

impressions of the MCD are 

anything to go by, we should be in 

for a very productive and enjoyable 

season. 

Thanks to Bob Stiles at King 

Cobra Racing for the review car 

and all the help so far, and to 

Multiplex for the excellent Rhino 

servos. 

RRCi 

28 RRCi 03/07 

RRCi 03/07 29

ALL WEATHER - Radio Race Car International Magazine

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