ELECTRIC FLIGHT U.K. - British Electric Flight Association

Letters to the Editor
In response to one of my editorial notes in the “From Failure to Phoenix” article in
the last issue, I received the following letter from Nick Fitton.
“I would like to point out that your statement that the Graupner Speed
600 Race 8.4v is recommended by Balsacraft for the Spitfire is incorrect.
I attach a copy of the original instructions in which is stated that the
Lightspeed 600 8.4v is the recommended motor, I don’t think anyone
knows what the equivalent Graupner or Mabuchi unit is, so finding it in
the MotoCalc database is impossible.
Whilst I fully agree that the Race unit, suitably geared and on up to 10
cells would have produced vastly improved performance, only experienced
e-flyers would have known this, and at the time I most definately was not
experienced!
My article states that pitch speed and thrust fly aeroplanes. I believe that
Watts/lb. is an overused and inaccurate predictor of aeroplane
performance. Maybe an informative article from Bedders the All Wise
would be a good thing for the readers.”
Firstly I did not say that Balsacraft recommended the Speed 600 Rave 8.4v motor.
I said “the designer of these models does not recommend the this motor (the
Lightspeed 600). For a brushed motor he recommends the Graupner Speed 600
Rave 8.4v”. Nick has misinterpreted what I said as the designer is not Balsacraft,
it is Pete Nicholson.
I do not know why Balsacraft recommended this motor, but they most definitely
got it wrong in this case. For the twin motor designs these motors are well suited
as 2 in parallel draw a reasonable current and give good power. In general most
kit manufacturers recommend the reasonable equipment to get good flying
characteristics, and some now offer options for brushed & brushless setups.
The motor Nick picked in his analysis of the Lightspeed 600 appears correct as it
seems to have similar performance to the Graupner 600 8.4v (Pt. No 3301). This
is a relatively slow running motor and definately not ideally suited for fast models.
The Graupner Speed 600 Rave 8.4v is extremely capable even direct drive. My
HMM Crossfire was flying extremely well on a Graupner Speed 600 Rave 8.4v,
Graupner 8” x 4” SlimProp and 8 RC-2000 cells. The static current draw was a
little excessive at 36A, but it unloaded a lot in the air and was not excessively hot
on landing. As the Crossfire is an aerobatic model less time is spent at high
throttle settings, but it should be fine with proper use of the throttle.
If any BEFA member is in doubt over the correct equipment for a model, they can
always contact our Technical Liaison Officer for free advice.
18 E.F.-U.K.