[yinewang]

Hi all
I just ordered a CMPro Marathon 20~24cc AEROBATIC ARF kit from nitroplanes. here is the link for more info of this kit.
> http://www.nitroplanes.com/ma20aeairera.html
So now I have a few questions:
(1). I believe standard servos can serve well, but how many grams of torque should the serve have? (i.e. 9g? 20g?)
(2). The description says 20cc engine should serve well, but I've seen people on youtube use 26cc engine for this plane as well, so any good source to get 20-26cc engine for a good price?
I had two electric planes and this is my first nitro one. I'm looking for any suggestions (not just to the above two questions I've asked)
Thanks
Mark

[Guest]

Couple of things:

1. It's not a huge plane, so really, servo's don't need to be any more than 80oz of torque. In fact, it wasn't that long ago that airplanes this size (goldberg Extra 300, Goldberg Ultimate, Midwest Sukhoi etc) were using standard servo's at 40oz of torque.

2. Keep in mind there is a huge power (and weight) difference between Gas and Nitro engines. This airplane appears to be designed around gas engines. If you want to go Nitro, a Saito 1.80 4 stroke would be great. Even a strong .91 2 stroke would be ok, a 1.20 2 stroke would be really good too. If you are going to use gas, then look at the SPE engines, Fuji, or even the old standard and reliable G26. I don't know much about gas engines, but I do know that if you are going to use a 26CC gas engine, the power made is about equivalent to a 1.20 2 stroke glow engine. The Nitro engines make more power for sure in the smaller displacements, they cost less typically to buy, but the cost of Nitro fuel is far greater than Gasoline.

[yinewang]

Thanks
For the radio system, I'm planning to use a DX5e TX and AR6250 DSM2 RX. DX5e is like the cheapest radio system from spectrum, does that mean it will have a smaller range compare to other 6,7 ch TX? Cause my plane requires only 4 ch, i don't see any point of getting a 7 ch receiver for it.
Mark