747FULLSCALE

My Feedback: (21)

I have a MOKI 2.10 that calls for a two bladed prop anywhere from 18x8 to 22x8. I would like to fly my P-51 with a four bladed prop. What is the conversion method to pick the correct size four bladed prop?
Thanks for any help you submit.
Clay

BingoFlyer

Unless you are going to use a reduction gear I would not use a four bladed prop. Use a four bladed prop for static display but two blades for flying.

I have tried both three and four bladed props (on smaller engines) and they just didn't have enough pull. The explanation I was given was that unless the prop is reduced in rpm the trailing blades are in the forward blades air stream so it has less air to push.

I don't know if this was the reason but I do know I had much better results with a two bladed prop., and the effect was not as great when running on a four stroke.

747FULLSCALE

My Feedback: (21)

Morris,

Thanks for your input. I have been told if you expect to fly 3 or 4 bladed props, go 1 or 2 engine sizes bigger because the props are so inefficient. I have a small P-40 that calls for a Saito 72. I put a Saito 100 with a three blade and it goes vertical out of sight. For three blades I've been told the conversion is decrease 1" in diameter and increase pitch by one. Does anyone know the conversion for a 4 blade prop?

Thanks,

Clay

Geistware

My Feedback: (16)

I would recommend that you get Thrust HP and try and see which propeller will give you the correct load

http://www.geistware.com/rcmodeling/...rusthpv20d.zip

Mitchell-RCU

My Feedback: (49)

When I had my four blade made for my 1/5 P-51 J&Z told me to take the size of two blade that i was using and decrease it by two in diameter and two in pitch, or by four in pitch. So if you are running a 20-10 two blade then you would try a 18-8, or 20-6 four blade.

Mitchell