3 bladed props

[john kirkham]

can you fly an 60.63in 52cu in 4 stroke pc9 on a 3 bladed prop

[Martin Harris - Moderator]

No reason why you can't but if it's for scale reasons, the prop will be less efficient that the equivalent 2 blader. The more blades, the more each one is operating in disturbed air.

 

The reason why full size use multi bladed props is to be able to use the power from the engine while maintaining ground clearance. This is why props evolved from 2 to 3, then 4,5 or more during the war years as engines became more and more powerful.

 

With models, ground clearance is rarely an issue unless modelling jets with a prop driven by IC or EP (particularly when geared down).  Sometimes, a 3 bladed prop can reduce noise as the tip speed will be lower compared with the equivalent 2 blader.

[dennis comeau]

 

    Hi John, did you c hange the prop on the PC9 ?  I also have the same model and would like a three blade operating on a  SC52 fs. Mine flies beautifully but i think the three blader  ie, Airscrew, would look better. Also what size did you use?  DC.   

[andy watson]

For size, take 1" off the size of 2 blade prop you would use with the engine (eg if you would need a 10" 2 blade prop you should select a 9" 3 blade).