Prop sizing question.
 

Hello folks.

I have a Saito FA-50 that's going in a Super Sportster 20. As you may guess, prop to ground clearance is a problem. I don't really want to lengthen the landing gear as I enjoy how the plane looks on the ground and in the air, as far as the gear is concerned. Now, the low side of the prop range is 10X8 and the upper range is 11X10 according to this: http://www.ewmaclub.org/fs0302.pdf

Now, it's been a while, but if I remember correctly- if you go down one inch in diameter, you go up one inch in pitch. So back to the ground clearance issue... I can't go bigger than a 10" prop, and because of the size of the airplane, I feel that a larger pitch and/ or more blades is nessicary to keep the engine from overspeeding in WOT level flight. Would a 10X9 or a 10X10 two blade, or a 10X6 four blade load the engine enough? I know three and four blade props aren't as efficient, but with the plane overpowered as is, I feel I can trade some efficiency for ground clearance.

Thanks in advance.

RE: Prop sizing question.
 

Anyone? :)

RE: Prop sizing question.
 

11-6 or 10-8 or 10-7 Two blade

or you could use a 9-7 or 8 three blade

Enjoy,

Jim

RE: Prop sizing question.
 

Thanks, Jim!

RE: Prop sizing question.
 

Hello!
As a Saito .56 swings a 12x6 prop at around 10000rpm I would say a 11x7-11x8 would be a good prop for your engine...naturally a APC. If you go for a 3-blade prop try a 10x7-10x8.
Regards!
Jan K
Sweden