ORIGINAL: dasintex
I will be running a Magnum 91 2 stroke on a Plane I just put together; the Engine Manual calls for 13X6 to 14X8 size Props; before I fly it, I am trying different size and style props on the test stand; so far the best performance was Master Air Screw S-2 14X6 at 12,000 rpm and Bolly Clubman 12.5X8 with the same rpm; what performance can I expect on a APC 14X5 Narrow Pattern Prop and a APC 14X4 Wide Fun Fly Prop; the reason I ask, I haven't used these 2 APC Props and are still in the unopened packages, I am happy with the other Props and I'd rather just return the 2 APC Props if their not going to any better.
Thanks, Doug.
Doug,
Here's my take on props for a .91.
I tried the 13x8, 14x7, 14x6 and 15x6, all APC. The plane that helped me decide was an old Cermark Sukhoi, used for aerobatics, no hovering.
I found a happy medium with the 14x6. It provides a little braking, to slow the plane for landing, better than the 13X8 or 14x7. The 15x6 was also good, but I found the braking to be excessive.
For me, the 13x8 and 14x7 were faster, but I didn't need fast. I needed straight, strong uplines. The 6 pitch props seemed to pull the plane straight up a little better than the others.
If you're looking to hover, you'll probably want a 4 or 5 pitch prop. For racing, one of the higher pitch props might be better.
Just my 2ยข worth,
Dave Olson