Ijust flew my new Shoestring Racer with a 61FX with a 13x6 Zinger prop. The engine maxes out at 10,300 RPM's and the plane doesn't seem to have as much punch as I expected. Am I using the best size prop? What's working for those of you who are flying this combo?

Try an 11X7 APC for more speed. You can also pick up another 800-1000 rpm with a Performance Specialties tuned muffler.

I was going to suggest an 118/apc. I thing the 13 is over kill for that engine.

I fly my shoestring with the OS61fx and a 13x6 APC. I get 10600 rpm. Using bisson pitts muffler.

Flies great, very light plane, vertical good but not unlimited.

Make sure prop is nicely sanded and balanced, and engine is properly broken in.

Used to use top flite wooden 13x6's but on the grass runways it is hard to avoid a few nose-overs with this airplane. after a few busted wooden props i switched to the APC's and liked them better.

crashed it on an 'impatient landing approach' at end of the fall and broke the fuselage completely in half. wing broke off, one wingtip shattered and then the other.

rebuilt it this winter and eager to see how she flies with a little extra weight, but should be a bit stronger now too.

i like the look of the wheel pants and will probably put them back on after a few flights.

attached pic is as she looks after rebuild.

I use a wooden 12X6 on my 61, in my Shoestring. Works fine, but I'm not looking for unlimited vertical, I just fly it.

12x4.5 the new props from tt. great for vertical/