Some propeller observations.

I've been able to put quite a few flights on my 48-oz #7 Easy. It now has a glow Tower 40 with a venturi and spraybar. The engine is unmodified except that the crank bearing has been honed to clean it up after the crank breaks it suffered as a diesel. It is still running the heavy hub and has perhaps 200 flights on it as a glow engine. Sig Champion 10%nitro, 20% 50-50 oil, muffler pressure to uniflow.

I have one Supercool George Aldrich petal-blade 11 x 5 which seems to be perfect for the engine and airplane. It gives me 5 sec laps and the engine runs steady through the whole pattern in a rich two-stroke. It runs the same in wind or calm. I am very pleased with it. I wish I had more than one, but I can't seem to get geared up to order same. So I have been looking for acceptable alternatives. All these props have been run at the same needle setting, which might not be optimum for each prop.

11 x 5 APC, my usual 40 prop. Way too fast, winds up in the round loops and loads the engine in overhead maneuvers. Not good.

11 x 4 APC A little faster than I want, a little wind up in the wind, OK but not as good as the Supercool upstairs. Useable.

12.25 x 3.75 APC. A little faster than I want. Winds up madly in the wind, OK upstairs. Useable on a calm day, perhaps.

12 x 5 Robbe red plastic. Flew it in calm. Very nice. I think airplane a little slower than the Supercool. Didn't time it. Wonder if it works in wind?

11 x 5 wood Zinger from my Fox 35 days. Inspired by Designman, I cleaned one up and but a beautiful undercambered airfoil on it. Lap time 0.1 sec faster than the Supercool but maneuvers seem to track a little better. Excellent! Have to try it in the wind. I was going to brag on this prop; however,

11 X 5 wood Zinger untouched by human hand. Performance just like my beautiful custom Zinger. Excellent! Darn!

Last flight today put the Supercool back on. It is still #1 because it does its thing in the wind. But I'm sure going to try the Robbe and Zingers in the wind.

All very interesting!

very interesting Jim.... specially liked the fact that you could admit that a stock 11/5 Zinger worked just as well as the one you massaged. We hardly ever hear about stuff that doesn't work out as expected. Thanks.

I agree - very, VERY interesting... all results are pretty much opposite from what I would expect based on my own experience (not with Tower 40, but OS 40 FP-S, which should be basically the same... except maybe for RC-type timing on the Tower sleeve, which could be the culprit here).
I found APC props to be far superior to any wood prop, including the ones I carved from scratch. I also found that low-pitch APC props tamed the plane speed and prevented (almost eliminated) wind-up, while allowing larger diamater and therefore better line tension on top. My favorite is APC 11.5-4 running on the stock OS 40 FP-S.