In the 11-13" diameter range what manufacturer makes the faster or fastest props? Have run the "run of the mill" APC and MAS props and most of the common wood props already. Any suggestions?

you could try those "vess" props. i've seen their ad here on rcu.

It depends. Which engine are you using? What kind of plane is it used on? What fuel are you burning? Lots of other factors. If you are looking for the highest static thrust for a given RPM, you will probably find that the APC gives about the best numbers at max power in the size range that you asked about. If you fall outside the numbers for max RPM, you may find that another prop design (wider blade) may give a higher number. It would help if we knew a little more about what you were trying to accomplish. I'm in Leesburg, so we can get together and try to figure out what you wish to do.

Bill, AMA 4720
WACO Brotherhood #1

At the races I have been to the most popular prop seams to be APC.

Actually, if pure top end speed is what you are after, the fastest is a single blade prop with a counterbalance on the other side. We all get into retreating blade stall (the blade has to bite into turbulent air caused by the passage of the blade in front of it), but that is more evident on a helicopter than on a model airplane prop, even though the problem is there. If you will send me a pm with your phone number, I will call and try to help you. You are just 10 miles down the road in Eustis.

Bill, AMA 4720
WACO Brotherhood #1

I run APC on all mine.

Well....the airplane in question is an Ultra Stick that currently has a Super Tigre G90 on it. My radar gun shows it at around 103 so far in straight and level flight as an average of two directions. Will be changing engines on it soon to another 90-91 size. The reason is a simple one....friendly competition!

I totally understand the concept of, "Friendly" competition. It will still depend on which engine in the .90-.91 size that you are considering. If it is something like a Webra .91 Speed, then you will need to run a different prop than say, an OS .91. You need to choose a prop that will take advantage of the engine's max RPM and torque numbers. A slower revving engine can make better use of a prop with tons of pitch, while an engine that makes more RPM with a lower torque number can really spin a prop with a little less pitch and still makes more thrust. The answer is still the same....It depends.

Bill, AMA 4720
WACO Brotherhood #1