Yup, misconceptions all over the place.

First one is that an 11x5 actually is an 11x5. OK, it is and it isn't. The mfg certainly printed it on the hub and sells it as such but.........

The point is that there are probably 8 or 10 11x5s sold today, and the performance you get out of the lot is quite a broad range.

To ask what rpm you can get out of propellers with just the diaXpitch to go by is worse than going by rules of thumb.

We recently ran some tests using about 6 props, all the same dia/pitch on an electric. A couple loaded the motor such that it drew way too many amps and one wouldn't reach the design rpm for that motor. We shut that sucker down quick, 'cause that is a burnout about to happen. A couple didn't draw amps worth spit. All props the same, right.

You wanna' know what works to answer questions about props for model airplanes? A handful of props and a runway. OK, and the time to test each prop on the engine/airplane you want to fly with a decent prop on it. Everything else, rules of thumb and rules of toes especially, is just BS against BS. Theory against theory.

In theory, practice and theory are the same. In practice, they seldom are.