Gents,

Without air speed controlling a variable pitch propeller will be complicated to use and isn’t worth the effort I think.

Pulling? How to control the pitch and throttle? A preselect ratio? In steps?
Braking?

To have a more constant airspeed my goal of research is, control of the angle of attack of the propeller depending of power and/or braking level (asked by airspeed controller).
Result will be a better controlled rpm on any moment.

If that RPM isn’t within calculated limits, too low or too high, an variable pitch is interesting but has to be automatic controlled also of course.
Because these kind of controllers, airspeed combined with AOA, I did not see used by others the variable pitch propeller wasn’t and will not popular either I think.

I show an old control picture, which explains, simplified, the action of airspeed control. Load factor is not compensated and the control parameters of pulling and braking are the same in this scheme.

Problem was, the propeller will stall in brake action when the deviation between wanted and measured airspeed is too much. A lot of interesting research to do and after that maybe a variable pitch propeller will be interesting for me

For electrical propulsion (not for me!) there is one much more interesting RPM to propulsion transformer with a lot of pro’s and nearly no cons. but for that the electronic propulsion “speed controller” in the plane must have the programmable actions of an industrial four-quadrant variable-speed drive. Maybe it already has, but not interesting for “classic pattern flying” I think. Or do you like a double, contra rotating, windmill on a classic pattern plane?

Cees