Variable-pitch props!

[tudordewolf]

Long discussed, finally a thing, in-flight adjustable pitch props: AliExpress link

Not sure how immediately useful they would be for variable forward pitch, that would be very useful on nitros, but these don't look like they would survive that stress. The big sell appears to be reversible pitch, so that a 3D plane could literally reverse in midair, which could make for some pretty wild displays.

 

[HPIguy]

They've actually been a thing for quite a few years now. They just never really "took off", pardon the pun.

 

[tudordewolf]

They've actually been a thing for quite a few years now. They just never really "took off", pardon the pun.

Interesting, I'd never heard of them actually being implemented.

I guess the point would be a high kv motor could still swing a large prop at a shallow pitch for static thrust, then increase it enough to keep pitch speed up once its in the air.

 

[tudordewolf]

Expanding on the thought, you could have it operate in a "fixed load" setting by having the pitch controlled by a current-sensing module constantly adjusts the pitch to maximize power without overloading the motor/ESC/battery, and a current threshold also tied to the throttle.

 

[A Big Kid]

In Large aviation these adjustable pitch props are known as Constant Speed Propellers.
Tip speed is kept sub-sonic and pitch is played with to gain maximum thrust w/o body of blades cavitating loosing efficiency.
As prop bites harder it loads up engine and more power can be apply, but once at max RPM where tip speed is just sub sonic you can't add any more RPM to the rotating blades. It is the Pilot/s job to keep the blade/s at there most effective pitch pending the work load of moving the aircraft.
Taxiing, Take off, Climb, Cruise & Speed all require different settings. In this equation is also EGT ( Exhaust Gas Temperature ) further manipulated with engine mixture richer or leaner again pending load.

This applied to some sort of sensors or R/C type control would be a pretty good hat trick indeed. Don't R/C fly but do understand the parameters involved.