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I'm designing a UAV that needs to reverse motors for some maneuvers, but unfortunately most of the commercially available propellers I've tested are optimized for single direction and only produce approximately half the thrust when spun in reverse.

If I wanted to design my own propeller with better "reverse thrust" than 50%, what considerations could I make?

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    $\begingroup$ What you can do with a UAV is pretty different than what makes sense with full-size aircraft, but for turboprops that can go into reverse, they do it not by reversing the direction of rotation of the engine, but by changing the pitch (blade angle) of the propeller. It keeps spinning in the same direction; halting & reversing the momentum of an engine + a large propeller wouldn't be a quick process at all, and the mechanism to change the blade angle is compact enough. Plus you need to change the angle anyway, so this just lets you change it a bit farther. $\endgroup$
    – Ralph J
    Apr 8 at 22:52
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    $\begingroup$ Since the considerations here are specific to UAV's and pretty distinct from non-uav Aviation, this may be a question to migrate to that forum rather than keeping here. $\endgroup$
    – Ralph J
    Apr 8 at 22:53
  • $\begingroup$ Amateur here but I feel at the end it's going to be a tradeoff between "trying to minimize loss of power in reverse mode" and "having more avalable forward thrust". Unless you can find a way to QUICKLY rotate the prop blades by 180 degrees, then the same thrust vector is just facing the other way, still at its best. A little bit like a constant speed prop changing it's blade angle but even in that case the reverse thrust is always lower than max forward thrust. $\endgroup$
    – PapaMike99
    Apr 8 at 22:53

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There are electric indoor radio controlled airplanes capable of doing "3D Aerobatics". This is what you want to search for.

They use a variable pitch propeller set up like a tail rotor on a helicopter. I.e. it uses a hollow shaft motor and puts the swashplate on the 'other' side of the motor.

The other keyword to search for is "EVP" for Electric Variable Pitch.

Something like this.

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    $\begingroup$ 3D rc flying generally does not involve variable pitch - mostly just post-stall maneuvering. Perhaps 4D is what you were meaning to say? $\endgroup$ Apr 9 at 2:42
  • $\begingroup$ Quite possibly. $\endgroup$ Apr 9 at 3:43

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