Presenting my tilt-wing VTOL plane

[sorenkuula]

Hi,
Time to show what I have made out of MultiWii! It's been good fun.
https://www.youtube.com/watch?v=dGSLhCV169U
and onboard: https://www.youtube.com/watch?v=86XNWOwFzAo
It is a home made balsawood and depron fuselage, the wings are from an Easy Star and the motors are 2x105g/1100kV with 11x4.7s and a very small and light 2204ish motor with a 8x4 on the tailboom.
The wing can tilt from 0 to 90 degrees using a servo with an external potentiometer and reduction gear. The wing motors were placed on long nacelles so the aircraft has good CoG as a plane, and will be tail heavy so the tail motor has some work to do when it is a tricopter.

The control is MultiWii. Because it supports both plane and copter, there were surprisingly few modifications, basically just supporting both at the same time with a mix of both to output.
I have a parameter 0<a<1 for the wing tilt, which determines the mixing:
ailerons<--copter yaw * a + airplane roll * (1-a)
wing motors<--copter roll * a + airplane yaw * (1-a)
tail motor<--copter pitch * a + 0 * (1-a)
(simplified the calculations a little but this is the essence of it. The ailerons, in the slipstream of the props, are yaw controls when the wing is vertical).
So I can have different PID tuneups for plane and copter, I have a similar 2-source mix for their factors.
After some trial and error, it flew really well in all wing tilt settings! It is almost more fun to fly in an in-between setting than as a purely one thing or the other. I was not sure if such a simple scheme would work at all. or if the best mix would be copter*a + airplane+(1-a), or copter+cos(a*pi/2) + airplane*sin(a*pi/2). It turned out linear is just fine.
The plane climbs fast as a tricopter, but it has a funny funny way to descend if throttled back too far - the tail will rise and the plane goes nose down, but the wing brakes it. Just throttle up again and it levels out.
Thank you Multiwii for making this so easy!
Regards
Soren

[Gartenflieger]

Nice project! Let us see some video, please!

regards
Christoph

[sorenkuula]

Hi, for video look at the beginning of my post...
I will upload some more eventually.

[o_lampe]

Awesome!
I guess you have much longer flight times than a copter with same weight?
The moment, when you tilt the wing to fly forward, does the plane keep it's height or does it sink?
How fast can you fly in "plane-mode" ?

[sorenkuula]

Hi,
I still need to test fly it some more, to see how it performs before I know speed and endurance. But both should be pretty good. I made this one just to test the concept. It flies surprisingly well at any wing tilt, so some time I will build a better one of the same kind (larger, more efficient).
When going from vertical to airplane, it climbs. It always shoots out of the top of the picture in the vid. When tilting the wing the final few degrees, it drops, picks up speed and then flies like any other plane.
There is a compromise between fast forward flight vs. efficient hovering when choosing a propeller pitch.
Regards
Soren

[copterrichie]

The transitioning is difficult for any VTOL including military versions. With this said, Kudos to your accomplishment.