That's not what was meant to happen!!

[hkfidget]

It was a pretty windy day and I was flying my Fidget which some of you may know I crashed quite a while ago, this was my first crash, and now I have crashed it a bit worse this time, however, thanks to the fact that it's made of EPP the snapped and removed from mount wing as well as bent fuselage (the spar also bent somehow) can be fixed. Anny way, to the way I crashed it:

I decided to try a new high speed low level maneuver which involves a sharp 180 turn after a longish speed up run which is then backtracked, now I had done this a couple of times before-but not in windy conditions- the run up went better than expected, almost hitting the long grass I pulled up to about a meter of the ground and started the turn but midway through the turn a gust hit my polly dihedral and I didn't have enough height to recover.

We just got some awesome aircraft from a friend of ours including a Sky Hawk, a little free fly (I don't know what it's called), a striker and a BAE Hawk! hopefully they don't end up in pieces.

 

[Hai-Lee]

We all are taught the polyhedral wings are self-righting. My experience with one of my mini tiny trainers says different. on 2 separate occasions I pulled up in a loop only to let go of the elevator control at the top of the loop. On the first occasion I had sufficient height to do a recovery maneuver but I was waiting, (totally surprised), for it to self right. I fed in down elevator and waited some more whilst watching in total disbelief.

Eventually its decrease in height became so marked that I wanted to return to normal flight but realized I did not have ailerons and I also did not have enough height to complete the loop.

I watched almost transfixed at the impossible I was witnessing and eventually found that the plane was coming for an inverted landing. It eventually came to a halt a few feet in front of me resting on its vertical fin and the 2 wingtips, (Zero damage).

Later I reproduced the maneuver, with the same plane, to show my son what I had discovered and it performed exactly as previously. Later I gave that aircraft away to a noob here and I have never been able to reproduce it again.

 

[Craftydan]

Polyhedral wings *ARE* self righting. It's not magic -- it's self righting because the lower wing creates force that is more downward than the other wing, creating a torque across the airframe and driving the lower wing back up as the CG pendulum swings back toward "center". That mechanism works over a surprisingly large roll angle, but it changes as you roll around to the other side of the pendulum's swing.

Inverted, you now have a high-wing plane with poly-anhedral which is producing more lift from Newton than Bernoulli. Anhedral on a high wing may not be inherently stable, but that doesn't mean it will overcome the drag-induced lift and moment from the long wing to lean back over once it's balanced at the top.

Plenty of strongly self-correcting dihedral and polyhedral planes will fly inverted with encouragement. They're balancing an inverted pendulum so they usually need a bit of encouragement to stay there, but with shallow inverted roll angles the "flip over" tendencies are still fairly gentle. As for your experience, I'd take that as a compliment for building a fairly clean-and-true airframe.