Folding Propeller Stuck During Flying (quad motor) , need advice

That’s what I thought too, however with a normal multicopter the props never stop spinning once you are in the air. With a quadplane the props are stopped during forward flying so perhaps the wind could cause issues with them unfolding properly?

I never really thought about this until it was brought up here. I only tried folding props twice. The first time a prop snapped on startup and the second time I couldn’t get enough lift from them. I’ve now moved on to a different type of motor that doesn’t accept folding props so I haven’t followed this up.

I’m very interested though as folding props would make a large difference in my case as my plane doesn’t fit in my car’s rooftop box with the props on. But after this discussion I’m not sure I would be willing to test them in flight. I’ve had a few crashes with my builds and they are very costly and time consuming .

I’ve been working on a project for a university (UAV Medical Express vtol)(as a pilot) - first prototype was equipped with 16’ folding props. They’ve tested this solution in a wind tunnel (cruising speed was ~ 20m/s) and sometimes they couldn’t open or it was taking too much time. Nevertheless they wanted me to try it in flight and yes there was a noticable delay (compared to non-foldable props) thankfully I’ve managed to bring it back safely although it was a really stresfull landing (even with 12 years of experience in flying many weird designs :wink: ). There was also another issue - they tend to bend much more than standard props and one of them hit the mounting bar. After this flight they were all changed to normal props and now it flies much better (also they give you improved efficiency).

Hi Julianz, thank you for sharing your important experience. Fortunately I have anticipated this problem before real flight. Based on my testing on the ground, I also found this problem. But I think I can install a custom make special protection guard at the holder propeller to avoid the blades getting stuck in the air. If this protector works then I will test it on my Vtol. By the way, what is total weight (Auw) of your Vtol?

21-25 kg (depends on the payload)