Hi all. I’ve had a problem with motors on two happymodel whoops now and I’m wondering if there’s something I’m doing wrong. Full disclosure: I’m just learning to fly, and I’m learning indoors, and I’m crashing a lot.
On the mobula7 I suddenly had a problem taking off, it just pitched forward and right on takeoff. I had a look at the motor (RS0802 20K) and 2 of the three screws holding it to the frame had gone missing. After finding some more screws and screwing it back in I tried again, but that motor just sort of twitched. I unplugged it, plugged it back in, made sure it was seated properly, possibly a small improvement but not a great deal. I ended up increasing the dynamic idle rate a bit in betaflight and that has sort of fixed the issue. I say “sort of” because very occasionally it does still fail to spin up properly, but it’s good enough.
On the mobula6 this evening (after crashing again) I turtle flipped it and took off again but it felt really wobbly and felt like the throttle was higher than I was actually holding it, it didn’t really want to land, just wobble around near the ceiling. I landed it by flying it above the couch and disarming it. Inspecting it I saw that it too had lost two screws from one of the motors (SE0702 28K), and the other one was almost out, so the whole motor was sort of flopping about. I found some screws, screwed it back in, and once again the motor wont spin up. This time it’s properly dead though, nothing in betaflight or esc configurator will make it do more than twitch a bit.
So firstly, I’ve learned that I need to regularly check the screws on my whoops, and I might use a bit of blue loctite in future to make sure stuff stays tight. Secondly, I know I’m treating them really rough, the mob7’s frame is broken and stuck back together in 3 spots now. The mob6 hasn’t got any visible damage but it’s definitely taken a lot of hits. I don’t really mind too much, I’d rather have fun learning to fly a bit recklessly than worry about them and feel like I need to be super careful with them. But I just get a bit of a vibe from the motors that I might be doing something else wrong; there’s no obvious physical damage to the motors, but one has failed completely and the other on the mob7 is clearly on it’s way out. Is it likely that flying while the screws had come loose generated a bunch of destructive resonances that made the motors rapidly burn out? Is it likely the other way round where a failing motor develops some harmful resonance that rattles the screws out? Is this just to be expected when you repeatedly smash tiny whoops into the walls and the floor?
In case it’s relevant, I hadn’t touched anything to do with the motors or pid tuning on the mob6 beyond setting my rates, but on the mob7 I had flashed bluejay @ 48khz onto the ESCs along with the corresponding increases to min and max startup power.
Anyone got any suggestions or should I just make sure I have spare motors kicking around while I’m learning?
