Make sure the prop screws are properly attached. DJI specs .4nm of torque. The least expensive torque driver I could find was $69 on Amazon.
Hmmm... interesting. Thanks. I had only found this as official guidance up until now:
http://www.dji.com/product/spreading-wings-s800-evo/faq
Fasten it as tight as possible, but make sure that the propellers can be unfolded smoothly when you start the motors. If they are too loose or too tight they could give excessive vibration.
Which is definitely unhelpful. I've tried several levels of tightness. From very loose, to fairly tight. Nothing seems to make a significant difference. I'm not sure if using a torque driver would help, because the hubs don't seem to be very accurately machined. The force required to move the blades does not seem to be very consistent even if the screws are consistently tightened.
I'm surprised to hear of your problems. I've followed these folding props with interest - they have so many advantages and really want to use them on my next build - everything I've heard so far seemed to be positive (including here). I know you to be a scientific head, so the obvious (but dull) next step is to start a process of elimination. I'm thinking the most obvious problem would be non-centered mounting holes on the bell. I wonder whether it would be possible to make a balance for the whole prop/hub/bell/shaft assembly - rig a kind of "cantilevered double Dubro"?
Yeah, actually I read that review as well. He did say they vibrate significantly more than the T-motor solid props.
It's entirely possible that the problem is being exacerbated by the Tarot 650 frame. It's a folding frame and there's a saying "if it folds, it vibrates". It's definitely not a rigid frame. It's also got a really crappy camera mounting system. I will probably end up re-engineering that part. I typically don't even bother balancing propellers anyway. You can spend infinite amounts of time balancing things, and then as soon as you start moving through the air, they start vibrating anyway. So the damping of the camera platform is critical.
I was just surprised how high the vibration is on this machine. I misspoke when I said this is the worst I've seen. I've got an F450, with NTM motors with bad bearings that are worse. That's just a basher frame. But the vibes are worse than any of my serious machines, and even my helis.
I'll say, the blades themselves look fantastic. Very accurately molded, and very very close in weight. And they seem efficient. The hubs I'm not happy with. The machining tolerances do not look great.
If I drilled the top hub, then I think I could put it on a balancer.
