Autel evo 2 propeller issues

Any one flying the Autel evo 2 Please check your props. There seems to be an issue with them.
I’ve flown 8.5 hours and a total of 43km without any problems.


Interesting as I have just purchased an aircraft with folding props. It obviously saves precious seconds having propellers attached to the UAV and it is a lot easier to pack away if the props fold. However, the more moving parts te more there is to go wrong.

My insire has one piece props that are removable for packing the aircraft away. Probably adds 30 seconds maximum to the setup time.

Would it make sense for Autel - or someone like Master Airscrew - to offer one piece propellers as an alternative?

Hi, there is loose, and LOOSE… I have the Evo 1 and 2 and not seen a problem, the Rivet / Pin that goes through the centre looks very similar to the Evo 1 which has never been a problem, overall some props are a bit looser than others, depends how hard the rivet was riveted in essence, they obviously have a machine, I hope, which has some tolerance on it so should always be pretty close to the spec. However, once running, providing the rotor is not slopping up and down, centrifugal force takes over and that will be hundreds of times more stressing than anything else, it also affords stiffening the rotor as if it was one part, this would start at about 20 rpm, any vibration would disappear, if it is vibrating then the rivet is really loose but I doubt it, some movement is essential anyway, the tightest one to the loosest one is down to what the spec is… hopefully Autel will check it out, you never know there could be a problem, but not seen by me, yet… ha-ha… Cheers.

A very interesting video indeed, that amount of lead / lag of the propeller can only be cured with a adjustable screw.
I think it’s back to the drawing board with that one…

This maybe pure science fiction but I’m wondering if it could be a motor timing/desync problem. For the blades to suddenly lead the hub as they do would require a significant momentary decrease in rotor speed, even if the blades were unbalanced and irrespective of how sloppy the pivot joint was.

When a folding prop is spinning the centrifugal forces are very significant to the point that the prop assembly can be considered as one solid structure. There are two axis of force in play. You have the horizontal rotational force provided by the motor, and the vertical upward force provided buy the difference in air pressure between the lower and upper sides of the prop. There’s also potential energy in the horizontal rotation of the prop which changes to kinetic energy when the motor slows down keeping the prop straight. But if the motor slows too sharply there’s not enough kinetic energy to overcome this resistive force and the prop starts to collapse.

Again could be science fiction on my part.


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The way I see it is, for a multi-rotor to change direction, it requires the speeding up of opposing motors and by doing so the centrifugal balance changes.
It’s quite clear in the slowed down part of the excellent video that as the motor slows down in flight, the centrifugal force is insufficient to keep the propeller from folding.

The propeller folds at around the point where the frequency controlled voltage is chopped to change motor speed. When this happens it’s like applying a break and at that point the prop folds due to its inertia.

The right amount of friction at the hub reduces the tendency to want to fold fully. The prop still folds somewhat but not enough to loose lift.

The friction between the yoke and propeller hub is critical for stable flight, if the “Cord-wise” C.G lags by a significant amount from the centrifugal vector it may never recover, but as in this case it will creat a new disc with its own new force’s and remain folded.
To overcome the folded prop, the motor would have to be sped up sufficiently for the tip to snap back out…:thinking:


That was my conclusion.

But - after that - why hasn’t the significant centrifugal force got them straight back out again? The prolonged vibration he mentioned seemed to suggest that they remained out of their correct extended position.

The “looseness” is also interesting, but from a slightly different angle.
The only time the prop pivots are actually used is when you unfold them or fold them away. So, quite rarely, and in that guy’s short ownership just a very small number of times.

So there has to be something unusual happening to make them lose?

I put a new set of props on my MP a year ago - they are nowhere near the looseness he demonstrated with his. (Oh - and incidentally - I probably let centrifugal force unfold mine for me. :crazy_face:)

It’s all a rather curious one.

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I only put up the post as a concerned UAS operator, I’d rather hi-light a potential situation, than hear of a situation that could of happened. It’s something to look out for. If you see your machine flying strangle then it could be the first place to look.
I’ve had mine for 6 weeks now and flown more than 43km without any issues.

@ShaunDy it’s a great post, thanks for posting, we are here to try and help each other out and also sound off what we may have learnt over the years in this hobby.
Your post will have armed anyone thinking of buying one of those Autel evo.

I fly my Inspire 2 with folding carbon props and part of the preflight is to check the friction for all the propellers.