Warning : anchorage fail of propeller in one rotor

[Maxnorld]

I think im the first one with this problem, actually its not a problem its a factory failure. I lost one propeller as soon the mavic did the landing, i did not see the exact moment when the propeller fell off, i just realize the propeller its gone when i check the Mavic on the ground. It was not a bad anchoraging by me. First i tought it was the propeller, but doing a full checking, i was realize that the inside rotor anchorage allows to remove de propeller only with my hand whitout pushing down! . It is only one rotor front-right. There was no way to solve the problem, i check several propellers in different positions. So i can take off the propeller of that motor just with mi hand without pushing first and that was the cause that mi propeller fell off. The other 3 motors have good propeller grip.
I send my unit to provider to check the factory fail, because it is a factory fail, not mine.

 

[Manskei]

Maxnorld,

I have just returned my Mavic under the care scheme as I have just had this exact same problem, same front right arm, same lost rotor except I lost the rotor after taking off & getting to 30 ft. The Mavic came down heavy at an angle & cracked the rotor arm at the hinge.

For a while I was kicking myself that I had not locked the rotor in correctly but, before packaging the drone, I satisfied myself that the rotor clip could be turned & pulled off the spindle without first pushing it down to unlock it.

My regret is that I did not detail this in the online summary which starts the care process & the drone is in transit now. Ho Hum! Lets see what DJI come back with.

It was seeing your report that had me signing up to this forum to reply. You might have been the first to suffer this but you are not the only one.

 

[dennyc39]

Maxnorld,

I have just returned my Mavic under the care scheme as I have just had this exact same problem, same front right arm, same lost rotor except I lost the rotor after taking off & getting to 30 ft. The Mavic came down heavy at an angle & cracked the rotor arm at the hinge.

For a while I was kicking myself that I had not locked the rotor in correctly but, before packaging the drone, I satisfied myself that the rotor clip could be turned & pulled off the spindle without first pushing it down to unlock it.

How much flight time on the drone? On the prop? If there is vibration and movement across the joint, I wonder if there could be wear occuring that gradually degrades the prop lock.

My MP has 8 flights and all four props lock, but one seems not quite as positive as the other three.

 

[Manskei]

Good question dennyc39,

I am a new pilot and have only flown the drone ~10 times and only 6 of those out of beginners mode. I did not pack the drone with the rotors in place between flights (even in the squash bag that was supplied) and I watched a youtube clip that suggested it was a good policy to remove the rotors when powering up the drone for updates when indoors so I guess the rotor blades / clips had been worked a few times. This also means that I cannot guarantee that the same rotor went onto the same arm each flight. I was careful to match marked rotors with marked arms (& unmarked with unmarked!). Rotors were in good condition before this flight.

It just strikes me as odd that two of us, Maxnorld & myself, have both suffered this fail in short order and, apart from this forum, it is not something that I can find reported generally by previous crash victims.

 

[dennyc39]

The props should each have a positive lock that you can learn to feel like this:
1. Push the prop down onto the shaft until you can just turn it.
2. Turn it just a little bit, then stop pushing; when you release it, the lugs should catch under the rim so it will not pop back up, and neither can you pull it off. Warning: it is not locked yet, and can still be turned.
3. Without pushing or pulling, turn it a few degrees further. You should then feel it pop up a little bit so that the lugs engage some kind of a notch inside. You can't see this, but you should be able to feel it pop and lock. In this state, the prop can neither be pulled off nor be turned in either direction without breaking something, and it is locked.

Note that you will also feel it pop up if you turn it in the wrong direction, but the shaft will not be flush with the prop hub, the prop can then be turned on the shaft, and the prop can then be pulled off.

If you push while turning, you probably will not feel the locking as it happens. It is then possible to believe erroneously that it is locked when it is not. This is especially true if you inadvertently let the motor rotate as you turn the prop.

If you can't feel this lock engage, then maybe something is broken in the locking hub.

I removed my props several times before I stumbled on to this. Until you get used to feeling this locking action, it is very easy to get this wrong---as I did on my second and third flights.

I was lucky. Once the prop came off just at liftoff, and the second time about three feet in the air. Damage was minimal; one broken prop, and a broken prop guard that I fixed.

 

[Manskei]

dennyc39,

The locking mechanism, with a catch at the end of the twist, is familiar to those of us who grew up in the UK as it is the same as the standard bayonet light bulb fitting.

For that reason I am confident that the rotor was twisted & locked correctly. My original post said: " ... the rotor clip could be turned & pulled off the spindle without first pushing it down to unlock it." and Maxnorlds clip also shows this clearly.

I wonder if this could be an issue with the clip on the rotor hub rather than the drone-arm rotor latch? The rotors I used were Mavic originals as supplied with the new drone. I real shame to risk trashing a $1000 drone for want of a $2 rotor. Reminds me of the old rhyme regarding losing a kingdom for want of a horse shoe nail.

Tell me though: In your Saturday post you said that "all four props lock, but one seems not quite as positive as the other three". Is it the same arm latch that seems looser each time, even if you switch to a new like-for-like rotor?

 

[dennyc39]

dennyc39,

The locking mechanism, with a catch at the end of the twist, is familiar to those of us who grew up in the UK as it is the same as the standard bayonet light bulb fitting.

For that reason I am confident that the rotor was twisted & locked correctly. My original post said: " ... the rotor clip could be turned & pulled off the spindle without first pushing it down to unlock it." and Maxnorlds clip also shows this clearly.

I wonder if this could be an issue with the clip on the rotor hub rather than the drone-arm rotor latch? The rotors I used were Mavic originals as supplied with the new drone. I real shame to risk trashing a $1000 drone for want of a $2 rotor. Reminds me of the old rhyme regarding losing a kingdom for want of a horse shoe nail.

Tell me though: In your Saturday post you said that "all four props lock, but one seems not quite as positive as the other three". Is it the same arm latch that seems looser each time, even if you switch to a new like-for-like rotor?

 

[dennyc39]

dennyc39,

...
For that reason I am confident that the rotor was twisted & locked correctly. My original post said: " ... the rotor clip could be turned & pulled off the spindle without first pushing it down to unlock it." and Maxnorlds clip also shows this clearly.

I wonder if this could be an issue with the clip on the rotor hub rather than the drone-arm rotor latch? The rotors I used were Mavic originals as supplied with the new drone. I real shame to risk trashing a $1000 drone for want of a $2 rotor. Reminds me of the old rhyme regarding losing a kingdom for want of a horse shoe nail.

Tell me though: In your Saturday post you said that "all four props lock, but one seems not quite as positive as the other three". Is it the same arm latch that seems looser each time, even if you switch to a new like-for-like rotor?

I think it could easily be a problem with the clip, especially if the rotor looks normal. That would be hard to check. I haven't observed yet to see if the questionable lock follows the rotor or stays with a certain arm. I've not had any repeats of them coming off or not locking.

Sorry I missed some of the details in your posts. The bayonet socket was an exact analogy, and would have saved me some words if I'd thought of it.

 

[Flycaster]

Check the "spring tension" on the springs. those might have to be replaced...
Thunderdrones has them....