Mavic Mini prop issue

[Energenie]

Good morning everyone,

Was curious if anyone else has had issues with the prop contacting the body/left front arm (one with Mavic Mini on it) of the drone. I’ve went through 4 props and at first thought it was a wind issue but this morning I went out, no wind and the 5th one shows signs of contacting the body and arm. I compared the screws that retain the prop and can see no issues, hole not straight etc.

The only thing I notice is a slight clicking noise when the left front arm is extended and retracted. Drone flies fine indoors and hovers flies fine slow outdoors but any fast movements forward/backwards will cause contact and a severe chattering noise. I’ll attach some pictures.

Thanks everyone for any help you can offer.

 

[FoxhallGH]

How tightly screwed on do you have the prop's? Are they still able to swing forward & back around the fixing screw in the hub? - or are they fixed tight??

 

[old man mavic]

How tightly screwed on do you have the prop's? Are they still able to swing forward & back around the fixing screw in the hub? - or are they fixed tight??

thats a good question the way they are designed should mean that once the screw bottoms out against the top of the motor then the prop as you say,should be free to pivot ,could it be a molding fault during production, that means the hub has not been molded properly,in the injection machine

 

[Energenie]

How tightly screwed on do you have the prop's? Are they still able to swing forward & back around the fixing screw in the hub? - or are they fixed tight??

All the props are able to swing freely, was just looking at it closer and it seems that the one prop under negative load will drop slightly causing it to hit the front of the drone next to the black grille on the left front then follow the side of the drone coming in contact with the left front arm. I don’t know if that arm is flexing more than the other or not? They seem to be the same rigidity.

 

[old man mavic]

perhaps its me but if you look at pic three in the OPs post it looks like the blade hub on the right is slightly thicker than the left one ,could just be the angle of the light who knows

 

[Energenie]

Example of what I think is happening

 

[Energenie]

The hub appears to be the same height all the way around. I’m thinking it might be that the left front arm is flexing under stress causing the issue. May try to fly it with the prop guard on and see if the added rigidity of the guard makes a difference

 

[FoxhallGH]

The thing is that the prop' won't - or shouldn't - be under negative load. Aircraft that use rotors have hinged prop's that allow them to advance and retard in their rotation. This is because the prop' that's swinging 'forward' into the same direction that the aircraft is flying, has a 'faster' rotation speed into the air, than the opposite prop' that's swinging in the opposite direction to the aircraft travel. The hinge allows the prop' blade to advance or retard to make up for that (it's not just to allow the blade to pivot and absorb some impact when we get too close to a tree branch!)... When your drone is travelling as fast forward as it can go, the prop's are spinning through the air as fast as they can, and fighting the 'drag' of the aircraft to do so - so to use your words - the negative load thing just should not happen!
Is there any 'play' in the motor that's swinging these prop's???

 

[Thomas B]

perhaps its me but if you look at pic three in the OPs post it looks like the blade hub on the right is slightly thicker than the left one ,could just be the angle of the light who knows

Agree. I’d recommend replace the prop... if the problem occurs again and hubs still look unequal then document as you did above and return to DJI under warranty claim.

 

[old man mavic]

The hub appears to be the same height all the way around. I’m thinking it might be that the left front arm is flexing under stress causing the issue. May try to fly it with the prop guard on and see if the added rigidity of the guard makes a difference

worth a go, maybe @FoxhallGH has a good point, as it only seems to be the one side thats affected

 

[Energenie]

As far as I can tell there is no play in the motor and I have replaced the props already. This is the 5th one and it is chipped out due to contact with the arm. Have had no issues with the right front arm at all

 

[FoxhallGH]

Forgive me if this is a stupid question - but - I don't own a Mav' Mini - so I don't know how the prop's are marked to make sure that you have them mounted on the correct motor hubs? - As I assume that like all other DJI drones, one opposite motor pair spins clockwise, and the other counter-clockwise. I would have thought that you'd not take off at all - but - have you checked that the right prop-sets are on the correct motors??

 

[old man mavic]

As far as I can tell there is no play in the motor and I have replaced the props already. This is the 5th one and it is chipped out due to contact with the arm. Have had no issues with the right front arm at all

even when you look at pic 4 it appears that the prop on the left is slightly higher than the right one it very likely an assembly issue when it was made

 

[Phantomrain.org]

Good morning everyone,

Was curious if anyone else has had issues with the prop contacting the body/left front arm (one with Mavic Mini on it) of the drone. I’ve went through 4 props and at first thought it was a wind issue but this morning I went out, no wind and the 5th one shows signs of contacting the body and arm. I compared the screws that retain the prop and can see no issues, hole not straight etc.

The only thing I notice is a slight clicking noise when the left front arm is extended and retracted. Drone flies fine indoors and hovers flies fine slow outdoors but any fast movements forward/backwards will cause contact and a severe chattering noise. I’ll attach some pictures.

Thanks everyone for any help you can offer.

It looks like you might have crashed the drone as it heavily marked, and that the prop motor is slightly off center to me. Is that possible ?

 

[FoxhallGH]

It looks like you might have crashed the drone as it heavily marked, and that the prop motor is slightly off center to me. Is that possible ?

The heavy marking is due to the prop blade 'raking' the side of the MM ... it's not a crash damage mark! But it would be useful to know if the MM has had a prang!

 

[Phantomrain.org]

The heavy marking is due to the prop blade 'raking' the side of the MM ... it's not a crash damage mark! But it would be useful to know if the MM has had a prang!

because this is what i see : Can you measure that to the other side ?

Phantomrain.org
Coal

 

[FoxhallGH]

because this is what i see : Can you measure that to the other side ?

View attachment 87655

Good eye sir! That could be significant!!

 

[Thomas B]

How about a pic of the two prop hubs off the drone and overlying a grid or ruler with the hubs on the same plane...

 

[FlyBoyRay]

I'm a total beginner, but here's my 2 cents. Just handling the Mini, the props feel very fragile. How the weight rests on them when stored, might be relevant. My other thought is, can the screws come undone in flight, with vibration.

 

[TDZHDTV]

I notice this prop damage on the rear today, I haven’t crashed. I’ve been flying this in some harsh wind conditions in all modes, i always check props before flight, it must have happened yesterday. it’s hovers perfectly still indoors with no vibration or misbalance.