Pay attention! (I didn’t)

[TDZHDTV]

I honestly think it flex of arms and props, this is frame from a recent flight, you can clearly see the prop in video.

 

[Starz]

Mini has arrived from round two. Funny part is they sent an email that says they repaired mine, but this one is wrapped like new in box and has a different serial number. Just seems an odd way to communicate. Say one thing, then do something else.

 

[Pablo]

So have you flown this new Mavic yet to see if the same thing happens?

 

[Starz]

Not yet. On my way out of town for a few days to Rocky Point. I’ll take it with me and test. Not very good internet there, so may be a few days until I can post results. I’m hoping the clicking noise doesn’t appear with this one.

 

[WooZie]

i would consider reinforcing its front arms preventively, i already did it yesterday, but not tested yet, i just changed the pieces of foam with 3d plastics, very good result, both arms are strong now

 

[Starz]

I’m wondering if the new build date on this one will make a difference. It shows 1/20 as date of build. Arms seem to be the same, but possibly updated internal components. We shall see.

 

[Topview]

i would consider reinforcing its front arms preventively, i already did it yesterday, but not tested yet, i just changed the pieces of foam with 3d plastics, very good result, both arms are strong now

Would be grateful if you could post images of the 3d component. Thanks

 

[WooZie]

these are the files

DJI Mavic Mini Arm Stiffener by redpiyaya

This is to make the arms sturdier, thus less motor vibrations. I got this idea from Lindsay White but made my own model from scratch. Printed 0.4mm PETG 100% infill. Removed foam and super glued the part.

www.thingiverse.com

 

[Topview]

these are the files

DJI Mavic Mini Arm Stiffener by redpiyaya

This is to make the arms sturdier, thus less motor vibrations. I got this idea from Lindsay White but made my own model from scratch. Printed 0.4mm PETG 100% infill. Removed foam and super glued the part.

www.thingiverse.com

Thank you. An excellent job.

 

[Starz]

As of now, with only two flights in on the new mini so far, no signs of the previous prop strike issue. First flight was sport mode with no wind and plenty of throttle. Second flight in p mode with some wind that did throw a wind warning. Haven’t had much more test time because of other things to do.

 

[WooZie]

Today I flew the first time after stiffening the front arms, no marks, no strange sounds, but beautiful weather and landscape. Enjoy !

 

[Thomas B]

Beautiful countryside!

 

[Phxbird57]

Check your props and see if they are doing a bit of self trimming. If you have ever heard a clicking noise that comes from nowhere, you may now have an answer. I never put the two together until someone else brought it up. I’m not thinking this is a pilot error issue at all other than the fact that my preflight was not up to snuff. This mini has never seen anything but air, so the material missing from the prop is definitely from the contact it’s making on the shell.View attachment 90440View attachment 90441

Question for you. do you use any thing to hold the props in place for storage? I was using a rubber band to hold them and notice that it was bending the props. My thought is it may deform the props and cause it to hit the body.

 

[Starz]

Question for you. do you use any thing to hold the props in place for storage? I was using a rubber band to hold them and notice that it was bending the props. My thought is it may deform the props and cause it to hit the body.
View attachment 96104View attachment 96105View attachment 96106

Nothing used to restrain the props. Always stored in its original case. I do always try to make sure the props are in the correct position when placing it in the hole it sits in. I am not thinking that prop deformation was a cause of the issues I had.

 

[TDZHDTV]

I’ve taped my front arms up twice now, each time you can hear a different pitch to the motors and the right hand prop starts to oscillate, my theory is there is a resonant frequency that develops in the arm(s) of some Mini’s which transfers into the prop which then results in great movement and AC body strike.

update. I added tape to the front of the arms and it resolved the prop strike issue. Very windy today was forced to a stop in S mode at 45ft but no contac.

 

[MavicMan17]

so I did some experimenting with my MM this past weekend. I do in Fact have the Prop strike issue. I have tried to be a "Test Dummy" for everyone and try some stuff to see what happens. So, before I realized I had the prop strike issue I was aware of it being a known problem. One day during a normal flight little to no wind I heard a click which sounded like a bug striking one of the props. Very rare this have I heard the dreaded "click" like around 1 out of maybe 8 batteries will I hear it. So this pass weekend one day was slightly breezy around 4-6 mph. I put My MM in Sport mode and flew very extreme. I did every harsh fast movement that I could do and never heard the click. I am still running the original props that have made the clicking sounds and yes they have some material missing from the two props. Regardless of the wind or sport mode or material missing from the props the MM flew like a champ like it always does. side note. people are gonna say I am crazy for running the same props, however I know it is at my own risk. The Props seem to be made out of a realitively flexible plastic. Has anyone bent a prop by hand to the point of "no-return" to see what happens, do the props bend as far as you can bend them then spring back a tiny bit but stay bent? Or do they snap in half? I am predicting that they bend till you can bend them anymore and when you let go it will spring back very so little like a couple milimeters and then stay bent with a noticeable white area over the center area of the bend.

 

[Red_Pyro]

As of now, with only two flights in on the new mini so far, no signs of the previous prop strike issue. First flight was sport mode with no wind and plenty of throttle. Second flight in p mode with some wind that did throw a wind warning. Haven’t had much more test time because of other things to do.

Any update on that ? No more of this problem ?

 

[Starz]

The new one has not had any issues at all. Firmware at the .300 mark and at this point, I don’t feel the need to change that. With the service provided by DJI, I came out a winner. I am fortunate to have one I can call a keeper!

 

[s2seyecle]

In a recent video, the host proposed another theory having to do with 'hard' flying.

He noticed that when flying in Sport mode and making hard turns, starts & stops, he noticed afterwords some marks on the body of the quad. He speculated that those hard movements cause the props to flex to the point of contact.

Extrapolating further, perhaps flying into strong headwinds could have a similar stress effect, even if flying under normal "P" mode.

 

[RogerDH]

In a recent video, the host proposed another theory having to do with 'hard' flying.

He noticed that when flying in Sport mode and making hard turns, starts & stops, he noticed afterwords some marks on the body of the quad. He speculated that those hard movements cause the props to flex to the point of contact.

Extrapolating further, perhaps flying into strong headwinds could have a similar stress effect, even if flying under normal "P" mode.

The problem I have with that theory is that bending the prop to hit the body would require a downward force, and it would seem to me that as long as the prop is spinning, there should be an upward force on it. However, the props get to be nearly flat near the tips, so I wonder if there's some condition that causes it to get twisted enough that the tip actually is generating a downward force while the rest of the prop is still generating an upward force. That would probably bend these props quite a bit. The alternate theory is that it's caused by twisting or bending of the arm, but it's hard to see how there could be enough of that to cause a prop strike without breaking the arm.