More Mavic Mini Mysteries

Questions & Answers
1

Trouble with props again; had an episode of rear props unscrewing themselves a while back which resulted in ‘motor running too fast’ warnings and instruction to land immediately, Solved eventually with replacement props.

But I was out flying this drone weekend before last and had a bit of an odd landing. Battery was low and I was bringing her in on RTF when, as she began the final descent, there was a snappy prop noise and she wobbled quite a bit, and tipped herself over on landing on the ground; she missed my hand!

No damage but one of the props had a nick in it, and I suspect something had interfered with it and distorted it upwards so that it hit it’s partner prop. Ok, check all screws for tightness (did this in the pre-flight as well), no problem, replace damaged prop, and test hover indoors; all seems well. Test hover included rapid movements to stress the propls and confirm they were fit for service.

Full test flight over the rec this avo. Problems very quickly, drone unable to keep station and not long before lost control altogether, abnormal prop noise again. Luckily the crash was onto grass from no great height! Inspected the drone, especially props, no damage found, decided not to fly with Maven in case that was upsetting her, took off again with DJIFly. Good signal, 16 satellites, good battery, all apparenty good to fly…

No dice; minute of proper flying, prop snappy noise, complete loss of control, crash (again, from low height, I wanted to test-fly a bit before going up much, just as well in the circumstances). One lh forward prop snapped off completely, only the root and the bearing left!

Again, checked screws, all nipped up tight. Is there perhaps a calibration issue? Calibrated compass before flight; this drone seems to require compass calibration about ever other flight, unlike the 4K. Inertia unit calibration perhaps?

That’s it, I’m out of ideas. I would like to keep this drone in service because of it’s ability to use Maven, which provides waypoint, follow me, & geofencing, which the 4K can’t, despite being better specced in terms of camera and control signal.

Any suggestions will be appreciated!

2

Try a different hobby? :thinking:

In all my years of being around this club I’ve never come across anyone that’s had so many critical issues with DJI drones - and in such a short space of time :pensive:

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3

Is this the original Mavic Mini? The only think I can potentially think of is that the original Mini came with a case that could potentially distort the props when you packed it away. From the Mini 2 onwards they changed to the shoulder bag design.

I did used to get the odd motor/prop error as a result of this, so if it is the same model then could be something similar. I would advise picking up a Mini 2 shoulder bag from eBay if you can!

4

Sorry I know you’ve been really, really unfortunate from all the things I have read recently, why don’t you share the Airdata & let one of those who understand it well have a look to see if you have just been truly unfortunate with your drones or the possibility that maybe it could be human error :thinking:
We all make mistakes it’s no shame & surely it’d put your mind at rest in the hope you can get to the bottom of it & why things keep going wrong, that’s what id do but that’s just me :+1:

5

Any suggestions except that one, PingSpike, even if it is probably good advice! The weather is probably not an issue btw; almost flat calm, 41F, 83% RH.

I am starting to think I’m cursed, though…

If no other advice is forthcoming, I’ll calibrate the IMU and test fly again. If that doesn’t work, I think I’ll retire the drone, which has suffered a series of problems and I don’t really trust it. Bought it as a fly more package from MTB with the insurance money from the Mini2 SE killed by seagulls, which had performed faultlessly for the few weeks I had it!

  1. RC supplied by MTB would not hold charge, would be ok for about 5 minutes then it would die.
  2. MTB had none in stock to replace it with so gave me £40 to buy a 2h one off eBay. This one didn’t work at all and had to be returned, and another one bought; 3rd time lucky!
  3. ‘Motor spinning too fast land immediately’ warning caused by prop-retaining screw bolts coming loose on rear props. Solved with replacement props, but these are 3rd party as DJI don’t supply replacement props for Mavic Mini any more. Can Mini2/2SE/4K props be used?
  4. Repeat of 3), screw bolts tight this time, one prop broken off ocmpletely no marks on the other 7.

That is, it must be said, a lot of problems for someone who only started flying DJI last May!!!

6

It can only happen when you fly it into something that is tougher than the prop, not the drone’s fault but the operator :wink:

7

Delivery time is a bit long though 3 March :man_shrugging:

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8

My advice would be…

Send the damaged Mini 2 to DJI for repair

This is the service and the sort of cost to expect…its first class

When you have it back, go and fly and share some images so we can believe you are a real person
and you can then enjoy the hobby

2 Likes
9

Thanks Kirky!

Quick squiz at Airdata reveals the following points of interest:

‘Low Risk’ at 7m 39s, 2.3’ altitude, 8 seconds after take-off, ‘Propeller guards detected’ (there weren’t any) 'Performance level lowered to ensure flight safety (code 120616). Warning Triangle 'Payload mode enabled &c (code 30232).

‘Tip’, and ‘Low Risk’ at 10m18s 'Not enough force error, Payload mode enabled &c (code 30232), 'Aircraft max power reached,
decrease altitude and fly with caution, if this issue persists land immediately (code 30168) Decrease altitude & fly with caution. Warning Triangle 'Not enough force/ESC error (repeated 2 times), (code 30232) again.

‘Medium Risk’ at 10m26s 'Motor error. Check propellers and fly with caution (code 120652).

‘Tip’ and ‘Low Risk’ at 10m 38s 'Not enough force error, (code 30232), Not enough force error (repeated 50 times)

‘Low Risk’ at 10m 43s 'Not enough force &C (repeated 50 times)

‘Low Risk’ at 10m 48s ditto repeated 20 times

‘Low Risk’ at 10m 55s code 30232

‘Tip’ at 10m 57s 'Max power load reached. Fly with caution

‘Low Risk’ at 10m 57s 'Not enough force, code 30232, code 30163, Not enough force repeated 50 times.

A tale of propeller problems, overloads, tips, motor errors, and imaginary non-existent payloads & propeller guards. I think the prop came off at 10m 43s, after which she was flying with 7 props! Clear air and no birds about, so no collisions.

1 Like
11

Share the bloody thing

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12

@TheJohnster John as sparky Wayne says share it he’ll know the probs straight away mate, that’s one I’m not brushed up unfortunately, I can read bits & bobs but not the depth of others who have way more experience than me :+1:

13

Sometimes I wonder if hes a troll too. I shouldnt laugh but its the weapons grade tangents he goes off on :rofl:

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14

You hit the ground

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15

when you replaced the prop, did you put the right props on the right motor?

you should not continually check the tightness of the screws, this is lightly to lead to the screws being over tightened (and possibly protruding into the motor or motor windings) but every time you check their tightness you are likely to break the thread lock compond.

the screws for props are 1 time use, because they come with a dab of thread locker compond on them (don’t put any more, and don’t try to reuse them), then the thread goes in the hole it will break the compound exposing it to air which allows it to reharden… if you keep nipping up the screws you are likely to break the compound

the props should be able to move freely so that centrifugal force throws them outwards, technically I suspect that the props actually act as a damper… when you throttle up they will move backwards and throttle down they will move forwards, if they are not moving this will lead to instability, as one prop may move and the other not

suggestion… change all of the props, use new screws, tighten them once, ensure that the props move freely back and forth smoothly, check none are binding… fit and don’t fiddle or tighten them again, unless you want to replace them.

16

This sounds like the next move, and I have spares here with new screws. Didn’t realise about the the tread lock compound; makes sense! I’m pretty certain the correct props are on the correct arms, but will double check when I replace, because that’s exactly the sort of simple mistake I’m quite adept at…

17

If this was mid-flight and you swear you definitely hadn’t pranged it at some point…

I wonder if over tightening a screw might’ve damaged/weakened the prop.

Or a balance/vibration problem.

Might be a daft suggestion, but can you find the centre of balance and is it off? I think they’re quite front-heavy but it shouldn’t be to the left or right. Perhaps a previous owner did a difficult-to-see repair that involves a great glob of glue inside the body that’s throwing it off balance?

If the centre of balance is good, maybe one of the motors is running fast/slow and the others are having to compensate. Might explain why it thinks it’s got a payload attached.

Share the whole lot rather than a few select lines. :+1:

1 Like
18

don’t be tempted to add thread lock to them, there is a whole load of youtube clips to this (I think even bardwell did one some years ago)

ok not dji props, but similar rule applies, just use the ONE TIME use screws.

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19

Lesson learned, new props with new screws going on this evening. I’ll do the centre of balance thing as well.

The only crash was after the first loss-of-control wierdness, which is what caused it and cracked a rear prop, so while it might have knocked things out of kilter a bit, it is not the root cause of the issue. That certainly seems to be related to prop issues, and this will be my intiial plan of attack, check the props & motors first, then anything that might affect them.

Second job this evo will be to find out how to load Airdata on to here for expert perusal. Going back through the data since the initial incident, there is quite a bit of prop-related stuff that comes up, along with minor signal problems. So far I am clearly being steered towards the whirlywhizzy bits.

Many thanks everybody for your input on this so far. As for being a troll, you spend one night under a bridge because you missed your last train home in 1972, and they never let you live it down…

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20

View the flight in question, click on the big green Share button :

Screenshot 2025-01-19 at 18.43.26
Screenshot 2025-01-19 at 18.43.261882×360 62.3 KB

Copy / paste the link here.

21

Ok, if I’ve got this right this is the Airdata link. I’ve included all the flights since the initial problem.

https/app.airdata.com/share/xXaAARA

Ok, cross fingers and…