Do Mini's props get "wobbly" (play at the rotor) with modest flight time?

[vindibona1]

I've grown to be very conscious of my Mini's propeller condition and find that the first signs of an issue tend to be in hover stability and fine control. I'm pretty meticulous about inspecting props to make sure that any issues will only be pilot induced. I wanted to do a hover test in a relatively confined space outside and fund that I had a little difficulty with fine control. I've changed out a couple of props due to nicks or inconsistencies and one warped prop. A few days ago I found one wobbly prop that wobbled even with the screw tightened down. There seems to have been minor play in the prop where it attaches to the rotor. That issue seems to have been fixed by replacing the screw because I ASSUMED the prop was fine after the wobble went away after screw replacement.

Today I found two propellers that had the same wobble. One was fixed with a new screw. The other only was fixed after replacing the propeller blade, though there were no signs of damage or distortion. The only issue was that it wobbled and a new screw didn't fix it... yet a new prop and new screw solved that issue.

Does anyone here have any experience with propeller HUB wear, where the screw can't tighten enough to take out any play in the prop??? Thoughts?

 

[Starz]

The screw is designed to only tighten to a fixed point in relation to the prop that it’s going to hold. There should be no wear between the screw and the prop hub if all is in working order per the design. I’ve not been impressed with the prop system on this aircraft at all. Their goal was to be below a certain weight and there are a few aspects of that design criteria that makes perfection seem to be elsewhere.

 

[old man mavic]

I've grown to be very conscious of my Mini's propeller condition and find that the first signs of an issue tend to be in hover stability and fine control. I'm pretty meticulous about inspecting props to make sure that any issues will only be pilot induced. I wanted to do a hover test in a relatively confined space outside and fund that I had a little difficulty with fine control. I've changed out a couple of props due to nicks or inconsistencies and one warped prop. A few days ago I found one wobbly prop that wobbled even with the screw tightened down. There seems to have been minor play in the prop where it attaches to the rotor. That issue seems to have been fixed by replacing the screw because I ASSUMED the prop was fine after the wobble went away after screw replacement.

Today I found two propellers that had the same wobble. One was fixed with a new screw. The other only was fixed after replacing the propeller blade, though there were no signs of damage or distortion. The only issue was that it wobbled and a new screw didn't fix it... yet a new prop and new screw solved that issue.

Does anyone here have any experience with propeller HUB wear, where the screw can't tighten enough to take out any play in the prop??? Thoughts?

i still have the original props on my MM with over a hundred flights now, and i have found that the props even when new are very loose on the screws ,i believe this is a design feature to allow the props to have some give in the event of a prop strike ,after my first few flights i experienced the front arms flexing that causes the props to strike the body of the drone
i cured this by adding a stiffening piece to the back of the arms and it has not happened again ,i have never had the rear motor overspeed warning that others have experienced or the uncontrolled descent ,i dont plan on changing the props till i get any problems, or notice any damage to them then i will just put a completely new set on all 4 motors

 

[KiloMeater]

I’ve done more than 200 km so far with the same props on my MM, they don’t have any sign of major issue neither did I ever have any warnings

 

[DanMan32]

i still have the original props on my MM with over a hundred flights now, and i have found that the props even when new are very loose on the screws ,i believe this is a design feature to allow the props to have some give in the event of a prop strike ,after my first few flights i experienced the front arms flexing that causes the props to strike the body of the drone
i cured this by adding a stiffening piece to the back of the arms and it has not happened again ,i have never had the rear motor overspeed warning that others have experienced or the uncontrolled descent ,i dont plan on changing the props till i get any problems, or notice any damage to them then i will just put a completely new set on all 4 motors

If by "loose" you're referring to the props being able to easily spin around the screw, that shouldn't be an issue. However any up/down play may be an issue.

I've not removed my props in concern that the replacement might not be re-installed as well by me.
I also use the Flymore case, being careful about how the props are folded before putting the quad in the case and closing the case.

 

[DrizzyDrones]

So i cant find or remember where I put the jew screws and i want to change out some props i thought i heard a different noise from the mini on last flight just like sounded different.. I know new screws are supposed to be done when you do props .. I have some props coming but they are taking forever do you think it would be ok to re use the scrwes until the new ones arrive as long as i keep an eye on theM and keep checking that they are tight

 

[vindibona1]

If by "loose" you're referring to the props being able to easily spin around the screw, that shouldn't be an issue. However any up/down play may be an issue.

I've not removed my props in concern that the replacement might not be re-installed as well by me.
I also use the Flymore case, being careful about how the props are folded before putting the quad in the case and closing the case.

Yes... I've found some up and down play at the rotors and the screws were fastened in as far as they would go. I have to wonder how close they can manufacture these props to stay within a tight tolerance. What alerts me to check is how solid the Mini likes to hover. The other night I let it hover and found I had to repeatedly correct for drift in one direction. That led me to check the props and screws. Once I got that squared away it hovered in place. But it is important to note that I have my method of storing the Mini is to minimize pressure in any direction and just keep them from flopping or the body "sitting" on the wings or pressed into the case. I would like to think I have a pretty good system that just loosely holds the props in place, diagonally, and the drone itself has a "belly pad" inside the case to make it so that the props don't get any pressure on them when in the case.

Here is a composite of photos where you can see that I very loosely run a velcro strip across the blades to keep them from flopping far from side to size. You can see by the photo by the case (to illustrate the belly pad) how the props can move freely but only so far, stopped by the strip. They sit in the case with a minimum amount of pressure, if any on them. I learned my lesson when I discovered a severely distorted prop. [FWIW, the velcro on the bottom is where I attach my Arc II strobe. It looks weird because it's cut around the switch and battery indicator lights. A female velcro patch on the gimbal guard allows for a nice "bridge" over the props to hold them in place.

 

[shaneb50]

So far I have flown over 187 flights on my mini.only having to change my back right propellers once.
They seem to be alright and still fly’s very good.
I often wonder how long the original ones will last [emoji846]
Blessings my friends

 

[Starz]

do you think it would be ok to re use the scrwes

The old screws would work if there is enough Loctite on them. If you need to apply more, be careful not to use too much.

 

[old man mavic]

just out of interest i decided ,after viewing this thread ,to go ahead and change out all my props for new ones, as i have several sets, i will not be throwing away the old ones ,as there is no damage to any of them
i wanted to see if there was any difference to how the new props felt on the fitting screws ,compared to the ones i took off,and i can honestly say none whatsoever
i then took the MM up for a short flight in my garden, and a good way to check if the screws are not cross threaded is to hover at eye level, and watch how the blades on any motor ,track in relation to each other as they spin
if all is well they will both appear to be at the same level ,all was good the drone seemed fine so i will let you know if it flies any differently after my next outing

 

[scro]

The blades on my MM have had a slight amount of play since new. I.e. the tips of the blades can be wiggled up and down by a few mm and the blade "rattles" on the screw. I've never changed the blades, and never had any issues, flight instability or uncommanded descents to date, after 10mths of use.

 

[vindibona1]

The old screws would work if there is enough Loctite on them. If you need to apply more, be careful not to use too much.

The amount of loctite has nothing to do with this in this case. The screws are tightly fastened down, but the props have had some vertical play at the rotor with the screws in as far as they could be tightened.

 

[Starz]

nevermind.

 

[DrizzyDrones]

So I should be good to use the same scrwes until my new ones get here? Check them before and after each flight ( i cant believe i cant find them **** screws

 

[Deleted member 103366]

I would be interested to know if, with high milage blades, there is any polishing of what would be the in situ 'inner' face of the screw's shoulder. I would also love to see some ultra slowed down video of how these blades behave when they are being 'driven'

i cant believe i cant find them **** screws

If you open a pack of blades and use only one pair why not tape the openings in the bag's screw and blade compartments closed, it keeps the remaining new screws with the remaining new props. I am a gold medal winner at loosing things like these screws and so far by doing this I have managed to deprive myself of even a bronze medal. Alternatively place the remaining blades and screws in a ziplock bag which is then closed

The amount of loctite has nothing to do with this in this case. The screws are tightly fastened down, but the props have had some vertical play at the rotor with the screws in as far as they could be tightened.

The suggested loctite is to aid the retention of the screw in the thread in the motor, it is has nothing to do with the play, vertical or radial, of the blade on the pivot screw.

 

[Starz]

So I should be good to use the same scrwes until my new ones get here? Check them before and after each flight ( i cant believe i cant find them **** screws

If the screws are properly installed, you should not have to check them each time.

 

[vindibona1]

The suggested loctite is to aid the retention of the screw in the thread in the motor, it is has nothing to do with the play, vertical or radial, of the blade on the pivot screw.

Yes. I knew that. The loctite was never the issue. When checking the screws were fully down and secure, yet I could see some vertical play at the rotors on SOME blades. Having had the Mini for about 5 or 6 weeks now I know it can hover rock solid in space. When it starts to drift or pull without cause ( C-mode, hovering indoors so no wind) that seems to be enough reason to ascertain why it isn't hovering without drift. The props are inspected every time I take it out of the case or put it back in. Most are brand new props with no incidents of contact with objects. No nicks. So what else is left but to check for prop wobble. And the screws are tightened down solid, as far as they can go. I think it has to come down to manufacturing tolerences of the propellers which, with such small dimensions and thickness has to be very difficult to get absolutely precise. As a side note there has to be one hell of a margin on these things. $12 on a good day and probably costs DJI all of 10 cents per prop to make.

 

[Starz]

Or less!

 

[Deleted member 103366]

Ah I understand you now. Thanks

 

[DrizzyDrones]

But i was thinking about using the old screws and not putting loctight on them new ones should be here in the next week or so. Im weighing the risks the drone sounded different when flying last flight however it flew with out incident and I didn’t have any errors. I believe a prop change is needed. Would I be better off leaving the props and waiting for the new ones or Changing the props and reusing screws .. basically do you think it’s likely that the screws would back out even if if check before and after the flights I don’t want to risk uncommanded decent or something happening because of deformed props but if the screws have a high chance of backing out I won’t bother... the sound change has me weary and im on original props