Propeller slightly chipped

[Max Headroom]

I am new to this but surely that would allow the props to move up and down on the shaft of the screw too much (image B) and effect flight, where did you get the screws?

Take one original screw and a new one out and compare the length of the shaft not including the thread.

 

[Txiku]

where did you get the screws?

These are the official screws with the DJI props. I have a few spare sets and from appearance they look genuine. In India, there is no official DJI store so have sourced these from people who seem to have purchased them in other countries.

Is there a way to verify whether what I have are genuine DJI props?

 

[Max Headroom]

Is there a way to verify whether what I have are genuine DJI props?

Did you compare an old and new one side by side as i suggested in my last post?

 

[Txiku]

Did you compare an old and new one side by side as i suggested in my last post?

Hmm, the old ones are just slightly shorter and also the screw circumference appears to be just a little smaller. Very minor but a difference none the less.

Thinking the DJI spare props I have must either be counterfeits or from a bad batch?

I have a couple of genuine Master Airscrew spares which were purchased in the US from their website, so maybe I'll replace all four sets with them.

 

[Max Headroom]

I have a couple of genuine Master Airscrew spares which were purchased in the US from their website, so maybe I'll replace all four sets with them.

I would, that sounds well dodgy.

 

[Droning on and on...]

Those are genuine DJI screws, this issue has come up before. DJI is shipping two sizes for some reason, has been made aware of it, and is seeming to ignore it.

At first thought, I can't see that it would be adverse in any way... the tiny bit the blade will slip up (and it will, given the forces) shouldn't affect normal, safe operation.

 

[Txiku]

At first thought, I can't see that it would be adverse in any way... the tiny bit the blade will slip up (and it will, given the forces) shouldn't affect normal, safe operation.

I flight tested with the protruding screw and there were no problems in terms of manoeuvrability etc. but did suffer from anxiety thinking what if something were to happen and affect normal/safe operation. It would obviously be safer to simply change the props and screws with a set that screws in well, but perhaps my remaining sets of DJI spare props are also of "different size".

Very weird that DJI are aware of the issue but have chosen to simply ignore it.

 

[Xi Zhou]

Those are genuine DJI screws, this issue has come up before. DJI is shipping two sizes for some reason, has been made aware of it, and is seeming to ignore it.

At first thought, I can't see that it would be adverse in any way... the tiny bit the blade will slip up (and it will, given the forces) shouldn't affect normal, safe operation.

I respectfully disagree.

Any change in Z axis of props due to a gap will affect harmonics and potentially lead to early damage of prop hubs as they WILL slam around in wind or during use.

As an example...

I accidentally used the wrong bolts on the clutch based radiator on one of my rotary powered RX-7's long ago, and within a few thousand miles the radiator fan was cracking, i noticed a change in sound when the rad fan kicked on, and noted cracks radiating from the hub onto the blades. The fan assembly had about 1/8" of play, and had become compromised within a few months.



OP, I would get the correct size screws and new (legitimate) props.

 

[Txiku]

OP, I would get the correct size screws and new (legitimate) props.

By appearance the spare prop sets I have do appear to be genuine but is there a way to verify they are DJI originals? @Droning on and on... mentioned that the ones I posted in the pics look genuine and the differing screw sizes is an issue that DJI is aware of. I'm confused since I have three sets of these spare props and am wondering whether I need to bin them if they are not legit.

 

[Droning on and on...]

I respectfully disagree.

Any change in Z axis of props due to a gap will affect harmonics and potentially lead to early damage of prop hubs as they WILL slam around in wind or during use.

It all depends on how much, eh?

The props already have a tiny degree of z-axis margin, that's why the screws aren't fully threaded. this is necessary for them to swing freely. No "slop" at all and they wouldn't easily rotate on the mount.

So, given that no margin at all is not possible, the question becomes is the extra margin enough to cause problems, like you've suggested, or is it inconsequential?

DJI has been shipping these slightly longer screws for quite awhile, people have been complaining, and nothing's changed. I suspect this is because the longer screws are not resulting in a higher failure rate of the props, and crashes.

Also, I'm not aware of anyone reporting a failure due to these longer screws. If there is such a case, we'd all love to know about it.

Theory vs. reality. Reality wins every time

 

[Droning on and on...]

By appearance the spare prop sets I have do appear to be genuine but is there a way to verify they are DJI originals? @Droning on and on... mentioned that the ones I posted in the pics look genuine and the differing screw sizes is an issue that DJI is aware of. I'm confused since I have three sets of these spare props and am wondering whether I need to bin them if they are not legit.

I've recieved the anomalous screws in spare prop kits for the Mini 2 and Mini 3 Pro, purchased from the DJI store (store.dji.com). I've used them (in fact, they're on 2 blades on different arms) on my Mini 3 Pro. Never had ANY sign of anything different, including noise, with dozens of flights.

Don't fly the Mini3P any more (replaced by an M4P), but FWIW, I'm not concerned by them at all.

 

[Droning on and on...]

One more point to consider, the engineers among us will be very familiar with this.

Those screws weren't just picked out by the janitor and tossed into manufacturing. They were spec'd by an engineer. So why are they different?

The original screw became unavailable for some reason. Doesn't matter why. An engineer was tasked with finding a replacement, and this one, while slightly different, met all the tolerance specs for the design, tested without issues, and was adopted.

We are not privy to all that internal discussion, testing, and data. What we can see is they keep shipping them, and not sending replacements when people complain.

Probably in part 'cause they can't get them