This whole thing just seems like a much bigger deal than it needs to be. First operators can't tighten props correctly, so you need prop locks...now they can't even use QR props, is it so difficult to monitor the wear and tear parts of your aircraft to ensure viability?
Avoid non-DJI 1345S Quick Release Prop Mounts
- Thread starter Tahoe Ed
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For some.....quite probably
I feel like DJI is working really hard (or hardly working) to make these things as easy as possible but they gotta be met halfway on somethings...
I agree I started a new thread on this maybe I shouldn't have? but I really do want to know the concensus on this from everyone, not just DJI.
I think its good discussion. While I have no confidence in the DJI hubs, they say use them and potentially have warranty issues if you go aftermarket - yet they've not said do not use knock off props, or other hub adaptors and T-motor props.. Seems weird to me, they should be making an overarching statement covering both hubs and props, and then following up with "if it fails we will replace your Inspire free of charge" - ascertaining 100% confidence in their own design.. After all, if there is a 200 flight limit, then they can see this via the blackbox recorder in the pilot app cant they?? 
I think its good discussion. While I have no confidence in the DJI hubs, they say use them and potentially have warranty issues if you go aftermarket - yet they've not said do not use knock off props, or other hub adaptors and T-motor props.. Seems weird to me, they should be making an overarching statement covering both hubs and props, and then following up with "if it fails we will replace your Inspire free of charge" - ascertaining 100% confidence in their own design.. After all, if there is a 200 flight limit, then they can see this via the blackbox recorder in the pilot app cant they??
I think this is a good discussion and needs to further on as well, I feel like that the right for free speech is being echoed, there are members who are insulted to see a DJI posting about a product that is unsafe without giving us some kind of research to back it up. I not picking on Tahoe Ed in any way shape or form but I feel its our Constitutional Right to question a statement release like this. and to make the claim that our warranties will be dismissed for using thease Alloy Hubs is utterly disappointing.
I feel violated that if I use the Alloy Hubs because I cant afford a Hub Failure is almost against my Constitutional Right to use them because DJI CLAIMS that they will not warranty my bird.
One of the best part of this community is the members here who share their questions and answers, I have learned so much from reading in this forum. I don't expect everyone to agree with my views but if I couldn't post them to share I feel this home would not be for me. I am glad to owners for what they provided for us and glad to be here to learn and share.
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Maybe someone should message Tahoe Ed directly asking for their test data, plastic OEM crap vs Alloy hubs used in accordance with their installation method.
For me as an engineer the whole design is flawed. The ~5mm gaps between halves of the hub allow the plastic to flex. A quick test on this would be to fix the plastic hub to a bench, tie a piece of string around the hub under the lugs and then pulling vertically. You will see the gaps reduce as the pulling forces force the hub inwards in order for the string to pull away. The same effect with a prop. As the dynamic vertical force applied increases the prop forces the 2 halves of the hub to close - and whether or not the lugs are worn, it will pop off. A rapid decent will be the worst case scenario here.
Look, if DJI wanted me to engineer a solution, I would choose the T6061 alloy long before any other material. I have seen some guy (Zac Hary) in the US making copies of the RimTai hubs out of T7075, but T7075 is way too hard for the plastic props and , and T6061 has better all round properties under load.
I just want to point out I don't work for RimTai (lol) but the product they make is bang on. They even minimised the torque vectoring in the lugs by making them slightly wider - reducing slop. The DJI hubs have way to much slop which is also nasty when the esc/motor combo has active braking....
For me as an engineer the whole design is flawed. The ~5mm gaps between halves of the hub allow the plastic to flex. A quick test on this would be to fix the plastic hub to a bench, tie a piece of string around the hub under the lugs and then pulling vertically. You will see the gaps reduce as the pulling forces force the hub inwards in order for the string to pull away. The same effect with a prop. As the dynamic vertical force applied increases the prop forces the 2 halves of the hub to close - and whether or not the lugs are worn, it will pop off. A rapid decent will be the worst case scenario here.
Look, if DJI wanted me to engineer a solution, I would choose the T6061 alloy long before any other material. I have seen some guy (Zac Hary) in the US making copies of the RimTai hubs out of T7075, but T7075 is way too hard for the plastic props and , and T6061 has better all round properties under load.
I just want to point out I don't work for RimTai (lol) but the product they make is bang on. They even minimised the torque vectoring in the lugs by making them slightly wider - reducing slop. The DJI hubs have way to much slop which is also nasty when the esc/motor combo has active braking....
I hate to think that the DJI notification was due to a loss of face (ie someone made a better product that works flawlessly and requires no additional replacement purchases - ever).. It is the Chinese way after all
BTW the reason the CNC alloy hubs would be quieter is all down to flex and balance. As the OEM plastic hub flexes (even 0.5mm) the prop is then off balance with the motor bell housing, and you will get vibration and other strange noises. I agree, the CNC alloy hubs are way quieter and smoother - and better for reducing visual vibration because flex is minimised and the prop stays in true alignment with the bellhousing.
One thing to point out, I know there are some "cast" alloy hubs floating around on the interwebs. Use only CNC hubs. There are so many issues with rotating cast parts, as well as they can be extremely brittle and have internal flaws during the casting, making them even worse than the DJI OEM hubs...
One thing to point out, I know there are some "cast" alloy hubs floating around on the interwebs. Use only CNC hubs. There are so many issues with rotating cast parts, as well as they can be extremely brittle and have internal flaws during the casting, making them even worse than the DJI OEM hubs...
I just hope the wheels turn inside the DJI "machine' and they produce some actual "independent, unbiased" testing evidence to substantiate their notification, because "real world" testing seems to be 1000% against them
Okay, I thought I heard cavitation sounding noises on my QR props that I didn't hear on my screw on props.
I can understand DJI posting something about this as if you look on most Inspire forums, including their own there are many people now saying that switching to the alloy QR hubs is a good idea. With no control over quality this can only be a bad thing for DJI.
The scary thing in all this is seeing the panic spread, considering there's no confirmed reports of the stock hubs causing a crash yet it's amazing to see so many people confidently announcing that the DJI hubs are not fit for purpose.
That being said, we're putting money, people and property at risk when we fly so naturally we're going to be concerned when we read this stuff. I picked up some of the alloy hubs to have a look at and they do seem to lock the props in more securely than then DJI supplied hubs. I'm no physics expert but maybe there's a reason why DJI chose a "self lubricating" material for the hubs with a little play in the fit. Could it be friction / heat related?
The scary thing in all this is seeing the panic spread, considering there's no confirmed reports of the stock hubs causing a crash yet it's amazing to see so many people confidently announcing that the DJI hubs are not fit for purpose.
That being said, we're putting money, people and property at risk when we fly so naturally we're going to be concerned when we read this stuff. I picked up some of the alloy hubs to have a look at and they do seem to lock the props in more securely than then DJI supplied hubs. I'm no physics expert but maybe there's a reason why DJI chose a "self lubricating" material for the hubs with a little play in the fit. Could it be friction / heat related?
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I tend to agree with your comments about pilots panicking and over-reacting.
These hubs and springs are very cheap to buy, so if you are worried about them why not just routinely replace them.
At least your DJI warranty will then be protected!
Can you please explain your comments that Pilots are "Panicking and Over-Reacting" This has nothing to due with this thread. The Discussion is the Statement that DJI made that their is no proof or facts being shared to support their statement.
Aviator I mean no disrespect!
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@Carlo
You have not offended me, so no worries..
I don't believe I am off topic with my comments as I was only agreeing with the previous post.
I think @skylabimaging has stated that he has more than 200 flights on the DJI QR system, so where is the problem?
I would agree though, that if you suffer a crash then the plastic hubs could be more vulnerable than the alloy ones, however, at only a couple of dollars for a set of hubs and springs, why not just keep a few spare for just such an occasion.
That is just my personal view..
You have not offended me, so no worries..
I don't believe I am off topic with my comments as I was only agreeing with the previous post.
I think @skylabimaging has stated that he has more than 200 flights on the DJI QR system, so where is the problem?
I would agree though, that if you suffer a crash then the plastic hubs could be more vulnerable than the alloy ones, however, at only a couple of dollars for a set of hubs and springs, why not just keep a few spare for just such an occasion.
That is just my personal view..
Thanks for the comments, I think there is NO panic or over-reacting whats so ever, when someone takes preventive action to keep their bird in the air that's their decision not anyone else's, I don't think anyone here is purchasing Alloy Hubs to Protect their Bird in a Crash, but the opposite they want to prevent a crash from in the Air from losing a prop due to a faulty hub. also I believe everyone here has a opinion that weather they want to use a certain product or not, I read allot maybe even to much but I can say in this thread no where any one is trying to convenience any from changing to Alloy Hubs, at lease from my prospective. I think this it is good to discuss the Statements that DJI made and some are looking for clarification, So here's a dumb example, if I President put out a statement that says the world is going to fail and every so go to the nearest bridge and jump, do you follow through? there is going to be some people who question that statement for its validity. Until DJI puts out facts to backup their statement I personally will use the Alloy Hub as they are far superior to DJI Hubs. I was sadden to see this statement and wish DJI would come forth, no onto DJI Hubs I have seen proof that the Tabs due wear prematurely and have seen cracked Hubs at the mounting points, this is why I don't want to take a chance since I cannot afford another 3K bird.
Again this is my personal view!
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There are many confirmed crashes because of props flying off. The most notorious one is the Inverted Inspire 1 crash. Do some google bro, and open your eyes LMAO
I think you need to read a little more, the one that went inverted was a fly away that eventually crashed with all props still attached, one was broken due to the crash however. Any other examples where the hub failed?
He might be a while answering your question Paul..
He is deep in conversation with his mate Mr Google LOL
Anyone had any luck finding a suitable torque wrench (that doesn't cost $1,000 USD)?
So it seems reasonable to conclude that any failures are likely due to over tightening of the hub?
I'm starting to think the folks that were hoarding screw on props are looking like geniuses.
So it seems reasonable to conclude that any failures are likely due to over tightening of the hub?
I'm starting to think the folks that were hoarding screw on props are looking like geniuses.
