Problems with "red Colour Props"

[2nd2non]

A piece of scotch tape on the hub works just fine. No glue or complex setup needed. Been working for months. Several on RC forum have done likewise

 

[RobUK]

I was supplied a brand new I2 on Monday this week. Horrified to see that all the blades (white and red) had more that 5mm free play at the rotor tips. Contacted DJI straight away. They fobbed me off and did not offer any replacement blades or blade mounts. Then they said that the loose fitting blades were not a safety concern. Then they said return the helicopter for a refund if I don't like it. I could not believe the response!! At that point, I decided to escalate the matter to the UK flying authorities, the BMFA and the CAA. The letter I wrote is on the "official" DJI forum for anyone who wants to chip in.

And yes, I know that I can "fix" the issue with tissue paper, sticky tape, cyano glue or replacement blades from a 3rd party. But the point is that DJI are shipping a product that is unsafe to fly, and that is dangerous.

 

[Mark Taylor]

Does anyone have any experience that suggests this is a problem under load?

They have been like this since the first deliveries a year ago and while it is noticeable when static on the ground, I've yet to see any issue in flight...

I'm surprised to hear that the white props are showing the issue now though, all my white ones are if anything a little too tight, it is only the reds that are a little looser than I'd prefer...

 

[RobUK]

Yes I have experience from flying other helicopters and drones, that under load if the props are loose there is much vibration and instability especially when hovering. Also you can see the wear being caused by the vibration while in flight because there are plastic dust deposits on top of and inside the motors, from where the blades and blade mounts are rubbing against each other. I have had blades fracture at the roots on previous helicopters due to play in the blade grips. I am not going through this again on a helicopter that has just cost me over 6,000 Euros!

 

[NickU]

Being perfectly honest, I don't think you've anything to worry about

Since getting my I2 at the start of the year it's clocked up 317 flights with nearly 70hrs flying time and 447miles flown. I'm sure there'll be others on here that'll have clocked up far more than that without issues too.

Living up north, some of those flights have been in pretty strong gusty conditions, and in very cold conditions, and some at speeds up to 76mph. Despite all that, my I2 is still on it's original set of props and mounts and so far they're not showing signs of stress (and yes I do check them regularly). I'm only just beginning to think about possibly retiring the props.

 

[Mark Taylor]

Yes I have experience from flying other helicopters and drones, that under load if the props are loose there is much vibration and instability especially when hovering.

I suspect you are just in the same state of mind that the rest of us were in a year ago when we first got the I2...

Many of us have flown other helis and quads and were similarly concerned when we first saw the problem, but we see no sign of vibrations or instability in flight over many, many flights and hours of air time.

That said, I'm not seeing any dust or other signs of unusual wear...

 

[jhardway]

I was supplied a brand new I2 on Monday this week. Horrified to see that all the blades (white and red) had more that 5mm free play at the rotor tips. Contacted DJI straight away. They fobbed me off and did not offer any replacement blades or blade mounts. Then they said that the loose fitting blades were not a safety concern. Then they said return the helicopter for a refund if I don't like it. I could not believe the response!! At that point, I decided to escalate the matter to the UK flying authorities, the BMFA and the CAA. The letter I wrote is on the "official" DJI forum for anyone who wants to chip in.

And yes, I know that I can "fix" the issue with tissue paper, sticky tape, cyano glue or replacement blades from a 3rd party. But the point is that DJI are shipping a product that is unsafe to fly, and that is dangerous.

I agree with this post, very well put and I feel the same, I do not like the looseness, it to me is programmatic, Having everything tight in the motor, motor mount, props, arm, etc... makes a difference in flying and although it may not be dangerous, to me eventually something with a loose component will show a problem before one with everything tight throughout. For me the quick fix is cutting a small piece of electrical tape and lay it across the top motor where the prop fits on, for both white and red blades but i have to stay on top of it mainly because they do wear out.

I am not surprised however disappointed that DJI has not fixed the issue here. Although they are doing well business wise, the day will come where this type of practice will be the downfall for them. I will say i am happy with their products to date but not the support, and it amaze's me how they have not made that a priority to help in making the company that much better.

best all

 

[RobUK]

Thanks for your replies Nick, Mark and JHardway. I'm not sending my I2 back to the supplier because of this. Yes, like all customers encountering this problem, I'm disappointed for any design flaw to exist in a machine this expensive. I'm fixing the problem myself in fact by modifying the stock propellers with cyno and keeping those as "spares", and also buying a set of after-market folding propellers. But I want DJI to resolve the problem instead of pretending that a design flaw does not exist.

 

[TheGrumpster]

Just remember, Rob, in China, flaws do not exist. Seriously. I've had to deal with this BS from my suppliers there for two decades now. You can get decent quality out of China, but you have to be absolutely ruthless about it and call them out on every last little thing because they will cheat in every possible way.
Now as to the props, I agree with you that the looseness is bothersome. There is no way you are not losing aerodynamic efficiency as a result of it. But I've flown something like 1000 flights on the I2 (and crashed twice) and never had an incident caused by loose props. Not indicative of a high-quality product, however.

 

[RobUK]

Well, I just fixed the non-existent flaw, using virtual cyano, and filed the cyano down to a virtual perfect fit. Here's a picture of the production run, the picture of course being virtually in focus ...

 

[RobUK]

The "red props" were the worst with 6 mm of movement at the blade tips originally, now 0 mm of movement. The cyano applied on red blades hardly needed any filing at all to ensure the perfect fit. The "white props" had 3 mm of movement at the blade tips originally, again now 0 mm of movement. The cyano needed three or four strokes of the nail file on the "white props". I believe that my props and I2 were the "latest generation", because looking inside the props, there was a layer of foam, and I understand that first generation props did not have the foam insert. But the foam is doing nothing at all to solve the blade vibration problem, because the foam is not stiff enough. Since these props are made in a set of injection moulds, the "fix" would be for DJI to remove material from the injection mould itself, to allow 0.3 mm more plastic compound on the bottom of the "red" blades, and 0.15 mm more plastic compound on the bottom of the "white" prop blades.

 

[Sligeach]

The "red props" were the worst with 6 mm of movement at the blade tips originally, now 0 mm of movement. The cyano applied on red blades hardly needed any filing at all to ensure the perfect fit. The "white props" had 3 mm of movement at the blade tips originally, again now 0 mm of movement. The cyano needed three or four strokes of the nail file on the "white props". I believe that my props and I2 were the "latest generation", because looking inside the props, there was a layer of foam, and I understand that first generation props did not have the foam insert. But the foam is doing nothing at all to solve the blade vibration problem, because the foam is not stiff enough. Since these props are made in a set of injection moulds, the "fix" would be for DJI to remove material from the injection mould itself, to allow 0.3 mm more plastic compound on the bottom of the "red" blades, and 0.15 mm more plastic compound on the bottom of the "white" prop blades.

This might fix it, but it will only be temporary. My white props had no play when I got them, but now they have a fair bit of movement, as have the red props, although I used the ‘super glue’ fix in the past. I have to fix them every so often.

 

[NickU]

That's all part of the problem with this design of props - it has to have some slack to be able to be mounted & dismounted. And the very act of dis/mounting wears the plastic. The foam insert inside the hub simply reduces the noise a bit at lower speeds.

I'm surprised they didn't use the type of 3 point QR mount they used on the Phantom 4's, with a lower leaf spring to push the prop up against the mount, but them I guess the blade size and forces on the props during heavy braking and manouvering might have led to the props uncoupling. I'm not sure what they're using on the M200 series as that seems to be something similar'ish to the Phantom design?

 

[RobUK]

Yes the blades wear in use, making this design fault even more critical. Why can't DJI provide a QR clamping mechanism with an adjustment knob or screw to compensate for wear or loose blades? It's It's not rocket science to fix this problem.

 

[roblevine]

I had the rattling with one of my red props. It sounds like there is something wrong with the motor but it is definitely the prop. It's incredible how tiny the amount of play is to cause all that rattling. I put a small strip of black vinyl tape under the prop on the flat part that contacts the mounting shelf. No more rattling... no problem locking the prop either.


Sent from my iPad using InspirePilots

Hey do you have a photo of that?

 

[roblevine]

I just noticed my forward red prop had the issue mentioned. I have flown my bird for a little over an hour and the rattling did not cause any noticeable vibration or unusual noise in flight. However on the ground I noticed the slight play (very slight) and when I turned the prop by hand it made the rattling sound... so I put a small piece of foam into the propeller, underneath where the top nub is and it seems to have fixed it. Hopefully DJI can provide a more permanent fix since as others mentioned, this should not be occurring on such an expensive piece of equipment.


Sent from my iPad using InspirePilots

Can you post a photo of this?

 

[Advexure]

Hey do you have a photo of that?

This is a DIY fix we've seen/heard people have success with. May be similar to what this user did.

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[Raymondo]

Interesting that there is so much about Red props. On my I2, it is the White props that have sloppy fittings. Using tape to pack it at the moment, but would rather I had correctly fitting mounts.

 

[bbad2k2]

I try to be as professional as possible (Safety, Part 107, CRM, good equipment) but this just ridiculous. I buy a new, high-end piece of equipment, put 4 batteries through it and lo and behold, the props are wobbling around like a carnival ride. Inspire grounded. Back to goto Typhoon H and P4. No response from DJI so I go through the fixes online from other pilots: tape, glue, toilet paper, folding props, spit, hope, maybe this, maybe that…..come on. What is wrong with this company. Poor customer service and English so bad that there is miscommunication. You don’t want bad comms when you’re in the business of flying machines through the air. The DJI CEO guy, a Frank Wang, who keeps spouting off about poor Chinese quality and how DJI is trying to lead with a difference doesn’t seem to get it or there would be factory fixes for this, and forthwith.

The problem is the red male hubs are too small. AC-20-37E, the Advisory Circular for props on real planes says “any unusual free play, and odd sounds” affects airworthiness. Is this issue "unusual"? Any AP would laugh at the matter and stand clear. I am going to stick with grounding the unit until there is an official fix. This thing is not a toy.

I’ve done the super glue/sand on prop base and the vinyl tape method on all prop sets and it seems to work, but I am not going to stitch together my flying-machine like MacGyver and hope for the best. So there you have it: a $3000.00 tree limb trimmer.


xièxie DJI

 

[jhardway]

I can not agree more and I played around with the fixes for a while, I would cut little strips of electrical tape for a year or so, it worked pretty well but i just go ties of it and ended up buying a pair of XOAR CF self tightening props.

No issues and putting them on takes just as long time as if you would doing the standard locking props.

Best