Motor Mount Reinforcement Braces

[Mad_angler1]

I2 underwater version = motor mount failure - this is a positive attitude! probably because he had full coverage insurance?

That looks snapped to me not come off ?.

Edit looked again and no actually it does look like mount.

 

[FlyaDrone]

Impact could increase initial damage from disconnect situation

Roostertail has the KISS remedy so far, which I hope provides a solution - a large industrial size electrical tie wrap = common sense approach a light weight, high strength product

 

[Fickert]

Sorry I haven't been on here in a while but I do not think you guys see how the mount is actually attached. There is no area where a zip tie will remedy this situation. The motor mount can still come off with a high strength zip tie attached.

See Below the carbon tube is cut in half on the cross sectional face.

Showing where the only attaching point of the motor mounts are. Held just by an expoxy.

A zip tie cannot possibly provide any additional support as the carbon tube is cut in half.

 

[FlyaDrone]

Most appreciated of your effort to help all of us to better understand the situation. Seems like since you have the motor off it would be a good time to apply some additional epoxy to those intersection points between the motor mount and the carbon fiber tube.

Have you come to any ideas that you plan to implement or just leave well enough alone? Super Glue with the pointed nozzle tip would be just too easy of a fix. But many others have stated that this adhesive would not make a proper bond between these 2 materials. And the LocTite 9460 or 9462 HYSOL based epoxy might be too viscous to properly administer in such a tight access plus bonding surface to get to. 9460 has a faster working hardener than the 9462.

 

[Advexure]

@Fickert Very good insight and thank you for sharing.

@FlyaDrone – In our opinion it is worth mentioning how extremely isolated the number of motor mounting security issues there have been reported. Less than a number that can be counted on one hand. We would not advise adding an epoxy or modifying these mounts in any way simply due to the uncertainty of how that will affect the original construction and materials/epoxy used. My personal insight has always been to not try to fix an issue that really does not exist. If it was widespread then maybe it would be worth a self-modification if voiding warranty is not a concern. Just our thoughts...

 

[FlyaDrone]

Preventative Maintenance? Pilot in Charge is responsible for the safe operation of his aircraft. This is a known issue and what would lawyers be able to present as evidence when a 7+ lbs out of control drone comes down and injures someone? Ignore the problem and it will go away because it is a satistically small number of occurrences? As a dealer of this product my concern would be that one of my customers did not end up hurting someone as a result of product failure due to a known issue regardless of how difficult it was to prove.

Has DJI offered a safety recall?

How many Inspire 2 machines have been sold and how many have fallen out of the air with circumstances indicating or similar to motor mount failure? I'd be willing to say that you nor I have any idea of how often this has actually happened worldwide.

Airframes are exposed to and susceptible to material fatigue resulting from vibrational resonance that affects not only adhesive joints but also such little thought of contact points as solder joints. Ignoring that fact will not make it go away. It really does exist throughout the flight industry and applies to all airframes. Commercial airliners are all routinely inspected for material fatigue resulting from vibration.

 

[Lesmess]

As of today 20th Jan another reported failure, I live in the North of Scotland and hope this is an ambient temperature issue. No chance of the frame work on my drone becoming to hot leading to the epoxy glue failing. On saying that, still a niggling worry as these failures appear to occur with no warning.

 

[bhuns57]

I'm really not sure on this issue at all, I have been watching for it closely and while I have seen a few cases posted is it anymore than usual failure I do not know, it does scare the hell out of me when I do see it but still of all the forums literally seen I think 2 or 3 posted on Facebook, on RCG there are a fair number of I2 users none have seen this, don't think their are any here either ?

Regardless even the fact it has happened at all is not good but their will always be failures with anything, cars and passenger planes are all bonded together these days so is nothing inherently wrong with the method, hopefully what has been seen is just rear QA failure such as bad adhesive or improper setting conditions.

As for the bracket it's a nice idea but my worry is it could actually mask issues beneath, it's much like the P3 motor mount plates, for some these will bring comfort and for others it's no more better.

All I would say is it's worth checking your mounts regularly just to be sure as part of the maintenance schedule I know your all doing .

 

[bhuns57]

Preventative Maintenance? Pilot in Charge is responsible for the safe operation of his aircraft. This is a known issue and what would lawyers be able to present as evidence when a 7+ lbs out of control drone comes down and injures someone? Ignore the problem and it will go away because it is a satistically small number of occurrences? As a dealer of this product my concern would be that one of my customers did not end up hurting someone as a result of product failure due to a known issue regardless of how difficult it was to prove.

Has DJI offered a safety recall?

How many Inspire 2 machines have been sold and how many have fallen out of the air with circumstances indicating or similar to motor mount failure? I'd be willing to say that you nor I have any idea of how often this has actually happened worldwide.

Airframes are exposed to and susceptible to material fatigue resulting from vibrational resonance that affects not only adhesive joints but also such little thought of contact points as solder joints. Ignoring that fact will not make it go away. It really does exist throughout the flight industry and applies to all airframes. Commercial airliners are all routinely inspected for material fatigue resulting from vibration.

I'm really not sure on this issue at all, I have been watching for it closely and while I have seen a few cases posted is it anymore than usual failure I do not know, it does scare the hell out of me when I do see it but still of all the forums literally seen I think 2 or 3 posted on Facebook, on RCG there are a fair number of I2 users none have seen this, don't think their are any here either ?

Regardless even the fact it has happened at all is not good but their will always be failures with anything, cars and passenger planes are all bonded together these days so is nothing inherently wrong with the method, hopefully what has been seen is just rear QA failure such as bad adhesive or improper setting conditions.

As for the bracket it's a nice idea but my worry is it could actually mask issues beneath, it's much like the P3 motor mount plates, for some these will bring comfort and for others it's no more better.

All I would say is it's worth checking your mounts regularly just to be sure as part of the maintenance schedule I know your all doing .

I have DJI prop mounts. It looks like they do the same thing as these reinforcements. What do you think?

 

[pepeticos]

Don't mind the print quality this was done for a quick mock up.

How are you? nice work ! do you sell them or can i have the design to print them myself?

 

[Fickert]

Preventative Maintenance? Pilot in Charge is responsible for the safe operation of his aircraft. This is a known issue and what would lawyers be able to present as evidence when a 7+ lbs out of control drone comes down and injures someone? Ignore the problem and it will go away because it is a satistically small number of occurrences? As a dealer of this product my concern would be that one of my customers did not end up hurting someone as a result of product failure due to a known issue regardless of how difficult it was to prove.

Has DJI offered a safety recall?

How many Inspire 2 machines have been sold and how many have fallen out of the air with circumstances indicating or similar to motor mount failure? I'd be willing to say that you nor I have any idea of how often this has actually happened worldwide.

Airframes are exposed to and susceptible to material fatigue resulting from vibrational resonance that affects not only adhesive joints but also such little thought of contact points as solder joints. Ignoring that fact will not make it go away. It really does exist throughout the flight industry and applies to all airframes. Commercial airliners are all routinely inspected for material fatigue resulting from vibration.

I agree 100 percent here. There is a reason I spent countless hours and may print attempted for these braces that I have so far. Still more development to go imo.

 

[Fickert]

Also I apologize, I have not been on this site much, finally had a message this morning that I spotted with an email notification.

I am glad my illustration was able to show where and why my concern for these motor mounts are. I don't fly over people often which is a relief but flying over multi million dollar wind farms and high voltage power lines from power plants is still a huge concern for reliability.

If anyone is interested in these braces my printer is seeing some down time, and I could start getting a few of these out if desired. I made a small revision for strength on them, and now should be good to go. Feel free to message me as well, usually see those easier than replies to this post.

Regards,
Dustin

 

[pepeticos]

Also I apologize, I have not been on this site much, finally had a message this morning that I spotted with an email notification.

I am glad my illustration was able to show where and why my concern for these motor mounts are. I don't fly over people often which is a relief but flying over multi million dollar wind farms and high voltage power lines from power plants is still a huge concern for reliability.

If anyone is interested in these braces my printer is seeing some down time, and I could start getting a few of these out if desired. I made a small revision for strength on them, and now should be good to go. Feel free to message me as well, usually see those easier than replies to this post.

Regards,
Dustin

I want one ot those Brase, can you print them in Black? how much are they?

 

[Fickert]

I want one ot those Brase, can you print them in Black? how much are they?

I do not have enough hardware for another set at the moment so this would be for just the plastic components. I can go and buy some if you are willing to wait. I can do the plastic pieces themselves for $65 shipped and $85 shipped with hardware. These will be a high end commercial ABS. I can also use a higher end plastic which would be a mixture of Nylon and Carbon Fiber. I only have enough of this though to print 2 or 3 sets at the most. I would sell that for $105 (the filament is $65 for 500g, so it doesn't go very far when you include failed prints and support structures, each set of braces including raft and support structures are roughly 125-130 grams)

I do want to say for the pricing, this is reflective of 200-250 hrs of design and printing I have done to get where the design is so far. Already killed a spool of ABS in the process (about $45 for 1kg for this high end ABS). If prices seem unreasonable please say so but they are based on what I feel has been involved and materials / machine time that has been used.

Lastly,

I also came across another design I had that I am going to look into again when I get home. The current design does not allow clearance in the GP or Drone hanger cases without modification. This other design could remedy that, and so far looks like it will be more sturdy in all. So if you are not in a rush I recommend holding off for me with an update, otherwise I have good confidence the current design I have posted here is very nice as well.

Let me know your thoughts.

 

[FlyaDrone]

Very nice posting! and great design work plus creating the product. My opinion is that you are entitled to the best price you can get if the product performs the intended job. The only other alternative I have found offered is $175 built in and shipped from NZ, they are made out of Aluminum.
DJI Inspire 2 - Feet Clamp

 

[Fickert]

I did see these before, and did like the design. The use of a lever arm is a bit concerning but the aluminum should be strong enough. The only real concern I could see with it is that it can be very prone to developing vibrations on the lever arm. But don't get me wrong looks like a robust design and well thought out. I just simply don't have a CNC machine XD.

 

[FlyaDrone]

@Fickert the total weight of their solution has just now been reported to me via email as 18 grams per corner = 72 grams for the 4 units = 2.5 ounces.

 

[924]

Hey guys sorry been very busy but I did manage to cut back a lot of weight on the braces. Old braces were 47 grams without hardware. The braces that I just redesigned at now down to just 17 grams. So that's good news.

As far as how many failures have been seen I haven't counted. But there have been enough that frightens me to design a brace. Hell I do inspections mostly with my Inspire 2 I at least need some peace of mind.

I do think DJI should fix this I really do. But let's face it. The only way it will be fixed is with the v2. A large price to swallow for just this fix. And I don't have the time to sit back and hopefully wait for something to happen from DJI. They don't care about us professionals let's be real here.

Geraldosansone, certainly when I get to a final concept I am happy with I will inform this thread and we can work something out

I personally will refuse to put a bolt through the arm for two reasons. First the design of the mount and how the carbon tube is cut I fear it would only create more of an issue. I could go more in depth but in short I feel it would break away the adhesive and likely break the carbon tube where it is sectionally cut. Second is I don't not want to monkey with the warranty.

Roostertail, these are the lynh prop adapters but I refuse to promote his products. He does not sit well with me and they are extremely overpriced. There are some other adapters out there I need to find the name though.

Pictures to follow

Safety and preventative maintanance were

Don't mind the print quality this was done for a quick mock up.

Safety and preventive maintenance were the reasons why I opted to replace the stock rattling props with after-market props that are fixed to the motors. For the same reasons I'm very interested in your design - the lighter version. The way I see it, even if they turn out not to have been necessary the cost is well worth the peace of mind.

If there is a legitimate issue - and I think your observations are sound - not having a appropriate option from the manufacturer will be a piss-poor excuse if my aircraft lands on some kid on his way home from school. In fact, if anyone's I2 injures someone due to separation of a motor and a lawyer finds this post it will be easy to make the case that the PIC knew or should have known that this was a risk that could have been averted - either with your product or with another.

Please let me know if/when you are taking orders because I think I'd like to have full sets for both of my I2s.

Don't think for a second that if/when "accidents" resulting from malfunctions happen there won't be lawyers out there scouring posts like this for indications of what might have been a fixable problem that now means PAYDAY. If I was a lawyer that's what I'd be doing. I prefer not to take the risk.

 

[FlyaDrone]

Your concerns regarding legal liability are absolutely correct. However lawyers also target deep pockets. Now I am not saying that with the way DJI treats their distributors and dealers that any of them are getting rich however next up the chain above the PIC is who they bought it from and the deepest pockets are obviously who the dealer got the product from = DJI.

The reality is that no amount of ignoring this situation will make it go away. Another reality from my research is that bonding metal to carbon fiber is a chemical challenge. There are vibrational frequencies which resonate throughout the airframe when in flight which put this bonded attachment under equal or more stress than the torque and push/pull forces. All of this realized by a 180 degree section of carbon fiber that is supposed to be permanently joined, well the results are less than 100%.

If DJI management is smart they might be taking an approach which is built around making absolutely no involvement in dialog from any of their employees while they investigate and implement a solution prior to anyone person being hurt or even killed. While they also plan to replace any valid claims with new machines until a fix is put in place.

The RC community who have built their flying machines for decades have recently recognized the difficulty of bonding metal to carbon fiber. In fact one serious hobbyist has written that he scored some super glue epoxy that **** Rutan uses in his aircraft manufacturing which is purposely crafted for this metal to carbon fiber connection. So from an engineering perspective it is a challenge and I hope DJI gets to the bottom of this soon.

 

[Fickert]

Your concerns regarding legal liability are absolutely correct. However lawyers also target deep pockets. Now I am not saying that with the way DJI treats their distributors and dealers that any of them are getting rich however next up the chain above the PIC is who they bought it from and the deepest pockets are obviously who the dealer got the product from = DJI.

The reality is that no amount of ignoring this situation will make it go away. Another reality from my research is that bonding metal to carbon fiber is a chemical challenge. There are vibrational frequencies which resonate throughout the airframe when in flight which put this bonded attachment under equal or more stress than the torque and push/pull forces. All of this realized by a 180 degree section of carbon fiber that is supposed to be permanently joined, well the results are less than 100%.

If DJI management is smart they might be taking an approach which is built around making absolutely no involvement in dialog from any of their employees while they investigate and implement a solution prior to anyone person being hurt or even killed. While they also plan to replace any valid claims with new machines until a fix is put in place.

The RC community who have built their flying machines for decades have recently recognized the difficulty of bonding metal to carbon fiber. In fact one serious hobbyist has written that he scored some super glue epoxy that **** Rutan uses in his aircraft manufacturing which is purposely crafted for this metal to carbon fiber connection. So from an engineering perspective it is a challenge and I hope DJI gets to the bottom of this soon.

Lawyers will not attack a the monopolizing drone manufacturer as they could afford some of the best defense attorney in the world.

I think the previous post above is correct that the PIC would likely get stiffed by a law suit.

That being said having some protection or at least attempting is better than nothing, on the field and in a court room (assuming worst case scenario).