This is just for everyone's entertainment and to be a bit informative on repairing of front arms (I noticed YT has some good videos on rear arm replacement, but not many on front arm).
Simply story, manual mode, I got over the nervous-stage, became 'comfortable'. And fatigue hit, perhaps (on my 3rd battery without rest). And boom, head on collision to a half-centry-old tree, at a speed around 40 MPH and relative altitude of 2 ft, the groud surface was grass. Sorry that I did not have the video of the moment of the crash (an expensive pitty).
Damage: right front arm broke off (in center m2.5 bolt part was tore off from the arm), cables are fine. Top of the drone's head toke a serius hit so that the metal shield give away and left a dent on the body of coolling fan. The bracket of middle frame connecting to the arm was tore open leaving two 3/4 inch cracks.
Temporary Repair: somehow the plastic material DJI used contain much fiber so that the tear damages exhibit rough and fiber-like connections to each broken piece. With good preparation, cleaning, I was able to epoxy-glue back the part. And supprisingly, the glued parts show fair strength. I tested the assembled arm with upto about 6 ft*lb torque and the repaired arm show similar deflection as the undamaged arm. Of course I wouldn't rely on this fix to be as strong and reliable as before. I plan to only take some casual and low-altitude flights until I get replacement parts.
Repair Tips: I found that the repair was fairly simply, but require soldering skills and some patience. one particular step is threading the cable through the arm. If I thread the cable from motor to the bottom of the arm, it often end up in wrong spot and it was frustrating. A good trick is the feed a wire backwards from the bottom of the arm to the motor side, then wrap the wire to the cable, and use the wire as a guide to pull the cable through. I suceeded on first try!
Follow-up: I will test fly soon and but groud testing, the temp fix is just fine. When the replacement parts arrive, I'm thinking of making a video of front arm repair with the tricks I learnt.
Hopefully, this is entertaining, or helpful. Fly safe, fly fun! EDIT (2021/05/30): Tested the temporary fix with 2 batteries, and from a pilot's perspective, nothing feel different. Some test flight videos are posted below.
I would rate the strength for flight load about 1/2 of original (I did not push too hard on throttle, and the fix did not show any sign of imminent breakdown). But the crash resilience/resistance of this epoxy-glue-fix is only 1/5 or so (I manged to crash it again, a much light crash, roughly equavalent to a 6ft free fall on grass. but the 'fixed' arm broke off again!). Overall, I would view this as only a temporary fix.
Expoxy glue: I used the Gorrilla two-part expoxy with 5-minutes set time. I deally, I would use some 'harder' two-part epoxy with longer set time (30 minuts). The longer set time will usually allow the epoxy to make better contact and bonding to parts surface.
Thanks for sharing your experience. I thought it was very interesting.
What brand of epoxy did you use?
I hope you post a follow up with how well the drone flies with the repair.
Hello there. I am sorry to know that your DJI FPV crashed before and thank you for sharing these information wit us. Since there was a crash that happened to the said DJI Drone before. It would be best to contact our DJI support team at https://www.dji.com/support for us to be able check and assess the said DJI drone. Just a reminder that DJI do not recommend doing a DIY in fixing the said DJI drone to avoid further damaging the said unit and voiding the said warranty of the said DJI Drone as well. Thank you.
Sympathy. I understand your worry. I'm wonder where you have ordered spares (ali?), DJI do not have it in the store witch is not understable for me (sic!). I wonder, how soon there will be third party carbon fibre parts...
Duane Degn Posted at 5-25 18:42
Thanks for sharing your experience. I thought it was very interesting.
What brand of epoxy did you use?
I hope you post a follow up with how well the drone flies with the repair.
Thank you. I used Gorilla two-part epoxy with 5 minute set time. I updated my OP with more info. I will try to shoot a replacement video when my replacement parts come.
DJI Stephen Posted at 5-25 20:46
Hello there. I am sorry to know that your DJI FPV crashed before and thank you for sharing these information wit us. Since there was a crash that happened to the said DJI Drone before. It would be best to contact our DJI support team at https://www.dji.com/support for us to be able check and assess the said DJI drone. Just a reminder that DJI do not recommend doing a DIY in fixing the said DJI drone to avoid further damaging the said unit and voiding the said warranty of the said DJI Drone as well. Thank you.
Thank you for the info. It's always good to know that DJI has support on repairing the FPV.
Depp Posted at 5-25 21:51
Very interesting. Looking forward to the video and it would be interesting to know where you got spare parts. Good luck!
I got my parts 'off the Internet'. I wouldn't specify here, but I think the reply just below you by 'stah' reveals some info. After all, I haven't seen my purchase yet, I don't know whether they are really genuine or copies, so fingers crossed.
stah Posted at 5-25 22:50
Sympathy. I understand your worry. I'm wonder where you have ordered spares (ali?), DJI do not have it in the store witch is not understable for me (sic!). I wonder, how soon there will be third party carbon fibre parts...
Yeah, right. I did order my parts from the place you suspected. But one thing is that I doubt there will be carbon fiber parts for this drone. I think the FPV's design has curved surfaces everywhere, and it is gonna be very expensive to make carbon fiber parts. The cheap carbon fiber parts for other hobby FPV drones are mostly cut outs from sheet materials. If one were to 'mold' a part with curved surfaces, we are looking at super-car body parts prices (wonder why their CF body parts cost so much).
did your replacements already arrived? I'm really wonder about parts quality and any other thoughts. Thx in adv.
I just got the replacement parts a few days ago. I replaced the arm and everything was good now. The quality of the parts seem exactly the same as the original, and they are fully functional. But there's no DJI official box/packaging or QR code or anything like the parts (e.g. landing gear) you purchase from DJI store. Also although the replacement parts seem new, there's some sign of contamination (like glue or dirt or something). I'd assume these parts are from savage drones. Hope this helps.
fans1c3d0833 Posted at 6-21 15:42
I just got the replacement parts a few days ago. I replaced the arm and everything was good now. The quality of the parts seem exactly the same as the original, and they are fully functional. But there's no DJI official box/packaging or QR code or anything like the parts (e.g. landing gear) you purchase from DJI store. Also although the replacement parts seem new, there's some sign of contamination (like glue or dirt or something). I'd assume these parts are from savage drones. Hope this helps.
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