Hi Mike,
Please don't think me rude for chiming in here. I'm a new pilot with DJI, but a RC Veteran as a whole, and HATE to hear such stories and am compelled to try and assist.
18 years in the IT industry has taught me that the obvious is more times than not the cause of most issues. It's simply overlooked because it is indeed obvious.
If you haven't already resolved this satisfactorily I would like to offer up some suggestions.
1. Are you flying / crashing in the same area or geographical locale? If so, from what you have described it sounds like you are losing not only GPS assistance but you may also be suffering from actual flight platform radio interference. (I also have a digital electronics background). From what you have described, it also sounds similar to some symptoms of "Geo-Fencing" , or even a malicious "Scrambler" that may be intentionally forcing your craft out of control.
Being a 10-year disabled veteran of the United States Air Force, I can tell you that
if you are indeed in the neighborhood of any SIGINT activity that you should cease and desist attempting to fly in those areas. I can almost guarantee you that this is your problem. They are most certainly detecting you're drone (not by radar but by frequency signature), and even if they are taking no action the resulting SIGINT EMI and excessive radio interference may unintentionally be scrambling you're on board system operations. There is also the possibility that the temptation for a "Bored Signet Interpreter or Operator" to scramble and down your bird may just be too great for him or her to resist. I have first-hand knowledge of the people who work with these systems and I can tell you that is not beyond the realm of possibility at all; we used to do some pretty stupid stuff in the Military to kill boredom.
In their defense, there may also be a distinct possibility that the radio emissions from your flight platform may be interfering with their operations , which would result in the same action.
Other potential signal interference to your platforms include many clubs and organizations that are
very much anti-drone, and they advertise and sell everything including downloads to free software, inexpensive equipment that can actually be pointed at a drone and scramble your drone, or upper end equipment to even Hijack your drone despite encrypted precautionary measures that could result with the exact same effects you have described.
Unfortunately there are those out there that seemingly feel obligated to ruin what is harmless fun on our part.
2. I would assume after this many mishaps that you most likely have enough parts to cannibalize and create one good flight platform.
I would be glad to offer my assistance with this , and subsequently give you some help in getting a platform that you can use to establish a Baseline in another geographical location verifying no such activity hopefully without mishap and not having to buy a new drone only to crash it again.
3. There are also some modifications and shielding precautions available on the Forum that you can take that will not only assist in better GPS reception/Satellite links, but also provide a certain level of protection against EMI and any other forms of intentional or non intentional interference. What and where depend on your model. I actually purchased enough copper shielding and some templates for under $10 taxes and shipping included to do just that as I live in a VERY Electronically Congested Area and it has helped immeasurably.
4. Addressing the issue of propeller loss due to "braking", have you ever found a wreckage with the propeller missing? That of course would be an obvious Tell-Tale sign. It would seem to me that you would have to lose a prop completely to lose total control for a sustained period.
Please feel free to reply to me directly as I am very curious with regards to your situation and how you resolve it or if you have already resolved it. Also if you would like to give me the actual geographic location of where your losses occurred, I would be more than happy to use my contacts to query the said signal intelligence activity agencies in the area (which are most likely operated by Air Force personnel) and perhaps even get unofficial verbal confirmation of a policy to actually ground drones operating in their area if drones are causing interference to their operations.
You don't sound like you are that totally inept that you would, due to your error, actually crash 3 drones successively without exception. The odds are against it and defend your intelligence!
Hope I can be of some help!
Best Regards,
A.J. Lebeau
Computer Network Systems Administrator/Engineer
M.C.S.E., M.C.P. + I., M.C.P., CompTIA+
[email protected]