RCT800 Takes a bath!

It was a beautiful day and a perfect time to make some aerial videos on a sweet marshy part of the Holland River. I wish I had taken some pictures to document the crash but at the time I couldn’t manage it because I was frantically running in a panic! The only real pictures I had of this event are in the Holland River somewhere.

About 2 minutes into a controlled flight my RCT800 became completely uncontrollable (stable mode) and stopped responding properly… while drifting away!! In a panic I threw the RTH (return to home) switch hoping that this function might be able to control the craft when I could not. This caused the RCT800 to start dive bombing the ground before flying up again (like giant Us in the sky). I stood there watching with a feeling of helplessness (and a little horror) for about a minute or 2 until the crash. Anyway, the Holland River really isn’t that big or wide in this area but this was (of course) exactly where my RCT800 ended it’s crazy flight… in the river with a giant splash! You can’t see the river from where I was standing but I saw the splash well enough and started running!! The RCT800 was in the River on the opposite bank from me and 100s of meters away! When I got to the craft some of the props were actually still spinning (slowly) underwater!!

Lost:

  • My Cannon Digital Elf – somewhere in the Holland River by Rogers Reservoir Newmarket. This isn’t a scary river at all but on the day in question it had a good current going and there is a nearby waterfall. Decided not to push my luck too much in the River and couldn’t find the camera from shore when it became detached from its mount.
  • My flip-flops!! There is a mud flat leading up to the River and as I ran for my craft I literally sank up to my thighs in some spots… alas my flippy floppies were claimed by the river bank!!

Damaged:

So far my tests indicate that I’ve got 4 blown ESCs.  I bought the DJI 30amp Opto ESCs so this was an expensive crash (around $80) but given what else might have failed I am pretty lucky. I have yet to receive my replacement parts (ordered) but I should be back up and running with this craft soon. I had also made landing gear extensions from wood; these were completely smashed by the crash but they were cheap and home made so not a big deal!

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The Cause:

It’s a little difficult to know exactly what went wrong when you retrieve your partially smashed helicopter from a river but I did notice one important point;  the GPS mount is made from a fibrous material and the pole seemed a little compromised and bent at one end. It’s not clear if this was from the crash in the river or a prior incident but I think this could have caused the antennae to bend mid flight. This would have caused problems for ALL the flight modes I used while trying to recover the RCT800. Ironically, I did not try full manual mode because I thought it would make things worse and this mode may not have been affected by a bent GPS. You can see the frayed material in this shot.  The next version will NOT use an antenna and the GPS sensor will be mounted flat on the airframe to prevent a recurrence. Also, if something like this happens in the future I will definitely be going for a controlled crash if the auto pilot modes don’t work. In hindsight, I let the craft hang in the air for too long when I still had throttle control and could have put it down (crashed) more quickly. The results may have been the same but hitting the river was a complete fluke!

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It’s really not much consolation but at some point everyone crashes. This makes safety and aircraft maintenance a paramount concern. If my little crash had happened in a busy area it would have been terrifying and dangerous! Anyway, as it turns out no one has more experience crashing UAVs than NASA (they’ve been doing it since the 60s). A little while back they released an e-book about it… It’s called Crash Course and dissects quite a few of their UAV crashes. Cool toys and expensive crashes these guys have!

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