Freefall

A few nights ago I took off to do some low light photo tests.  I flew above an uninhabited construction zone near my house.  I decided the shots would be great if I got the hexacopter to a very high perch so I ascended, keeping it in sight.  The newly installed LED lights made seeing the bird very easy.

I proceeded to shoot photos while leveling off the bird.  Suddenly I was puzzled to see no lights and hear no prop sound.  In the dim light I could see the hexacopter freefalling, and fast.  I’d been flying in attitude mode so I flipped the transmitter into GPS mode quickly.  It was the only thing I could think of.  I could hear the props spin up and the bird hit the air brakes as hard as I’ve ever heard/seen.  In what seemed like only a second or two, the hexa was hovering in place.

I brought the bird down and nervously landed, tipping over in the grass but causing no damage.  I anxiously checked the arms and motors, figuring something had come loose.  The structure checked out fine.  All solid.

I’m glad that the SuperX flight controller I use keeps flight logs.  In the logs many stats are kept from the flight like altitude, speed, heading, motor thrust percentage, flight modes.  The log also shows an animation of the location overlayed onto a google map.  What I found in the logs was quite stunning.

Due to the night flying and the brightness of my LED’s, I’d flown far higher than I had realized or intended.  The bird was at the highest logged altitude I’ve ever flown, 760 feet.  Not only was it much higher than I thought, it was much farther down range than I thought as well.   The fall was a total of 460 feet.  Had my altitude been lower, the bird would have been demolished as I would not have had time to recover attitude.

Somehow I saved the hexa from what was surely to be complete and utter destruction.  I need to get some altitude telemetry and FPV (first person view) installed so I can make sure the copter is safely where I intend it to be.  I’ve flown twice since, very conservatively.  Flights only 60 feet high and perhaps 75 yards down range.