This picture is a frame from a prior FPV flight conducted (safely) by the victim.

http://blogs.wsj.com/metropolis/2013/09/05/remote-control-helicopter-kills-man-in-brooklyn/

A 19-year-old model helicopter enthusiast was killed Thursday when a toy helicopter he was flying struck him in the head, a law-enforcement official said.

This is really sad. I cannot fathom being the father standing next to him.

Pilot culture can appear slightly morbid from the outside. We tend to reflect on and rehash accidents more than non-pilots. I think reflections like this are good for safety culture in amateur UAVs too.

I recently constructed carbon/XPS blade-guards for my 20 lb hex... Sometimes during the tedious machining I doubted it was worth the time.

Some may cite the kinetic energy danger in a helicopter rotor vs. multicopters, but the longer you fly, the more likely it is you'll know someone who's had an accident on a multirotor. The more accidents we have, the more we promote the "drones are usually dangerous" misconception. Consider: this WSJ article has a QAV500 FPV video as it's lead media. Concepts distinct to you and I will be conflated by the public.

Let this incident scare you, and be careful.

I'm attempting to build a 9kg hex that can drop 6 beers on parachutes to people floating between houseboats on a lake.

I need your ideas: How can I adjust the tuning parameters in-flight to account for the loss of 6 x 400g beers, which is 25% of the AUW?

The beers are released by the rotary latch release pictured above. I can mix (copy) this to channel 6 and use the channel to vary something like CH6_RATE_KP along the range of the drops, but this doesn't let me also adjust other valuable params such as stabilization P.
Safety is a primary concern, and I won't fly over my floating friends unless it's rock solid. Safety prompted the heavy structure that is now my challenge. I have a large blade guard superstructure that sits on the floats and serves as a frame for a protective net of thin UHMWPE thread.

It's been tough recognizing the right PIDs no matter how many videos I watch of other people tuning, or how much I practice on Jason's PID sim. My thrust-to-weight ratio is 2.0 with four beers; the flight above was with two.

Compassmot result is <1% and vibration looks OK, right?

I'll skip detailing my design until it's really working, but thanks to everyone for the ideas and inspiration, particularly Robert's offset motor build thread.

I have three days left, so I'm looking for software tuning ideas. I don't have time to reduce the moment of inertia or re-engineer a better frame. I'll leave it at home if it's not ready for safe flight.

Thanks for your help and ideas!

At Maker Faire, Chris said auto-land is a hard problem. While I don't have much to contribute to that yet, I did want to try deploying a ballistic parachute mid-air to bring a plane down. A few others have 
shared successful parachute systems before.

So obviously the parachute shock cord just ripped straight out. The lesson is you can't use that simple paper shock cord mount design you glued into little model rockets as a kid to slow down a 3 pound Bixler mid-cruise.

I am kind of surprised that the ignitor circuit worked on the first try, and that the Sugru + masking tape tube mounting held!

I was also surprised at the pitch moment; I guess I could have computed it beforehand. I didn't think the rocket's moment arm against the vertical CG would cause it to flip forward that much. Also, the parachute was slightly burnt. I should switch to that "dog barf" fiber insulation instead of using recovery wadding.

Here's the pre-fail overview.


If I get around to finishing a lighter and more reliable parachute deploy, I might try using my MaxSonar to detect an approaching object (like the ground) and deploy it automatically.