You need to be a member of diydrones to add comments!

Join diydrones


  • Well, a few seconds thought, and I realize the helicopter blades have more mass, and different shaping, making them more capable of being, "flung," into a rotor disk. Lighter blades and sharp pitching on quad blades would likely cause problems.

  • Sam Birch, why not have the blades pivot on the hub, and be able to "fold back" on a strike, like many smaller helicopters do? It doesn't completely eliminate the danger, but mitigates some of the risk. I still think Parrot has a good idea going with protective encasing of the blades. 

  • Lets ban lawn mowers. They are so much more dangerous.

    Your neighbor could fall off! And it could run into YOUR Yard! 

  • @Dan Banks et al

    Detecting that you've hit flesh and stopping the prop before it actually does damage seems like it'd be a hard thing to do, but then if you'd suggested doing the same thing with a saw bench (very high energy and extremely dangerous) I would have said 'too hard' to that too - until I saw this 13 year old piece of tech:

    Saw blades are actually easier to stop since they're quite strong and you can simply crash them into something else to dissipate the energy. Doing that with a heli blade would dislodge parts of it from the heli and send them flying, unfortunately. You may have more luck stopping something lower-inertia such as a quadcopter prop though.

    Another way to improve prop safety would be to add a ring that ran the circumference of the prop. You could still stick a finger into it from the front, but if you touched the edge you'd hit the barrier before getting hurt.

    Yet another possibility would be to keep the blades under high tension and then 'release' them on impact with something so that they folded/slotted away into a lower-diameter unit and took the blades further from whatever they'd hit.

    Or we could start using ducted fan designs where the blades aren't exposed in the first place

    Using anything that has an unshielded, rotating mass is fundamentally dangerous and should be restricted to controlled areas away from yourself or other people. That doesn't mean that we should just accept the danger and not bother to do anything about it. 

  • I sliced my thumb up pretty bad with an 11x4.7 APC prop on my quadcopter about a week ago. The prop went about 1/16" into the top of my thumb and sliced through about 1/4" of skin and 1/2" of nail. Pretty clean slice too, looks like it could have been cut by a razor blade. The wound was deep enough that it got infected. I had a fever and had to take antibiotics to get rid of the infection. This was on about 25% of full power while doing a flight check. Luckily, a week later it seems to be healing up ok, but it was a good reminder that a reasonably sized RC aircraft can be seriously dangerous (both to the pilot and potentially innocent bystanders) and needs to be used with forethought and caution.

    Based on what happened to me, I could definitely see a quadcopter doing some serious damage, especially if it's on medium to full power or flying at a high speed and/or with a heavy payload

  • Dan, I have advocated for a check in the code where, if we are not in Acro mode, and the roll or pitch goes beyond 135° (ie: 45° upside-down) then something has gone horribly wrong, and we should immediately disarm.  I guess others don't feel the same, maybe that there is a chance they could save it but...  the odds that you could save that are extremely slim.  Well, not the the least because you'd first have to clear up the cause of the flight system failure before even attempt saving the copter.  You can't get a copter upside-down accidentally, something has to be wrong.

    The only exception I would make to this is that, say you are doing flips in Acro, lose it, flip to Stab to save it.  Then obviously we don't disarm, but that is relatively easy to protect for I think.

  • @Stefan,

    Cutting power would only be useful for preventing additional damage after an initial collision.  The real damage comes from the energy stored in the spinning rotor, and there is very little we can do about that when an obstruction suddenly presents itself in the path of a blade.

    There is merit, however, to the idea of not making a bad situation worse by allowing a damaged bird to flail about, especially a multicopter that probably has three or more rotors still spinning.

    The logic for detecting a collision and executing a shutdown would not be so simple, however.  An ESC would have to detect a loss of sync with the motor, determine whether that loss of sync indicates a real collision or some other issue, and then communicate an emergency shutdown request to the other ESCs, likely via the flight controller.

    Alternatively, a flight controller could attempt to detect serious deviations from the commanded position or orientation, and initiate a shutdown upon loss of control.

    Both approaches certainly seem possible from an engineering perspective, but consider the consequences of a false collision detection - we have enough cases of quads falling from the sky when we don't want them to.  There may also be situations where shutting down and dropping out of the sky following a collision is more harmful than attempting to recover.

    So really, the worst damage has probably already been done by the time a collision is detected, and a well-intended automatic shutdown system may actually make some situations worse.  A better solution, IMHO, is to always have a pilot with a finger on the kill switch.  And of course, don't fly near people - including yourself.

  • Cheers RD.

    I have children of my own, and this video scares the crap out of me.


    The one time they did come out to the field, they were managed by mum and both grandparents from 10m behind, and behind a wire mess fence.

    It was still the most stressful flight of my short time with the hobby, and I vowed never to bring them again until they're much, much older.

  • Of course, the poor was probably the pilot, not an innocent, so I'm casting false dispertions.


    It's Friday afternoon, it's beer o'clock and the brain is shut down already...forgive me.

  • RL, thank you for posting this. People often think 'It won't happen to me."

    For those of you who are video bandwidth challenged...

    3692770536?profile=original....add to my list PEOPLE!  The pilot probably thought he was being skillful. The cameraman(woman, person?) frequently seemed too close though it might have been zoom lens employment.



This reply was deleted.