Warning ! Do not try this.

It has been a couple of weeks now and I'm getting more comfortable with my STABALIZE and LOITER set up on my 3DR quad. Still having some yaw issues but yesterday morning I was enjoying the fruits of my labor out at my local RC field.

In one of my last few flights I was testing the high decent stability oscillation I noticed from way up high about 150-200ft  the props would almost stop while decending very rapidly and I applied power and it would keep level and stop the decent.

I did the stupid phrase with my friends cheering me on and said "hold my beer, and watch this!"

Well, I didn't have a beer. but I'm sure you all know what happens next..........

Took it up to about 200ft and cut the throttle all the way off. It never recovered and hit the ground quite hard.

Not too bright.

I'm up late collecting damage costs to repair and the DIY Drones store should see a nice order monday morning ;>)

Would a log file help?

Watch this.tlog

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  • If you want to stop the motors, first flip upside-down.  Then as it falls, the motors will spin in normal direction and can easily re-start.

  • Hi,

    Yeah its not so good that the motors can stop completely when taking down throttle - because they might just not restart. I have done this stunt 100 times with my MikroKopters - no problem because they idle at zero throttle. The first time I tried to repeat it with my ArduCopter, same result as you.

    I now have set up a mix between throttle and a switch on my tx. The switch adds a little throttle. It is OFF when arming motors and when calibrating R/C. Once armed, I flick it to ON and the motors idle and wont stall again..

    Regards

    Soren

  • Not knowing that this could even happen with the ESC's.  You are a lot braver than i am to cut the throttle in mid-air.  I have had my 3dr quad a couple of months and even in loiter when it starts to drift a little I panic and bring it back. 

  • Developer

    #define MINIMUM_THROTTLE 130 // = 13% of throttle with the throttle stick to lower position (with motors armed)

    Then explained why go with the throttle stick to zero in flight... :-)

  • Damage wasn't too bad. Flew it again the next morning, Happy Easter

     

     

    http://youtu.be/Kx5munuub-g

  • What ESCs are you using? I did this many times with Plush on my hexa and it always recovered... (so far ;))

  • Matter of fact, it's almost a definite the motors would be turning the wrong way.  When you cut the throttle entirely, the motors would have stopped, and auto-rotated the wrong direction during descent.  When doing that, the ESC won't be able to start the motor again, and will probably cut out.  When an ESC does that, it usually won't start up again until power is taken away.

    In this case you piled into the ground before you got to restart the ESC :D

  • Stopping the motors is the problem; hobby grade ESCs may not be able to re-spin the motors again, since at worst they may be spinning backwards from the descent. They have no tachometers and rely on the back-emf from the three wires to time their pulses to get the motor started, and that job gets too hard if they get stopped in mid-air in a multicopter. In a plane a prop would almost certainly always spin the right way, actually helping with the re-start; not so in a multicopter. There have been some videos posted about accidents similar to this, if you want to hit YouTube for some peer support. My condolences. :)

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