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Elev-8 Another Crash — Parallax Forums

Elev-8 Another Crash

trangertranger Posts: 179
edited 2013-10-15 14:57 in Robotics
This time I was up 20-30 feet. The copter suddenly flipped out of control and did a couple of rotations on its way down. It landed on its feet and bounced. Not sure of the damages yet. No props are broken. Some of the landing gear is visibly bent.

This was the second flight of the day. It flew fine during the first. It does show some instability on descent, but I think that has always been there.

Similar situation happened before. Haven't found a cause yet. I checked all the wiring and the ESC settings. Ran thru a couple of batteries on the bench. I can hear a "knocking" sound on occasion coming from one or more of the motor(s). I believe this is always a low speeds. However, none stop or show any visible or audible speed variation.

I suspect an ESC or the controller loses its mind momentarily, but am not sure how to troubleshoot.

After the crash, the green "armed" light was on, so I suspect the controller didn't reset.

I have video and also downloaded the Hoverfly flight log.

Crash is shown here: http://www.youtube.com/watch?v=UBxWTHbfx9Q

Prior flight here:

I'm afraid this thing is grounded until I figure out what is going on.

Hoverfly log: AnotherBigCrash.zip


-Russ

Comments

  • whickerwhicker Posts: 749
    edited 2013-10-11 10:57
    Sorry about your crash.

    If you buy any kind of battery powered wireless remote control aircraft, you unfortunately need to purchase it with the expectation it will crash. repeatedly.

    If I could offer a suggestion: don't blame the part you understand the least (the ESC). I see this time and time again, where the most complicated part gets the most attention.

    Could a wind gust have hit it? (Test: Fly safely indoors like in an empty gym)
    Could radio interference have hit it? (Test: uhh, that's hard to troubleshoot, somebody's keychain remote car unlock could have given it a bad command).
    Loose wiring connection?
    Operator error?

    Many, many avenues.
  • trangertranger Posts: 179
    edited 2013-10-11 11:34
    No wind. Not sure how I would be able to detect a radio interference. I'm using a Hitec Aurora 9 radio with an Optima 7 receiver. I thought loss of communication would result in neutral positions for the sticks.

    Operator error. haha... well I'm not a skilled flyer, but this is so quick that it wasn't me.

    Wiring - the esc connections seem tight. The wiring from the receiver to the controller is tight. I checked all the motor to ESC lead connections before. The ESC leads are then connected via bullet connector to the ESC's and those were checked. I didn't cut open the shrink wrap on the main harnesses. This was the most difficult part of the soldering and I wanted to avoid dealing with it. I'll be sure to check it.

    IF it's not a wiring problem, then I'm left with nothing but complicated stuff. The behavior is very abrupt and dramatic. There is some kind of equipment failure that is only happening intermittently.
  • trangertranger Posts: 179
    edited 2013-10-11 12:14
    Update. Looks like motor 4 is having problems on the bench. I bypassed the Hoverfly so it's in the wiring/motor/esc for that corner. I'll swap motors and ESC's to see if the problem moves. At least now this issue is not intermittent.

    Edit: Swapped 3 & 4 Motors with 3 & 4 ESC's. #4 Motor now runs fine and #3 acts like #4 did. #4 ESC won't talk to programming card.
  • xanaduxanadu Posts: 3,347
    edited 2013-10-11 14:34
    Looking at the crash video I'd say you lost a motor or esc. If your camera was pointing forward I would think it would be the front left.
  • trangertranger Posts: 179
    edited 2013-10-11 16:35
    Yeah, you got it. :smile: Camera is facing forward and front left corner is having the problem. That motor won't run now off of its ESC - it was erratic and notchy on the bench initially. However, it runs fine when connected to another ESC. Looks like the front left ESC has probably failed. I have one on order.

    Not sure why it would fail so soon. There's maybe only 15 or so flights on it.
  • trangertranger Posts: 179
    edited 2013-10-14 12:09
    IMG_2839.JPG
    IMG_2840.JPG
    IMG_2853.JPG

    Failed ESC. One cooked IC, marked (fairchild) P52AD.
    800 x 600 - 97K
    800 x 600 - 98K
    800 x 600 - 53K
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2013-10-14 15:52
    We all know these are Chinese-made ESCs and that one big benefit Parallax wants to offer is support, so I'll see that these are replaced. Please contact Jim Carey jcarey@parallax.com printo and I'll let him know you're coming.
  • ercoerco Posts: 20,256
    edited 2013-10-15 14:57
    Gotta love the Drake.

    And even moreso, Ken! A total standup guy and the number one people pleaser I know!
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