My Crash

Discussion in 'Cinestar 8' started by Gary Haynes, Jan 6, 2013.

  1. Gary Haynes

    Gary Haynes Administrator
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    A couple of months ago I wanted to start an upgrade process for my CS8, moving from MK electronics due to high BL temps flying in Colorado.

    I settled on the HoverFly Pro setup with Castle Ice 50 esc. The weather finally got a bit warmer yesterday and today so I started a series of test flights to really dial in the setup. I was getting little bumps in video, small jerks really, so I started playing with the main gain setting and adjusting the gains for the tilt/roll servos.

    I ran a full range from a gain of 50 to 110 for the primary gain (that's the primary way to adjust an HF board). Between flights, while charging I would review video from the FPV, Sony NEX7 and a Go-Pro I had aimed from boom 5 onto the back of the roll servo to see what was changing.

    Last pair of flights I started at the 110 setting and had moved the GoPro to the top of boom 1 facing forward to see if I could see any vibrations. Flew an out and back pattern that I was using for each flight. Landed and bumped the gain to 130 to see if things got any smoother.

    The result was at the end of the outbound portion I had a loss of control. The attached video shows this last flight, first from the GoPro, then the Sony followed by the FPV camera.

    The ship was nearly vertical doing a classic tail slide and struck on boom 5, driving that boom through the center section destroying my Dean's connector power distribution harness.

    I've sent the HF flight data log over to HF to see if they have any suggestions.

    Any thoughts or ideas as a post mortem appreciated.



    Things I have checked and my thoughts.

    1. Battery was damaged but still showing 15.2 volts when I checked it afterwards. Sounds like there is power if I slow mo the GoPro until the ground strike. You will hear the LiPo alarm trigger, set at 14.4 volts.
    2. HF boards checked ok postmortem.
    3. Broken props on Booms 1, 4 and 5 were broken approximately 1 1/2 inches from the Hub.


    IMG_0769-10.jpg
     
  2. Tim Joy

    Tim Joy Active Member

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    Ouch. That was pretty bad. Sorry for your crash.
    What firmware were you on with the HF?

    You can see your compass going crazy, like mine seems to do all the time now.

    130 sounds like a really high gain. I don't think I would dare to go that high. I'm at 50 on my CS8.
    I've had it happen before that the copter moved a little during arming, and then it flies like a drunk sailor. Since the 360 gimbal when landed has some play, this can happen just from a decent wind. When it gets a bad arming it's as if it's in manual mode on a very low gain setting.

    Seeing that your horizon indicator stops working once the big swings start, I think the HF was very "lost" .
     
  3. Gary Haynes

    Gary Haynes Administrator
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    Thanks Tim. Latest firmware. Dozen flights in the last two days and not indication of problems until... Compass, looking at the log and the rest of the video, was pretty stable on a 125 degree bearing. Consistent with the other flights. I did a compass calibration yesterday and everything seemed to align. Of course if boom 1 is pointed at the moon the compass would be wacky, of course I had bigger problems at that point.

    I was flying at 100 since getting the HF boards based on a starting point of 70 I got from another CS flyer. Tested everything from 40 to 110. Once past about 70 didn't see much difference in the videos.
     
  4. Jason Smoker

    Jason Smoker Active Member

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    sounds like a low battery alarm when you went over the fence?
     
  5. Nick Kolias

    Nick Kolias Moderator
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    Damn, Gary, hate to see this. I don't know anything about Hoverfly but I hope you get it sorted out and you're back in the air soon.

    nick
     
  6. Dave King

    Dave King Well-Known Member

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    Its been crash city this weekend! I feel your pain! I wish I could help!
     
  7. Gary Haynes

    Gary Haynes Administrator
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    Jason, yes the alarm went off. It was about 4 minutes into the total flight time. I have it set for 14.4 volts. On that battery i get a solid 5 minutes and up to 6 minutes, but that gets me down to 20% and I don't want to go any lower. Surprising that those little alarms can be heard even out at 300 feet or so.
     
  8. Josh Lambeth

    Josh Lambeth Well-Known Member

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    WOW Gary! Sorry to see that happen! Hope it won't cost to much to fix!

    Josh
     
  9. Jason Smoker

    Jason Smoker Active Member

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    I have mine set at 14volts maybe your battery was need of replacing? I Hope you get your bird back in the air soon!
     
  10. Gary Haynes

    Gary Haynes Administrator
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    Did some more post analysis. The battery alarm triggered when I goosed the throttle to avoid the fence. It was transient. Last voltage shown on the log from the Castle ICE 50 was 14.2 volts. Battery was about two months old so relatively new. Checked it on the ground, no load, though it was damaged and it still was showing 15.2 or about 20%.
     
  11. Tommy - KnightDesignDev

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    Sounds like the kind of crash(s) that made us change from MK to WK-M.
    Hope you get it back up to speed ASAP.
     
  12. Michal Liska

    Michal Liska New Member

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    I'm so sorry about that crash :(.. Good for you is, that you have lot of recorded materials from the board..
     
  13. Gary Haynes

    Gary Haynes Administrator
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    And total silence from the manufactuer.
     
  14. Brad Meier

    Brad Meier Active Member
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    Customer service is everything
     
  15. Dejan Mugosa

    Dejan Mugosa Member

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    When i see the deans plugs which were probably used for powering esc i must say i have seen better solutions.
    THere are powerboards on market that solve the problems. Well we all learn the hard way but in my opinion this is a poor job if this was a RTF unit. Hope you rebuild it fast.
     
  16. Emanuele Chiocchio

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    Sorry to hear about the crash, Gary. It's always sad when those things happen... and they happen, unfortunately... As said by others, Deans plugs aren't the best solution around: we got rid of them long time ago and now we're using the XT-90 (EC-5s are also a suitable way). As for the power system, if I could give you any advice, based on our experience on the field, I would look at the Herkules III boards with interest: they're incredibly reliable and very well built. There's a lack of information about how to correctly mount and configure them, especially with electronics like WKM, but if you want we're willing to help. Actually we fly a perfectly balanced 16 motors co-axial setup that we're using to test our carbon frame but it's possible to build configs even bigger (not that they're actually useful but for testing purposes).
     
  17. Howard Dapp

    Howard Dapp Active Member

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    Hi Lanzar, which battery connectors do you guys use when you're building those beastly machines lifting 15kg? Thanks
     
  18. Gary Haynes

    Gary Haynes Administrator
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    This happened the first of January. Cause was a defective flight controller. At the time there wasn't much choice for power distribution and the deans were overkill for the purpose since a number of other boards use 3.5mm bullet connections. Battery connectors were EC-5s. I've been running the I2C/MK stack after the quick rebuild. Waiting for the release of the Synapse.
     

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