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FC40 first hard crash, what now?

Discussion in 'Phantom FC40 Help' started by llindeen, Mar 23, 2015.

  1. llindeen

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    I have had several great flights with my FC40 but wanted to go to "the next level". I got the walkera G-2D gimbal, tilt lever, and gopro 4 installed and balanced pretty well. It was windy, probably too windy for the first flight and I put it into a tree... broke two of the carbon fiber props.... I am wondering what I should do now post crash to make sure it's ready for the next flight and what to change to help make it handle better.

    Observations:

    1) The extra weight of the gimbal + gopro make it feel front heavy. When I took off it almost tipped over before gaining altitude and flew out out and up instead of straight up like before.
    2) It seems to drift and not hold its position well in GPS lock mode ( It was pretty windy that day, 9 mph and gusting to 15 mph)


    Change Factors:
    1) Extra weight
    2) New carbon fiber props 9443

    Build
    Phantom FC40
    Carbon Fiber 9443 props
    Walkera G-2d gimbal (metal)
    gopro hero 4 black
    stock 3s 2200 mah LiPO

    On order:
    More rubber cushions (lost one in the crash)
    Phantom (9450 props)

    Diagnostics ran:
    Gimbal works fine still
    All four motors turn and arent grinding when powered (yay)
     
  2. IflyinWY

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    IIindeen,

    Welcome to the party. It's a wild and crazy ride, hope you have tons of fun at it. :D

    Do we get to see your tree landing? Those moments should be few and far between, we hope.

    Prop guards, for the P2, since you are using the 9 inch props. ;)
    9450 props are great.

    When you open your bird to inspect for damage from the crash, you should do the IMU thing.
    When it tells you it's waiting to cool down, just ignore that and try again. It's a stupid built in glitch. ;)
    Any time you make a change you should do an Advanced IMU Calibration. http://www.wynotweb.com/Advanced_IMU_Calibration.html
    And the Compass Dance.

    If you do those two things and have DJI props, you should be fine. You will certainly be much better off than you were.
    Yep, it's nose heavy now and will try to run forward on liftoff. As soon as it figures out that it's traveling, it will correct itself. Hopefully there's nothing in front of it when it lifts off, or else... :eek: and then :cry:
    Some folks like to punch it on takeoff and climb rapidly to about 10 feet. That does work pretty well.

    Have fun :D
     
  3. dirkclod

    dirkclod Moderator
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    +1 on the take off ! Don't play just get it up quick !!
     
  4. llindeen

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    Thanks so much guys! What a great forum! I flew my Phantom fc40 today with the new 9450 props and some slight gusty winds 7-10 MPH. I also flipped the walkera base plate around backwards which moved the gimbal and gorpo back about 3/4 of an inch. It still lurched forward on take off but only 3-6 inches instead of 3 feet. It still flew a little shaky in the air. But with that much wind and weight I cant expect to be as agile and super smooth as before I am guessing. I also noticed that as the gimbal adjusts it shifts the weight too, further playing with the handling. I did bring it in very close to my garage to eliminate as much wind as possible and it seemed to stay almost perfectly level in GPS mode. I even did a complete access spin and didnt notice much if any drift! I half wonder if my problem all along was the gopro being a bit too far forward and not doing an advanced IMU and compass dance after adding all that weight. When I went into the advanced IMU the software even said, "Ummmm you need to do calibration you are WAY off". I didnt have a level just set it on my nice amish table and let it calibrate. All the numbers then came back within the DJI recommend values. I will do another IMU after I order a spirit level.

    I do notice when filming I can see my props and even the tips of the arms when filming straight ahead... I am guessing this is normal behavior due to camera position and the wide angle on the gorpro. I am sure pointing the camera slightly down would help too.

    For those interested I will post both flights... the epic fail and the flight afterwords.... especially the yaw spin for pointers on if things look like they are flying right to the expert eyes on the forum.

    THANKS AGAIN FOR THE AWESOME HELP!
     
  5. IflyinWY

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    Hey IIindeen,
    Any updates for us?
    7 to 10 mph of wind is nothing. You should be good up to 20 without any issues. Some folks, me included, go more than that, just not a great idea until you've got some experience, in my opinion.
    If your bird is spinning on a dime, I wouldn't do another IMU calibration, until you change something. You're welcome. It really helped that you provided so much info right off the bat.

    Now, where are those videos? :D
     
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  6. lake_flyer

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    The carbon props are less forgiving and snappier in GPS mode with wind and yawing. And they break pretty quickly when tipping over. Hand catching is even dangerous with CF's.

    If you like the looks just die or spray original plastic 9450's black. You don't even have to calibrate them after that. I didn't, after spraying them satin black with yellow tip markers, they were just as good.
     
  7. llindeen

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    Ahh yes, I forgot to deliver.... It does fly some better now but it still doesnt stick in the air anymore like it used to... I wonder if something was damaged in the crash and I cant see it. Maybe a slight bend to the frame or something. if I make it spin on a dime it spins but more of in a 2 foot circle.... not right on axis like before. It seems to get caught by the wind and get pushed around a lot easier. Is this just due to the extra weight and the gimbal shifting around changing the flight characteristics?


    BTW I am using the 9450 props now as well. I havent edited any video yet of flights after calibration. I also went and got a long bar level that balances perfectly on the posts with the props off. I get level on both axises with some business cards and did the advanced calibration. It seemed better but still doesnt stick in the air like it did with the stock camera.

    Is there any video I can shoot and upload for help diagnosing my flight problems... or more likely me just expecting identical behaviour and having realistic expectations of it handling the same now that I have over 200G more weight on it with the gopro 4 and the gimbal.

    Here is the promised crash video in glorious 1080p.

     
  8. llindeen

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    Where at in Wyoming? I was born and raised in the cowboy state, in a little town north of Laramie.
     
  9. dirkclod

    dirkclod Moderator
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    Why he's where the deer and the antelope play ;)
     
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  10. IflyinWY

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    Hey Lindeen,
    Bravo on the video, great music too. ROFLMAO

    I'm up near Buffalo. Well, if you're from Medicine Bow, you're the only person I've ever heard of who left there.

    You're still, or again, getting some pretty good forward motion at lift-off. Take a look at how you have the gimbal mounted to the bird and see if you can move it aft at all. The closer you get the gimbal mounted to the center of gravity/center of the bird, the better for weight and balance and stability when maneuvering. Your 2 foot circle may be due to the weight being forward. If you are able to move the gimbal back to the CG, you will then have your shots framed by the landing gear. A little farther aft should help though.

    1) What model gimbal do you have?
    2) What elevation do you fly from?
    3) Why don't you head for some open space and give yourself and the bird a chance to get better acquainted with each other?
    4) Can you post a pic of your setup?
     
  11. llindeen

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    1) Walkera G-2D metal (may get the white to save weight)

    2) 900 foot elevation

    3) In an open field I notice it still drifts quite a bit almost like in atti mode

    4) Here are the pics. I got some after market wide landing gear. You have to pull the compass off the old stock gear. I wonder if it isnt perfectally horizontal and that is also causing my drift.


    image.jpg
     

    Attached Files:

  12. IflyinWY

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    You may want to go back to the original gear for a test with the compass in its original location.

    Do you notice any improvement after flying around for 5 minutes or more? I've watched a video of a Phantom which hooked left quite a bit when first flown. A few minutes later the hook was reduced and a few minutes after that, it was gone. I'm not sure if this is the same issue or not.

    Sounds more like IMU or Compass to me, but could be the GC being off due to your gimbal and camera. I can't tell from the pic but it looks to be pretty well centered which would eliminate the CG issue.
     
  13. llindeen

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    Yeah I wam going to try the stock legs again and do an advanced IMU calibration again. Looking at the legs it doesnt appear the compass is 100% straight up and down. Does that matter much or just that it is super secure?
     
  14. IflyinWY

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    I wish I knew the answer to that question. Your going to have to experiment or wait for someone smarter than me to reply.
     
  15. llindeen

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    Thanks for all your help IflyinWY... You have been very helpful. Its a great forum with some great help that I really appreciate!

    BTW I didnt live in Medicine Bow, I was 15 miles away in Rock River. Went there all the time for gas and groceries.


    I think I may know the flight issue too... Take a look at this pic. I noticed my gimbal was slightly bent from the crash and I noticed that the way I head was CLOSE to center but now the gopro is EXACTLY center.
     

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  16. mark99

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    I always start the props and pick up the fc40 carefully and with one hand let it take off away from my hand.
    Some of the later models do appear to duck on take off power regardless of what you do