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The Drone-Eating Tree

Discussion in 'Phantom 2 Vision Discussion' started by Mark The Droner, Feb 19, 2016.

  1. Mark The Droner

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    The day before yesterday I made a big mistake: I crashed my beloved Vision.

    I wanted to get low altitude footage over the area I've been flying over lately, and the only way to get it low is to do a waypoints mission because low altitude is over the tree line. I know the trees around my property top out at about 120 feet. I also knew the elevation went up about 50 feet on the other side of the farm I wanted to fly to. So I figured I'd start off at 150 feet, giving me 30 feet to spare, and then do a gradual climb to 200 feet using waypoints. I was planning to fly 6800 feet distance straight out and back which I've done before manually. Piece of cake, right?

    So I sent it on its way. And I lost FPV in less than a minute. As expected.

    So... as it disappears over the tree line, I run in to my desktop and check flytrex to see if I can see it on its mission (I do not have a smart phone). And it was there! I could actually see my baby flying across the farm land. Everything is going perfectly. I'm watching it as it heads across the field... and I'm grinning.

    Wait a minute. What's it doing? Why is it turning around??? Wait. What? No.

    Then I get a message: NO LIVE FLIGHT AT THE MOMENT

    Fight back waves of panic, I stare at the screen. Nothing.

    I go outside. I listen. I wait. Nothing.

    Go back inside. NO LIVE FLIGHT AT THE MOMENT

    Back outside. Nothing.

    Inside. NO LIVE FLIGHT AT THE MOMENT

    ****.

    I hit the refresh a few times. F5. F5. F5. F5. F5. F5. F5.

    After a couple minutes, flytrex finally shows me that I have a new flight recorded! It's from today. It's my flight. So I look at it and put it on satellite view, and I can see what happened. It went right across the corn field and just when it was at the tree line, the mission ended. I could see exactly where it ended. I hit the tree line BANG at 27 mph, the craft then went directly backwards, then did a small half loop and ... that's all. It had only dropped about five feet and then the flight ended.

    So I took some notes in my head about the shape of the tree line at that spot and what to look for on foot, and jumped in my truck. Drove a bit, then got out, walked through some woods and then started walking along the edge of the field. I looked in the distance and instantly knew my problem. There was a DRONE EATING TREE right there at the tree line! It was literally a half mile from me, but it was a MONSTER even at that distance. It just towered over the other trees. It stood 30% higher than all the other trees in those woods. It was on the east side of the woods (west side of the field) so it was protected from the prevailing west wind and was allowed to grow to its enormous height.

    Remember reading Peanuts in the comics back in the 60s and 70s? Poor Charlie Brown had to deal with the Kite Eating Tree every March. What comes around goes around and now I am Charlie Brown. My childhood memories have come back to haunt me.

    So I trudged through the snow and frozen corn stalk stubs directly to the Drone Eating Tree, because I KNEW my drone got ate by that tree! I KNEW IT. I went straight to that tree and ... sure enough - there was my Vision - in pieces - right at the base of the tree. The camera/gimbal was laying there, and about ten feet away I saw my battery, laying there, still on, showing three green lamps glowing and the 4th one blinking happily as it faced me, and about 15 feet to my left was my Phantom, upside down, right next to a huge pile of rocks - literally inches from the base of the rock pile.

    Rock pile?

    ****. What are all these rocks doing here in the woods? It's a big pile about two feet high and five feet wide. Then it occurred to me. When the farmer finds a rock in his field, he has to put it somewhere, so he hauls it over to the tree line next to the biggest tree in sight and throws them in a pile. If he ever needs rocks, he knows exactly where they are.

    And I bet my Phantom landed right on that pile of rocks too.

    Mother ******.

    So I pick up the pieces and take it all home (hoping the farmer doesn't take a shot at me thinking I'm a deer).

    I assess the damage. All four props are broken. Broken gimbal arm. Both modded FPV cables are ripped out from the camera, of course, and dangling from the air craft. One cheap-*** linear control antenna sheared at the nub.

    Next day: thorough damage assessment at my kitchen table. I'm missing two rubber gimbal supports. Nice big chip on the plastic silver front of the camera. The little case that holds the compass is open a bit, so I snap it closed. I take a magnifying glass and go over every inch of each wing, top and bottom. Would you believe there is not a single crack anywhere on this aircraft? Even the landing gear is solid. How is that possible?

    Next I open it up. One of the wing tip phillips screws has wood or bark embedded so deeply in it, I had to dig it out with a tiny awl, and still couldn't get it all. But I got enough to turn the screw. Obviously that wing hit the tree pretty **** hard.

    I look at each solder on all four wings. They are all perfect. I look at each plug on all four wings. I look at the solders on the main board. I look at each plug on the main board. I look at the ufl cables on the transmitter board. I check the torque of every screw I can find. Everything is solid. I push all the plugs down anyway.

    Next I look at the GPS module and antenna. I really expect it to be broken. But it's not. The antenna is perfect. It didn't move at all. Wow.

    Put it all together.

    Now the outside. My FPVLR dipoles were a little bent but not broken. That was lucky. My camera still had the SD card intact. My Flytrex Live 3G was unharmed and still had the SIM card intact. I replace the FPV cables to the camera. I had a broken camera gimbal part that I had kept (the little black nub that acts like a hinge had broken clean off on my very first flight last summer because of a bad battery - not my fault!) and I drilled into that and replaced it with a short 3/16 set screw. It worked perfectly! It was the perfect width and length. So I used this newly-repaired gimbal to replace the broken gimbal part with the broken arm. I replaced the two missing rubber gimbal supports.

    Put it all together. Replaced the props. Tested it out. P2V boots up perfectly. Camera goes on perfectly. FPV comes on perfectly. Flytrex boots up and lights up with a blinking green. Perfect. I press record on the Litchi app. It records perfectly. Test the gimbal - gimbal works perfectly.

    I take it outside. Right away it finds six satellites right next to the house - perfect. I start the motors and they all spin up normally - perfect.

    I'm not going to try to fly it right now because I don't have a fully charged battery. But I wish I could.

    Because it's a very sunny day.
     
    #1 Mark The Droner, Feb 19, 2016
    Last edited: Feb 21, 2016
    henick, piccoloflyerr and dirkclod like this.
  2. kirk2579

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    awesome.

    These p2s are actually pretty forgiving and can take a beating. I have had multiple incidents..lol

    I too crashed at speed into a coconut tree on beach and survived. like you all clear till that darn one 50 ' tree behind me.
    picked up , cleaned off and it was ready to go the rest of trip.
    I did have uavbits camera guard and gimbal guard on
    Of course 1 hit in wrong spot....

    You are also one of few I have seen recover drone under that situation that was still usable.. good for you.

    good luck and have fun flying
     
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  3. Mark The Droner

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    It's fun to blame the tree but,

    I know it's my own **** fault. -Jimmy Buffett

    First mistake: I didn't turn on the video. I'm used to it turning on automatically, but because I just changed my litchi app to the newer Litchi For P2 app, the settings didn't transfer for some reason and the video camera never started.

    Second mistake: I should have taken into account that just because the elevation changes to +50 doesn't mean it does it exactly at my end point. And I knew that, but I didn't think of it when I planned the flight path. And that's just stupid.

    Third mistake: I didn't plan on The Drone-Eating Tree.

    Fourth mistake: I never reset my RTH height. My RTH height is 180 ft which is more than enough for close by, but if the elevation is +50, there's not enough spare space. I should have thought of that. Not that it mattered in this case.

    I'm sure I made a few more mistakes too.
     
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  4. dirkclod

    dirkclod Moderator
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    Glad you were able to find it Mark. Been there and they are tough . Hope it fly's well when ya try . :)
    Them tree's do love our P2's
     
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  5. dirtybum

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    Here ya go!

    ImageUploadedByPhantomPilots1456609209.012880.jpg
     
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  6. drquest

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    ^^ That one is my design..... : )

    Sorry about your Vision but it took a pounding like a trooper!... Sounds like that tree has been waiting a long time for it to come by,
     
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  7. Mark The Droner

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    I've already got it up and flying perfect. I didn't have to shell out a penny. The Visions are tough, no question!
     
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  8. dirkclod

    dirkclod Moderator
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    I got away from these :)
    Was in RTH and ya can see when I looked at my screen :eek:
     
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  9. Mark The Droner

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    Wow - nice evasive move!
     
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  10. dirkclod

    dirkclod Moderator
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    Not evasive but lucky as crap .How I made it through that I don't know but that last one would have got me :)
     
  11. Mark The Droner

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    So you clicked the S1 switch 5x and then pulled it up just in the nick of time? The flight is very smooth.
     
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  12. dirkclod

    dirkclod Moderator
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    That was the Standard and when in RTH you can control yaw ,go up or down or just act like a crazy chimp :)
     
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  13. matti

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    How do you check your minimum safe flight altitude?

    Our neighbourhood is flat. I mean FLAT. Ancient sea floor.

    But there are some birch trees around... I set Litchi at 30 meters but I have had a few panic throttle-ups when approaching a drone-eating tree ;-)

    So today I decided to check just HOW tall that wicked tree really is. I set the P3P at 30 meters because Wikipedia claims birch trees are max 30 meters (the national record is 37.8 meters, though :-[ At long-distance I thought I was safe (pic1).

    So I then (foolishly) just ran over that tree. At ground level I was a bit nervous but I thought it was just the perspective.... ...the flight ended well ...but at post (pic2), a few frames of the footage made me wonder if I should set my minimum safe height to at least 35 meters :-|
     

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  14. Mark The Droner

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    Okay you're talking about flying FPV so it's a bit different than my OP which was a GS mission. Yeah, the video is more dramatic if you can fly close to the tops of the trees. So it's tempting to get close as you can. Flying FPV, first I decide whether it's valid to assume that the tops of the trees in my flight area are no higher than the tops of the trees I see on the horizon. With that assumption, I creep up in altitude until I see nothing on the horizon but the horizon. There are no tall trees sticking above the line of the horizon in any direction. So whatever my height is at that point should be a safe height.

    In your case, it looks like you might have a mountain range in the background, so my plan wouldn't work for you. :(
     
    #14 Mark The Droner, Mar 19, 2016
    Last edited: Mar 19, 2016