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1st flight destruction

Discussion in 'Phantom 2 Vision + Discussion' started by walt, Jun 13, 2014.

  1. walt

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    Well I had an awesome first flight. I lifted it up to about 30 feet and was just looking at the screen when a strange noise happened and then it dropped like a rock straight down and broke the camera off the gimbal. I think 1 prop flew off to cause the crash. I did not think this was possible with the self-tightening props.

    I have since purchased another one, but I am trying to find out if this is a common problem or if I just did something wrong. I know I put the correct props on the correct dots, and I spun them the correct way to get them tight. Should I have used the thing to tighten them also?

    Thanks in advance for any help with this so I don't waste another 1300 bucks.

    Cheers,
    Walt
     
  2. Dirty Bird

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    As you stated, the props are self-tightening, and it is not necessary to tighten them with the wrench. It is unfortunate that you weren't watching the Phantom so you would have a better account of what happened. Did the prop come off in mid-air? I assume you have the pieces? Did the prop fracture?
     
  3. benny3878

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    I only lightly tighten the props. On my sixth flight with no issues. But i did notice that it works better if you make sure you have at least 6 sat's and let it hover at 6 ' for a few seconds. Moving it back and forth.

    Yesterday it was windy and it started going in a small circle ( i think it was tying to get back in line ) and kept getting bigger n bigger so i took over and stop brought it back to position ... then everything was great.

    Finger crossed
     
  4. walt

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    One prop was cracked, 2 were fine, and I never found the 4th. It just vanished
     
  5. walt

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    Forgot to add that I did look up when the noise it was making changed. The drone just flopped over and dove like a guided missile to the ground. Battery popped out and camera popped off. The broken prop was right there with the rest of the debris but 1 prop is missing. I looked all over and can't find it
     
  6. Dirty Bird

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    The broken prop you recovered likely broke on impact. I am more concerned about the one you can't find. The fact that it isn't right there, with the rest of the aircraft, supports your contention that it may have came off in flight. You should go back and search carefully for that missing prop. It may contain the vital clue behind your crash.
     
  7. yali

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    There are 2 way that self tighten prop could go off:
    1: it was very loosely screwed on and you did an acceleration followed by a quick deceleration, the prop will fly off.
    2: You tightened it too tight and the prop did not go into the right thread and it ended up torn apart during flight
     
  8. srandall25

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    He said he spun tightened them and didn't use the tool to tighten so i would assume he couldn't have tightened them too tight. I don't think being 'loosely' screwed would have anything to do with it. If it was loosely screwed but still properly threaded, the centrifugal force would have tightened them to what was needed long before 30' high in the air. You mentioned that an acceleration followed by a quick deceleration would cause the prop to fly off.... this is the first I've heard this. I'm not saying it's wrong, but I'm definitely interested in this.. I would have thought that DJI would have engineered the software/hardware in such a way that would make this almost impossible.. i.e. test and identify the force required from a quick deceleration to loosen the prop and control the throttle input via software to not exceed that level of velocity. Has anyone experienced or heard of others who have lost props mid-air due to a quick deceleration?
     
  9. srandall25

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    My best guess as to what might have happened would be that the one prop that went missing, was cross threaded... having said that, if you 'spun' them tight, meaning you threaded it a bit and spun it so it freely spinned on its own until it tightened and stop on its own, then that would be an indication it was not cross threaded... if you manually had to spin it down until it felt tight and stopped, then it's likely it was cross-threaded.

    Can you verify for certainty that you had two black caps and two gray cap props? Did you inspect the threads on the motor of which the prop was missing? Do you still know exactly which motor the prop went missing? If so, inspect it thoroughly. If the threads have a defect in them, then this could certainly cause the prop to have not been properly threaded.. It seems so unlikely to me, but anything is possible.
     
  10. rcfanhi

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    Walt - This is my first post but I've been reading these forums for a while and I want you to know you aren't the only one this has happened to. I bought my phantom about a month ago. After 20+ hours of trouble-free flight time over the 1st 10 days of ownership, I had the phantom hovering at an altitude of about 40 feet and no more than 30 feet away from me flying in Phantom GPS mode when as I'm staring at it, the left rear propeller suddenly went flying off and my phantom plummeted to the ground like a rock. It had only been up in the air a total of 2 minutes during this particular flight. Bent the gimbal arm and the camera up against the base of the phantom rendering it useless. Currently still working with my dealer about getting a replacement camera/gimbal assembly. Other than one missing landing gear screw, the phantom itself was fine. The remaining 3 propellers were fine and like you, I was unable to find the missing prop. Replaced the missing prop and it's been flying fine for the past 2 weeks. No camera/gimbal since I removed it and sent it back to my dealer but I have been able to work on my flying including discovering the utility of flying in Naza mode. Don't pay attention if anybody posts that you must've done something wrong. Putting on the propellers is perhaps the easiest part of setting up this phantom and is virtually idiot-proof unless you're using a wrench to tighten them on because as the instructional video shows, you just lightly spin them on the motor until it stops spinning. I have 2 theories of why this happened:

    1. left rear motor failure/malfunction- because since the motor spins in the same direction that you would loosen the prop, if the motor suddenly stops then inertia would continue spinning the propeller in the same direction as you would to loosen the prop. Theoretically, this could cause your propeller to fly off if the force of the spinning propeller was sufficient enough to overcome the amount of self-tightening of the propeller. This is the same reasoning behind the potential of losing a prop with an acceleration followed by a rapid deceleration as mentioned by a previous poster.

    2. defective propeller - I was never able to find the missing propeller but since the replacement prop I put on along with the original 3 remaining props have had no problems that past 2 weeks and the phantom seems to be flying fine without motor glitches of any kind I've concluded this to be the most likely scenario. This includes testing the previous poster's theory with multiple accelerations followed by rapid decelerations.

    The phantom 2 vision plus is a great little machine with technology available to the consumer at a price point unheard of just a few years ago. But I think they get churned out so fast, there's bound to be some QC issues along the way. For those who haven't had any problems with yours that were not user error, you got lucky. Some of us weren't as fortunate. This is true of anything we buy.
     
  11. yali

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    You can do an easy test on your p2v+: Have someone hold your p2v+ over head with loosely screwed on props, you start motor and push throttle all the way up and then quickly pull all the way down and watch how the props fly off. ( you should stay a safe distance to test this)
     
  12. myvrodrocks

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    Centrifugal force??? Please. It is resistance that causes self tightening...
     
  13. srandall25

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    i stand corrected... not sure why i said centrifugal but you are correct. since you said please, i'll say thank you.. ;)
     
  14. srandall25

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    Copy, during this test, do I wait long enough on the push throttle up (before pulling down) so that ample time would be provided to allow for the props to tighten as it would presumably be in a flight to 30' ?
     
  15. rcfanhi

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    srandall25 - You don't need to do this test unless you want to. As I mentioned in my previous post, after my first mishap of having a propeller suddenly fly off, I replaced the missing propeller and I've done this acceleration followed by a rapid deceleration in real flight multiple times on my phantom and never had a propeller fly off. It was the closest thing I could do to reproduce a condition similar to a malfunctioning/stopped motor when I was trying to figure out what might have happened to my phantom. Albeit, I never tried the method yali mentioned where he intentionally left the propeller loosely screwed on and held the phantom. My own testing confirms to me that the resistance placed on the propeller to allow for flight would be sufficient force to adequately self-tighten a non-defective propeller and exceed the force required for the propeller to loosen itself when the motor slowed down as you decelerate. I let the phantom fly and hover at least 1-2 mins before doing the acceleration/rapid deceleration. Now if the motor suddenly seizes is a different story since I am unable to reproduce that.
     
  16. srandall25

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    Yes, what you say makes sense and pretty much what I assumed. Once the self tightening props tighten, they will not come off during flight with a simple quick deceleration. Key words in that sentence 'once the props tighten'... In Yali's proposed test, I could see the props possibly flying off only if the deceleration action occurred before the props had a chance to fully tighten in the acceleration or full throttle.. and that would have to occur very soon after full throttle as it doesn't take but a second to tighten at full throttle... which is why my assumption would be that the gentleman who lost his prop in mid air, was due to either a seized motor or an improperly threaded prop. The prop would have had more than enough time to tighten from launch to 30'...
     
  17. rcfanhi

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    I wouldn't call it an improperly threaded propeller since the OP said he followed the directions and let it spin on the motor to self-tighten, so I assume he meant he didn't have to manually thread it on and tighten and thus potentially stripping the threads. I would say a properly threaded propeller with perhaps defective/weak threads. DJI has to keep these as light as possible and we're all aware that Chinese made products tend to use the cheapest materials. I accept that. What worries me is that my propeller failed after already having logged 20+ hours of flight time. I fly in both calm and windy conditions. I have to wonder as these propellers self-tighten are they slowly weakening/damaging the threads in the propeller? My motor threads were fine and I wish I could've found the missing propeller to examine the threads. However, all my other propellers have held up including the original 3 that didn't fail this past 2 weeks. So I think it was a defect with that particular propeller. It does scare me that it wasn't an immediate defect though since it's easy to get lulled into a false sense of security.
     
  18. srandall25

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    Yep, in my other post i mentioned that it was not likely improperly tightened if it did indeed spin freely until it tightened and stopped on its own. That indicates it wasn't cross threaded. I highly suspect a seized motor or defective prop thread housing.. perhaps it had a crack in the thread housing or something... It does appear to be a highly unusual scenario.. I've read hundreds of posts and yours and his are the only ones I've read that experienced this issue. I hope that it's similar to getting struck by lightening and that it would be highly unlikely to happen to the same person twice..
     
  19. rcfanhi

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    I sure hope so and that's why I've been flying my phantom the way I have. That way when I finally get my replacement camera/gimbal and put it back on my phantom, I hopefully won't be as worried about it crashing like that again.
     
  20. pyrophantom

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    Touch wood I have had no issues with either my plus or P2V but funnily enough my first flight with the plus I did get a slightly strange noise from the motors reminiscent of flying in breezy conditions with the whine you get when the aircraft is adjusting to the wind, but it was calm conditions, but it had gone from the second flight onwards and I was wondering at the time if the motors were a little tight until run in a bit as they are fine now.

    Anyway im not a hardware engineer so who knows - I know motors should not need running in but they did sound a little tight first off.

    :cool: