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Could it be a fly away cause?

Discussion in 'Phantom 2 Vision + Discussion' started by quadcopter, Jul 1, 2014.

  1. quadcopter

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    Ianwood said:

    Any prop that is a CF copy of the stock prop is a almost guaranteed to be problematic. The stock blade works well because it flexes. It has an aggressive pitch and the flex helps to keep it from losing laminar flow in turbulence and hard maneuvers. Take the flex away and you have a prop that is too aggressively pitched for the P2.

    I had a flight where I ran my p2+ into a tree branch. The p2+ immediately took off! pretty much straight up ( about 300 feet up) and away. I was sure I was experiencing a fly away moment. I turned the Tx off and the copter was fighting real hard to come home. I finally got it to about 30 feet over head and it just laid over to one side and crashed in my neighbors yard. When I picked it up the front port blade was missing about a half inch of its blade. I found the piece across the street from where it crashed at the tree it hit.

    The p2+ was really out of whack and unbalanced . I'm sure the imu was really struggling to compensate for this damaged prop.

    My though is that maybe some of these fly aways are due to prop failure, I don't know "losing laminar flow" due to fatigue or using aftermarket product and if the prop fails maybe she just can't overcome the aggressive pitch. Thought?
     
  2. quadcopter

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    Wow, not one opinion :shock: that is odd on this site but I guess my thought was kinda out there but worth discussion. Thx for reading...
     
  3. JWarren

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    Sorry amigo, I didn't see this thread until now. I have an interest in fly aways and that interest would be avoiding them. So any thread that has it as a subject always gets my attention. I think you have a good theory but don't most fly aways happen with the aircraft taking off like a Babe Ruth home run out of sight? I don't think you'd get that far with a damaged prop. Good idea though and who knows?
     
  4. Great Pumpkin

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    I've flown my P2V with chipped DJI props - no problem, but they were small chips. On the other hand, is it possible that many of the crashes and fly aways we read about after many successful flights could be due to one of the 4 motors finally failing or at least not putting out as much power as the other three? Does it make sense to replace all four motors after some number of flights?
     
  5. tch1972

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    Carbon props suck. Period. The end.
     
  6. kitesurferpete

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    as with a lot of things that work out of the box. mess with it and they screw up.. if it ain't broke, don't try and change it.
     
  7. Meta4

    Meta4 Moderator
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    If crash damage to props was a factor you would expect it to be mentioned in reports as it should be an obvious relevant point.
    To date I haven't seen a lot of talk about it.
     
  8. Dirty Bird

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    The aircraft flies so well with the stock props that I've never seen a reason or need to upgrade.
     
    doomclam likes this.
  9. quadcopter

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    Exactly, what if a prop fails, not breaks, but fails in a way that is loses grip on the air. I don't know, from a quick manuvere or a wind gust. Would that not be like a motor failure. The bird would obviously lean to that side and the engine would probably rev higher in rpm but what if it could not overcome the loss of lift. Would it just lean and go?

    I have first hand experience with a badly damaged prop (lost 1/2 inch after hitting tree) and let me tell you. The P2+ just flew away. I was doing nothing but watching it gain altitude. I finally initiated RTH and it struggled and bounced around and I finally was able to crash it next door.

    I hear a lot on this forum about staying away from after market props and carbon fiber props so it was just a thought.

    I have not heard of anyone recovering their fly away and having prop issues but if mine flew away and I recovered it in one piece :lol: I would definitely change all 4 props....
     
  10. quadcopter

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    But how do you know. If it crashes and the props are damaged you would assume they were damaged when it crashed. When mine acted like a fly away my initial reaction when I picked it up,was the prop was damaged when it crashed. It was only when I went the next day and searched around the tree I hit that I found the piece of prop. 100 yards from where it crashed..
     
  11. AndysAdventures

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    They "suck" out blood apparently from what I've seen on YouTube. :eek:

    I was hand catching my P2V+ after every flight, I'll stick with the flexible DJI props.

    (I crashed my + in to a tree branch. Partially my fault, partially my dog lunging for it while attached to my belt. Easily sold the old one for $800 and have a new one on the way.)
     
  12. sergekouper

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    Wouldn't it be the shock with the tree that messed up your IMU or your GPS? (Gps I don't think so since it came back) But to me it's worth a check in the assistant.
     
  13. Gizmo3000

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    well prop failures are no fun, that's for sure.
    but as mentioned, are definitely not the cause of a fly-away.
    prop loss or damage usually results in the Phantom becoming unstable and then tumbling/tossing and turning towards the ground.

    definitely no need to replace props if you encounter a fly-away either (since they're not the cause), but always good to inspect and replace any visibly damaged props
     
  14. Mori55

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    I really think a lot of theses flyaways are gps intereference related. I think dronexpert is on to something with their video on sheilding the gps.
    Not all but some , you can't tell me if your flying in gps mode and it drops out and your pretty far away , your not going to be disorientated and not even sure what direction your flying ? So I can see a lot of newer pilots calling this a flyaway.
     
  15. vagspel

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    Hi,

    I had a long talk yesterday with a friend who works at True Heading (http://www.trueheading.se) with AIS transponders.
    AIS transponders get their position from an on board GPS and he told me that normally it takes around 6 minutes for the GPS to read down the almanac.
    From what I understand DJI technicians are very clever guys so they must have figured out a way how to solve this. How?
    It would be nice if there was a flag in the app showing when the satellite fix is valid. In the GPS string coming from the GPS there is such a flag.
    Showing that you have 6 or more is not satisfying if the data coming in is not valid unless the 6 is only shown when the data is ok.
    //gunnar

    Attachment: Specs of the RMC data that DJI might use for their GPS. It could also be GLL or GGA!?
     

    Attached Files:

  16. Phantom_Menace66

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    I intended to reply when I stopped laughing.... How on Earth can props be the cause of fly-aways, irrelevant of what they're made of?
    I switched to CF props months ago and have never had a problem with them and clocked up around 55 flights with the same set. Which kinda debunks your theory of them being almost guaranteed to be problematic... Perhaps cheap rip-offs sold on ebay, yeah.