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How to Eliminate your flyaway concerns in 13 steps

Discussion in 'Phantom 2 Vision + Discussion' started by DrJoe, Jun 4, 2014.

  1. DrJoe

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    *** I will be editing this post based on new information/comments***

    DJI Phantom 2 Vision Plus is a fantastic, cutting edge product, but has had some serious concerns. It is advertised as an RTF (ready to fly) unit for "everybody". It is not. It requires reading the manual, watching videos, researching various topics online, and practice, but most of all, it requires switching the shipped software settings to another mode before flight (NAZA mode) in order to counter the loss of GPS signal during flight.

    In a nutshell, if your Phantom drops below 5-6 satellites during flight, GPS mode is cancelled. It will not hover in one position, but drift with the wind. Worse, the RTH (return to home) function DJI touts as a "failsafe" will not work.

    Many Phantoms seem to operate perfectly fine without the following steps, but more than a few "fly away". The following list isn't a requirement, but if you want to limit your long term risk of a "fly away", please invest the time and effort:

    When you get your Phantom, do the following:
    1. Read the manual.
    2. Watch the videos
    3. Read this board
    4. Charge your batteries
    5. Open your phantom (plenty of YouTube video on this) and seal the exposed electrical connections with GE Silicone II (non-acetic acid formula). This eliminates poor quality control during assembly or just plain shaking a connection loose during flight. Not definitively needed, but a worthwhile thing to do if your comfortable with it.
    6. Install the drivers and DJI Assistant software into your computer. Connect your Phantom. Test transmitter function, switch to NAZA mode, enable IOC, set height and distance limits, perform an IMU calibration, check compass variables are within normal limits.
    7. Check winds aloft (if the winds exceed 30 mph at the altitude you are flying, your Phantom may not be able to fight them and will "fly away".
    8. Calibrate the compass (and repeat prior to flight any time you change geographic area significantly). Place the phantom on the ground or a box, being careful to keep it away from metal (manhole cover,etc) or reinforced concrete, which can screw up the compass.
    9. Inspect the prop tips and hubs carefully for cracks/damage. If you hit a big bug (cicada), or have bumped the props, they could fail during flight. Your Phantom will not be controllable and the NAZA flight controller will respond by trying to correct the imbalance in unpredictable ways.
    10. Do not take off until your DJI FPV smartphone app is connected, the camera is functioning, and the app indicates at least 6 satellites and you are sure your home point is "locked". The RF (radio frequency) shielding of the Phantom has been observed (in a lab/small sample size) to be poor and can interfere with weak GPS signals. If the Phantom falls below 5-6 satellites during flight, it will drift with the wind, and the RTH (return to home) function will not work. Switch to ATTI mode using the S1 switch immediately.
    11. Following take off, hover at 10 feet or so until the Phantom is stable and you confirm basic flight commands are functioning. Then ascend above the highest local obstacle (trees, houses, buildings, etc).
    12. Avoid rapid descents, as this is known to cause VRS (vortex ring state). This results in the Phantom fluttering to the ground at high speed, despite full throttle. It is easily avoided by moving in any lateral direction during descent (right stick input). Be aware this may occur in hover as well, and that DJI prop guards are known to increase the likelihood of VRS.
    13. Learn how to use the various IOC modes and flight modes in a big, open field with soft grass. In the event of any erratic behavior of the Phantom, switch to ATTI mode and land immediately.

    If you take the time to learn these 13 steps, you will eliminate a vast majority of fly away concerns. You still need to be concerned with motor failure, ESC (electronic speed controller) failure, and RF interference. They have not yet invented a flying machine that is simple and idiot proof. Chinese labor and manufacturing is cheap for a reason, as Quality control and worker skill is questionable. The P2V+ is fragile. A bump or hard landing could effect the NAZA flight controller, its sensors, or especially the gimbal/camera. If you are new to this, buy a $400 Phantom FC40, which takes a beating before you bang up a $1369 P2V+ that does not (at this time) have a good replacement part or repair availability. You could always sell that FC40 and recoup at least half of your investment.

    Other safety measures:
    Repeat Advanced IMU calibration after any "hard" landings or bumps. Perform a compass calibration after IMU calibration.
    Purchase a "Getterback" water retrieval device and mount to landing skid.
    Purchase a GPS tracking device to mount on your Phantom (many topics on this board about different ones).
    Purchase the third party FPV Boost app.
    Upgrade your antennas with FPVLR.com stage 2 kit to have a lower chance of connection loss. (requires some modification and skill).
    S1 and S2 switches are easy to inadvertently bump, be careful. Periodically check their function in DJI Assistant software as some have reported bad switches after some use.
    Write your name and number on the Phantom in case its lost and found by a kind heart.

    Emergency Check List:
    VRS: apply right stick input immediately
    If anything seems out of the ordinary: switch to ATTI mode immediately. Land immediately. Figure it out before you fly again.
     
  2. N017RW

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  3. Rickesco

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    Thanks Dr Joe,

    Very useful advise. I guess we should all think it's not "IF" it's "WHEN" and we sould be ready.
    Thanks again for the tip

    Rick
     
  4. syotr

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    14. Put your name, number and "REWARD" on it so when a flyaway happens some kind soul may return it.
     
  5. sergekouper

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    Great post, great job. Thank you for that.
     
  6. Skipholiday

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    The eXtended range of the plus oVer the vision2 is substantial. There's no real need to upgrade the antennas for most photography and videos.
    I've been 3000 plus feet with the stock Vplus. I did upgrade my vision2 antennas and my range did improve to about where my plus is now.
    I would suggest against this mod unless you're sure you need it.
    The added antennas are troublesome to attach before every flight and seVeral people have broken the ufl connector off the board in the controller removing the silicone.
    FPVLR is a great guy a friend and an asset to this community.
    But I believe adding antennas should not be done until you are 100% sure of your piloting skillz.
    Then if you feel you need eXtra range there are plenty of howtos and FPVLR offers a great antenna.
     
  7. Rebelvis

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    Good advice, but something that needs...

    further discussion:

    One thing I see mentioned here (item #12) and elsewhere repeatedly is the notion that prop guards are inherently bad. I've seen claims that in addition to causing VRS, they make the phantom less stable and even the absurd claim that they alter the center of gravity. My question is; where is the empirical evidence for any of these claims? Are we basically saying that DJI by manufacturing and recommending them to beginners has no idea what they're talking about in regards to a machine they designed and built?

    I don't know the answer but, all I've seen on the issue OPINIONS presented as absolute facts.

    In my own case, I put them on not because I think I'll bump into something in flight, but because after touch down many quads tend to be "light on their feet" until shutdown and can be pushed over by even small winds thereby dinging the props. On my very first flight I was assisted by a very experienced quad and DJI pilot who flies his bird w/o prop guards. One of my first questions was, how does it handle with the prop guards? His answer was that he couldn't tell the difference.

    There are some logically reasonable aspects of prop guards....at least to me. This would include things like: 1) added weight thereby making for shorter flight times by a tiny amount; 2) I would guess that prop guards by increasing the surface area of the quad would make it more susceptible to wind pushing it around; and 3) they won't fit in most cases.

    As to the claims of decreased stability and greater chance of VRS all I'm saying is what's the proof and what does DJI say about it? Admittedly, I'm a fairly new vision plus owner and have thus far (thankfully!) experienced none of these prop guard issues. At some point I'll probably take them off, but for now I'd really like authoritative evidence, not opinions or speculation on all these claims.

    DJI? Anyone? What are the facts?
     
  8. Skipholiday

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    Re: Good advice, but something that needs...

    Fact is my Phantoms will not fit in my cases with prop guards.
    I've also read where some screwed through the guards into the engines.
    Crashes caused by increased prop wash during landings.
    Some have damaged props when they hit the prop guards.

    Some need them I don't.
     
  9. N017RW

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    Since I had 2 cents in my pocket :p , I'll throw it in too just for discussion's sake...

    Full disclosure: I have never used them.

    Well without testing or modelling there can be no facts specific to these guards.
    (I doubt DJI has done either)


    So what are we left with?...

    ...Applying single rotor theory and/or phenomenon to a multi-rotor situation.
    (This alone is not well understood as far as I know, except maybe the V-22.)

    This along with empirical and anecdotal analysis results in opinions (including mine below ;) ).
    We all know about opinions and to be fair some are more well-founded that others.


    We know tip vortices add drag and propagate down and away from the rotor, wing, or propeller tips.

    We know these vortices essentially stop moving down and away, propagate along the rotor's chord creating the VRS and basically increasing the angle of attack thus stalling the rotor resulting in free-fall.

    The location of the guards curved surface MAY potentially trap or corral these vortices keeping them within the rotors working area, if you will, possibly accelerating the ring envelopment process or reducing the margin of error to produce them.

    Additionally they MAY inadvertently act as ducts or guides preventing stable or non-moving air to be allowed to interject into the downward moving air to help stabilize it.

    Or MAYbe not.

    Again, just my 2 cents.
     
  10. sergekouper

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    Re: Good advice, but something that needs...

    I would add a 4) The prop guards come badly in the picture when you pitch.

    Tilting the camera hits the the border of the fish eye, mostly over exposed,and ruins your landscape pictures... Besides, it may hide this low branch you didn't see, crashing the phantom in the river nearby. (true story :oops: ) Also, I would add the extra weight at the end of the arms, not only makes it waving unecesseraly and being less stable. Not mentioning that a phantom 2+FPV+Gimbal+Gopro+Tracker is fairly close to its max for a safe flight. IMO if you like, but it's quite a matter of fact actually.
     
  11. Rebelvis

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    Thanks 17RW, for a thoughtful and intelligent reply. I guess I'm tiring of some folks presenting as fact their opinion on these things based on anecdotal evidence and/or personal bias. My guess is the verdict is out and likely to remain so.


     
  12. DrJoe

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    My post was meant as recommendations to reduce "fly aways" and other issues based on my experience. In reading the boards over the past few months, I notice a lot of pilots with VRS accidents had prop guards on. My prop guards came very late, so **IN MY EXPERIENCE**, the Phantom responded differently, then I had a VRS incident. Didn't have on before, didn't have one since removing them. I suppose most of the info on this board consists of opinion, as many of us don't have access to 50 Phantoms to empirically test with different variables and parameters.

    If you like prop guards, that is fine. They seem like a good idea for safety. All I would like to express is that you should be prepared for a VRS incident and know how to handle it. Agreed?
     
  13. Rebelvis

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    I will agree that your VRS incident may or may not have had anything to do with prop guards. No other conclusion is possible. Look, I'm not defending their use or nonuse. I'd just like to deal in facts so I can act accordingly. In this area there seems to be many more opinipns than facts. Agreed?

     
  14. N017RW

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    Have you done any research Rebelvis?
     
  15. DrJoe

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    Agreed. Unfortunately, individual experience is opinion. Just pointing out that there **may** be an issue to those interested in reducing risk, based on my experience, and that of many other posters. This opinion does not include those that haven't posted or those that had a VRS without prop guards. No animals were harmed in the formation, though many insects have died.
     
  16. plasmo

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    You could also add the tip to NOT take off on any metal surface (tables, manholes, etc)
     
  17. quadcopter

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    Thx Dr. Joe!
     
  18. Skipholiday

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    Agreed thanks for posting joe
     
  19. Flying Cephlopod

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    Thank you for posting this. That's very thoughtful, Dr Joe.
     
  20. tedw123

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    I've always wondered about labeling mine, great advice unless it falls into someones back yard and they call the police and press charges!