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another hard landing....

Discussion in 'Phantom 2 Vision + Discussion' started by Hotrod, Oct 24, 2014.

  1. Hotrod

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    The other day I was flying my P2+ around my home, just getting a little practice. As I started to come down to the lawn for a landing at about 3 ft it just "fluttered down" to a hard landing on the lawn. I thought it strange, but sort of shrugged it off. Today I was flying at a gravel pit a few miles from my home. My intention was to fly for about an hour using my extra batteries. I had flown for about 10 minutes and I was in the process of bringing it back close intending to grab it by hand when it got close. At about 30 ft away and at around 10 ft in height it just "fluttered down" again. This time it was over a cliff and fell another 10 feet from where I was setting. I tried to hit the up to save it, but no result. Now I am a little worried that something is wrong with my Phantom.

    I was using the return to home mode. I have prop guards. There was a little wind, not too much. GPS was in and out, from 4 to 9 satellites. This time it broke the landing gear, and two of the prop guards. But the camera seems OK, so maybe the extended landing gear did it,s job. Does this sound like ring vortex?

    I hate to say that I am starting to dread my flights rather than enjoying them. Any ideas?

    Thanks
     
  2. Dirty Bird

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    Fluttering down would appear to be VRS. Glad the camera appears to have been spared.

    I know some are adamantly stubborn on this, but lose the prop guards and I bet things improve. ;)
     
  3. rbhamilton

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    I would suggest hand catching it (that's what I do) but if it makes sudden movements on you... well that could cost you a finger or two. Probably the prop guards are the issue because these drones are very stable when everything is working properly.
     
  4. sbarton

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    Latest firmware also can cause hard landings if you are below 30% battery life.
     
  5. Hotrod

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    I was at about 30% battery life, both times. It seems that it just decides it is time to land all at once. Is there a way to prevent this? And I do prefer to hand catch it, when I can get it back.
    I ordered two more sets of extended landing gear from Amazon. Although they break easily, maybe they saved the camera. I intend to remove the prop guards too to see if that helps stability.
    Thanks for the information.
     
  6. DrD

    DrD

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    Regarding landing, I no longer let my Phantom land by itself. It is very easy to hand catch:, let the phantom hover just above head height, and watch it for a little bit. Any movement in its position becomes very predictable, with minimal worry to just walk up to it and grab a single landing gear leg. It is very safe, so simple to do, and eliminates the $expense$ of landing carnage. I wouldn't consider doing it any other way.

    To build initial confidence, slowly fly it near to you. Just let it hover, it will move within the GPS tolerance, but not so very quickly that it would be threatening to grab it. Be aware that when you hold it, your moving it will cause the phantom to counteract. You will learn that the phantom motion is easily managed with so little effort on your part, that the shut down sequence becomes a minor formality.
     
  7. sbarton

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    Go back to 3.04 or earlier firmware. Droneslinger.com has old firmware
     
  8. djczing

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    I just went through a scenario like this, and am thinking that alot of these hard landings arent VRS at all (I thought mine were at first).

    Usually it was when I pulled up and got slow to set up for landing - and then the thing would sometimes just drop to the ground.

    I think when these ESCs start to go bad, they do so slowly - and their first failures are at low RPMs. If hear any of your motors 'chug' at startup (the startup whine is a bit intermittent on a motor/esc until it finally spins up), then I think you may have an ESC going 'weak', or a motor.

    I had had my P2V+ for about a month, and it had had a couple hard crashes. I never had VRS issues though, and at times, I /tried/ to induce VRS - Id get the wobble, but would recover before it turned worse. After a certain point though, it got prone to just dropping outa the sky - never at speed, always coming down-throttle to a rest, or maybe moving slowly forward wiht even slight down-throttle.

    My issue progressed to where the left front motor wouldnt start normally - and sometimes wouldnt start at all.

    I replaced the front-left ESC and motor, and havent had an issue since (other than the 4 extra beeps from teh ESC, which I wish I could get rid of).

    My hypothesis is this:

    When you crash the thnig, especially in a tree or upside down, where the motors still try to spin up to right the aircraft but are bound by a branch or the ground, it /may/ over-amp the esc (?).

    Also, if you hear a motor chugging on start-up, I think thats an early-warning that an ESC (or motor) is going weak and has a problem.

    I dnt know what the mtbf of these ESCs are, but I know the motors mtbf is like... what.... 3000 hours ?

    I read posts about the phantoms just falling out of the sky, and I think this is a major reason, that many might not suspect, as the problem, at the beginning, is not obvious.
     
  9. singapore_phantom

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    I had a total of 2 of these drops since I got my Phantom, both in my first week of flying it. I have them both on video and from watching these, I know that they're not true VRS, but it's similar.

    Both of these flutters, were the result of the copter overtaking its prop wash and basically eating this frothy air and losing bite as a result, which causes the copter to lose altitude. It just sort of sags for a foot or two.

    In both cases, motor whine increased for a moment. But in both cases, the copter broke out of its prop wash and regained its traction after a few seconds, auto-correcting the sag before hitting the ground, i.e. without me having to work the sticks in any particular way.

    I don't fly with prop guards and neither case was during a hard descent. However, both times, the copter did a fairly aggressive sweep and turn.

    Nowadays, whenever I come in at speed and I pull a sharp turn, I compensate by pitching up a bit. This has effectively put an end to these drops.
     
  10. 4wd

    4wd

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    When you get close to the ground you can get ground effects interacting with the considerable air flow, it often starts to do odd things like tending to bounce up and down
    Another good reason to hand catch.
    If you do land on the ground don't dither about - pick a spot then come in and land decisively.
     
  11. Hotrod

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    Well, in an odd way I feel a little better knowing it may not just be my lousy flying. I think I will remove the prop guards. Then go somewhere where there is some grass and let it hover at low altitude as the 30% battery comes up. Hopefully this will tell me if it is something with the firmware causing the sudden landing. I have noticed it do a little wobble while higher in the sky.I attributed that to a sudden wind gust at altitude. With enough height it has always come out of it. Buy I have noticed how unstable it seems to be when I try to descend. I always try to be moving in a direction when coming down to avoid the vortex problem.

    Thanks everyone for your input. I hope to get this figured out so I can get back to enjoying the experience instead of worrying what will break this time.
     
  12. MapMaker53

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    Well, I would guess that this could be the reason for your most recent crash. First of all, you probably shouldn't be relying on the RTH mode, just to bring the bird back to you when you are done flying. It's pretty much meant for situations where you find yourself flying blind without FPV due to wifi loss, and you've also lost sight of the bird in general -- so the RTH is a last ditch effort to get your bird back. You also say your GPS was in and out that day, and if you throw it into RTH mode with less than 6 satellites (or it drops below 6 and loses GPS on its way home) I believe it just lands at that point no matter where it is or what is under it.
     
  13. Phantom_Menace66

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    All these 'hand catchers' lack the intestinal fortitude and very basic skill required to land the thing on the ground... It's so simple, it has me baffled why people fear their Phantom crashing upon landing....
     
  14. 4wd

    4wd

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    It's not only crashing ( or rather tipping over) - but finding a spot where the camera and gimbal won't get muddy/dusty/bumped with barely an inch of clearance.
     
  15. Pacific Barbarian

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    I like to practice both as the opportunities arise. There is a place for both methods. With standard landing gear, hand catching is softer on the phantom. I just find it not so stable bringing it in, yawing to get a free leg, when it yaws it tends to drift a little.
     
  16. singapore_phantom

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    ^ This.
     
  17. SanCap

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    X2! Learn to LAND your aircraft!!
     
  18. vicdevore

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    VRS is more common with the prop guards, but there are techniques you can use to reduce VRS. First, descend very slowly. Don't jam the stick all the way down. Also, slowly descend in a wide spiral, or while moving forward. Pay attention to the wind and try to descend into the wind and not while moving with the wind. I would consider evaluating the risk vs. benefit of the guards. VRS will destroy your bird. But, as a pilot you can avoid obstacles. If you do experience VRS go forward or backwards or sideways (or into the wind) full speed. Take your hand off the throttle (left stick). This might help.
     
  19. Idbird

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    :D I've had Fastsmiles gimbal/camera guard on my bird since I started flying in wilderness and desert locations. The guard is perfect for protecting the camera and gimbal as well as a nice place to attach a GPS locator. I also put a small foam pad between the guard and the gimbal lock for storage and transport. Due to the flat surface between the landing gear, landing on grass is difficult (usually too tall anyway). Landing on a dirt trail can foul motors.

    Through experience, I've learned to always launch from my case or backpack, and hand catch for landing.
     
  20. Mako79

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    I agree with 4wd.
    I'm sure there are pros and cons in both methods.

    I can land and its not hard. Just hold down and wait till the props turn off. meh. The problem is that the camera and gimbal does not have much clearance and the phantom is top heavy with bad centre of gravity and is highly prone to tip overs.

    There are much more pros in catch landing if you take precautionary safety (check surroundings, down wind, use lanyard, have the phantom arms reach slightly above the head etc.)

    I prefer it because:
    Phantom at 6 feet or less suffers from its own prop turbulence.
    Phantom sometimes switches to ATTI at low altitude and all you need is a gust and tip over.
    Prevent kids or animals running up to it.
    It saves my gimbal. Bounce landings may in the long run cause the horrid camera tilt. The shaft is press-fitted meaning its held by friction.
    It saves my props.
    Prevents dust and sand.
    Allows me to catch on boats.

    Now with the auto shut off in firmware 3.06, all you need to do is hold the phantom still for 3-5 seconds.

    If you aren't un-coordinated, I'd suggest practicing with props guards until you are comfortable.