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landing the p3a with sonar on.

Discussion in 'Pro/Adv Discussion' started by lotusteve, Sep 15, 2015.

  1. lotusteve

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    did my first flight this evening, took it up to 10 foot and tried to land, I brought it down very slow and when it was just about to touch down it started to bounce up and down close to the ground....why ?. I then took it back up and used auto land and that was a perfect landing, could it be something to do with the sonar system on the bottom. is it advisable to turn this off when out side.
     
  2. dlbyers

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    Just like take-off, you have to be decisive & not tentative about it. When it gets a few inches from the ground it starts to bounce due to prop wash. Landings take a bit of practice, but you'll get it.

    I actually learned a lot about takeoff and landing by watching auto-pilot do it. I now hand-catch more often than not.
     
  3. msinger

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    This is a known issue when using VPS outside. My recommendation is to always turn off VPS when flying outdoors. There is really no benefit to having it enabled.
     
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  4. D4T_PoM

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    Steve I used to get the bouncing when I first started then slowly with practuse got used to landing and no more bouncing.

    VPS is always turned on unless I'm flying above water.

    MSinger may be rite, switch it off and practise, my understanding is every P3 may react differently.

    As said, now my VPS stays on and I have no issues with bouncing at all.

    When I'm close to the ground the updrift of the wind does make the P3 play but you just have to practise and it goes away, make sure the surface is level, also another thing I normally do is hand catch but my advice for now is switch off VPS and practise landing yourself as auto landing can sometimes be very harsh.

    I used to CSC (both sticks down) to switch off/shut down rotors then I learnt that its actually left stick down for 3 seconds.
     
    #4 D4T_PoM, Sep 15, 2015
    Last edited: Sep 15, 2015
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  5. dlbyers

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    I've never turned VPS off and have not had problems. Only reason I'd ever turn it off is when over water.
     
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  6. Reed L

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    Honestly, I sit in a chair while flying and set it up to catch in my left hand when landing. It just feels great to be able to land in your hand.
     
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  7. III% Streve

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    There is never a real reason to turn it off. Water is certainly nothing different. Just another surface!
     
  8. Simonb3526

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    Two options. Hit the home button and let it land. If it's flat and there's room for a little gps error it does a great job. Or get to within 6 inches and just hold down and go for it. If it's a few inches above and your not going down fast enough it will pop up but a few tries and your be good. Hand landings are the best option for the bird on rougher terrain.
     
  9. Oso

    Oso

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    I also never turn off VPS since it finally fixed for me in 1.3.2.

    I do wonder sometimes if it saves battery to turn it off. VPS off, red LEDs off would add what? 5 seconds of flight time?
     
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  10. bbfpv

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  11. Viral

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    Agreed. VPS never needs to be turned off, not even over water. It just can't be relied on to keep altitude over water. Think about what VPS is supposed to do. If you're flying at, say, 10 feet, the ground isn't perfectly level, it may slope up or down but the barometric pressure doesn't change. Without VPS, the P3 wouldn't know the ground level is rising and it is now only 5 ft up instead of 10. VPS uses sonar to give a more accurate measurement of height from the surface for those last 10-12 ft, except over water or other mirror like surfaces where an accurate signal reflection can't be attained. So VPS is attempting to hold a given altitude when flying low if you are NOT forcing a change in altitude. If you ARE raising or lowering the P3, VPS doesn't come into play, so it doesn't have anything to do with landing.

    Like others have said, either hand catch or get it down to about 8-12 inches then full left stick down until the motors stop. I've never had a bounce doing it that way.
     
  12. TonG

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    I'm not fully agree with you. The VPS is also playing a role. If you landing very slowly or flying forwards on a very low altitude the quad will sometimes stepwise go up and down to find al new balance. This behavior is merely caused by de VPS who cannot decide/measure how high it is due to a bas surface (grass beneath it)
    If I turn off VPS that up and down movement also happens but much smooter and certainly not in discrete steps.

    By the way Lotusteve, learn to land in all circumstances and modes. Its a very basic and needed manoeuvre. And also, learn to handcatch.