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Shaving altitude - ATTI mode

Discussion in 'Pro/Adv Discussion' started by m0j0, Jan 29, 2016.

  1. m0j0

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    I have noticed a few strange things when I fly. One is probably an illusion. Since I'm an inexperienced pilot I'm sure it takes getting used to before you can really judge. First, as the AC goes away it looks like it is getting closer to the ground. I have noticed this on flat ground. It is really weird. I put the AC up about 30 meters and as it flies away it looks like it is getting closer to the ground. I check the telemetry and note that it isn't showing that it is gaining or reducing in elevation. As I fly it closer to me it seems like it is getting higher. Does anyone understand why this is?? or is this just old man eyes.

    Second, I know when I fly my Phantom in ATTI mode it absolutely does shave altitude. It is something that you really have to pay attention to if you are at the edges of VLOS. To be honest I haven't flown ATTI and looked at telemetry to determine if the AC is showing a rate of descent. I just am not confident enough to do that yet. Is there something wrong with my Phantom or does everyone have a similar experience when flying ATTI.
     
    Chris K likes this.
  2. CatMan42

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    In regards to the first part of your post I have to assume (without knowing distance you are flying away from you) that what you're seeing is the same thing you would see while watching an airplane leaving a con-trial. As the plane flies closer to you it looks like it rising in the sky. As it flies away it looks like it's lowering. It would be very helpful to know the distance that you observe the deflection from.

    As for the second part of your post, I have to leave that up to the masters on this forum!!

    Mark
     
  3. TheRealNick

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    I flew old school RC helicopters before the Phantom 3. The Phantom 3 taught me that I used to fly up as my helicopters went away and down as I approached although the I thought I was flying level....I knew it would look a little lower as I flew away but not that low....
     
  4. Mark The Droner

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    When I first started flying, I just flew without FPV so I could concentrate on learning the flying contols. I flew at a rec center field which as far as I know should be perfectly flat. But I noticed when I flew at about head high, the craft would be inclined to hit the ground 100 yards out. I'd have to elevate it to avoid hitting the ground. I thought this was odd.
     
  5. alokbhargava

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    1. As you fly away, your angle to aircraft wrt ground decreases and gives an apparent feeling that it's losing altitude. Fly at 250' height, you would feel differently.

    2. Flying in ATTI mode needs skills as you need to control it all the time. You can't leave the control to let it hover at one point. It will drift. You should not fly far in ATTI mode unless you got good feel for it.
     
  6. Dirty Bird

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    I have asked the ATTI/altitude question several times without receiving a response & keep forgetting to test for myself. Your message confirms my suspicions.

    A Vision+ is much faster in ATTI mode than GPS mode. It's faster because the FC allows it to bank steeper, but it bleeds altitude when you are really kicking it. You had to keep a close eye on the altimeter & apply a bit of upward thrust to maintain. Sometimes this was useful. Returning from a long flight at high altitude you could switch to ATTI, gun it, & come home quickly while bleeding off the altitude. I suspected the P3 might behave the same since it is also considerably faster in ATTI mode.


     
  7. m0j0

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    I'm comfortable in ATTI mode. I fly it often. Definitely every time I take the aircraft out I fly it in that mode. I know it drifts. I want it to so that if I ever have a need to fly it that way I won't have a problem.

    My question is more about losing elevation than drift. I am certain my phantom loses elevation when I have the stick full forward. I just curious if other who have been flying the Phantom 3 sees similar flight characteristics.


    Phantom 3 Pro / iPad Air 2
     
  8. m0j0

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    Answers my question. Thought I had a problem. Now I know. Appreciate the response.



    Phantom 3 Pro / iPad Air 2