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Wind Vortex when Landing

Discussion in 'Pro/Adv Discussion' started by AgentOrange2015, Jan 2, 2016.

  1. AgentOrange2015

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    Years before DJI came out with their Drones, my younger brother, Jim, was a Cobra Helicopter Pilot in Korea and dam good one. When in Hawaii I was able to go with him to the Armies training center for pilots and we got to fly around in a Huey. This was not my first time flying in a Huey, I had done it many times in Vietnam and then again when I worked offshore and flew out of Grand Isle in Louisiana with PHI helicopters.

    Flying in helicopters is much like trying to fly a Phantom, but alot easier in the Phantom. But the Science behind both is undeniable and can not be changed. My brother Jim, explained to me that helicopters have very limited time based upon the height of the Hover. The closer to the ground, the less time they have to hover because of the Wind Vortex (AIR CIRCULATION) that the rotors create. Simply put, the rotors, suck down air from above them and need fresh air coming in from above to maintain a stable hover. But what happens is that the wind becomes very circular and the more the Cobra or Phantom stays in one place or position, the circulating air that comes out of the bottom goes around in a circular motion and comes back in at the top. So these vehicles get caught in the Wind Vortex and is downward in nature, so it drops.

    Give it a try, hover your phantom at a foot or two off the ground and see how long it will stay perfectly still, it will begin to move one way or another or take a hard landing. So the best thing to remember is to stay moving, even if very slowly when landing. Hope this helps those having trouble landing manually.
     
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  2. 480sparky

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    That's why I hand-catch.
     
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  3. AgentOrange2015

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    Hand catching is OK for some but not for all. I have done both but it seems to me that landing on the ground is much more of a challenge and for me, preferable. Yes, when I was learning to land my Phantom 2 it was a real challenge and yes, I busted up a few props along the way but even though, still prefer the manual landing. Living out in the country, landing on concrete or asphalt is a luxury, so you learn to land quickly as possible and turn off the motors as soon as you can.

    At one time, they recommended that you pull both sticks back to the inside to turn off the motors. Well, being a novice, I did just that. This caused the P2 to lurch to one side and fall over when landing manually, thereby busting up props. So out of a necessity and to keep from having to replace props (ha ha) I learned to land and only use the left stick pushed all the way to the bottom to kill the motors. I actually began flying over a hay field so that if I crashed, I would have more of a cushion with the tall grass and it worked a few times. Tall grass is a pilots friend believe it or not. Not so much for landing, but if your having to ditch, it beats asphalt and water by a long shot.
     
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  4. 480sparky

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    The reason a CSC to turn of the motors off can tip you over is it causes the motors to rev up before shutting down. Using the left-stick-full-descent method does not.
     
  5. Brian T

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    Exactly why RW pilots rarely simply "low hover" but "hover taxi" instead, additionally if you are in the hover taxi it is easy to progress to transitional lift for forward flight and gaining altitude.
     
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  6. ELCHEAPO

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    Try hand catching a Huey!
     
  7. MrMcfly

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    The vortex is most noticeable in ATTI. The P3 is very good at staying relatively still at very low altitudes with sensors and GPS working
    to its advantage. I flew R/C single rotors, and the biggest mistake I made as a novice, was trying to get it 'just above the ground' to hover.
    Bad idea.... You think it has less distance to fall, when in fact it's the least stable environment to fly in.
    I learned to get it right up to 6 ft, then try to hover... solely due to the 'vortex'. You get a true appreciation for what the P3 does when
    you were the one making all the control inputs before owning one. Even flying ATTI in the P3 is child's play due to its automated stability.
    I spent a lot of money on replacement blades starting out due to that frikkin' vortex.

    I fly the UDI 818a Discovery for actual 'flying', just got an Estes Proto X FPV for fussing around inside. Both of these 'cheap' quads
    offer much more 'fun' when flying, because they are less stabilized by tech, and require more input from the pilot to fly well. I feel the effects
    much more in these birds... especially when the ground goes from 6 feet below it to 1 foot. (Flying over a ledge)
     
  8. 480sparky

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    I have.

    As well as hand-catching a Louie and Dewey.
     
  9. John Locke

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    This note, I get amused when I fly indoors with my Blade Inductrix micro quad and I go too high and hit the ceiling. It sticks like a magnet to the ceiling. I practically have to shut off the power to get it off the ceiling, then when it starts to fall it's like dead weight, you have to be quick to gas it again. It's opposite the vortex effect.
     
  10. Deputy Dog

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    You mentioned spending a lot of money on replacement blades due to the vortex, try flying two P3P's close together to get video of each flying....now that get's expensive. My buddy and I did it and the vortex pulled both P3P's together resulting in two broken gimbles and cables. OUCH!
     
  11. WetDog

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    That's because it's a ducted fan. You are really just creating a suction affect.
     
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  12. Deputy Dog

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    Found out the hard way. Next time we'll stay about 20' apart.
     
  13. JickMagger

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    I agree that landing is more of a challenge, but unless I have a nice clean flat landing area hand-catching is super-easy with the Phantom because it hovers so very nicely!
     
  14. MrMcfly

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    Ouch! NOT GOOD! I will learn from this mistake! Single Rotor Copters are much more challenging to fly, and even with 'cheater' or novice landing gear, low altitude
    hovering usually ended bad. Throttle/Rudder input is an art, and my skill level was at finger painting. I did eventually start getting successful flights, but the learning
    curve is MUCH steeper. Quad copters are much more enjoyable to fly due to their stability, but I did like the challenge of Single rotor helis.
     
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  15. BigAl07

    BigAl07 Moderator
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    Ground Effect . . . I believe the key term here is ground effect and it's messy air to say the least.
     
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  16. Helijoc

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    Yes ground effect. Nothing dangerous about it. You are just pulling more power when hovering in ground effect. Someone above mentioned translational lift. On a running takeoff you leave ground effect and enter translational lift when the rotors become more efficient. The nose will pitch up and you apply forward cyclic the resulting acceleration is awesome. Freaked many friends out doing a running take offs off of a cliff.
     
  17. Brian T

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    Ground effect causing "Messy air" Ha ! Try jumping out of the middle door on a Chinook at 7,000' THAT is messy air ;-)
     
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  18. BigAl07

    BigAl07 Moderator
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    That's way beyond messy.. that's insanely messy LOL! I can't even start to imagine that first hand