Ground effect: is it real?

Jul 09, 2012 4 Comments by

When a helicopter is hovering at a height that’s approximately less than the diameter of one rotor disc, it really does encounter “ground effect.” This is because the downwash velocity created by the rotor blades can’t be fully developed because the helicopter is so close to the ground, so the helicopter rests on a “bubble” of higher pressure air. (This gets even more complicated, but this basic¬†explanation will work for our hobby purposes.) In my limited experience in hovering/flying full-scale helicopters, a helicopter does handle differently when it encounters ground effect. It’s almost like sitting on top of a balloon and trying not to fall off. Some model helicopter pilots say that they, too, can feel when their helicopter encounters ground effect and that it acts in the same way on their helicopters. But I personally can’t tell when I’m in or out of ground effect. The amount of ground effect is also determined by the wind; it will have a maximum effect on a calm day and less as the wind’s velocity increases to “push” the higher pressure air from under the helicopter.

What about you; have you experienced ground effect?

Editors Blogs, Paul Tradelius

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4 Responses to “Ground effect: is it real?”

  1. mike rowse says:

    Heck yah!
    I hated learning to fly with training sticks, with the plastic balls on the end, because I felt like I was trying to balance a marble on a beach ball

  2. Bill says:

    yes indeed as mike mentioned most disconcerting as a beginner, now it feels cool bouncing the bubble so to speak.
    It is noticeable to me and yes more on calm days, windy days see me leaning the heli into the wind for a similar but heavier effect :D

    Its kind of like leaning on the flimsy net around a trampoline -its there but you probably wouldnt want to rely on it to hold your full weight.

  3. Flying Dutchman says:

    Yeup, I can tell when I’m in ground effect as well. I seem to notice more when I’m flying my smaller helicopters such as the MSRX, or MCPX. When I try to do precision landings I can fly in nice and smooth to the spot I am going for just to have it start bouncing around the spot when I get close to landing. Don’t seem to notice it as much on my 450 helicopter though, but then again I am flying it outside, and there is usualy some sort of wind.

  4. Ney Azambuja says:

    Brazilian flyer July 29, 2012 at 4:30 PM
    Flying ower yor table, with a smal coaxial heli, you can see cleary the grond effect doing this maneuver:
    Try to do a takeoff leaving the table surface. At the end of the table, when the ground effect disapears, you wil note a fall of your model,
    To avoid this, you need encrease the the power!

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