Ground Effect in the Lancair 360

Flying in ground effect is quite a bit different than flying at altitude. In ground effect the stall angle of attack goes down whiel the lift curve slope or effectiveness of the wing goes up. The net effect is that one can fly at what would have been stall speed while close to the ground.
Here a Lancair 360 flies close to the runway while flying at, and occasionally below, free-stream stall speed. This technique is used to exposed new pilots to the sight picture of high angle of attack just prior to touch down. The pilot has no visibility of the nose at touch down thus peripheral vision is used to judge height. (the camera is several inches higher than the pilot's eyes)
A long runway allows an expended period of time in this flight condition.

[@jimydoolittle3129]

That is a Loooooooong flare 😝✈️ great show , awesome aircraft ❤️

[@v1_rotate638]

Great demonstration!

[@xboyPToficial]

Very good...thanks.

[@igor-orzhevskii]

Thanks!

[@Zanzabar5]

Are you a CFI? I'm looking at a 360 and need training.

[@azat941]

How to landing??(touch down)

[@cokeforever]

go 5 knots less and see your "ground effect" diminish within a second... that is just a very low pass, with 1 ton mtow of Lancair and wing+flaps surface area you can easily calculate the ground effect... it is miniscule at 55kts

[@N91CZ]

Two things happen when flying in ground effect.
First, drag goes down. The power maintained during the final approach is sufficient to maintain level flight in ground effect. i.e. the plane will float forever and never touch down.
The second thing is that the lift curve slope increases. That is, the lift coefficient for any given angle of attack is higher. This allows for a lower airspeed in ground effect than what can normally be flown. This is countered by a reduction is critical angle of attack. In the configuration shown, free stream stall speed is about 61 KIAS. In the video one can see the ASI dipping below that value while the plane keeps flying.
Ground effect goes up sharply with ground proximity. Since this is a low wing configuration, I can maintain a distance of 10-15% of span where the effect is quite pronounced.