Originally Posted by Jovanx
One of my favorite things to do with the Radian is to milk the ground effect for all it's worth. If the field is big enough, you can get it down to about 2 feet off the deck and still go an amazing distance before finally setting it onto the grass. My question is...does this still apply when the wind is blowing hard and the plane is hovering in one spot?
On Saturday the Radian was put to the big wind test and it did great. Usually I fly the RP on those days, but it was at home. The wind sock was sticking straight out and there was only one guy flying (an edf jet). I did a few loops and spiral dives just for fun, but most of the time was spent with it pointed into the wind and staying in one place. I did about 5 or 6 vertical landings, and all were good except one was hard enough to knock the canopy off.
One of the landings was amazing, and the pilots who were watching were impressed. It just hung there, hovering 2 feet off the ground, for an unbelievably long time. (gliding, not under power). Was the ground-effect cushion still a factor in this wind?
my view is that, as the wind blows horizontally, it has to be some sort of vertical draft, a surface thermal coming from warm air from the ground, mild but strong enough to keep the plane afloat. i have seen this with some of my planes. i used to fly free flight towline gliders. once early in the morning i launched to test trim with a short line, about 20 feet, and the plane remained turning around at 10 feet for 3 minutes, until the dethermalizer made it drop. it was a surface thermal, not stronger than the plane needed to stay at same level. when the speed of the plane is the same as the wind, and there is a thermal strong enough to balance the weight of the plane, it stays there as hanging from the sky. it also happened to me when flying another r/c sailplane: it didn't move for over 10 minutes. people came asking how was it hanging. i had to bring it down because there was another fellow on same frequency and was asking me how long i would be there.