On Fri, 10 Jun 2016 08:36:40 -0700, moshe.braner wrote:


In my current glider -- the AC4a
prototype with above-and-below way-more-then-necessary spoilers -- the
spoilers seem to have a significant effect after flare and well into the
rollout. Induced drag may be reduced in ground effect, but there's
still some, plus the spoilers probably add parasite drag.

That matches my experience with my Std Libelle. When I first got it, on
one flight I underestimated its (minimal) airbrake power and by the time
I'd completed a slightly too fast flare, found that I was going to land
long enough to touch down just before a hard track that crosses our main
run. Not a good idea as the track is slightly proud of the grass surface.
Closing the brakes easily floated me over the track and re-opening them
made the glider settle once past it. The effect of closing and then re-
opening the brakes was quite noticeable, even when floating in ground
effect.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |