David Rind wrote:

I haven't been following this thread that closely so I may have missed
something, but "full flaps"? I thought that once you got to 40 degrees
of flaps on a 172 you were just adding drag without any appreciable
reduction in stall speed. I can't see how that would get you into ground
effect any quicker....

With an aircraft which has the ability to dump the flaps quickly (about anything
with a "Johnson bar"), you can get a remarkably short ground run by accelerating
with no flaps until just past the full flap stall speed. Drop the flaps down,
use a little elevator to yank it into ground effect, immediately put the yoke
forward to keep it a few feet above the runway, and milk the flaps up in ground
effect.

Obviously you aren't going to be able to drop the flaps that rapidly with a
172N, but the full-flaps stall speed is only 51 mph. Perhaps accelerating to
about 55 with the flaps down wouldn't incur much of a drag penalty?

Note that you *do* get a hefty drag penalty while the flaps are down, so your
distance to clear the traditional 50' obstacle is likely to be longer than a
normal takeoff.

It's a fun technique to try when there's no pucker factor involved. I used to
almost always spoil the effect by banging the tailwheel getting off the ground.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.