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Old March 9th 10, 11:13 AM posted to rec.aviation.soaring
Doug Hoffman[_3_]
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Posts: 26
Default Full-span flaperons as airbrakes?

On Mar 9, 12:59*am, Eric Greenwell wrote:
Bruce wrote:

The ASW-20 was the first to get the ailerons back up as the flaps went
on down, getting the plane into what a previous poster said is called
"crow mode" in the model world. *I think the biggest thing it does is
makes it so the ailerons won't stall once you are on the ground in two
point, tail low attitude. *I don't think it was done for added drag or
improved in flight handling. *You already get ENORMOUS geometric twist
when your inboard flap is down 50 degrees and your ailerons are still
down 8. *However, these flapped ships like to have the ailerons up
when sitting two point on the ground in order to have aileron
authority, and Schleicher got this (among so many other things) right
by putting them back up so you can leave the flaps all the way down
after you land. *That way, your left hand doesn't have to keep jumping
around in the cockpit grabbing different handles. *Set the flaps, use
the dive brakes and land. *No more needed hand changes.


Steve Leonard


And unfortunately Schleicher patented the mixer - so one of the more
effective safety innovations has not been widely used.


About 15 years ago, Gerhard Waibel told me they purposely did not patent
their system. They thought it was such an important safety feature it
should be available to the other manufacturers; to Schleicher's surprise
and dismay, none had ever used it, even though it was introduced on the
ASW 20 in about 1975.


Good to know that I didn't violate any patents. Years ago I installed
this feature on the RS-15 I owned. Actually, any HP series glider
with a flap/aileron interconnect can easily be set up to have this
behavior and I believe that many/most are. One needs only to modify
the cam slot in a piece of 3/16" aluminum plate. The guy to whom I
sold the RS wanted the ailerons to go "crow" at smaller flap
deflections. He was able to easily change it himself. In general, it
makes a huge difference in maintaining control during landing rollout
as described and the best part is crow mode happens automatically.
Just set the flaps and land. Dive brakes/spoilers? What are
those? ;-)

Regards,

-Doug