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motorgliders as towplanes



 
 
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Old March 19th 09, 06:09 PM posted to rec.aviation.soaring
Jim Logajan
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Posts: 1,958
Default aerodynamics of gliding

Bob Cook wrote:
Not many took a stab at the "spoilers and flaps" questons!


Probably because it was a no-win situation.

Spoilers do not "reduce lift". Spoilers increase drag. As drag
increases, glide slope steepens.

Spoilers redistribute lift, but not reduce lift.


You're claim conflicts with that in the FAA "Pilot's Handbook of
Aeronautical Knowledge":

"Found on many gliders and some aircraft, high drag devices called
spoilers are deployed from the wings to spoil the smooth airflow,
reducing lift and increasing drag."

http://www.faa.gov/library/manuals/a...apter%2003.pdf

Flaps do not "increase lift". Flaps increase drag. As drag
increases, gilde slope steepens.

Flaps change the coeffecient of lift, but not lift.


Again, from the PHAK, same chapter:

"Flaps are the most common high-lift devices used on aircraft. These
surfaces, which are attached to the trailing edge of the wing, increase
both lift and induced drag for any given AOA."

(But I see you're being pedantic. Now you make a distinction between
"lift" and "coefficient of lift".)

Another question:

Q) Two gliders, one is 40:1 racer and glider two is 20:1 trainer.
Both weigh 800#

Glider one has twice the lift of glider two. True or flase and why.


Another no-win situation, since you don't indicate what they are doing.
Are they sitting stationary on the ground? Then both have zero lift. Are
they turning and if so, are the turn radii and descent rates different?
 




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