The "Flap-only" system appear most often on homebuilt sailplanes. (Schreder
series, BG-12-16, etc) I am sure the designers realized that simplifying
wing construction was one of the advantages of the flaps-only system.

BTW, I don't use the flaps to fly a lower my approach speed. I use them for
the massive amount of drag that they produce.

Wayne
HP-14 "6F"
http://tinyrul.com/N990-6F


"toad" wrote in message
...

On Aug 15, 10:55 pm, BobW wrote:

The 'purpose of flaps' - Is this where philosophy enters the aerodynamic
world
definable by flaps' effect on a glider's polar?
....
Where I'm headed with this is, one can reasonably conclude the 'purpose of
flaps' is whatever JGP decides, within their aerodynamic capabilities. ...

Joe Pilot didn't put the flaps there, Bob the designer did. He had a
"purpose", which was probably to lower the stall speed and thus the
approach speed and all the other good things that come from that.