Btw, the distance of the ground run after touchdown has little to do
with flaps & airbrakes - it's a function of the speed at touch down,
and your gross weight.


Ah, the potential fuzziness of free, condensed, advice!

While some of the above statement is absolutely correct, specifically the,
"...it's a function of the speed at touch down, and your gross weight" bit,
the, "Btw, the distance of the ground run after touchdown has little to do
with flaps & airbrakes..." lead-in may be just a tad misleading for readers
either lacking the specific engineering background, or, otherwise new to flaps.

Because the large-deflection landing flaps used on some sailplanes definitely
do increase lift, this gives Joe Interestedly-Capable Glider Pilot the
*option* of consequently touching down at a slower speed than would otherwise
be safely possible without the flaps' presence. Hence I disagree with the
lead-in statement, IF we presume Joe Glider Pilot is interested in learning
how to get the most (i.e. shortest) landing performance from the glider.

To this point, considering the lead-in video of this thread,I dare say few
gliders of any semi-modern ilk would be capable of touching down and rolling
to a halt, on a paved surface, in a(n ~)5-knot headwind in *only* 300' (twice,
so it might not have been pure luck!) withOUT using that flap-specific
advantage. Kinetic energy remaining after touchdown of a landing glider, after
all, is proportional to speed *squared*, while also being proportional to
touchdown weight (not squared).

Quibblingly,
Bob W.