Mark James Boyd napisal(a):

I'm wondering if anyone regularly rolls gliders
down a cliff for launch.

I was thinking that a suitable slope off the edge of a cliff
would work just as well as any tow/winch/auto/bungee/rotax.
And if there is reliable lift nearby, you can come back and
land.

I know this is commonly done with hang gliders, but haven't
heard of a location that does this with gliders. Maybe somewhere
in the Sierras or Alps or something like that? Any of you
Europeans heard of something like this regularly used for gliders?
I'm thinking of a place where you launch, then find lift, do some
circles, and then come back and land.

It has been done regularly (provided proper wind direction&speed) at the
famous Bezmiechowa airfield in southern Poland. In 2001 we went there
with a group of friends from the Aeroklub Poznanski to try it out. The
weather was perfect for the task. 3 days, many, many flights (Bocian,
Puchacz, SZD-55) - GRAVITY LAUNCHES ONLY. No winch, no towplane, no
bungee, no release. See my start in SZD-55;

http://www.aeroklub.poznan.pl/szybow...ez01/bez09.htm

or an animation on a "Bocian"'s launch...
http://www.aeroklub.poznan.pl/szybow...ez01/bez22.htm

or the whole picture story of the expedition starting he
http://www.aeroklub.poznan.pl/szybow...ez01/bez01.htm and
to continue click the 'unvisited' link to the right of the thumbnails...

Note the wind strength on the trees and on the windsock. Just one turn
after being airborne was enough to get higher than the start point and
above the heads of those down on the ground. Unforgettable!

Not to mention the NIGHT RIDGE SOARING from a gravity launch on a
"Bocian"... No kidding.

BTW: Why "the famous Bezmiechowa airfield"? Alone in 1939 about 400
glider pilots were trained there. Check FAI files for pre-war records
flown from Bezmiechowa:

1938-5-18 Tadeusz Gora in a cross country flight between Bezmiechowa
and Wilno achieved distance of 577.8 km in recognition of which FAI
awarded him the first ever Lilienthal Medal.

1937-5-14 Miss Wanda Modlibowska finished her 24h 14 min flight which
set a new duration record.

In the links above, old historic pictures are added to give an idea what
Bezmiechowa used to be until the total distruction in WWII. Slowly being
rebuilt in recent years - very far away from its former glamour.

Tomasz Sielicki