"Eric Greenwell" wrote in message
news:ei5ch.74$R_1.4@trndny08...
news wrote:
Eric,

the forces are all the same.

there is no difference in forces strengths launching to 1000ft or to
5000ft
the applying forces just last longer thats all.

I agree with that, but what I asked about was the rate of climb (fpm =
feet per minute):

Surely the cable tension must be greater to provide a 3500 fpm launch
instead of a 1000 fpm launch?

--
Eric Greenwell - Washington State, USA
Change "netto" to "net" to email me directly

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Not surprising.

A typical launch will have the glider climbing at a 45 degree angle and 60
knots. That works out to a little over 42 knots vertical speed. Of course,
that the peak climb rate. The average on a high launch can be around 35
knots. The stresses are about the same as mild aerobatics.

There are a number of GPS logs on the web that show rates of climb about the
same as these figures.

If you want to work out the stress for yourself, the peak cable tension will
roughly equal the flying weight of the glider. The cable pull vector will
start horizontal and swing down to 70 degrees during the launch. At
approximately 70 degrees, the CG hook will automatically "back-release" the
cable.

Serious fun.

Bill Daniels