JJ Sinclair wrote:
Just some facts, Eric. At Stead 2 gliders that were tied down at wing
tips and tail with 3/8" poly rope, broke all 3 ropes and performed a
near perfect half loop landing upside down after experiencing a
reported 100 knot wind (ships were tied down facing the wind).

At Minden 2 ships did much the same maneuver after experiencing about
the same wind (Winter storm frontal passage).

Raising the tail to get a negative angle of attack and locking the
spoilers open can go a long way in preventing the above OR, put it in
the box!

Does anyone know the force required to break those ropes; for example,
were the ropes tested afterwards for breaking strength?

Was there any analysis of the forces on the gliders? A 100 knots might
destroy a glider, even if the ropes held. That happened to our club
Blanik years ago in winds of about 70 mph.

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

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

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