TOST Release Failure - Two Uncommanded Release's

Had two cases like this. One was a broken over-center spring in the release
(on one side only, only visible after dismantling the release). The other
an extremely heavy pilot making the seatpan sag and push against the
release lever. My bet is you have a spring problem.

At 06:38 12 October 2012, Peter Scholz wrote:
Am 12.10.2012 07:29, Bob Kuykendall wrote:
As others note, that is the classic symptom of the overcenter spring
being broken on one side. The spring in question is a two-sided
torsion spring with anchors on both sides of the overcenter arm. The
result of this failure is that the hook will seem to operate normally,
but it will self-release under very low loads.

It could also be the other failures suggested in this thread, but my
money is on the spring being broken on one side.

Thanks, Bob K.


This is the reason why the TOST release has a nominal TBO of 2,000 tows
(i.e. 10,000 cycles to the spring). Send it in to be services and be
happy for another 2.000 tows...
--
Peter Scholz
ASW24 JE

On Thu, 11 Oct 2012 17:03:04 -0700 (PDT),
wrote:

Weirdest thing today. On the grid, ready to takeoff. I had a highly experienced contest pilot hookup the small ring into my TOST hookup. When the towplane started rolling, after about 20 feet, it released uncommanded.

Hi Scott,

three questions:

- What kind of glider is it?
- How many launches are on the TOST hook?
- Am I correct that it is a CG hook?


Andreas