Replacing TOST release at 10K activations

So, what's the real test, Bob? Would simply giving it a good tug after
hookup disclose a failure? Or would it simply not close over the ring, once
installed by the wing runner? I have only a CG hook - wouldn't it suffer
the same failure mode?


"Bob Kuykendall" wrote in message
...
On Tuesday, January 28, 2014 9:16:06 AM UTC-8, Dan Marotta wrote:
...Checking it again before takeoff will probably be the last
time it functions properly and it will fail during the launch and I'll
have
to land on tow ...

Dan, the vast majority of Tost E85 nose hook failures are caused by
failure of the torsion spring that keeps the hook closed. The result is
that the hook will open just fine, it just won't close properly.

Thanks, Bob K.

On Wednesday, January 29, 2014 3:36:56 PM UTC-8, Dan Marotta wrote:

So, what's the real test, Bob? Would simply giving it a good tug after
hookup disclose a failure? Or would it simply not close over the ring, once
installed by the wing runner? I have only a CG hook - wouldn't it suffer
the same failure mode?

I'm sorry, I don't know the answer to that one.

The one failure I was directly involved with was where one side of the spring had broken, but the other side was intact. The result was that the hook appeared to function correctly, but it sprung open as soon as the towplane powered up. JJ can probably tell you more about this.

Bob K.

On Wednesday, January 29, 2014 6:17:11 PM UTC-7, Bob Kuykendall wrote:
On Wednesday, January 29, 2014 3:36:56 PM UTC-8, Dan Marotta wrote:



So, what's the real test, Bob? Would simply giving it a good tug after

hookup disclose a failure? Or would it simply not close over the ring, once

installed by the wing runner? I have only a CG hook - wouldn't it suffer

the same failure mode?



I'm sorry, I don't know the answer to that one.



The one failure I was directly involved with was where one side of the spring had broken, but the other side was intact. The result was that the hook appeared to function correctly, but it sprung open as soon as the towplane powered up. JJ can probably tell you more about this.



Bob K.

Same thing on CG hook, at least with two up. Pull on rope was not enough for the release to open. On another CG hook, release failure, but this was attributed to wear on one of the shafts. CG hooks get a lot of dirt, water (in come regions), and probably an annual cleaning.

Frank W.

I guess I could also examine one closely and try to figure it out!


"Bob Kuykendall" wrote in message
...
On Wednesday, January 29, 2014 3:36:56 PM UTC-8, Dan Marotta wrote:

So, what's the real test, Bob? Would simply giving it a good tug after
hookup disclose a failure? Or would it simply not close over the ring,
once
installed by the wing runner? I have only a CG hook - wouldn't it suffer
the same failure mode?

I'm sorry, I don't know the answer to that one.

The one failure I was directly involved with was where one side of the
spring had broken, but the other side was intact. The result was that the
hook appeared to function correctly, but it sprung open as soon as the
towplane powered up. JJ can probably tell you more about this.

Bob K.