First of all, if the weak link breaks, the overload would be 33% (I don't
know what you do to get 50-75%).
Secondly, the point is not to get the weak link breaking at all. As long as
you stay within the limits of max winch tow speed, the overload is zero.
You might be not aware, but there is a good number of clubs who don't use
any weak links _at all_ (or launch marshalls...).

And I stand my point - it is my responsability to deal with my security, my
insurance and my legal authorities. Good luck? Go tell that to those who had
an accident initiated by a weak link failure. After 25 years of flying, I
still have to learn about a case of structural overload during winch launch.
However, I can accept that if I don't fly my glider, that I am imposed to
the owner's rules.

--
Bert Willing

ASW20 "TW"


"Ian Johnston" a écrit dans le message de news:
dzZo7CxomoOm-pn2-8g13dep07KYM@localhost...
On Tue, 5 Jul 2005 12:45:41 UTC, "Bert Willing"
wrote:

The book says it should be red.

Which is 750dN, and you are launching with black, which is 1000dN.
That 250dN (33%) extra probably represents around 50 - 75% overload at
the wing fuselage junction. With all due respect, that's an insane
risk to take. Would you fly your glider with a cockpit load or ballast
250kg above the maximum permitted? Would your insurance company let
you? Would your national aviation authority let you?

And as long as I'm operating my private
ship, it's me who is responsible for which weak link I ask for.

Indeed, but as long as you are being launched by other people it is
their responsibility to assess your request and, if it's unsafe,
refuse it, just as it would be their duty to refuse to launch you if
you were drunk, or if your airbrakes were open.

Launch
marshals may comment on that, but not decide.

On the contrary, I believe that launch marshalls /should/ decide.
Nobody should be complicit in dangerous behaviour of this sort.

I have seen (from the ground) quite a couple of critical situations
resulting from fatigued weak link breakage, and I prefer to watch angle
of
attack and speed, and pull the knob myself if necessary.

Well good luck - and here's hoping that by the time you pull the knob
the hook (and wheel on an ASW20?) isn't on its way to the ground along
with sundry control connections. That's if a good unexpected bump on
the way up hasn't taken your wings off.

Ian