On 5 Jul 2005 21:16:28 GMT, "Ian Johnston"
wrote:


As Bert already stated: As long as you stay within the safe speed
range, there is no way to exceed the stress limits of the glider -
simply there isn't enough lift available.

Um, must check, but am pretty sure angle of attack influences lift as
well...

Indeed... but if you stay within the allowed speed range, you'll get a
stall if you pull too hard instead of overstressing the glider.


Besides: I've never seen an ASW-20 break a weak link on my home
airfield. We were using the blue ones for the 20.

So why would anyone fly with a 33% over strength link?

Ask Bert - he's got his reasons!


Unless the glider hits a gust, or the pilot pulls back too hard, or
the throttle of the winch suddenly shoots open or ...

Nope.
Either of these cases results either in a stall (pulling back too
hard) or overspeed... but does not lead to overstress. If you leave
the safe speed range, you pull the release... problem solved
immediately.


It's been ages since I did a winch launch in an SF34 and I really
can't remember much about it, but surely in that case the manufacturer
should be approached about changing the link officially, and issuing a
strengthening modification if required?

Indeed... but nothing has happened.

I wonder if Centrair changed this on the Alliance 34? I must check the
handbook - we have one at my current (all aerotow!) club.

Please do - I'd be interested if it's different for the Alliance 34.




Bye
Andreas