"Gary Nuttall" wrote in message
...
Not as much as it disturbs me that there might be people
out there who will stake their lives against a set
of numbers in a book. The margins of safety are so
much tighter in a glider/sailplane than a powered aircraft
and a minor change in any one part of the equation
could have dramatic results.

Let's be clear here.....Some numbers you can be confident
in becuase they've been measured in a certain, calibrated
and controlled environment and as such I 'trust' them
- e.g. VNE/VDF are tested in still air with a new airframe.
Even then, I'm not going to fly right up to the limits!

The problem I have with calculating a takeoff run is
that there are just so many variables involved that
you cannot consistently and safely rely on the results.
As Todd's post suggests, work out a go/no go point
and if you're not airborne, release.

As a glider pilot I act within both my and the glider's
limits. I trust my instincts that if something doesn't
feel right, I abandon the launch while it's still safe
to do so. Maybe it's a US vs UK thing but here in
the UK we take personal responsibility for our actions.
If you're not sure that you have sufficient distance
to take-off then why would you trust a set of numbers
that say otherwise ? I think the concept of calculating
takeoff runs is actually quite interesting but the
sheer number of variables involved make it an impracticable
exercise.

Gary

Wow....I certainly didn't think that this question would degenerate into a
US bashing exercise but ya just never know on ras!

You clearly have a bug up your patoot re quantitation Gary. I think that
Bill, Tuno and I are on the same page though. I would challenge Gary's
remark that "The margins of safety are so much tighter in a glider/sailplane
than a powered aircraft". In fact I think that the opposite is true but
then that is for another discussion. I'll only say that the glider on tow
is always in better shape than the towplane if the engine quits.

Nowhere did I say that this is a matter of inches and would choose to "push
to the limits" based upon an equation without the usual margin of safety
added to it. Currently we have no place to begin the discussion based upon
facts so that is what I'd like to see happen. And also who said anything
about the FAA getting involved???

Whether any of you like to admit it or not you are all using data on each
glider flight....esp if you go XC. If L/D is worthless then why not try to
make that field far off in the distance in your 1-26?

So I would surmise that some of you would choose to head up to a high
altitude site on a hot day, take a tow then while rolling make a decision as
to whether you feel safe continuing. That would seem like a big waste of
time to me.

And Gary.....I love you guys in the UK......great sense of humor, great
beers and some awesome racing pilots......but lets face it......you ain't
got no high altitude soaring sites....at least not in Great Britain. ;-)

Cheers,
Casey Lenox
KC
Phoenix