On 21/02/2014 06:21, Steve Leonard wrote:

Not to be to "chicken or egg" here, but, I don't think the horizontal
tail of the towplane stalled. I think the glider provided an upward
force, creating a nose down pitching moment far greater than the
elevator could counter (obviously, right?).

Mmm. ...and how would that differ from a stalled tailplane? Isn't it
the same as an accelerated (1g) wing stall?

We know that this event does not happen often, but when it does, it
often has catastrophic results. I don't think there is a practical
way to attach the rope to the CG of the towplane. So, we are left
with training (which we have seen does not eliminate the problem) or
some sort of automatic system (since it has been documented that it
is unlikely a pilot can react fast enough to be able to save his or
her own life if it goes really bad).

Experience shows that training NEVER eliminates problems but can reduce
a problem's frequency to acceptable levels. Kiting is already a very
rare event as another poster (Chris himself, IIRC) showed and this is
largely due to training.

Experience also shows that automation may eliminate a problem but also
produces failure cases (which must, in any case, be trained for).
Further, as Air France's A330 showed, automation almost always means
that pilots aren't as good at dealing with the problem as they would be
if they knew their training was the only thing stopping the accident.

No. In this case, well-trained, alert glider and tug pilots are the
cost-effective solution to the problem. The automated release is pie in
the sky.

GC


Time to start working on a secondary pull system (sorry, Kirk. No
explosive bolts or missles. Would be more fun, though.) using
attitude and elevator positon. Or maybe attitude and pitch rate.
Need to keep it as simple (fewest inputs and software) as possible.
I do like the idea of initial tests of set values to turn on a light
in the cockpit for the pilot to see that the automatic system will
have operated. Got any reasons not to start at 10 degrees nose down
pitch attitude and half way to max nose up elevator travel?

Steve Leonard