Safety of winch launch vrs. aero tow?

Teaching aerotow launch failure options with a motor glider.

JJ has always disliked the idea of using a motor glider for any purpose
whatever, and he has the same opinion of turbo and self-launching gliders
(unless old age is getting to him and he has changed his opinion recently).
His opinion is purist, aesthetic and emotional, and I can remember him
admitting this. Dunstable never used a motor glider for training while he
was running things, they got one after he retired from the club management.
It is a matter of what is most fun, flying with JJ has always been fun
(unlike some instructors I could name).

It is now a BGA requirement that glider pilots get a "Cross-Country
Endorsement" to their Gliding Certificate before deliberately flying
cross-country. See "Laws and Rules for Glider Pilots" edition 14 (BGA),
page 44 section 17.12. In the section on Field Landings it states: "The
candidate must make a minimum of two successful approaches, selected by
himself in a motor glider. .....". The motor glider is used of course so
that an approach can be made without actually landing.

The use of motor gliders for glider pilot training generally has always been
controversial in he U.K., the strongest advocate was always Derek Piggott.
However whenever a club has got used to using a motor glider for teaching
the cross country skills of Navigation, Field Selection and Field Landings
it has always been accepted as being valuable, and its use for teaching
Field Landings is now mandatory.

In the case of aerotow launch failures the training I had in mind was for
the cases where turning back to the airfield is not a safe option. This
then becomes an exercise like any field landing, except that the decision to
land is immediate and unexpected, but should be into a field already known
about.

As for the case where it is possible to turn back to the airfield, if it is
not possible in a motor glider with a very experienced instructor
supervising, and the exercise known about in advance; would it be sensible
for a rather inexperienced pilot solo and taken by surprise?

The type of motor glider almost invariably used for this area of training in
the U.K. is one of the Falke series.

Winch launching at Dunstable.

I flew 917 launches at Dunstable as instructor between 1992 and 1994, almost
all of them by winch, most in the K21 the remainder in the K13. I did many
launch failure exercises (we all did) and none of them finished in a field.

The field is fairly small, and roughly rectangular in shape so all the winch
runs are short. I recall that 1,200ft was a good launch, and sometimes on
some runs we got 800ft or less. 150m or 450ft would be far too high to
land ahead unless the wind was strong, on a no wind day such a height would
be considered easy for a short circuit.

As for congestion on the airfield, of course one would not launch if there
were nowhere to land, it is simply that one seldom had the whole area
available.

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.


"Robert Ehrlich" wrote in message
...


"W.J. (Bill) Dean (U.K.)." wrote:
...
There is a lot to be said for using a motor-glider for
teaching aerotow landing options, though JJ won't like this idea!


I agree with JJ's opinion. My computation identified the minimum of
Vz*V as an important factor in the possibility of turning back, and
this values is usually much higher in a motor-glider, due to higher
wing loading and worse aerodynamic.

...
As to wire launch failures at Dunstable, yes there is often a very
narrow gap between being too low to turn and too high to get in straight
ahead.


I don't understand clearly what is the problem at Dunstable. What is the
length of runway ahead of you when you reach 150m?

...
Often the field is partly blocked by gliders
awaiting retrieve, and tractors on their way to do the retrieve.


In this case, if they don't allow a sufficient free space to land
in case of a cable break, you should delay the start.