"Kilo Charlie" wrote in message
news:9D3we.3579$Qo.3471@fed1read01...
Your input re winch launches is appreciated Bill....esp for those of us
that
have never done one!

Please don't take this as a criticism of winch launches but through this
thread there has not been any mention of what happens at the critical low
level altitude when the cable breaks. There is clearly also a zone of
real
problems with aerotows too.....esp here in the desert with few, if any
landing options straight ahead. What do you guys teach re breaks at 100
feet? It seems like landing ahead would be good but how much altitude
does
it take to regain the necessary speed to be able to control the glider for
landing when at a high angle of attack? Sorry if this is too obvious for
those of you that do it all the time!

Casey


Thanks, Casey.

The climb profile must be such that a safe recovery with generous margins be
possible from any height that a cable break occurs. Safety is the product
of airspeed, altitude and attitude - and good training.

If the break happens at 100 feet, then 90%+ of the runway lies ahead to
receive the glider. At 100 feet, the glider will have full climb airspeed,
approx. 60 knots, but then pitch attitude will only be 20 - 30 degrees. A
prompt, gentle pushover to a glide at approach airspeed is all that is
needed to land straight ahead.

If the break occurs higher, say 300 - 400 feet, then the straight ahead
landing is still possible with spoilers but a tight 360 pattern is also
possible. The two options overlap by a good amount of height depending on
the airfield. At this height, the climb attitude will be about 45 degrees
nose up (although from the cockpit it will feel like 60 degrees) so a more
aggressive pushover is needed.

All these situations will be practiced over and over until the instructor
feels the student reacts instinctively and correctly to each. The student
must firmly push the nose down until the airspeed is observed to be at a
safe value and increasing before establishing a glide for a straight ahead
landing or a turn for an abbreviated pattern.

I must admit that winch launch LOOKS scary and FEELS scary to the
uninitiated but the procedures worked out over literally tens of millions of
launches in Europe and elsewhere make it actually safer than air tow.

As for releasing over the winch instead of wherever the tow plane takes you,
I see by looking at a lot of On-Line Contest IGC files, that most air tow
releases happen within a mile of the takeoff point and the glider is rarely
in a thermal at release but must glide around looking for one just like with
a winch launch. If you don't find a thermal, a winch re-light will cost you
less than $10.

The latest European winches are getting even heavy gliders to over 1000
meters AGL so finding lift shouldn't be a problem.

Bill Daniels