Ground launching equipment question

Jim,
My experience is with winch launching. Have done it for many years in
Europe.
By looking at the video, the climb angle is way too shallow, at least
of it were a winch launch. The chute opens while following the rope
after initial lift off.

Following the rope is never a good idea unless you're going to
release. At least with winches.

Right after lift off, one should start climbing gradually and increase
the angle once more than 100ft. That way the rope tension stays firm.

If the air speed should become uncomfortably slow or remain too slow,
you can release safely at 100ft or more. Height = safety - even when
slow. So you always want to get some air under the wings and keep the
rope tension up.

By pushing the nose over even at low airspeeds and then releasing, you
won't stall and land straight ahead and see why the speed was too low.

But following the rope on initial launch for more than 2-3 seconds
because the speed isn't high enough, is not proper technique, at least
not on the winch and I would say probably on a car tow as well.

Either release immediately and abort or gently climb out for the first
100ft and then release if speed remain too low for comfort.

Ground launch requires very quick reaction without any hesitation.
There for it requires a plan of action firmly in place ahead of time
that needs to be followed during launch. If the pilot is prepared
properly and knows how to react given the situation, I think it is
much safer than aero tow.

Once you're over 100ft, nothing much can go wrong.
Tom

Even on the second video, the pilot is heard saying "almost level
attitude" on initial climb out. That is totally wrong technique and
the chute is opening in front of him as a result. That as we saw, is
dangerous.

He would need to climb out a little steeper for the first 100ft and
all would be OK.

Even on winches the chute can open for split second sometimes, but as
the pilot pulls, they close back up again.

Also the climb in the second video is not done very smooth. Proper
technique is to gradually start easing back on the stick and leveling
off as maximum altitude is reached. You will know this because the
sailplane will start rocking back and forth, pitching the nose up and
down, if you don't ease back and the angle remains too steep. The
plane does not like to be dragged through the air at a high angle of
attack, which is what happens when the angle is too steep - regardless
of the airspeed.

Suddenly leveling out and releasing means the maximum altitude was not
reached. Either they leveled off too soon or too late.

Then again, maybe the car had to stop due to a limited ground run.
Then the release technique used in the second video is understandable.
Otherwise not.

This thread was started by someone asking fairly basic
questions about ground launching, and from the responses
doesn't seem to have much (any?) experience of it.

It's been said several times before, but ground launching
is a potentially dangerous business, and before trying
it one should go to an operation which is experienced
in it. You would learn about how the equipment is put
together, how the car or winch is operated and how
the glider should be flown. Also how to cope with potential
problems when things go wrong - low level cable breaks,
wing dropping, use of weak links, just for example.
Life is too short to learn all these things by making
your own mistakes - and it could become even shorter.

In any case, I haven't looked at the rules for my US
glider pilot's licence for a while, but I have a feeling
that it only allows me to use the launch methods which
I am qualified for (which does include winch and autotow.)
If you haven't got a ground launch qualification don't
you need at least an instructor's sign-off, which would
need at least some training in how to do it properly?

Neil

On Nov 7, 9:57 am, Neil MacLean
wrote:
This thread was started by someone asking fairly basic
questions about ground launching, and from the responses
doesn't seem to have much (any?) experience of it.

It's been said several times before, but ground launching
is a potentially dangerous business, and before trying
it one should go to an operation which is experienced
in it. You would learn about how the equipment is put
together, how the car or winch is operated and how
the glider should be flown. Also how to cope with potential
problems when things go wrong - low level cable breaks,
wing dropping, use of weak links, just for example.
Life is too short to learn all these things by making
your own mistakes - and it could become even shorter.

In any case, I haven't looked at the rules for my US
glider pilot's licence for a while, but I have a feeling
that it only allows me to use the launch methods which
I am qualified for (which does include winch and autotow.)
If you haven't got a ground launch qualification don't
you need at least an instructor's sign-off, which would
need at least some training in how to do it properly?

Neil

Yup, signed off 3 years ago. AFTER not only training, but
experiencing the following WITH an instructor:
1. overspeed requiring release at around 150 feet.
2. Rope break at around 200 feet
3. Rope break at 12 feet
4. Succesful climb to 1100 feet (SGS2-33A on 1800' Poly rope)
Since, I've taken some auto-tows in the club 1-26, and several in my
Speed Astir.
The tow in question was my first behind a rope with a chute.

OK, training done, my apologies if I misinterpreted
from the first posting where you were coming from.
But I still think there might be something wrong with
the parachute setup - it shouldn't open under the normal
tension of the tow.
And 65 to 75 mph does seem too fast for the tow car.
I drove tow cars for many years before we changed over
to a winch, and I don't recall ever going as fast as
that even in no wind conditions.
I hope you sort out the problem.

Neil

On Nov 10, 9:51 am, Neil MacLean
wrote:
OK, training done, my apologies if I misinterpreted
from the first posting where you were coming from.
But I still think there might be something wrong with
the parachute setup - it shouldn't open under the normal
tension of the tow.
And 65 to 75 mph does seem too fast for the tow car.
I drove tow cars for many years before we changed over
to a winch, and I don't recall ever going as fast as
that even in no wind conditions.
I hope you sort out the problem.

Neil

It will have to wait until our next dry lake weekend. The BLM insists
on 6 months lead time to obtain a 'use permit' for the dry lake.

I agree with Neil, I think there is a problem with
the chute set up. I got my sign off a long time ago
on auto tow and we didn't use a chute. I have more
recently become somewhat active in the Prescott Soaring
Society where we winch launch exclusively, and I am
in no means an expert at this but, our chute systems
all have at least 8 gore lines. I seem to remember
that yours only had four. I would think that the more
gore lines would allow less of the chute to to be exposed
to the relative wind when under tension, each line
holding in less of the chute. Just a thought.


At 06:18 12 November 2007,
wrote:
On Nov 10, 9:51 am, Neil MacLean
wrote:
OK, training done, my apologies if I misinterpreted
from the first posting where you were coming from.
But I still think there might be something wrong with
the parachute setup - it shouldn't open under the
normal
tension of the tow.
And 65 to 75 mph does seem too fast for the tow car.
I drove tow cars for many years before we changed
over
to a winch, and I don't recall ever going as fast
as
that even in no wind conditions.
I hope you sort out the problem.

Neil

It will have to wait until our next dry lake weekend.
The BLM insists
on 6 months lead time to obtain a 'use permit' for
the dry lake.