Safety of winch launch vrs. aero tow?

On Sat, 25 Oct 2003 12:43:35 -0700, "Gary Boggs"
wrote:

Someone must have already compared the safety of these tow launch methods.
What do the statistics show is the safer method of launch? Aero tow seems
to involve more inherent dangers to me. For one thing, there is just more
time for things to go wrong. What could be more dangerous than to tie tow
airplanes together and try to fly?

Gary Boggs


I've only done about two winch launches but have done several hundred
car tows and driven several hundred also.

Ground launches involve lots of wire, rope etc. It is probably a good
observation that the more rope you have the more trouble you can get
into! With one exception below.

I've had the glider run over the wire and tangle in the wheel well.
Not good as you now cannot release and depend on the tow driver..

Pilot reactions to a low altitude winch launch failure are utterly
critical. I suspect we've killed dozens if not hundreds over the years
this way around the world.

You may need more than one launch to get away(rare with aerotow). This
increases your launch risk exposure.

Someone mentioned the stresses in the wire and the glider. Both are
much lower in properly executed arotow.

Aero tow may have a higher exposure to an off airport landing in
unsuitable terrain but the failures seem to be much more rare than
winch wire breaks. If you don't use toy towplanes(less than 180HP)
then any place suitable for winching probably gives you the
opportunity to do a 180 or land straight ahead from an aerotow.

If you want gliding to be popular aerotow involves less running around
on the ground per flight hour.

Flying towplanes is more fun than driving a winch or tow
car.(Allegedly - I last sat in a towplane in 1971 writing down CHT's
for the cooling test for 4 tows in a row and haven't felt motivated to
get into a towplane since despite the aquisition of a PPL 9 years ago)

Aerotowing danger can be reduced by using a longer rope. One of the
local clubs around here tried it and liked it so much the towpilots
won't fly with short ropes. The long rope gives everyone more time to
handle upsets. I suspect the rise of the towplane upset accident
coincided with using shorter ropes.

Mike Borgelt

"Mike Borgelt" wrote in message
...

If you want gliding to be popular aerotow involves less running around
on the ground per flight hour.


A cable retrieve winch such as the one in use at the Long Mynd in the UK
makes a winch operation even slicker than aerotowing!

Ian

On Mon, 27 Oct 2003 05:41:06 +0000 (UTC), "tango4"
wrote:


"Mike Borgelt" wrote in message
.. .

If you want gliding to be popular aerotow involves less running around
on the ground per flight hour.


A cable retrieve winch such as the one in use at the Long Mynd in the UK
makes a winch operation even slicker than aerotowing!

Ian



So how many winch operations involve two people?
I've had tows where the only people present were the tow pilot and the
glider pilot. Least I got with auto tow was three. Both were no radio
ops.

And for you guys who operate on nice green grass airfields which allow
things like cable retrieve winches - it don't happen in Oz.

And lastly we did have a winch driver killed during a winch launch a
few years ago. The wire (basically high tensile single strand fencing
wire) shattered as it was being reeled in after the glider released
and one of the pieces of shrapnel hit the winch driver in the upper
torso and he died shortly thereafter before anyone got to the winch.
The lexan shield had been bought but not installed.

My favourite launch method involves a motor in the glider.

Mike Borgelt

"Mike Borgelt" wrote in message
.. .

And for you guys who operate on nice green grass airfields which allow
things like cable retrieve winches - it don't happen in Oz.

***********
You have obviously never been to the Long Mynd - I have heard it described
rather unkindly) as " a barely levelled granite hilltop".

The retrieve system ( a small winch pulls the cable back to the launch
point) originated out of necessity many many years ago when the airfield was
much smaller and the winch had to be positioned outside the boundary. The
cable crossed a deep, (approx 15/20 ft) gully at the airfield boundary and
then on up along a slope covered in bracken and heather, any other method of
retrieving the cable was impracticable. However the system was so efficient
in terms of launch rates that it has continued to this day even though the
airfield is now big enough to site the winch within the boundary. There is
of course a small penalty in terms of launch height but this is of little
significance.

On Mon, 27 Oct 2003 11:59:17 -0000, "Silent Flyer" ]
wrote:


"Mike Borgelt" wrote in message
.. .

And for you guys who operate on nice green grass airfields which allow
things like cable retrieve winches - it don't happen in Oz.

***********
You have obviously never been to the Long Mynd - I have heard it described
rather unkindly) as " a barely levelled granite hilltop".

Actually I have in 1988.
The surface looked pretty good compared to most Oz airfields. There
are one or two which I've jokingly said you would fail an outlanding
check if you picked the airfield.

I'm sure there are good statistics available for the safety of winch
vs aerotow but nobody has come up with them.

Winching is cheaper for training but has anyone noticed that gliding
is shrinking worldwide? Perhaps the old way of doing business is no
longer successful?

I think we need to realise that gliding is a sport for *pilots*.

First turn a newcomer into a pilot.

There is a wonderful array of small light aircraft and /or
motorgliders available nowadays at very reasonable prices. In Oz a
Pipistrel Sinus costs about the same as a new ASK21 and for the
purposes the K21 would be mostly used for (primary training) the Sinus
might be not quite as good a sailplane but will more than adequately
do the job and lets you teach cross country navigation, outlanding
field selection etc as well as being a not bad two seat bugsmasher.
Combine training in one of these with motivational rides with cross
country pilots in high performance two seat gliders(minimum - Janus,
Duo etc preferably with self launch or turbo to prevent outlandings)
and I think you might have a 21st Century soaring movement that might
have a fighting chance of actually retaining the people that come to
it.

Mike Borgelt

A winch driver won't get killed if the winch is equipped properly. And a
cable breaking near the winch under full power is something very, very
dangerous, so sitting on a winch without shielding is asking to be killed.

The min team for winch launches is the pilot, the winch driver and the wing
runner (the winch driver can retrieve the cables on his own if the winch has
properly working brakes on the drums). If pilot and winch driver are
suffiencently experienced, a chair may well replace the wingrunner (although
stating that in public may not be politically correct :-)

During winch launch, any accident is related to pilot errors so you can
basically keep the accident rate fairly low.

On aerotows you may have situations were a cable break *will* induce an
accident, and the pilot may just be able to influence the damage.

--
Bert Willing

ASW20 "TW"


"Mike Borgelt" a écrit dans le message de
...
On Mon, 27 Oct 2003 05:41:06 +0000 (UTC), "tango4"
wrote:


"Mike Borgelt" wrote in message
.. .

If you want gliding to be popular aerotow involves less running around
on the ground per flight hour.


A cable retrieve winch such as the one in use at the Long Mynd in the UK
makes a winch operation even slicker than aerotowing!

Ian



So how many winch operations involve two people?
I've had tows where the only people present were the tow pilot and the
glider pilot. Least I got with auto tow was three. Both were no radio
ops.

And for you guys who operate on nice green grass airfields which allow
things like cable retrieve winches - it don't happen in Oz.

And lastly we did have a winch driver killed during a winch launch a
few years ago. The wire (basically high tensile single strand fencing
wire) shattered as it was being reeled in after the glider released
and one of the pieces of shrapnel hit the winch driver in the upper
torso and he died shortly thereafter before anyone got to the winch.
The lexan shield had been bought but not installed.

My favourite launch method involves a motor in the glider.

Mike Borgelt

"Bert Willing" wrote in
message ...
A winch driver won't get killed if the winch is equipped properly. And a
cable breaking near the winch under full power is something very, very
dangerous, so sitting on a winch without shielding is asking to be killed.

The min team for winch launches is the pilot, the winch driver and the
wing
runner (the winch driver can retrieve the cables on his own if the winch
has
properly working brakes on the drums). If pilot and winch driver are
suffiencently experienced, a chair may well replace the wingrunner
(although
stating that in public may not be politically correct :-)

During winch launch, any accident is related to pilot errors so you can
basically keep the accident rate fairly low.

On aerotows you may have situations were a cable break *will* induce an
accident, and the pilot may just be able to influence the damage.

--
Bert Willing

ASW20 "TW"


I was recently shown (very discretely) a wing runner replacement by a pilot
who uses ground launch.

I was comprised of a long tripod made of PVC pipe, topped with an inverted,
felt lined, ski-type runner, on which the wing tip slid. It would hold the
wings level for the first 2 meters of the takeoff roll. It could be
dismantled and stored in the glider trailer.

The successful use of this device depended on excellent radio communication
between the glider pilot and the tow car/winch driver plus a very good wheel
brake on the glider so that the pilot could prevent being pulled off the
tripod as the slack was slowly pulled out. I was told that it worked very
well.

Way back in the 1960's a friend and I would trailer our gliders out to
remote dry lakes in the Mojave Desert. We would take turns auto-towing the
other into the air. The obvious problem is that the pilot driving the tow
car was left on the ground with his glider if the other found lift.

On one occasion, I caught a thermal and soared away leaving my friend on the
ground. I felt bad about leaving him on the ground but thought - but hey, I
have lift. Shortly afterward, my friend joined my thermal in his glider.
He had talked a curious passer by into driving the tow car.

We just started the launch with the wingtip on the ground. Ground launch
crews can be very small.

Bill Daniels

Mike Borgelt wrote in message . ..
On Sat, 25 Oct 2003 12:43:35 -0700, "Gary Boggs"
wrote:

Someone must have already compared the safety of these tow launch methods.
What do the statistics show is the safer method of launch? Aero tow seems
to involve more inherent dangers to me. For one thing, there is just more
time for things to go wrong. What could be more dangerous than to tie tow
airplanes together and try to fly?

Gary Boggs


I've only done about two winch launches but have done several hundred
car tows and driven several hundred also.

Two winch launches. Helps to understand why you say what you say later
on.


Ground launches involve lots of wire, rope etc. It is probably a good
observation that the more rope you have the more trouble you can get
into! With one exception below.

I've had the glider run over the wire and tangle in the wheel well.
Not good as you now cannot release and depend on the tow driver..

Pilot reactions to a low altitude winch launch failure are utterly
critical. I suspect we've killed dozens if not hundreds over the years
this way around the world.

Yes, the reaction is critical. But even more important is the correct
attitude corresponding to airspeed and altitude at all times. This
does make the reaction when something goes wrong a quite a bit less
critical.
I guess we have about 0.5 cable breaks and 2 or 3 weak link breaks per
1000 launches. We do about 3500 winch launches a year. It can happen
and if the pilot is properly instructed he knows this and is prepared.
I do not consider cable break or engine failure to be a _problem_ when
launching even when it happens.


You may need more than one launch to get away(rare with aerotow).

Normally not.

Someone mentioned the stresses in the wire and the glider. Both are
much lower in properly executed arotow.

Stresses are normally higher, but where's the problem in that? The
glider is built to easily take those stresses and we change the wire
once a year anyway.


Aero tow may have a higher exposure to an off airport landing in
unsuitable terrain but the failures seem to be much more rare than
winch wire breaks. If you don't use toy towplanes(less than 180HP)
then any place suitable for winching probably gives you the
opportunity to do a 180 or land straight ahead from an aerotow.

Definite 'No' on the 'probably gives you' bit.
From a winch launch you should _always_ be able to land on the
runwyay. I know lots of airfields where you have a certain time,
sometimes only two or three seconds, sometimes ages, in the aero tow
when you definitely do _not_ want _anything_ to go wrong. The
suitability of the airfield for whinch launching has no relevance
here.


If you want gliding to be popular aerotow involves less running around
on the ground per flight hour.

Don't see why. Only thing to do additionally is retrieveing the winch
cable. And the guy drives, he doesn't run.
And: If you want gliding to be more popular among the people living
near the airfield you should stop making such a racket with those
ancient technology fuel to noise converters. Instead we do 80% of our
launches with 0.4 litres of Diesel.


Flying towplanes is more fun than driving a winch or tow
car.(Allegedly - I last sat in a towplane in 1971 writing down CHT's
for the cooling test for 4 tows in a row and haven't felt motivated to
get into a towplane since despite the aquisition of a PPL 9 years ago)

Aerotowing danger can be reduced by using a longer rope. One of the
local clubs around here tried it and liked it so much the towpilots
won't fly with short ropes. The long rope gives everyone more time to
handle upsets. I suspect the rise of the towplane upset accident
coincided with using shorter ropes.

Agree to all that.

Regards
Marcel