Almost perfect payout winch launch.

At 02:45 10 May 2013, Bob Kuykendall wrote:
Don, I can respect that you have reservations about the method in
question. But it would be a lot more constructive if you'd provide
specific examples of why the method in question is inadvisable, and
are prepared to tell us how it can go wrong. Otherwise, when you call
people "foolhardy" and tell them flat out to "stop it," you mostly
just come across as a disagreeable curmudgeon.

Furthermore, I think that anybody who has used a winch but decries the
"complexity" of other ground launch methods does not really understand
how complex a good winch is, and how many points of failure there
really are.

Thanks, Bob K.

Fair point Bob

If we consider the simplest winch where the engine is connected to a
transmission via a gearbox of some kind. In this type of winch the driver
is seated and controls the throttle to control the speed of cable
retrieval.

What can go wrong? Three basic things as regards the operation of the
winch.

1. A break in the cable
2. A mechanical failure of the winch
3. Winch driver error or incapitation.

All of these eventualities are dealt with by practising launch failures or
launch abandonment. As far as mechanical failure of the winch is concerned
there are only two main components to fail, the engine (Uncommon but not
unknown) and the transmission. In all cases the winch driver is seated with
a good view of what is going on and can react to problems as they arise, in
particular using the guillotine if required in a timely manner.
The first winch I drove was of this time, a 3 litre petrol engine driving a
winch drum through a conventional 4 speed gearbox.
The most complex winch I have driven was a Munster Van Gelder winch with a
ginormous turbo diesel engine providing power for 6 seperate drums through
a torque converter. The engine control, transmission and drum select
functions were complex but once the transmission was connected to the power
module the principle was the same as for the simple Eagle winch described
above. Failure of either winch by mechanical failure of the
engine/transmission during launching was very rare. The MVG winch was
however less reliable in that faults within the more complex system meant
that it was U/s far more often than the simple winch, and took longer to
fix. Having said that the components making up the MVG winch were of top
quality and specifcally designed or adapted to provide the proper function,
it was just that there were more components to go wrong. In both cases the
winch was fixed, the driver had control and could see the glider at all
times and take the appropriate action.

The payout winch provides an additional level of complexity and reduces the
ability of the operator to control the launch. Some aspects of the launch
rely totally on unsupervised mechanical/electrical operations, the payout
part of the operation. The system is really a combination of two launch
methods, an auto tow and a winch launch and is just one level of complexity
too much when the proven technology already exists to provide a good
launch without introducing more complex procedures, especially ones which
rely totally on a mechanical/electrical function with no human input or
control.
During an auto tow the driver is facing the wrong way or is peering over
his shoulder so his ability to offer proper control or reaction to an
emergency is compromised, add to that the fact that cable payout is taking
place while the vehicle is moving in the opposite direction and while the
glider is on the cable and the things that can go wrong increases
exponentially.
Winch launching has hazards, no denying that, some of them completely
outside the control of the winch operator. A fixed winch with the operator
in a good position to observe the launch provides the best and safest
solution.
I have of course assumed that the launch is contolled by one person, the
implications of having two people controlling a launch (or not) are too
horrible to consider. I cannot see that anyone would be daft enough to do
that.
I can see that the payout winch launch is dangerous, I have said so. I may
or may not be believed. Like all human activity it will continue until
something goes wrong. If god forbid someone is killed then many people will
pipe up saying they knew it was dangerous, I am just saying it in the vain
hope that people will look at what they are doing and see that however
attractive it might seem it is not woth the risks, before it ends in
tears.
Bottom line, a vehicle driving down a runway with a glider on tow and a
winch paying out cable while the launch is taking place is not something
that I would ever be involved in. Been gliding and winching for 50 years
and would like to continue for a few more years.