New winch height record

Del C wrote:
John,

With the Tost winches we use at Lasham, the pilot has
no control over the speed, unlike the torque or tension
controlled Supacat or MEL winches.

Exactly the same applies to a V-8 diesel Supacat with its high torque
output - an Ash-25 might control the winch speed but a K-21 has no chance.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Del C wrote:

With the Tost winches we use at Lasham, the pilot has
no control over the speed,

We have a Tost winch, too, and the pilot has definitely some degree of
control over the speed. The winch driver gives the tension depending on
how much the pilots pulls. But then the winch driver holds that tension
and the pilot makes the fine adjustments. No way a winch driver could
adjust precisely and quickly enough.

It's like a dialogue between the winch driver and the pilot. It requires
a certain experience and feeling from both to yield good results.

But having winched at many sites, I know that there are huge differences
among the "winch cultures". A pilot must be able to immediately feel how
he is winched and to adopt accordingly.

"John Smith" wrote in message
...
Del C wrote:

With the Tost winches we use at Lasham, the pilot has
no control over the speed,

We have a Tost winch, too, and the pilot has definitely some degree of
control over the speed. The winch driver gives the tension depending on
how much the pilots pulls. But then the winch driver holds that tension
and the pilot makes the fine adjustments. No way a winch driver could
adjust precisely and quickly enough.

It's like a dialogue between the winch driver and the pilot. It requires a
certain experience and feeling from both to yield good results.

But having winched at many sites, I know that there are huge differences
among the "winch cultures". A pilot must be able to immediately feel how
he is winched and to adopt accordingly.

Winch culltures and varying winch driver techniques is one reason computer
controlled cable tension is such a good idea. It puts the airspeed control
firmly in the hands of the pilot. You get a near perfect launch every time
in every glider pretty much regardless of conditions.

Bill Daniels

You don't say what engine you have in your Tost winch
John, but ours are fitted with powerful 8.2 litre,
410hp Chevy marine engines. Except for the very heaviest
two seater gliders, pulling back harder on the stick
will not reduce the airspeed and may even have the
opposite effect due to increasing the vertical speed
vector - the so called 'water skier' effect. Easing
the stick forward may momentarily reduce the speed
for the same reason (reduces the vertical speed component)
but will signal to the driver that more power is required
so you will still speed up again! The only way to slow
down if the launch gets too fast is to signal to the
winch driver by wagging the tail with the rudder.
Having said all that, we have very well trained winch
drivers who nearly always provide correctly speeded
launches.

I have launched on a number of low powered, 'torque
controlled' diesel engined winches where speed is supposed
to be controllable from the glider end, but I wonder
if this is just because pulling back harder slows the
winch engine down and easing forward allows it to speed
up again? These winches seem to become less easily
controllable by the glider when re-fitted with more
powerful engines, as has been confirmed by another
correspondent.

Maybe the answer is to provide just the right amount
of power to launch the specific glider type in the
prevailing wind conditions. In this respect throttle
tabs as found on the latest Skylaunch winches may be
the KISS (Keep It Simple Stupid) way to go, rather
than very expensive and complicated tension controlled
diesel-hydraulic or electric winches.

Del Copeland

At 20:24 01 December 2007, John Smith wrote:
Del C wrote:

With the Tost winches we use at Lasham, the pilot
has
no control over the speed,

We have a Tost winch, too, and the pilot has definitely
some degree of
control over the speed. The winch driver gives the
tension depending on
how much the pilots pulls. But then the winch driver
holds that tension
and the pilot makes the fine adjustments. No way a
winch driver could
adjust precisely and quickly enough.

It's like a dialogue between the winch driver and the
pilot. It requires
a certain experience and feeling from both to yield
good results.

But having winched at many sites, I know that there
are huge differences
among the 'winch cultures'. A pilot must be able to
immediately feel how
he is winched and to adopt accordingly.

Del C wrote:

You don't say what engine you have in your Tost winch
John, but ours are fitted with powerful 8.2 litre,
410hp Chevy marine engines. Except for the very heaviest

Frankly, I don't know. It's a gas engine with I guess something like 300
or 350hp. We can definitely slow down the engine when pulling the stick
hard back in a two seater. With a single seater, the winch driver must
winch with reduced power, but then the pilot has some control again,
slowing down the winch when pulling.