New winch height record

tommytoyz wrote:
Bartek,
Most winches have more than one drum. In Europe, one winch can have up
to 8 separate drums and lines. This enables a launch every 3 minutes
or less.
http://www.hydrostart.nl/EN/

I've watched them launch gliders at Lasham at that rate using a single
drum of a Tost winch and a retrieve winch. There is a price to be paid,
of course, maybe 200 feet less altitude (if that much), but a retrieve
winch is somewhat less expensive than upgrading to an 8 drum Hydrostart...

Marc

brtlmj wrote:

Oh, sure. But what if a club wanted to have one winch for high
launches, located at the far end of a runway, and another one for
circuit practice, located in the middle of the runway?

I don't see the point. I've never felt that a winch launch was too high,
even for primary circuit training. There are always some exercises which
you can do with students. I know a couple of maneuvres which destroy
altitude pretty efficiently... And if everything else fails, you can
always practise a rope break.

"brtlmj" wrote in message
...
Most winches have more than one drum. In Europe, one winch can have up
to 8 separate drums and lines. This enables a launch every 3 minutes
or less.http://www.hydrostart.nl/EN/

Oh, sure. But what if a club wanted to have one winch for high
launches, located at the far end of a runway, and another one for
circuit practice, located in the middle of the runway?

Bartek

I think one winch would be enough. You don't need to do high launches and
low launches at the same time. It's just ascheduling. Plan some high
launches early and some landing practice late. Give the guys who want to
soar the mid-day slot. A winch can be moved around easily.

That said, many European and British clubs do use several winches at the
same time. Again, it's just a scheduling and organizational problem.

One thing a lot of US pilots seem to miss is that a winch can, and probably
will, operate from sun up to sun down. There's no noise problem. Cost is
not an issue. If you find lift, great. If not, the cost of a winch launch
is so low and it's so much fun, just glide down for a landing and do it
again.

Spending a day trying to get that glass racer down in the smallest patch
possible is huge fun. Since you have to push it back to the start line, you
have a big incentive to land short. Knowing you can land very short if need
be is a big relief on a XC. 20 or so consecutive landings will do that.

Another fun thing is to watch is the private owners who arrive at 11:00
expecting lift to start at 12:30 when the find out a solo student has been
soaring for two hours off a winch launch.

Bill Daniels

tommytoyz wrote:
Bartek,
Most winches have more than one drum. In Europe, one winch can have up
to 8 separate drums and lines. This enables a launch every 3 minutes
or less.
http://www.hydrostart.nl/EN/
Tom

A properly motivated crew and non-chatty instructors can manage 20 launches
an hour off a dual drum winch. Its probably hard to beat that no matter how
many drums you have because you start to be held up by pilots getting ready
or, depending on your field layout, landing gliders interfering with
launches.


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

On Nov 27, 3:36 pm, John Smith wrote:
I don't see the point. I've never felt that a winch launch was too high,
even for primary circuit training. There are always some exercises which
you can do with students. I know a couple of maneuvres which destroy
altitude pretty efficiently... And if everything else fails, you can
always practise a rope break.

Yeah, I am probably looking for nonexistent problems ;-)

Bartek

"Martin Gregorie" wrote in message
...
tommytoyz wrote:
Bartek,
Most winches have more than one drum. In Europe, one winch can have up
to 8 separate drums and lines. This enables a launch every 3 minutes
or less.
http://www.hydrostart.nl/EN/
Tom

A properly motivated crew and non-chatty instructors can manage 20
launches
an hour off a dual drum winch. Its probably hard to beat that no matter
how
many drums you have because you start to be held up by pilots getting
ready
or, depending on your field layout, landing gliders interfering with
launches.


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

The payoff for multiple durms is when you use very long cables (ropes?)
When retrieve time becomes a large part of the time budget, it's better to
be pulling a lot of ropes back at one time. If you are using a 3000 meter
runway, 4, 6 or even 8 drums really do make sense.

With heavy steel cable, it wasn't really possible to pull more than 6 cables
at once - the tractors just didn't have enough traction. With the
widespread use of super lightweight UHMWPE, 8 drums is easily possible.

For short runways, a single drum and a retrieve winch is probably
unbeatable.

Bill Daniels

On 28 Nov., 01:00, Martin Gregorie wrote:
tommytoyz wrote:
Bartek,
Most winches have more than one drum. In Europe, one winch can have up
to 8 separate drums and lines. This enables a launch every 3 minutes
or less.
http://www.hydrostart.nl/EN/
Tom

A properly motivated crew and non-chatty instructors can manage 20 launches
an hour off a dual drum winch. Its probably hard to beat that no matter how
many drums you have because you start to be held up by pilots getting ready
or, depending on your field layout, landing gliders interfering with
launches.

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

We use a 6-drum winch and about 1km (3300ft) steel rope. We actually
achieved 34 launches one time during regional championships. Of course
everybody was ready and plenty of ground crew available.
Amazingly, the theoretically possible maximum is over 40 launches per
hour (10-15s hookup and pull up slack, 30-35s launch, 15-20s pull in
rope, 120-150s retrieve @ 30km/h = 8-10min/6launches).

regards
Marcel

Bill Daniels wrote:

The payoff for multiple durms is when you use very long cables (ropes?)
When retrieve time becomes a large part of the time budget, it's better to
be pulling a lot of ropes back at one time. If you are using a 3000 meter
runway, 4, 6 or even 8 drums really do make sense.

Yes, I can see that - I'm used to 1000 m and was talking from experience
at that length.

However, I suspect my other point still holds with a lot of drums, that
once you get up towards 20 launches an hour the readiness of staged
gliders to accept a launch starts to become the critical factor.


For short runways, a single drum and a retrieve winch is probably
unbeatable.

I know about them but have never seen one in action. How long can the
run be before this becomes impractical?


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

To see Lasham's retrieve winch set in action see URL:

http://uk.youtube.com/watch?v=1Slucbodmzo

In normal club use we get about 25 launches per hour
from this set up. The biggest problem is getting pilots
in their gliders and ready to launch. That is why we
line gliders up 3 at a time, so at least the second
two are ready! If all pilots were ready to launch and
we had a good team of helpers, we could easily achieve
30 launches an hour or more. We use just one drum and
4.7 mm steel cable on a normal two-drum Tost winch.
The retrieve winch is a Skylaunch product fitted with
2.5 mm steel cable: see www.skylaunchuk.com

Derek Copeland





At 23:24 27 November 2007, Marc Ramsey wrote:
tommytoyz wrote:
Bartek,
Most winches have more than one drum. In Europe, one
winch can have up
to 8 separate drums and lines. This enables a launch
every 3 minutes
or less.
http://www.hydrostart.nl/EN/

I've watched them launch gliders at Lasham at that
rate using a single
drum of a Tost winch and a retrieve winch. There is
a price to be paid,
of course, maybe 200 feet less altitude (if that much),
but a retrieve
winch is somewhat less expensive than upgrading to
an 8 drum Hydrostart...

Marc

"Martin Gregorie" wrote in message
news
For short runways, a single drum and a retrieve winch is probably
unbeatable.

I know about them but have never seen one in action. How long can the run
be before this becomes impractical?


Not sure - somebody needs to do some believable side by side tests. The UK
retrieve winch operations are still using steel cables on fairly short runs.
Those don't seem to suffer much from lifting two cables. Obviously, Dyneema
cables will have a large effect on retrieve winch operations by reducing the
losses associated with lifting a second cable.

It depends on what you are trying to do. Landing practice or launching into
local ridge lift makes launch frequency the most important thing so retrieve
winches are attractive there. Getting high enough to cruise around for a
while looking for thermals probably means long runs and multiple drums are a
better approach.

Very high launches for training probably eliminates retrieve winches from
consideration.

Bill Daniels