New winch height record

"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

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 |

"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

As an aside,
back in 88 we at 611 VGS at RAF Swanton Morley flew from legal sun up to
legal sun down on the longest day.
Utilising our Van Gelder 6 drum winch and 6 GROB 103's achieved in
excess of our 611 launches in a single day target.
Logistics were fun but just demonstrated what is possible.

Phil


Bill Daniels wrote:
"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

611 launches in one day with one winch! Wow! I think that's a world
recond.

Bill Daniels


"Phil Collin" wrote in message
...
As an aside,
back in 88 we at 611 VGS at RAF Swanton Morley flew from legal sun up to
legal sun down on the longest day.
Utilising our Van Gelder 6 drum winch and 6 GROB 103's achieved in excess
of our 611 launches in a single day target.
Logistics were fun but just demonstrated what is possible.

Phil


Bill Daniels wrote:
"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