"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