SAFE Winch Launching and automatic gearboxes

On Jul 20, 1:00*am, Derek Copeland wrote:
Our Tost winches were originally fitted with Powerglide gearboxes that were
locked in top gear as a Tost modification.

A trial was carried out about 4 years ago by fitting one of them with a
very slightly modified, 3 speed, shifting TH400 gearbox supplied by
Skylaunch, which we found gave no problems at all and had several
advantages, in that it can safely be run backwards (as long as you leave
the engine running to give oil pressure) which we needed for retrieve
winching, better acceleration for the heavier gliders, and less gearbox
oil over-heating. As a result of this trial, both of our Tosts were so
fitted. The overall gearing was such that the upshift gear changes occured
during the ground run and the main part of the launch is done in top gear..
The same applies to our new Skylaunch winches. *

In August 2008 our club hired a 'pre-owned' Skylaunch winch and ran that
for an extended trial period. Compared with the Tosts we found it to be
very easy to drive and to give smooth, nicely speeded launches, with non
of the problems suggested by Bill! As a result of this trial the club
commitee decided to buy two of them, and to sell one of the Tosts, which
we have already done. We still have one as a back up, but it hasn't come
out of the MT hangar for months. If a club is looking for a half decent
secondhand winch, perhaps they should make an offer to Lasham? If it was
fitted with the Skylaunch throttle system it would be three-quarters
decent.

In answer to Bill Daniel's other point, you can bang open the throttles
of the above winches, or of our new Skylaunches by over-riding the
throttle dampers, as fast as you want without causing harsh gear changes,
but then you over-accelerate the gliders, and bang the tails down for nose
sitting gliders, such as K13s, Grob G103 and K21s, too hard with a risk of
structural damage. Again that's due to that pesky belly hook to c of g
rotational couple!

Comparing a Gerhlein winch to a Skylaunch is somewhat like comparing a
Ford Model T to their latest models. Similar basic components but
developed over many years.

I believe the Hydrostart winch, on which the Hydrowinch is based would
cost something like 500,000 Euros with all new components, compared with
about 90,000 Euros for an all new Skylaunch 2 in Europe. Shipping costs
and import duties make it more expensive in the States, so it might be
worth making them under license over there. All of the development work
has already been done.

Derek Copeland

Bull! The Skylaunch is no better than a cleaned up Gerhlein. It uses
the same technology and EXACTLY THE SAME components.

You need to read more carefully. The total receipts for the
Hydrowinch is much LESS than the selling price of the Skylaunch.
Those receipts were mostly quantity-one retail pricing. If the winch
goes into production large discounts would be available from suppliers
reducing the price still further.

That's for a Cummins QSL-9 turbo diesel and the Danfoss-Sauer
hydraulics as well as the rest. This is a modern clean sheet of paper
winch, not a warmed over 50 year old design. With it's embedded
computer control you get exactly repeatable launches - and NO SHIFTING.