On Jul 11, 9:15*am, Derek Copeland wrote:
Unlike Bill Daniels, I tell it as it is without exaggerations and unproven
assumptions. The figures I gave are for a K13, which winch launches less
well than a K21 because the belly hook is too far forward. K21's get
about 200 feet higher, especially when flown solo.Also Bill Daniel's
winch is using synthetic Dyneema cable which adds about 150 feet to the
launch compared with the 4.5mm stranded steel cable we use.

Dynema cable is superb stuff, but unfortunately 5 times more expensive
than steel. As cable replacement is one of the major costs in winch
launching, this makes it less economic.

The Skylaunch winch gives well controlled, correctly speeded launches for
every type of glider from slow old vintage single seaters up to big heavy
two-seat DG1000 turbos. It is also very easy to drive (I am a winch
driver). The gear change all occur during the ground run and are totally
smooth and imperceptible from the glider end.

If you build a winch with an automatic gearbox, you have to disable the
kick down function and tweak the box so that it changes up at fairly low
revs. I agree with Bill that you can't just stick an unmodified automatic
gearbox into a winch without encountering the sort of problems that seem to
beset Gerhlein winches. It is also important to get the overall gearing
correct.

For a good quality Skylaunch launch of a K21 to 2300ft into about a 5 knot
headwind see:

http://www.youtube.com/watch?v=4ArI5_1PE_Y

BTW. My reply was genuine in response to an email from a gent called Alan
Larson. I tried twice to reply by email, but got delivery failure
notifications with the text:
The following message to email address was undeliverable.
The reason for the problem:
5.1.0 - Unknown address error 550-'5.0.0 All tiscali sends is spam'

OK Tiscali is not the best ISP in the world for keeping out spam, but even
so.....? I have removed Alan's actual email address to prevent him getting
any spam.

Derek Copeland

At 13:36 11 July 2009, bildan wrote:

On Jul 11, 2:00=A0am, Derek Copeland *wrote:

At my club we typically get about 1600ft in no wind and
2000ft launching into a 10 knot headwind. Our standard aerotows are
2000ft
,
but you can go as high as you like, depending on your needs and the
depth
of your wallet.

This week we were getting as high as 1900' from 3900 feet of rope at
9000 feet density altitude with little wind with the Hydrowinch. *With
no gear shifting at all, the Hydrowinch is MUCH smoother than any
winch with an automatic transmission.

Skylaunches are just like old Gerhleins with new paint - they use
exactly the same components. *They are not particularly well
controlled since they use road vehicle torque converters and automatic
transmissions free to shift gears when they please. *The old junk
Gerhleins around most US clubs are probably the only winches in the
world worse than a Skylaunch - but they are a LOT cheaper.

BTW, notice how Derek has to reply to himself to get any conversation
at all?

The Hydrowinch is currently fitted with Spectra 12-strand, not Dyneema
nor Plasma-12.

Having now driven some number of launches and having trained another
to drive the Hydrowinch, I'd say it has some very nice features.
There are a some others that I've suggested to the developers.
There've been a couple of set backs, one of which led to a three month
delay. These folks have day jobs also and since some of the team
comes from overseas, it does slow things a bit. I'd like to put it on
line today, but that's not my decision to take. They aren't so
compromising, but it's close.

Frank Whiteley