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Old July 5th 09, 04:08 PM posted to rec.aviation.soaring
Frank Whiteley
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Default SAFE Winch Launching

On Jul 5, 7:50*am, "Alistair Wright" wrote:
In all this discussion of winches, and the building thereof, no one has
mentioned auto towing. The 'reverse auto tow' is the most efficient launch
method I have ever encountered. We used it at the Essex Club at North Weald
while I instructed there.

You need a nice long runway, about 6000ft is ideal but shorter will do. The
ingredients a

1) Two large automatic cars of about 100BHP - we used retired V6 Ford
Zephyrs - we will call them car1 and car2. A driver and observer (who
watches the glider) are required.

2) A large grooved pulley about six feet in diameter on a rotatable gimbal
and anchored firmly to the ground. The pulley is at the opposite end of the
runway to the launch point.

3) A piece of single strand piano wire the length of the runway.

4) Gliders with pilots.

The wire is passed over the pulley and attached to car 1 which is sitting at
the pulley and the other end to the glider via the usual rope, parachute,
and weak link. Car 2 is sitting at the launch point. Slack is taken up, and
at the all out signal car 1 sets off down the runway towards the glider
which most obligingly lifts off, and sets off up what is now effectively a
winch launch. Meanwhile car 2 sets off following the glider towards the
pulley avoiding car 1, of course, which is driving at about 35- 40 mph
towards the launch point. Glider releases, (we often got nearly 2000ft on a
good day), and car 1 carries on the launch point while car 2 arrives at the
pulley. The cable has launching tackle on both ends, so the next glider is
coupled on and car 2 is connected to the cable and does the next launch ....
need I go on? *We used to get 20 launches an hour using this method. No time
is wasted retrieving cables. No need to buy an expensive winch, and the
cheap cable lasted a long time. Ford Zephyrs were also fairly cheap from the
scrap yard, and we had people in the club adept at fixing them. *As quite of
lot of American clubs seem to have access to runways I cannot see why they
cannot try this method of launching. I recommend it.

Alistair Wright


Having launched with EGC at North Weald a couple of occasions many
years ago, my experience was a bit different. We got maybe 800ft in
the K13, but I think the normal launch cars were broken down and a
manually shifted Vauxhall was in use. Each time it shifted, the
drogue chute was over the nose of the glider. I got 1200ft in the SHK
on the other day. IIRC, airspace was limited to 2200ft until about
five miles north. (Have to dig out an old chart that's archived
somewhere). On the days I was there, only one vehicle was in use and
on the first day, there was a wire snarl up on the pulley system (two
big wheels) that delayed things for well over an hour.

However, I do agree that the system may be very efficient. To that
end, the old Cotswold GC system was, IMVHO, more elegant and required
less people to operate
http://www.coloradosoaring.org/think...ey/default.htm

In addition to the long runway, CGC insisted on a lateral 2000ft clear
zone around the pulley. Piano wire is nasty stuff when it breaks
under tension. They also used rather more substantial tow vehicles
and you couldn't launch modern K-21's, DG-50X's and 1000's and single
seaters with Zephyr's. You can't discount the cost of powerful tow
vehicles. We did okay at Enstone GC with an XJ6 Jag on auto tow.
After many years, Cotswold GC reverted to winching.
http://www.cotswoldgliding.co.uk/ They formerly had a history page
about the reverse pulley, but I don't find anything on their web site
now. They do mention that learning to glide is cheaper than learning
to drive though;^)

We do have some long runways in the US, but few are lacking runway
lights or other obstacles that are too close to entertain reverse
pulley launching. On these same runways, it's quite feasible to winch
using the UHMWPE ropes.

Regards,

Frank Whiteley