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Old November 11th 18, 11:44 PM posted to rec.aviation.soaring
Dan Marotta
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Posts: 4,601
Default Parachute source for gliders and winches

I hesitate (not really) to ask how you learned what the Spectra could do.

I've only launched and driven with steel cable or plain rope with auto tow.

On 11/11/2018 4:26 PM, Martin Gregorie wrote:
On Sun, 11 Nov 2018 14:10:03 -0700, Dan Marotta wrote:

The simple response to that is:Â* Don't drag it on the ground.Â* When I
was driving a winch back in the 90s, the technique was to increase
throttle sufficiently after the glider releases to keep the parachute
inflated and drop the chute right in front of the winch. The driver had
to have the skill to stop the drum before the chute got jammed in the
rollers.Â* On days without cross winds, just carry enough power to keep
the chute inflated until it lands.

Spot on for normal operation, but there is one unavoidable difference if
you're using Spectra rope.

On steel cable, you do the last launch of the day, suck the cable in,
pack the winch up and tow it back to its roost and everything is fine.

But if you do the same with Spectra rope, it will destroy the winch drums
because tightly wound Spectra is likely to crush the drum in overnight
cold, so after the last launch both cables are pulled out again. The
winch then pulls them in slowly enough to avoid inflating the chute. This
leaves the ropes loose enough on the drums to prevent crushing problems,
but has also dragged the 'chutes along the ground for the length of your
airfield.



--
Dan, 5J