After getting the bug again, I turned up this really nicely engineered
pay-in
static tow setup.

Ignore the 1500N rating listed, the sailplane version has a much thicker
side wall.
It's rated to 1500lb tension.
A follow up e-mail suggests a tost release can be used for a quick
release, and the
auto-level kicks in for the electric motor powered retrieve.

http://www.tow-systems.com/en_vijesti.php

It is NOT cheap though!

Chris



Gary Boggs wrote:

Bill, this is a payout winch. The starter motor is for reeling the line
back in after the truck mounted winch gets to the end of the runway. Check
out the video:

http://www.nwskysports.com/




"Bill Daniels" wrote in message
news:QIV6d.147361$D%.8795@attbi_s51...


"Gary Boggs" wrote in message
...


My guess as to the force on line is probably something like 300lbs? I


think


the next mod we will incorporate will be a tensiometer on the line.


Right


now we use a pressure gauge on the brake line and as the disc brake


heats


up, the pressure required to get the correct tension on the line goes


up.


It would work much better if our winch operator was able to monitor the
actual tension on the line, instead of the pressure on the brake. If we
could find an electronic tensiometer, we could program it to operate the
brake, but this would make the winch even more complicated and


expensive.


I've searched the web for available tensiometers, but found nothing
suitable,
so I think we will just build one into our system.


The tension on the line should be about the same as the gross weight of


the


glider. 300 pounds will result in a poor launch. The tension on the line
is the result of cooperation between the pilot and the winch operator. No
matter how hard the winch tries to increase the line tension it won't


happen


unless the glider pilot pulls up.

A better idea is to use an RC model airplane telemetry package like RCAT


to


send the glider airspeed to the winch operator and let him control that.
The glider pilot can then control the line tension with the elevator.

I think it will require more power than a starter motor for that though.

Bill Daniels