I built one of these, back then, had it for many years, as well.
that thing trainred many of the Cincinnati club, so many years ago,
I ended up giving the frame to another club member several years ago.
I still have the plans for it as well.
up until my BAT winch, this one was the best out there...
Jack
--
Jack Strother
Granger, IN
LSF 2948
LSF Level V #117
LSF Official 1996 - 2004
CSS Gold
Jack Strother
Granger, IN
LSF 2948
LSF Level V #117
LSF Official 1996 - 2004
CSS Gold
-------------- Original message --------------
> My club, the Coffee Airfoilers. developed a tension limiter winch about 30
> years ago. It was published in the Jan/Feb 1977 issue of Sailplane and a
> number of clubs built the winch. We set the tension at the tow ring at 25
> pounds and was able to launch sailplanes up to 11 pounds without
> problems. We used 110 pound test line and never had problems with broken
> lines unless the contestant elected to launch without the tension
> limiter. The tension limiter could be be bypassed, but if the contestant
> launched without the tension limiter, he got no reflights for broken
> towlines. Most flyers with larger models found that they could get better
> launches by standing on the winch petal and let the winch do the
> pulsing. The only disadvantages to using the tension limiter winch was the
> extra work required to maintain and setup the winch. It was also necessary
> to periodically adjust the tension for variations in line ground drag as
> the day went on and the wet grass dried out. The remains of the original
> tension limiter winch base is still in the woods behind my storage shed.
>
> Chuck Anderson
>
> At 10:54 AM 10/1/2004, you wrote:
> >----- Original Message -----
> >From: "Michael Lachowski" <[EMAIL PROTECTED]>
> >To: <[EMAIL PROTECTED]>
> >Cc: <[EMAIL PROTECTED]>
> >Sent: Friday, October 01, 2004 7:28 AM
> >Subject: Re: [RCSE] Contests, Landings, etc.
> >
> >
> > > The correct way to limit launches is on the motor side, not on the
> > > line side. Broken lines just slow down contests and make everyone
> > > unhappy.
> > >
> >I agree with Michael. The motor side is the place to limit pull on the
> >winch line, if that is what is desired.
> >
> >There is a simple technique that I have heard has been tried with some
> >success in the past. It involves mounting the winch on a spring loaded
> >pivoting device that electrically limits the force on the line. A
> >microswitch interrupts the circuit between the foot switch and solenoid when
> >the pull on the winch line moves the winch on the pivot against the pull of
> >the spring (the weight of the winch itself is also involved). This cuts
> >power to the winch motor until the line tension lightens enough to allow the
> >spring to pull the winch off of the switch. The spring is adjusted against
> >the pull on the line using a simple spring scale such as is used to set up
> >highstarts to set the trip point. If you just stand on the pedal, the
> >result is a near constant force pulsing of the winch line throughout the
> >launch. Actually the pull slightly declines as the diameter of the stack of
> >line on the drum increases with line taken in. This scheme works without
> >breaking of the line or releasing the model early.
> >
> >This is 1920's technology, but effective. A more expensive technique using
> >strain gauges and electronic motor speed controls could be devised. 8^)
> >
> >I am sure that with proper launch technique, towering launches can still be
> >achieved with such a system set at 80 pounds pull launching 4 pound models.
> >I suspect that experimentation will show that 20 to 30 pounds will be more
> >than adequate.
> >Tim
> >
>
>
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