How about taking the running gear from a salvaged Tesla or similar? A
quick look found several in the $10K range and I'm sure you could find
something for less.Â* Also, simple research (looking at one website) says
that the Tesla's battery provides around 400 VDC which is fed to an
inverter to provide the AC voltage to run the motor(s).Â* Surely someone
could put together a battery bank (assuming the car's batteries are not
functional) or even have a 480 V 3-phase service installed to run the
motors.

Now, we just need someone to build the hardware to connect the motor(s)
to the drum.

Or buy a ready-made winch.

On 3/4/2020 12:21 PM, ian wrote:
On 3/4/20 7:38 AM, Paul Remde wrote:

Any thoughts...?Â* I'm just dreaming about the future of gliding...

Speaking as a winch instructor. One requirement for a safe winch
launch is for the glider to always be in a position to make a safe
landing in the event of a launch failure. Thus the launch profile must
be such that by the time that you are too high to land straight ahead
you have sufficient height to fly a small circuit and land back on the
runway. You also want some overlap between the two options to take the
stress out of decision making. If you winching into zero or low winds,
a 180 deg turn and landing "downwind" is also an option.

If you are winch launching a sustainer, the requirement must be for
the glider to launch, release, attempt an engine start and then still
be in a position to make a safe landing if the engine fails.

What you do not want, is to make a habit of releasing over the
downwind threshold, to low to fly a circuit back over the runway. (Yes
this is accepted for aerotow. But the launch failure rate is much
lower and simulated launch failure training is done in light winds
which allow landing downwind.)

One option is a conventional ground launch, car or winch to say 1000'
AGL. Glider can then fly a circuit, start the engine on downwind and
be in a position to land if the engine does not start. This would work
for any sustainer technology. The ground launch is an "existing art"
and you can get training and ratings for it. There are also
established clubs with the means to provide the launch.

Next option is the "launch to 100'". This must be done such that you
can release, attempt an engine start and still be able to land
straight ahead if it fails. A variation involves deploying and even
starting the engine before launch, with a pylon mounted engine, like a
jet, but not possible with FES. This saves some time for the engine
start and reduces the risk of a start failure. These launches have
been done, but you wont easily find an "approved procedure" accepted
by manufacturers and authorities etc.

Last comment, is do not assume that FES cannot suffer a launch
failure. They have safety control systems and all it would take is one
contact breaker "trip" to spoil your day. Also remember that any
battery energy you use to get from 100' to "start of soaring" will not
be available for a retrieve later in the day.

But yes, this could be the future of gliding ...

Ian

--
Dan, 5J