People trying to design tension controlled winches are re-inventing
the wheel. Conventional winches already do that. IF the power setting
is retained constant in conventional winches with a torque converter,
the tension will be constant excluding the inertia factor. Every winch
will have inertia and delay and none will be able to respond
instantaneously to changes in wire load.

A tension meter can be installed in any type of winch, electric,
hydraulic or conventional. There is no difference between the
different types there and power can be controlled by one if desired.
The issue is, does it make sense? Is the approximation calculated by
the British design good enough? Or do we need a real time tension
control winch? Would the inertia i the system even make this possible
or desirable?

I would say that setting the desired tension according to type and
conditions by approximation, ala Skylaunch, and not worrying about the
fluctuations is plenty good enough. The main reason is because
designing a winch to be truly controlled in real time by the actual
and current tension, micro second by microsecond, is probably very
expensive, unproven and would not solve the inertia delay issue of the
winch. Trying to chase the gusts so to speak - how would that work? A
conventional winch type already lets the drum slow down and/or pulls
the engine revs down if the cable tension increases due to a gust or
thermal - thus reducing the tension - this is already a mechanically
built in constant torque effect.

This is by no means perfect, but certainly good enough to give mostly
smooth launches. In gusty conditions, there is no winch in the world,
not even on paper, that can react fast enough to dampen away the
oscillations in cable tension and airspeed, due to the time delay in
reacting to the changes in cable tension.

We just need to figure out how to make a cheap reliable winch and find
places to use them at. At $10-$15 a launch, a glider club or operator
would quickly make a nice income, like European clubs do. The real
cost of a winch launch is something like $3-5 per launch including
maintenance, reserves and replacements. 30 launches a week x $10
profit = $1,200 extra a month. That's one very nice glider upgrade
every 5 years. This is one of the main reasons why European clubs have
such nice equipment.
Tom