Yes I've also done reverse pulley.
It solves a few of the auto-tow issues: Angle of pull, length to tow out
cable after release but still leaves the others: Time and distance to
accelerate great moving mass. It also introduces much more cable wear as
part of the cable is always on the ground. Reverse pulley is better than
straight tow but still less effective than the winch.


At 11:13 05 October 2015, Roy Pentecost wrote:
Having done both in the UK, at two different sites, I can compare an
contrast:
1. Auto-tow needs a hard surface, realistically at least 1000m an
preferably nearer 2000m long. Winch launch can be done off grass surface
needing only a route for cable tow out using a tractor or 4x4.
2. Winching only accelerates the glider (plus a small amount of engine
transmission and drum inertia) thus reaching take-off speed takes much
les
time than auto-tow where you also accelerate close to 2 tons of auto a
well as the glider (say about 0.6 tons). Typical winch launch reache
take-off speed in 2-3 seconds whereas auto tow takes 10-15 seconds to ge
airborne. This longer ground roll also exacerbates cable wear (along th
hard abrasive surface for auto-tow, compared to soft grass surfaces o
winch strips).
3. The angle of pull is more favourable as the winch is always further
awa
than the auto would be at any given point. There is rather more down tha
forward pull with an auto, mid-climb onwards. This increases cable tensio
(limited by the weak link) for a given level of 'thrust' so makes cabl
breaks more likely and reduces the amount you can use back pressure t
increase the angle of attack and hence climb rate.
4. With an auto, you have to terminate the climb before the end of th
runway so you can stretch out the cable, as it falls by parachute, so i
does not end up in a big knotted pile. This reduces the effective useabl
runway length.
5. Heavy cars with auto transmission generally need a lot more maintenanc
than a winch (lots more effort in accelerating and decelerating the to
vehicle itself).
My experience is that, all other things being equal, you typically ge
around 50% higher for a given runway length using a winch.
Ther may be occasions, such as on expeditions, when auto-tow is expedien
but for regular training operations such as those done in Europe, you
can'
beat the winch.

Regards,
Roy Pentecost