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Old May 25th 08, 07:44 PM posted to rec.aviation.soaring
Derek Copeland[_2_]
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Posts: 146
Default Winch launch clinic at Faribault, Minnesota

Tost axles on the other hand came out of a Mercedes light truck (I
believe), so tend to be too low geared! They are also turned upside down
to get the correct direction of rotation for the top loading drums, which
doesn't exactly help the lubrication of the crown wheel and pinion. The
Skylaunch has fairly large diameter, narrow, bottom loading, drums with
guide tubes and rails, so the axle is the right way up (for good
lubrication) and the need for level wind pay on gear is avoided. Simplify
and add lightness, as they say. The hallmark of good design.

Derek Copeland

At 17:10 25 May 2008, Frank Whiteley wrote:
On May 25, 1:44 am, Derek Copeland wrote:


I am rather curious to know why this particular winch is so highly

geared?
This probably justified your decision to launch in second gear. With a

more
sensible axle ratio, automatic gear changes during the full climb in
'drive' would have been avoided. Our experience in the UK suggests

that
automatic gearbox up changes during the ground run do not cause any
problems.

You cannot succesfully repair winch cables by tieing knots. The same

is
also true for aerotow ropes. Synthetic cables and ropes have to be
spliced, and steel cables have to be spliced or crimped with brass
ferrules. We tried out synthetic cable at our club, but went back to

steel
cables, partly for reasons of cost, but also because it seemed to take

an
age to splice broken cables back together. As Frank rightly points out
below, having the right tools for the job and a bit of training in how

to
do it for the winch drivers would have speeded things up a lot.



I suspect many 'Gehrlein' type designs used the differential that came
with the vehicle the supplied the original engine and automatic
transmission. Typically, final drives were in the 2.7X-2.9X range.
My F150 is a 4WD Off-Road with a final drive of 3.73, which also
increases the towing capacity, but it also has a tall overdrive gear
(4th) and locking torque converter. These final drives became more
common after 1990 when locking torque converters, electronic shifting,
and overdrive automatics became standard. Higher ratios of the
'muscle car' ;and 'hot rod' types were commonly matched with 4-speed
manual transmissions from the 1950's through the 1970's. Refitting
cost a few hundred dollars, time and effort, so it wasn't done.

The Amsteel II in use takes a bit longer to splice with the covering.
Uncovered 12-strand can be spliced almost a quickly as steel swaging
with a good fid and a little practice. I'm not talking about the
Class II tuck splice on the Samson site, which involves tapering and
stitching, but a simple 3x3 or 4x4 tuck splice.

Frank