On Aug 15, 9:03 am, toad wrote:


I got 2 questions about setting up a winch operation.

1) How the hell do you get qualified to fly off a winch in the US ?

I have been looking for a operation that I can learn to winch
with,
and 1 club in Texas seems the only place that I could do it.

The problem is that insurance precludes 'temporary' memberships in
clubs. However, some clubs have associate and long distance
memberships at reduced rates. Although it's not entirely clear, I
think one club may have lost their 30% SSA discount due to advertising
temporary memberships (AIG sees that type of activity making a club an
FBO) for winch training. There is some talk of possibly winching at
Moriarty on a commercial basis.

Finger Lakes has a long distance and an associate membership. Contact
Tom Roberts and see what's available. (585) 746-1642,

Philadelphia Glider Council is a bit more expensive without the other
membership options, but a bit closer.

2) How much land do you need to run a winch launch that can get the
glider to 1500-2000 ft altitude ?

It depends. I've flown from UK clubs that were located on ridge tops
where a 600-800 foot launch was enough. I've also flown from a ridge
bottom site in Wales where 1500 feet was marginal to reaching the
ridge and returning unless there was at least 20mph wind against the
ridge (assuring ridge lift). Those winch runs were on the order of
2500-3500 feet long. Flat land sites may require more length if the
wind direction is inconsistent. Every 5kts of wind is effectively
several hundred feet of length. Our club site is 5500msl and we get
one or two wind shears and convergence zone migrations during the
day. This sometimes forces us to restage the winch one or twice or
even three times during a long winch day. We have a mile fence to
fence, but generally use about a 4400-4500 foot run, as it takes time
and manpower to push the gliders back to the fence. Staging with the
shorter run, we can land back, hook up, and go. We use a single drum
and can just hang two trainers when there's no lift but minor headwind
and a good crew. If it's soarable, about 85-90% of the launches will
hook a thermal. Some get caught if the sky cycles and land back. If
conditions are good, we've managed 2700agl about three times with our
Blaniks and Grobs. We use 3/16" 7/7 galv aircraft steel wire rope
(read heavy).

If the site will only support launches to 1500-1600agl when conditions
are good due to limited length, then the winch rope media doesn't
matter much. That is, larger diameters of cheaper synthetics might be
used or twisted/solid wire. For example, Finger Lakes is currently
using 5/32" dacron. It's lighter than steel, but the diameter means
more cross section in the wind. Even at the diameter, I suspect it's
a bit weaker than desirable. A New Zealand club uses 10mm
polypropylene, thicker still and stretchy. They've modified their
launch method to use the stretch and recoil and get 1500agl from a
3300ft run. So rope diameter and media don't matter too much if
1500ft is the limit due to length. Solid wire had no stretch recoil,
but requires some special considerations. For example the bending
radius is 60 times the diameter to avoid fatiguing, so larger rollers
are usually needed. It also tends to have a memory from the winding
and recoils as a result. Breaks can result massive snarl ups and a
large safety zone is needed to avoid possible injury. That said,
Prescott Soaring in Arizona uses a 6000ft run and gets lauches to
2000ft and more. Solid wire is cheaper and easy to repair but must be
used with more caution. It works well with reverse pulleys also,
given the space.

7/7 steel wire rope is generally used in 3/16" and 5/32" diameters,
though 5/32" is often hard to source, resulting is higher costs from
shipping. 5000ft of 3/16" weighs over 300lbs and 2-33's don't have
enough elevator to overcome much of the weight and get about the same
height on a 4000ft run as a 5000ft run. Grobs, Larks, and Blaniks can
lift a lot more weight and do better, but generally 1800-2200agl is
achieved when conditions are good. We did use a 1000ft piece of
untreated spectra on the end of our steel wire rope for a few hundred
launches and immediately got 200-400ft higher on each launch. That's
200ft higher with the 2-33, and 300-400ft higher with the Grob, Lark,
and Blanik L-23. That piece of spectra was not like the spectra's in
more general use on winches in Europe and elsewhere. Steel is harder
to work with, but relatively cheap, and somewhat more dangerous do to
it's inertia when moving. Breaks may also cause minor damage to the
winch and to the steel. 7/7 steel wire rope is a twisted product and
under load untwists, so it has some recoil when it breaks under
load. Kinks eventually turn into breaks.

New on the winching scene are Spectra type ropes. They are as strong
or stronger than steel for a given diameter at 1/6 to 1/7 the weight.
They do have low melting points, so winch design must take that into
consideration. They are easily spliced, don't stretch and have no
recoil. They are highly UV tolerant. Overall they are much safer to
use and give better results. They really come into their own on long
winch runs, that is, greater than about 4200ft. The longer the run,
the better. My club is looking at spectra products, but the cost is a
factor. However, 25% higher launches can command a 20% higher launch
charge to offset the cost. But if winch launches approach 50% of an
aero tow cost, that will dampen interest. IMVHO, they shouldn't be
more than 33% of an aero tow. My estimate is that 100% spectra
launches at my site would consistently produce 2200-2500agl launches
in good conditions. Good meaning 5-10kts headwind, temperatures under
85F. Hotter and less wind will reduce things. YMMV depending on
winch design and power.

Bill Daniels and I went to Hinton, OK, in April to help the Soaring
Sooners start winch launching. Many members have ground launch
endorsements and auto tow experience. They bought the old Prescott
Soaring winch and re-engined it and tidied up the winch over last
winter. They bought 6000ft? of a spectra rope, of which we loaded
just over 5000ft on the winch. They launch from a small public
airport (4 power transitions each day while were were there) with a
4000ft paved runway and 500ft overruns to the fence at each end. The
winch can be parked at the fence at either end. The south end could
be used for a launch and landing zone if the wind were out of the
north and the ground dry. So they have a nominally a 4500ft run.
They also have runway lights on the sides and ends. I would never
have presumed to use steel rope there, but with the spectra it was no
problem as it fairly floats in the air and it was easy to fly the rope
and tackle over the end lights and drop it wherever I liked. They are
charging $12 a snap, but the concept is to grow the club with the
cheaper launches and pay for new equipment. To date they report about
350 launches. The FBO also provides aero tow services. They pay him
$1 per winch launch. The second ever launch we did was a 1-26 with a
CG hook and the pilot soared away for two hours. Their 2-33 doesn't
get that high, but manages to soar away. They have a project Blanik
they are restoring, which will give them much better results. Finger
Lakes might be the better option for you for training and observation,
as they also are located at a mixed use airport with reportedly 25
power transitions per day.

Clubs with short runs have generally been unhappy with winching. That
is, where they get 1100-1300agl normally. The Lawler winch was in
common use with the Southern Eagles for many years until they ran into
problems with airport management about the cross runway utilization.
It moved to Chillowhee, TN, for a number of years, where one drum was
fitted with spectra and the other with steel. Their run was short.
But I think they also may have had local issues which resulted in low
effective usage. From there it moved to Memphis. Again, short run,
lowish launches, so it wasn't as popular at it might have been. It's
now at PGC, and PGC sold their old winch to Finger Lakes. PGC has
been working to improve their winch run, but I don't have any reports
on activity from there. Finger Lakes is very happy with their winch
operation.

One thing about a winch is that it can run over uneven ground, so can
be placed well past the end of a runway. I've heard of a European
operation that built a trestle and wheel to put the launch rope over a
fence and another that turned a corner with the launch rope as there
was a dog leg in the runway. To me the perfect setup is a 5000ft run
with 1000ft land back area to the launch point. Next option is extra
width so land backs could parallel the launch run safely, though
gliders would have to be pushed back to the launch point. This isn't
so bad if there's a launch queue. When working with one or two
gliders, it slows the launch rate. If so narrow that you can't launch
until the gliders are retrieved, no one will be very enthused.
Minimum length for long term interest, in my opinion would be 4000ft,
but I'd keep looking for 4500ft. As airports usually have clear zones
off the end of the runways, there may be more options than are readily
apparent.

There is a winchdesign yahoo group with a lot of discussion, much
worth reading.

Regards,

Frank Whiteley