Using Plasma Rope For Winch Tows

Bill, I appreciate the lead. Given the relatively high initial cost,
operating cost, and manning problems for a decent tug, 19,000 USD for a
new first-class winch doesn't seem unreasonable, particularly since they
can go for years with mostly only fuel cost to consider. And since
practically any club member can be quickly taught to drive a well
thought out winch, it's a wonder they are not more popular. I see that
Skylaunch has chosen to follow Craig's example in choosing the big-block
GM V-8 engine 8') while Supacat is sticking with the 250 hp Diesel.

We were hoping for the magic 2000-ft light wind launch height. Given our
5000 ft runway length, Plasma rope and a 20 kt wind, we may make it yet.
What fraction of the runway length in launch height are you getting with
these high powered winches?

Thanks and best regards,

Bob Johnson

Hi Bob

Depending on the aircraft 2000' launch is a very reasonable height
expectation for a good day.

We have 1800m of runway / steel cable. (approx 5900')
Runway is 4740' MSL
Density altitude is regularly above 9000' (it gets hot here, even in winter)
Launch in still air is around 1/3 of cable length.
In calm conditions we get

- 1400' -1600' dual in a trainer.
- 1600' -1800' solo in a 15m (Cirrus)
- 1600' + solo in a 17m

When the wind is down the runway and over 10kt the launch heights
improve dramatically. Personal best is 2300' in solo in one of the
trainers into a 20Kt wind. This thing is flying within 10m under those
conditions and pulling up at minimum safe winch speed makes a big
difference.

This is achieved with what can most kindly be described as a tired
winch. It is fifteen years old homebuilt job, with a Ford 352 Windsor
engine connected to a three speed auto transmission. We launch in second
gear to control the take up and prevent those big moments this thread
started on. We also seldom use the full (nominally 220hp) power
available, only the heavier two seaters need more power.

So the caption goes, vast power is no requirement - we don't have it.
You also don't NEED plasma, though we would love to replace our steel
wire for the convenience of plasma. Lots of reliable torque and a decent
run of cable do the trick, as long as the pilots and winch driver know
their stuff.

As for the cost - the winch will probably be the best investment a club
ever makes. Ours has had minimal maintenance, never been overhauled and
still works adequately although it is getting due for an upgrade. Our
club has been sending pilots solo on this winch for 10 years - over
15,000 launches, no injuries. If we had been aerotowing the club would
have folded financially years ago. Because it is cheap we do a lot of
flying on marginal days and the club stays active, and members stay current.

Bob Johnson wrote:
Bill, I appreciate the lead. Given the relatively high initial cost,
operating cost, and manning problems for a decent tug, 19,000 USD for a
new first-class winch doesn't seem unreasonable, particularly since they
can go for years with mostly only fuel cost to consider. And since
practically any club member can be quickly taught to drive a well
thought out winch, it's a wonder they are not more popular. I see that
Skylaunch has chosen to follow Craig's example in choosing the big-block
GM V-8 engine 8') while Supacat is sticking with the 250 hp Diesel.

We were hoping for the magic 2000-ft light wind launch height. Given our
5000 ft runway length, Plasma rope and a 20 kt wind, we may make it yet.
What fraction of the runway length in launch height are you getting with
these high powered winches?

Thanks and best regards,

Bob Johnson

The Van Gelder http://www.proximedia.com/local/neth...el/various.htm is built in units of 2, 4, 6, or 8 drums and can be on a truck or as a trailer.

I have not seen the version mounted on a truck, all the ones I have seen were trailers and were 6 drum; this includes the one at Dunstable with which I have had many launches.

If you have a winch mounted on a truck (I have seen other winches on a truck, e.g. the Tost winches at Lasham) then you have to buy a truck as well, and if the truck has problems or needs work then the winch is out of service as well. Winch maintenance when on a truck tends to be more difficult because access is more difficult.

I think the best layout is a trailer winch which can be towed on the public road and on the field by any decent SUV or reasonably sized car. The Skylaunch has done a demonstration tour of Germany like this, the trailer Van Gelder and the Supercat would have to go on a low loader truck or be towed by a large vehicle. Note that the Air Training Corps http://www.621vgs.co.uk/works.htm use a Bedford 4 Tonner (probably 4-wheel drive), all very well for them, the taxpayer pays for it!

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.
"Bill Daniels" wrote in message ...

"W.J. (Bill) Dean (U.K.)." wrote in message ...
The Van Gelder was a superb winch when it first arrived in the U.K., but the reference winch today is the Skylaunch http://www.skylaunchuk.com/ . I have done many launches in solo gliders and in two-seaters by both winches, and I prefer the Skylaunch. I have no commercial interest in that company.

The reference you gave is to 621VGS, which is an Air Training Corps squadron, and therefore part of the Royal Air Force. Their equipment is bought and maintained by the taxpayer, and their economics are rather different from the civilian clubs.

Note that the Van Gelder needs a substantial vehicle to tow it, the Skylaunch can be towed on the road by any reasonable SUV. The Midland Gliding Club have a Skylaunch which is towed round our rough airfield by a Range Rover.

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.

Bill, would you expand on the reasons for your preference for the Skylaunch winch?

Aren't most of the Van Gelder winches mounted on trucks so the towing issue is moot?

Bill Daniels

I understand that Supercat http://www.supacat.com/ have not in fact built
any new winches for some 10 years. The company still trades but is busy
with other products.

See the article by Gordon Peters on the on-line Gliding & Motorgliding
International site,
http://www.glidingmagazine.com/ListF...Dtl.asp?id=345 . His club
is the one where the Clayton winch originated in the late 50s or early 60s,
and the Supercat is a development of it. Remember that the original layout
of the design, still seen in the Supercat, was done to work with piano wire
(single strand) as distinct from stranded wire. The Tost, Van Gelder and
Skylaunch winches would almost certainly fail with piano wire, but this does
not matter because nobody uses it any more.

Big V-8 engines from the USA, petrol (gasoline) converted to run on Propane,
are now the engine of choice for winches in the U.K. I understand that the
engines used in the Skylaunch are the marine versions. They are of course
fitted with the usual automotive automatic transmission, I don't know if
these are modified for winching.

These engines have been in use in the U.K. for many years, for instance in
Tost winches of which there are a number here. The special features of the
Skylaunch are the detail design, and in particular the power control and the
ease of driving.

I think that when the quality of winch driving is less than perfect it is
due to one or more of the following factors:
1/ Bad driving.
2/ A winch that is difficult to drive.
3/ Difficult conditions.
For instance, one site I know has trees on the borders, so whenever there is
any wind there is marked turbulence and gradient just at the height where
the glider is rotating into the full climb.
It is easier to drive the Skylaunch well compared with other types of winch.

I do not know how the heights we get at the Mynd http://www.longmynd.com/
compare to the length available. We tend to be reasonably conservative in
our driving and flying methods, that is we leave a bit in hand. We
practically never break weak links, and we try to fly some way from the edge
in rotating into the full climb. Sites with restricted runs sometimes have
to try harder.

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.


"Bob Johnson" wrote in message
...

Bill, I appreciate the lead. Given the relatively high initial cost,
operating cost, and manning problems for a decent tug, 19,000 USD for a
new first-class winch doesn't seem unreasonable, particularly since they
can go for years with mostly only fuel cost to consider. And since
practically any club member can be quickly taught to drive a well
thought out winch, it's a wonder they are not more popular. I see that
Skylaunch has chosen to follow Craig's example in choosing the big-block
GM V-8 engine 8') while Supacat is sticking with the 250 hp Diesel.

We were hoping for the magic 2000-ft light wind launch height. Given our
5000 ft runway length, Plasma rope and a 20 kt wind, we may make it yet.
What fraction of the runway length in launch height are you getting with
these high powered winches?

Thanks and best regards,

Bob Johnson.

It is not unknown for the biggest and busiest clubs to do 15,000 winch
launches per annum.

Usually at these clubs both the driving and the maintenance are done by
employees. It costs so much if the winch is mechanically unreliable, the
driving is of low quality, or the launch rate is poor.

The better clubs have worked this out. This is why they are prepared to
pay for good production winches, good drivers, good maintenance and to
change the cable before it is worn out.

Compare the value of the gliders waiting for a launch with the value of the
equipment doing the launching.

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.


"Bruce Greeff" wrote in message
...

Hi Bob

snip

As for the cost - the winch will probably be the best investment a club
ever makes. Ours has had minimal maintenance, never been overhauled and
still works adequately although it is getting due for an upgrade. Our
club has been sending pilots solo on this winch for 10 years - over
15,000 launches, no injuries. If we had been aerotowing the club would
have folded financially years ago. Because it is cheap we do a lot of
flying on marginal days and the club stays active, and members stay
current.

On a glider only site you would be in the very vicinity of the pattern. It
is obvious that if there are many gliders at this altitude, you need to
think about what you do.

On a site shared with power traffic, patterns are usually seperated, i.e.
gliders on left hand pattern, power on right hand pattern, and there are
restrictions as to thermalling on final approach.

Just for completeness, these 800-1200ft release altitudes relate to fields
which provide something like 3000ft ish cable length.

With my Calif on a 5000ft cable, I typically get 1800-2000ft release
altitude. I'm not convinced that a Plasma rope would get you much higher -
there is nothing like length of the cable to increase height, and recent
tests on a military airfield in France have shown that there is no
saturation to be seen at 6500ft of cable length: you get about 40% of the
cable length as release altitude with a single seater.

--
Bert Willing

ASW20 "TW"


"Todd Pattist" a écrit dans le message de
...
"Bert Willing"
wrote:

In Europe, 500-600ft is normally considered as ok to thermal up. Many
launch
sites will give you 800-1200ft as release height from the winch.

How far from the traffic pattern would you be located when
thermalling at 500' and do you have to share with any power
traffic?

Todd Pattist - "WH" Ventus C
(Remove DONTSPAMME from address to email reply.)

On 12 Aug 2003 14:46:22 GMT, Ray Lovinggood
wrote:

The club, 'DJK' in Landau in der Pfalz, Germany, had
many GREAT winch operators!

Although I know you are biased, thx a lot for the compliment, Ray!

The only instrument, I
think (hey, this was from 1983 till 1986), was a tach
and maybe a engine coolant temperature gauge. I think
they operated mainly by sight and sound. Yep, they
were great operators! I think their rules stipulated
at least 100 operations with an instructor before they
could operate solo.

The 100 launches (on at least 10 deifferent days) are standard
requirements in Germany before you are able to work as a winch driver.
And in 2003 we have a 280 hp turbo Diesel winch that is easily able to
catapult any glider into the air - and we still use the same hightech
gauges you mentioned - the winch is basically driven with the RPM
meter and visally (rope slack).



Ray Lovinggood
Carrboro, North Carolina, USA
(who misses winch launching in the Land of Aero Tows)
.... simply go back to the club of your youth...


Bye
Andreas