SAFE Winch Launching

At 18:15 20 July 2009, bildan wrote:

Constant tension during the climb phase is exactly what you want.
Read George Moore's article in this month's Soaring Magazine. Tension
telemetry is a great idea - someone please build it.

A kite string or a winch rope forms a catenary arc due to it's weight
and air drag. The tension on each end of a catenary arc is the same
except for the rope/string weight difference if the ends are at
different heights. If 2000 feet of Plasma rope were hanging
vertically the tension due to its weight is zero at the bottom and
only 20 pounds at the top - that difference doesn't matter much.


I think we have established two facts, firstly that you have absolutely no
first hand knowledge of the operation of a Skylaunch winch so I think your
opinions on that subject can be safely ignored. I have driven many types
of winch, for many hours, including the Skylaunch and I know that it works
extremely well with none of the "faults" that you imagine it has. It is
not the best winch I have ever driven but it is very close and the MVG is
not an affordable option for most UK clubs. The MVG is also too
complicated for use at most clubs, too many advance features.

Now consider the following case. A glider at the top of the launch, the
cable is exerting a force on the release hook of x pounds which you deem
to be tension. This force is due almost entirely to the weight of the
steel cable and is considerable. At the winch end the cable is being
retrieved very slowly or not at all, the measurable tension at that end is
close to or maybe even equal to 0. The force exerted at either end of the
cable is totally different, that is the extreme case of course but, as a
glider climbs the "tension" or force exerted on the release will
increase as the glider takes more of the weight of the cable. Please
explain how this increase can be measured or taken into account at the
winch end.

Please do not evade the question by discussing plastic rope.

All the winches I have ever driven or observed have had something which
takes care of the changing circumstances very well, we call that something
a driver and a skilled driver does not need gizzmos to give a good launch.
I am fast coming to the conclusion that the real problem here is that you
are actually afraid of winch launching and if that is the case, don't do
it.

What we here in the USA need is a cheap good winch option. We need
price quotes. Bill says his will be cheaper than the Skylaunch. Well,
what the price then? Skylaunch publishes theirs. However, I agree with
Bill in that 90,000 Euros is way too expensive. They're certainly
making a nice profit at that price.

Perhaps a US bases shop could offer a similar system as the Skylaunch/
Tost for much less than European prices, especially if some clubs get
together and make a combined group order. I think one of the problems
is the very low volume of production for commercial manufacturers.

Or perhaps an easy set of plans could be drawn up and digitized to be
ordered and manufactured by a machine shop for any club or operator
whenever a new winch is desired? Bottom line, we have to get the price
down from 90,000 Euros.
Tom

On Jul 21, 2:59*am, tommytoyz wrote:
What we here in the USA need is a cheap good winch option. We need
price quotes. Bill says his will be cheaper than the Skylaunch. Well,
what the price then? Skylaunch publishes theirs. However, I agree with
Bill in that 90,000 Euros is way too expensive. They're certainly
making a nice profit at that price.

Perhaps a US bases shop could offer a similar system as the Skylaunch/
Tost for much less than European prices, especially if some clubs get
together and make a combined group order. I think one of the problems
is the very low volume of production for commercial manufacturers.

Or perhaps an easy set of plans could be drawn up and digitized to be
ordered and manufactured by a machine shop for any club or operator
whenever a new winch is desired? Bottom line, we have to get the price
down from 90,000 Euros.
Tom

Why talk euros? Skylaunch are a UK firm and the price is around
60,000 pounds sterling (possibly less with negotiation) - I think the
euro price of 90,000 quoted above represents a very out of date pound/
euro exchange rate of 1:1.5 and is therefore meaningless in the
context of this discussion. Other European winches such as the MEL
are way more expensive.

http://www.skylaunchuk.com/

(For the record my only connection with Skylaunch is hoping that our
club buys one soon)

John Galloway

If you can live without a heated and air-conditioned cab and a few other
gizmos, Skylaunch do a cheaper version of their winch called the Skylaunch
3. This can also be bought as a kit, so if you can locally source engines
and transmissions it could work out a whole lot cheaper. See:

http://www.skylaunchuk.com

As to capital cost, our winches do over 10,000 launches per year, so they
pay for themselves quite soon. And think how much clubs will happily lay
out for a decent tow plane.

Derek Copeland


At 01:59 21 July 2009, tommytoyz wrote:
What we here in the USA need is a cheap good winch option. We need
price quotes. Bill says his will be cheaper than the Skylaunch. Well,
what the price then? Skylaunch publishes theirs. However, I agree with
Bill in that 90,000 Euros is way too expensive. They're certainly
making a nice profit at that price.

Perhaps a US bases shop could offer a similar system as the Skylaunch/
Tost for much less than European prices, especially if some clubs get
together and make a combined group order. I think one of the problems
is the very low volume of production for commercial manufacturers.

Or perhaps an easy set of plans could be drawn up and digitized to be
ordered and manufactured by a machine shop for any club or operator
whenever a new winch is desired? Bottom line, we have to get the price
down from 90,000 Euros.
Tom

I note from the Skylaunch price list that a new diesel engine equivalent in
power to a new GM marine 502 V8 costs £21,000 (31,000 Euros) more! The
cheapest Skylaunch 3 kit excluding engine and gearbox is £26,237 (38,072
Euros). As this includes all the difficult to make bits, it would be a
good starting point.

Derek Copeland


At 06:23 21 July 2009, johngalloway wrote:
On Jul 21, 2:59=A0am, tommytoyz wrote:
What we here in the USA need is a cheap good winch option. We need
price quotes. Bill says his will be cheaper than the Skylaunch. Well,
what the price then? Skylaunch publishes theirs. However, I agree with
Bill in that 90,000 Euros is way too expensive. They're certainly
making a nice profit at that price.

Perhaps a US bases shop could offer a similar system as the Skylaunch/
Tost for much less than European prices, especially if some clubs get
together and make a combined group order. I think one of the problems
is the very low volume of production for commercial manufacturers.

Or perhaps an easy set of plans could be drawn up and digitized to be
ordered and manufactured by a machine shop for any club or operator
whenever a new winch is desired? Bottom line, we have to get the price
down from 90,000 Euros.
Tom

Why talk euros? Skylaunch are a UK firm and the price is around
60,000 pounds sterling (possibly less with negotiation) - I think the
euro price of 90,000 quoted above represents a very out of date pound/
euro exchange rate of 1:1.5 and is therefore meaningless in the
context of this discussion. Other European winches such as the MEL
are way more expensive.

http://www.skylaunchuk.com/

(For the record my only connection with Skylaunch is hoping that our
club buys one soon)

John Galloway

I see that their main business is making winches and that's why they
charge what they charge. But it doesn't make sense to spend $90,000 on
their cheaper system, not including transportation costs to the US,
when the engine/transmission costs less than $10,000. I mean, $5,000
for a GUILLOTINE ASSEMBLY for over $5,000 on a double drum - come on.

Perhaps the best way to go is buy the bare bones Kit for a "mere"
$44,000 not counting transportation. Any way you slice it, with
Skylaunch, it's not possible to be operational for less than $60,000,
which would include a lot of sweat equity. I think it's a bit much.
Tom

Perhaps the way to go is just buy a good used winch from a European
club. What was the offered price again for that old Tost winch at
Lasham?

On Jul 20, 7:59*pm, tommytoyz wrote:
What we here in the USA need is a cheap good winch option. We need
price quotes. Bill says his will be cheaper than the Skylaunch. Well,
what the price then? Skylaunch publishes theirs. However, I agree with
Bill in that 90,000 Euros is way too expensive. They're certainly
making a nice profit at that price.

Perhaps a US bases shop could offer a similar system as the Skylaunch/
Tost for much less than European prices, especially if some clubs get
together and make a combined group order. I think one of the problems
is the very low volume of production for commercial manufacturers.

Or perhaps an easy set of plans could be drawn up and digitized to be
ordered and manufactured by a machine shop for any club or operator
whenever a new winch is desired? Bottom line, we have to get the price
down from 90,000 Euros.
Tom

Tom, the Hydrowinch is not "my" winch. I have no interest other than
as a cheerleader for both the Colorado Springs and San Diego makers of
advanced US winches. My association with Hydrowinch is as a volunteer
gofer, test pilot, wrench turner and sometimes airfield mower. I know
they want to sell the winch at little over their costs but until the
testing and development is complete, the final price will not be
known.

Yes, you can build your own winch and save a lot of money doing it. I
started advocating that in 2000 but very few people today want to use
their hands or learn the skills needed to build one. I actually wrote
a 36 page proposal with suggested sources of parts and materials.

If you ask machine shops to make the winch or even major components,
be prepared for some serious sticker shock. You have to do all most
all the work yourself to gain significant financial advantage. Try to
keep all the "fiddly" work to yourself and farm out the absolute
minimum to machine shops. Above all, stay away from the "prototype
shops" and look for one whose main business is repairing farm
equipment - they're cheaper and they understand the machine better.

Most of all, stay away from the "mechanical sculpture" disease. Study
the problem extensively before cutting metal.

On Jul 21, 4:12*pm, tommytoyz wrote:
Perhaps the way to go is just buy a good used winch from a European
club. What was the offered price again for that old Tost winch at
Lasham?

Actually, if you look at the German web site www.segelflug.de click on
the English flag and then on "commercials" (and discover it's still in
German) but persist by scrolling down to "Biete Sonstiges", (other
gear) you find several used European winches for sale along with a lot
of other interesting glider stuff.

However, you're right. Shipping costs are a deal killer. Most likely
it's still better to build your own.

On Jul 21, 4:01*pm, tommytoyz wrote:
I see that their main business is making winches and that's why they
charge what they charge. But it doesn't make sense to spend $90,000 on
their cheaper system, not including transportation costs to the US,
when the engine/transmission costs less than $10,000. I mean, $5,000
for a GUILLOTINE ASSEMBLY for over $5,000 on a double drum - come on.

Perhaps the best way to go is buy the bare bones Kit for a "mere"
$44,000 not counting transportation. Any way you slice it, with
Skylaunch, it's not possible to be operational for less than $60,000,
which would include a lot of sweat equity. I think it's a bit much.
Tom

Note their Skydrive. Add your big block engine and transmission, pay
on rig, and controls and you're away.

Just the ticket with a retrieve winch setup.

Still too much? I just had a drum built for a CAP owned Gehrlein Model
62 winch (late 1960's vintage). Based on a 22-inch truck wheel, the
machining, welding, and materials cost $1165 (we crushed the old drum
last year). Runs true and well balanced. The Amsteel Blue rope we've
been using for over the past couple of weeks cost close to $3000 and
is being rented on a per launch basis. The basic winch is about 40
years old with a 351-Windsor 2bbl and FMX automatic. Kind of wheezy
for our 5500msl field, but still knocking out 1400ft launches in nil
wind. Last year on a longer run and lower elevation we got
2200-2600agl.

Frank Whiteley