I second the yahoo groups.

Frank Whiteley

"Mark Zivley" wrote in message
news
We all know "cheap" is a relative word. Cheaper than a Skylaunch leaves
a lot of ground. Just like any design project, we need to start with
some goals.

Reality is that a 2 drum winch probably is the peak in operational
efficiency coupled with simplicity of design. Piggot's book recommends
multiple 2 drum winches over winch designs with more than 3 drums.
Safety for the operator is paramount and clearly we need to be providing
enough power to handle a glider on a Black weak link. In general this
design should keep cost in mind, but surely as any club or group starts
to embark on construction they will have a lot of latitude as to how
they control costs. Do they buy a crate motor for $3-4k or buy that
little old lady's Cadillac for $500.

However, the first thing needs to be a forum off of RAS where we can
work. Ulrich started this, so I'll defer to his preferences. The Yahoo
groups are free, offer file sharing (I think) and it's easy to set up
topics to be voted on by the members. With that, we can start nailing
down the design goals.

Bill Daniels wrote:
"Ian Forbes" wrote in message
...

Mark Zivley wrote:


This project should probably be moved to a slightly different forum
like a yahoo group where people interested in participating can do so
without
filling up RAS. This also allows the sharing of files and even voting
on ideas as the project starts to take shape. We're definitely onto
something here, lets get started. We should start by doing some
deciding as to what will be designed. 1 or 2 or more drums.....

Now you are talking!

Lets get the fundamentals right. We want a design that is easy to build,
not too expensive, simple to operate, easy to maintain and with safety
standards to meet current best practice. Performance should be capable
of launching a glass 2 seater trainer to a hight not less than 1/3 of
the runway length in zero wind conditions.

I vote for a big block V8 petrol motor powering a double drum winch. For
the guys who want to talk about exotics electric winches and diesels
with modified ECU's - go for it but lets separate the threads. I think
the successful 'one design' winch is going to run on petrol and will be
made from readily available hardware. If we have any spare cash left in
the budget we will spend it on plasma rope.

As a starting point, lets get some specs on winches that have been built
already together with performances achieved. We need to start off with
parameters like engine capacity and size, drum dimensions, final drive
ratios, gearbox/torque converter details and the source make and model
of the components used.

Then we need detail engineering drawings for the clever bits. Winch drum
axle mods, guillotines, guide pulleys. These should best be based on
proven designs. Details for a Skylaunch like throttle control would be
nice. Good engineering detail for the safety items like the operator's
cage and cable guards might save a few home builders from unexpected
injury.

The engineering should accommodate a choice of cables. Single strand,
multistrand or plasma. We need to spec those too.

We should also put together a "bill of materials" for anybody planning
on establishing a winching operation. I am thinking of a comprehensive
list of things like weak links, rings, 'chute, snake, signal lights,
radios, cable retrieve vehicle... That in itself would at least allow
for drawing up a proper budget.

As for a forum - if we are going to move off RAS, Al's gliderforum.com
might be a good home. If we want to run off an e-mail list, I can
probably make a plan to host it. We will also need a repository for
information - a web site - perhaps a "wikki".

Finally we need to establish some ground rules regarding copyright and
ownership of the design. My vote is to follow the "Open Source" model
used by Linux etc. Publish everything and allow anybody to use it - but
under the condition they publish details of what they build and how
well it works.

Who's in?

Ian



Ian. I admire your enthusiasm and support your ideas, but the economics
need
a bit of discussion.

Winches are VERY profitable. The operational cost is less than $2US per
launch and most people will find $10 is a reasonable launch fee. That's
a
500% profit with a volunteer crew in a club setting. The Return On
Investment for a $30,000 winch is just 63 operating days figuring an
average
of 60 launches a day. A dual drum winch in a training environment can
do a
LOT more than 60 launches a day.

After the club has its ROI it can buy a new glider every year with the
profits. That's the REAL secret of how those European clubs own all
that
nice glass. They put their money into gliders instead of air tow fees.

My concern is that by focusing on the "build it cheap" aspect, the
productivity of the machine will be lost. That's where American winches
have gone wrong in the past. Just a couple of weekends lost to winch
repairs is significant. If the "Hassle Factor" is too large, people
will go
back to air tow.

Build it right, make it reliable and as productive as possible no matter
if
it costs more to build. If a diesel engine is more productive than a
spark
ignition engine then pay the extra money for one. If Spectra improves
the
operation by reducing cable breaks and tangles then pony up for it. The
ROI
comes very quickly. Almost ANYTHING that increases the number of
launches
per day or makes the whole operation easier and more pleasant is worth
the
investment.

Bill Daniels