tango4 wrote:
"Mark James Boyd" wrote in message
that often? How about one winch, right next to the existing
power lines (at least for the darned prototype)?

You guys crack me up with your "glider winch and power station
industrial complex" designs. If you're that rich, good
for you! ;P

http://www.glidingmagazine.com/Featu...cle.asp?id=293 covers just the
kind of thing you guys are re-inventing. By the way the unit cost them 56000
Euros and that was a year ago, at the time they considered it cheaper than
the alternatives.

Some details
up to 20kw draw from the 3 phase mains supply
200kw launch power
850 kg max glider weight
1 g initial acceleration
Euro 1.90 per launch including cable, winch and battery replacements
Electronic motor control

Just to be clear, I personally have no interest in winching a 850kg
glider, laying 5000 meters of copper cable, or paying for a winch
AND a spanking new semi truck (all mentioned in the glidingmagazine
article).

I'm interested in about 1/4 of that weight glider (226 kg),
a few hundred feet of copper power cable, a 4000# total weight towed
as a trailer behind a truck, and spectra rope that doesn't weigh 300# or
lash around and leave pieces of metal in the
winch driver when it breaks.

If an electric motor of 100hp like the one at
http://www.electricmotorwarehouse.co...sion_proof.htm
for about $5,000 and 2,000 pounds can do the trick, I'm guessing
the other $60,000 (US) would cover the trailer and copper wire and
spectra and knicknacks with enough left over to
make four spare mini-winches and still buy a used AC-4c Russia :P

That's a big IF. I still don't know the apples to oranges
electric to fuel based engine UMPH...(tension that actually gets to
the glider). Is 100hp enough? If boat engines or car conversions are
any indication, electrics are 3 times as efficient as gas motors
in terms of HP actually delivered. So maybe an electric "100 hp"
winch is equivalent to 300hp of gas engine? Also, do the electric
motors really put out the same UMPH at lower RPM? I dunno...

I also don't put too much credibility to european pricing.
I remember the metal price tags on the trees in Germany
(in case you hit one and killed it you'd have to pay for it.)
$12,000 for a TREE?! Those Germans seemed to heap on a lot
of expensive fertilizer... ;P I'm all about clean air,
sunshine, some water, and soil. Besides, if Marc will
do all the labor for free, we can avoid the 100% to 200% retail
"markup," right?
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Mark Boyd
Avenal, California, USA