I would always choose the 15 meter glider.......following what you have been
saying the 15 meter would then not be the "same" performance as the 13 meter
glider.....but better!
Also.having flown a lot of different types of glider and airplanes over
several years, including some ultra-lite or 'lite" types there is still no
way to compare these with the extra mass and groovy feeling of the (for the
lack of a better word) real sailplanes.....
tim

"Eric Greenwell" wrote in message
...
Erik mann wrote:

What is it that economists always throw out... ceteris paribus...

I agree that if one started with a clean sheet of paper, then maybe you
can lop off a few pounds on the fuselage, change the planform, etc.
(though, having looked at the structure of some of these ships,
I'm not so sure I would want to fly them or land them off-field...
but I digress). Keeping everthing else equal, is the "best" use of
engineering to start with a shorter span as a design goal? Maybe it
is, as the weight savings on the spar and carry-through structure allows
for a good range of wingloading while bringing along the other
benefits mentioned elswhere (ease of assembly, transport, etc.)?
Or, maybe the design goal should be 40:1 performance at the lowest
cost, irrespective of span?

That was my proposed goal: LS4 performance at the lowest manufacturing
cost. The obvious solution will be a smaller glider, made possible by
the improved aerodynamics, design, and materials that became available in
the 24 years since the LS4 was designed.

A few have suggested 40:1 is not possible at less than 15 meter span, but
when 15 meter spans can now do 48:1 or better, this is not sensible.

Most people that have objected to this smaller span solution have done so
mainly on the "it doesn't cost THAT much more to ..." grounds; i.e.,
proposing a more expensive glider than one that will just match the LS4.
This might indeed yield a more viable product, but it doesn't meet the
goal of a "cheaper LS4".

Which would you prefer, at the same price: a new LS4, or an new 13 meter
with identical performance, handling, and safety? I would choose the 13
meter glider, but many/most would not, even though it's smaller size and
lighter weight would make it easier to rig, to push around, to retrieve,
to tow (in it's trailer or behind a tow plane), even to wax!

Old habits and dreams die slowly, I think. Glider pilots are mostly a very
conservative bunch.

--
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Eric Greenwell
Washington State
USA