Thanks for the interesting replies.

It was interesting to hear that yes, gound assembly
and
handling was a consideration. It seems that the convenience
of self-launch, or assembly, etc. do have a notable

effect on choices in gliders. Cost is just another
factor
that is put in with these factors.

I also thought I saw a 750kg limit total for contests.
Is this right in the U.S.? I guess that would be a
bit
of an arbitrary disincentive for more span too

At 23:00 18 April 2005, Steve Leonard wrote:
Mark,

As one qutoe says, 'There is No Substitute for Span.'
Then, some Bird
came along and said 'There is a Substitute for span.
It is called
Talent. But you can buy Span!'

Handling qualities are relative. If you are looking
for a ship to do
acro in, I would not recommend an ASH-25. Of the big
ships I am aware
of, the handling is not bad. Just slower in roll.
Forces are still
generally light. And they take more work to fly well
in circles. But
as some pilot here in the US said when someone complained
about how the
Ventus requires lots of effort to fly, 'A REAL pilot
does not have any
trouble flying a Ventus.'

Ground rigging is probably the biggest reason for people
not liking to
deal with the open class ships. Face it. Most have
six pieces of wing
to attach. No matter how bad your two piece wing might
be, it will
probably take less time to assemble than a six piece
wing. Runway
width can be an issue, as we generaly will hang out
near or over lights
on both sides of the runway. Know your airplane and
you can offset one
way then lower the other wing.

As for performance, I personally think they have gotten
too big. Look
at the Schleicher site on the ASH-25. Partly marketing,
but they make
the comment that higher minimum wing loadings do not
seem to hurt the
open class gliders. And with a 750 KG weight limit
for contests, the
current open class ships are stuck at under 9.5 psf.
The Nimbus 4 is
about 8.7. Read what others have written, and almost
all of them want
more weight.

I came up with the idea that best L/D can be approximated
by Span in
Meters plus Aspect Ratio. This generally gets you
within about 10%,
except on the new 15 meter class ships, where it falls
a bit short of
the claims by the factories. If the span was cut back
to, say 22
meters, and the aspect ratio run up to about 40 (heck,
Eta is 51,and
the long tipped 25's are pushing if not above 40, but
with 26 plus
meters of span), that puts the area at about 130 square
feet. Chords
would be similar to an ASW-27, but over longer sections
between the
taper breaks.

Now, if my ultra preliminary estimation for performance
holds true, you
would have about the same best L/D (22 + 40 = 62) as
a N4, but you
could ballast up to about 12.8 psf at 750 KG. Wouldn't
that make for a
rocketship! And if you could keep the minimum wingloading
to about
8.5, this leave about 900 lbs for the empty weight
(200 lb pilot).
Seems doable to me at a first glance.

Of course, this view is US Based. In Europe, there
doesn't seem to be
the desire for the ultra-high wing loading. And do
you think any
manufacturer would put out a smaller Unlimted Class
ship than what they
have now? Not bloody likely.

So, is 24 meters too much? Maybe, for the US and the
weight
restriction. You might do better with less. I see
lots of pictures
of German registered ASH-25s that have been stretched,
some to as much
as 27 meters. So, I am suspecting that L/D max is
more important than
the ultra high speed cruising in Europe. That, and
the crossover for
the longer wings is above the often used cruising speeds.

And just to confuse things, I have a 604 that I am
looking to stretch
from 22 to 24 meters. Being in the more sedate, flat
lands, I am
looking for more low end performance, and hoping the
cross-over will be
above my typical crusie speeds.

But, if you know of anyone willing to part with an
ASH-26 fuselage, I
could get started on a set of thin, 22 meter wings
to try and prove my
point... Could be intersting to plan a 40:1 final
glide at 115 knots,
no wind.

Steve Leonard


Mark J. Boyd