sliding wings?

Hi, I don't think they built seven of those FS 29.



"The "Akademische Fliegergruppe Stuttgart" (in short "Akaflieg") is a
scientific aeronautical association at the University of Stuttgart. Its aims
is to develop new methods in aircraft construction and to put them into
practice. The main focus is sailplane development"



Their aim is normally not making any sailplane production...

You can take a look on http://www.uni-stuttgart.de/akaflieg/e-home.htm

(Text in German).


KH

schrieb im Newsbeitrag
oups.com...

karl-heinz: thank you. interesting russian designs. alas, they do
not tell us what the speeds and engine performances were. the IS-1
actually flew, so this would have been interesting.

I tried the aviafrance website, but cannot read french. fortunately, I
can read German, and on a google search found yet another one---and
this one from 1976 (i.e., not WW-2). it was for Akaflieg Stuttgart eV,
which apparently tried a telescoping wing plane called fs-29.
searching for airplane by name, I find indexes to "P. Lert, translator,
The FS-29, a telescoplng-wing sailplane [Aerodynamics; Lee Waves;
Sailplanes\FS-29], page 21" in Soaring Mag. more info is at
http://www.sailplanedirectory.com/stutgar.htm, which says they built 7
of these. [oops, just saw bill's post mentioning them, too.]

smitty---having internal strengtheners slide by one another should not
be too tough to accomplish, either.


What is the drag contribution of the wings in cruise flight? Is it
high? If so, this would make sense. Otherwise, not. Would it be
feasible to build an airplane that is a 60mph/150mph (stall/cruise) in
wing-extended config, and an 80mph/200mph airplane in non-wing-extended
config (i.e., not deadly if the wing extension mechanism fails at
landing time)? presumably, it would also save fuel.

in the realm of tough technology, extending wings does not seem too
difficult or error prone (e.g., compared to lowering wheels), whether
it is telescoping, or covering two successive wings, or raising up a
wing to become a biplane. the transition airflow might be tricky with
the latter two, but apparently the Russians thought it would work in
WW-2. also, if the wing does not extend, it wouldn't be so bad.


richard---it was my misunderstanding that I thought they primarily
change the angle of attack. but compared to more wing, they seem
somewhat "limited."

/iaw