At 03:05 22 May 2017, Steve Leonard wrote:
On Sunday, May 21, 2017 at 5:40:06 PM UTC-5, Martin Gregorie
wrote:
On Sun, 21 May 2017 13:39:31 -0700, Bruce Hoult wrote:
=20
When someone says "the first Cirrus was essentially a glass
SHK, the
prototype inherited the V-tail, the production versions went
over to
th=
e
conventional tail-plane and elevator" I tend to the assumption
they're
talking about "early" ones -- which are the vast majority of
examples
i=
n
NZ.
=20
Understood: apparently only the first prototype had a V-tail, so
I'd=20
expect the "early" Cirruses in NZ to be T-tailed with all flying
tails.=
=20
=20
I also know that the first production Std Cirrii had 1.5 degrees
washout=
=20
on the wing and were a bit prone to tip stalling and spinning.
Later Std=
=20
Cirrii had 3 degrees of washout which, apparently cost them
some=20
performance but killed the tip stalling tendency, but I have no
idea
what=
=20
Wrk.Nr this change applied to. It would be interesting to know
which=20
group most NZ-registered Std Cirri fall in.
=20
I've heard it said that Std Cirri dominated Club Class until the
ones=20
with 1.5 degrees of washout had all been broken and that after
that Std=
=20
Libelles took over. Make what you will of that!
=20
=20
=20
--=20
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

What Scott said, and then some. Martin, I think you have
confused the
Cirr=
us (17.74 meter) with the Std Cirrus (15 meter).

Also,to imply the Cirrus is "basically a fiberglass SHK" is
comparable to
s=
aying "the Corvette is just a fiberglass body on a Monte Carlo."
Two
ENTIR=
ELY different sailplanes. The ONLY similarity is that the prototype
Cirrus=
had an SHK tail on it. Different wing span, airfoil sections and
aspect
r=
atios. different cockpit layout and geometry. They came from the
same
man=
ufacturer, but other than that...

Just my 2 cents worth,
Steve Leonard

Steve is entirely correct. The SHK was derived from the HKS-3
which was designed by Haase, Kensche, and Schemmp. E.G. Haase
flew and won the WGC in 1958 (Poland) with it. It used wing
warping as opposed to ailerons for increased performance. The
HKS design was modified for series production as the SHK.

Later, when Klaus Holighaus came to S-H straight out of Akaflieg
Darmstadt, he brought along design/constuction ideas and concepts
that he had learned and used (along with Waibel and Lemke) when
they built the D-36 at the university. The Open Cirrus was Klaus'
first venture as the new owner and glider designer of S-H. It is a
totally different glider than the SHK.

RO