On Sat, 09 Dec 2017 09:20:40 -0800, Mike C wrote:

On Saturday, December 9, 2017 at 9:07:18 AM UTC-7, Kiwi User wrote:
On Fri, 08 Dec 2017 19:52:04 -0800, Jonathan St. Cloud wrote:

Akaflieg Karlsruhe AK-X

Looks like they've got a 25% scale model built and awaiting test
flying.
If you read German, this looks interesting and has lots of photos:
https://akaflieg-karlsruhe.de/project/ak-x/

Be aware that your browser may object, though, because its an https
site and the certificate expired a few days ago.


--
Martin | martin at Gregorie | gregorie
| dot org

Exciting work!

I hope these students design and build a contest viable swept wing
sailplane.

Lets hope that, unlike the Horten gliders and their earlier SB-13 Arcus,
it doesn't have a nasty high-speed pitch oscillation, that seems to be an
unwanted feature of swept wing tailless aircraft.

I've seen flight reports about a Horten S.IV when it was being flown in
US comps that mentioned that a 'pecking' oscillation limited its cruising
speed and flight reports about the SB-13 show that it shared this
behaviour.

The DH.106 Swallow, an early British swept-wing jet, also showed the same
high speed oscillation. That killed Geoffrey de Havilland Jr. when the
pitch oscillation broke his neck during a high speed run in the 2nd
prototype and almost killed Eric 'Winkle' Brown in the 3rd - he said that
the oscillation was very violent and thought he only survived because he
was smaller than de Havilland and so didn't get his head slammed into the
canopy. When he slowed down below a critical speed the oscillation
stopped as suddenly as it had started


--
Martin | martin at
Gregorie | gregorie
| dot org