Akaflieg Karlsruhe AK-X

Has anyone seen the Akaflieg Karlsruhe AK-X photos. They have flown a scale model and it looks very interesting. Wonder how it will compare to "traditional designs"? If it proformed as well or better than moe traditional design I would purchase one.

From the website

"The time has come, after years of advanced development, testing, evaluation of concepts, construction of models, discarding and regenerating ideas the AK-X project is rising to a new level: We build the man-carrying flying wing of 15m glider racing class!"

https://akaflieg-karlsruhe.de/2016/0...g-flugzeugbau/

DG have started making the full size molds for them on their CNC machine.

Looks interesting,

Paul

On Wednesday, January 27, 2016 at 2:46:10 PM UTC-8, Glidingstuff wrote:
From the website

"The time has come, after years of advanced development, testing, evaluation of concepts, construction of models, discarding and regenerating ideas the AK-X project is rising to a new level: We build the man-carrying flying wing of 15m glider racing class!"

https://akaflieg-karlsruhe.de/2016/0...g-flugzeugbau/

DG have started making the full size molds for them on their CNC machine.

Looks interesting,

Paul

Interesting project. I remember seeing some interesting flutter modes on the similar SB-13.

Any idea what happened to the SB-13? How did it fly, what was it's performance...?

On Wednesday, January 27, 2016 at 4:50:40 PM UTC-8, Craig Funston wrote:

Interesting project. I remember seeing some interesting flutter modes on the similar SB-13.

On Friday, January 29, 2016 at 10:43:28 AM UTC-5, Jonathan St. Cloud wrote:
Any idea what happened to the SB-13? How did it fly, what was it's performance...?

On Wednesday, January 27, 2016 at 4:50:40 PM UTC-8, Craig Funston wrote:

Interesting project. I remember seeing some interesting flutter modes on the similar SB-13.

https://en.wikipedia.org/wiki/Akafli...ig_SB-13_Arcus

I did see this, plus the short write up at Deutsches Museum Flugwerft web site. Was looking for someone with personal knowledge of this program or a technical write up of the program.

On Friday, January 29, 2016 at 7:56:26 AM UTC-8, Dan Daly wrote:
On Friday, January 29, 2016 at 10:43:28 AM UTC-5, Jonathan St. Cloud wrote:
Any idea what happened to the SB-13? How did it fly, what was it's performance...?

On Wednesday, January 27, 2016 at 4:50:40 PM UTC-8, Craig Funston wrote:

Interesting project. I remember seeing some interesting flutter modes on the similar SB-13.

https://en.wikipedia.org/wiki/Akafli...ig_SB-13_Arcus

On Fri, 29 Jan 2016 11:34:02 -0800, Jonathan St. Cloud wrote:

I did see this, plus the short write up at Deutsches Museum Flugwerft
web site. Was looking for someone with personal knowledge of this
program or a technical write up of the program.

On Friday, January 29, 2016 at 7:56:26 AM UTC-8, Dan Daly wrote:
On Friday, January 29, 2016 at 10:43:28 AM UTC-5, Jonathan St. Cloud
wrote:
Any idea what happened to the SB-13? How did it fly, what was it's
performance...?

On Wednesday, January 27, 2016 at 4:50:40 PM UTC-8, Craig Funston
wrote:

Interesting project. I remember seeing some interesting flutter
modes on the similar SB-13.

https://en.wikipedia.org/wiki/Akafli...ig_SB-13_Arcus

Its also covered pretty well, with 3-view drawings, in Martin Simon's
book "Sailplanes 1965-2000".


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

If you have FSX or FS2004 you can also fly the SB13. Download he
http://simviation.com/1/browse-Glide...tralites-130-5
Seem to remember reading the SB13 was fairly tricky to fly hence it's
early retirement, and the performance was somewhat disappointing.

On Fri, 29 Jan 2016 23:39:37 +0000, Paul T wrote:

If you have FSX or FS2004 you can also fly the SB13. Download he
http://simviation.com/1/browse-Glide...tralites-130-5 Seem to
remember reading the SB13 was fairly tricky to fly hence it's early
retirement, and the performance was somewhat disappointing.

Yes, indeed. The students spend 6 years working on a 1/3 scale RC model
and building it, followed by another 2 years making modifications and
retesting the aircraft, but they found that it remained tricky to fly
(stalls with a rear CG usually resulted in a spin and stalls with a
forward CG resulting in the glider 'pecking'. Unless spin recoveries were
very precise the glider often flicked into the opposite spin instead of
recovering. Its behavior on tow was diabolical, it was very tricky to fly
and, as its performance was no better than contemporary Standard Class
gliders they gave it up as a bad job and put it in a museum.

'pecking' was a large amplitude, rapid pitching cycle whose causes and
mitigation were never understood.

FWIW this is a rapid summary of the two page description in "Sailplanes
1965-2000", which also includes an excellent colour photo and a full
page, dimensioned 3-view drawing of the SB-13.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Sat, 30 Jan 2016 02:06:21 -0000 (UTC), Martin Gregorie
wrote:

On Fri, 29 Jan 2016 23:39:37 +0000, Paul T wrote:

If you have FSX or FS2004 you can also fly the SB13. Download he
http://simviation.com/1/browse-Glide...tralites-130-5 Seem to
remember reading the SB13 was fairly tricky to fly hence it's early
retirement, and the performance was somewhat disappointing.

Yes, indeed. The students spend 6 years working on a 1/3 scale RC model
and building it, followed by another 2 years making modifications and
retesting the aircraft, but they found that it remained tricky to fly
(stalls with a rear CG usually resulted in a spin and stalls with a
forward CG resulting in the glider 'pecking'. Unless spin recoveries were
very precise the glider often flicked into the opposite spin instead of
recovering. Its behavior on tow was diabolical, it was very tricky to fly
and, as its performance was no better than contemporary Standard Class
gliders they gave it up as a bad job and put it in a museum.

'pecking' was a large amplitude, rapid pitching cycle whose causes and
mitigation were never understood.

FWIW this is a rapid summary of the two page description in "Sailplanes
1965-2000", which also includes an excellent colour photo and a full
page, dimensioned 3-view drawing of the SB-13.


.... and here are a couple of videos that illustrate some of the major
problems:

First flight:
https://www.youtube.com/watch?v=GY6FJZF-hS4


First (and only) winch launch attempt:
https://www.youtube.com/watch?v=WqlYORF0-oQ

Note the nose gear, and learn some German curses.


Cheers
Andreas