Akaflieg Karlsruhe AK-X

At 20:41 11 December 2017, Andreas Maurer wrote:

Comparison to previous flying wing designs:

All previous flying wings had one huge basic fault:
In order to pitch up (or to fly slow), you had to deflect the controls
up, therefore reducing airfoil camber and thus lift coefficient -
basically exactly the opposite of what you'd like to have
aerodynamically.

The wing of the AK-X works exactly like that of any flapped glider:
Low-speed flight: All flaps deflected "down"
High-speed flight: All flaps deflected "up"


The idea behind this aredoynamic design is, frankly spoken, a
touch of
genius. It's the first ever flying wing design ever that in theory
will be able to compete with a conventional design in all areas of
the
flight envelope up to very high speeds.

Plus, there are a couple of other benefits:
The wing uses conventional airfoils whose aerodynamic qualities
can be
predicted well today. The flapped wing creates the same lift
coefficient as the wing of a conventional design, allowing high
aspect
ratio and wing loading.
Behind the cockpit there's a 40 liter water tank (directly at the
center of gravity) and no other structural parts - pretty simple to
replace this tank with an angine and some serious battery capacity.


To me, the only remaining question is the influence of the wing
sweep
on spanwise flow - but as I heard the guys are pretty optimistic so
far (they've got a 1:2 model flying with very good results).

Cheers
Andreas


Andreas,

Thank you very much for the insights. If my father were still alive
today, he would be wanting to follow the progress very closely. The
aerodynamic genius of using the wing sweep to emulate canard
characteristics as opposed to using the sweep for high speed flight
is extremely intriguing. Being able to use current modern airfoils
while reducing drag considerably, should result in very noticeable
performance increases. Also, the advent of newer construction
materials and methods which enable the builders to achieve the
stiffness that is required to overcome other previous wing's
aeroelastic issues cannot be overstated.

Please post any progress updates here whenever you may hear of
them in the future....

RO