Now i am done with reading the .pdf in the first Post.
My Summary: Short Prandtl without mentioning key facts, Aeroelastics- the only mention in this Article, Missing parts of Computed Analysis, Computer coded Darwin-without Darwin, induced Drag is not Suitable for "classic" layouts @ M0.8, Overwhelming Conlusion without criticism.
The most disturbing fact is that he mentioned Aeroelastics only once in the whole Paper but is planning to include an forward swept Wing(part).
Thats also a Point of Criticism in the Openers Post. It is nice to get extra stiffness from installing the upper Wing nearly directly onto the Airframe. There are 2 things to obtain about this:
Firstly you get all the loads of both Wings directly into the Airframe which causes high stress.
Secondly you get in serious trouble with the aft wing when the plane has to ditch, it would be better if this wing would fall off at thus moment without big issues to the hull.
Thats why all BW concepts have thier aft wings installed on the Tailrudder.
P.S. The Wingbox is a highly stressed Part as you can see from Above. It has to be monitored on an regular Basis, no one wants to dismantle half of the Cabin for that.
The right conclusion in the Paper is that BW is a great concept for regional Airliners. To complete this thesis, slow flying regional Airliners, maybe fitted with RR Propfans. (Transonic Airfoils not needed for that)
P.p.S it is funny to see that aircraft designers use firstly CFD and then Euler, especially from a turbine point of view.
Greetings,
Last edited by Sokol; 9th Feb 2016 at 15:49.