The efficiency of the flying wings due to the lack of a fuselage and tail surfaces is just a myth, very well known among airspace engineers: the drag from the special airfoil and other parasity drags created by the auto stabilisation wing requirements are quite bigger than those from a well designed classic airframe.
It was well documented by scientific studies and comparatives between top performance classic gliders and flying wing gliders (mainly Horten ones) and the results and conclusions were clear and kep up today. Flying wings developed since then were from other requirements (reentry requirements for the Space Shuttle and stealth for the B-2 bomber), but never performance.
The academic reference book on th ematter is "Tailles Aircraft in Theory and Practice" by Karl Nicker and Michael Wohlfahrt and English translated by no other one than Eric M. Brown, the world famous Royal Navy test pilot.
Last edited by jescardin; 11-21-2020 at 02:57 AM.