Hitler's Stealth Fighter

That's why Northrop's B-35/B-49 design was unsuccessful; the aircraft was not stable enough and in the 1940s there was little that could be done about that. The B-2 was able to make the concept work mainly because of the advent of computers since then.

Of course, other aircraft also need computers to maintain stability; I believe even the F-16 falls in that category. And the X-29 would have been unflyable without 3 computers that operated 40 times a second to maintain stability.

 

It isn't that flying wings are unstable in pitch, if they were they couldn't have flown them at all before computer controls became available. The issue is that they don't have a wide range of CG before they get unstable. The same is true for any aircraft with a small tail volume, if you don't have the horizontal stab area, you get a small CG range... Same thing about yaw stability, there isn't much vertical tail moment length, and the deisre to eliminate vertical surfaces to reduce RCS makes that whole thing even worse... I find the fact that they can function with so little amount of vertical surface area more than amazing.

I spent some time working some advanced propulsion concepts with the ex MacD group in Long Beach that was taken over by Boeing and were working on the "Super Frog" (Boeing didn't like that name so we had to call it the NOTAIL-ATT). It was amazing to me how much weight was saved by eliminating the vertical stab, not just in the weight of the parts, but the weight of the airframe to support it.. Here is a link to a blurb on that tailless aircraft... http://www.flightglobal.com/articles/1998/09/23/43107/boeings-tailless-super-frog-hops-on-to-the-drawing.html

Here is a great article on flying wings, written by a test pilot who flew the early Northrop aircraft. I found it really intersting. There is a discussion about pitch stability issues that starts about page 9....

http://findarticles.com/p/articles/mi_qa3897/is_200310/ai_n9341981/?tag=content;col1