Looking at images and videos displaying B-2 spirit, it seems like split elevons are most of the time deployed, even at high speed. Why is it so?
Having some aerodynamic surface deployed generates drag and one might think it should instead most of the time fly in a clean retracted configuration.
Is this a tradeoff related to stealth capability which tends to reduce or totally suppress vertical stabilizers?
If not, why isn't sweep angle or negative wingtip twist increased, so that it can actually have yaw stability in a more optimized minimal drag configuration?
Are those split elevons actually fully retracted when cruising at high speed in a straight and level flight regime?
(I'm sure it's absolutely state of the art optimised, yet it does not look like it is for the reasons mentioned above)