Conventional moving control surfaces also have reduced effectiveness at slow speed. The thing is, though, that an airplane will not be flying unless it is trave

Conventional moving control surfaces also have reduced effectiveness at slow speed. The thing is, though, that an airplane will not be flying unless it is traveling at a speed sufficient for it to create lift at least equal to its weight, and the forces needed to control the aircraft are a fraction of that (you can get an impression of the size of that fraction by comparing the area of the control surfaces to the area of the wing.) I doubt DARPA would commission this aircraft without having already established that it is likely to work, and it will have conventional control surfaces as a backup. I am curious as to whether they intend to keep conventional moving surfaces for trimming in pitch, especially if they are going to give it flaps.