If you are talking about flying wing then maybe you're talking about the B-2, not the B-1 which is a conventional aircraft.
The predecessor of the B-2 flying wing stealth bomber that inspired the design were several flying wings developed much earlier and which started testing at MUROC or Edwards AFB in 1947, developed not far from where I live now.
Many propulsion options were tried...(experimental designation for turbine engine driven prop flying wing was XB-35, and RB-49/YRB-49 for flying wings powered with turbojets). German scientists were not even on the scene in the US at the time - however Germans did develop their own flying wing bomber at the same time.
This is what they looked like back in the day in 1949...
XB-35
YB-49
German experimental WWII Flying Wing bomber Horten 229, a much, much smaller design. Never flown.
B2
And here's the B-1B Lancer with wings swept full forward, a more conventional design.