It was 1943 when Northrup began experimenting with the idea of a ground to altitude interceptor that had no horizontal tail, only a tiny vertical tail, and the wing itself was half the width of the plane. Making a flying wing would solve problems of drag on too many surfaces. Development was slowed when designers switched engines midstream. The plane was made of a magnesium alloy because aluminum was gin to be hard to get during war production. The two prototypes suffered from low powered engines and the production was cancelled.
sources: American Warplanes of World War II. Editor: David Donald. Barnes & Noble Books. 1995, Library of Congress.