One notable design element was the XP-89’s robust construction, which prioritized durability and ease of maintenance.

The YB-49 had a wingspan of 172 feet and a crew of six. It was powered by eight Allison J35-A-15 turbojet engines-upgraded to J35-A-19s in the YRB-49A variant-each producing 4,000 pounds of thrust.

In contrast, the D-558-1 took off and landed under its power generated by the 5,000-pound static thrust Allison J35-A-11 engine housed in a cylindrical fuselage whose shape inspired a nickname for ...