The design of Northrop Grumman’s B-21 Raider points to a conservative approach on the part of the U.S. Air Force’s Rapid Capabilities Office. The B-21’s resemblance to the original B-2 bomber design is close, but it is a smaller aircraft, with a wingspan estimated at 132 ft. compared with the B-2’s 172 ft., and is approximately half the empty weight. The planform itself is driven by the need to accommodate complex inlets and exhausts and a large weapon bay within the flying-wing profile while staying within a maximum thickness-to-chord ratio compatible with efficient flight above Mach 0.8.

The B-21 planform, which has not been officially released, was depicted in a video that accompanied a presentation by Gen. Duke Richardson, commander of the U.S. Air Force Materiel Command, on Sept. 11 at the Air and Space Force Association’s (AFA) Air, Space & Cyber Conference at National Harbor, Maryland. A new set of images released that week included an undistorted head-on view that permitted a reliable estimate of the wingspan. Recently recovered unclassified imagery from Pratt & Whitney presentations dating back to the early 2010s proved to be a close match for the B-21’s inlets.

• U.S. Air Force Rapid Capabilities Office prioritized use of mature subsystems
• Northrop draws on aspects of B-2 bomber and X-47B UCAV

The B-21’s low-risk design in part stems from the program’s origins. Before 2009, the Air Force was working to a requirement known as Next-Generation Bomber (NGB). It has been characterized as complex and ambitious, with a full suite of intelligence, surveillance and reconnaissance (ISR) sensors, a self-defense capability and long endurance. This was canceled in April 2009 by then-Defense Secretary Robert Gates.

The following year, the Air Force proposed a different approach to the mission, which Pentagon leadership found acceptable: a Long-Range Strike family of systems including classified uncrewed aircraft systems for ISR and electronic attack (the former becoming the Northrop Grumman RQ-180), a replacement cruise missile (now the Raytheon AGM-181) and the Long-Range Strike-Bomber (LRS-B), for which a contract was awarded to Northrop Grumman in October 2015.

Aside from scrubbed and scaled-back requirements, the LRS-B project differed from NGB in three ways: Unit cost was a key performance parameter; two competing teams were funded through preliminary design review, which normally takes place after contract award; and management was assigned to the Air Force’s Rapid Capabilities Office (RCO). The RCO modeled its approach on the Lockheed F-117, developed using mature subsystems in a new platform so that the program could focus on applying new technology.