March 30, 2020 | International, Aerospace
New USAF Materials Hint At High-Altitude Role For B-21
Steve Trimble The design of the Northrop Grumman B-21's trailing edge has led to speculation about a high-altitude role for the secretive stealth bomber, and new U.S. Air Force statements appear to confirm that analysis. As the U.S. Air Force enters a legally required environmental impact review process for basing the new bomber, service officials disclosed a few new details about the design on large poster boards displayed at public meetings since February. The posters are now available on B21EIS.com, a clearinghouse web site set up by the Air Force to share data during the year-long process to complete the final environmental impact statement. “The B-21 is not expected to use low altitude training routes,” the Air Force poster says. The B-2 was originally conceived as a high-altitude bomber, but a last-minute requirements change during the development phase forced Northrop Grumman to redesign the bomber for a low-altitude mission. As a result, the trailing edge was transformed from a simple W-shape to the sawtooth design seen today. The B-2, like the preceding B-52 and B-1B fleets, need low-altitude training routes. The renderings of the B-21 released by the Air Force so far reveal a trailing edge that resembles the original, high-altitude design for the B-2. The Air Force has never confirmed operational details about the future stealth bomber. Another comment on the Air Force's poster provides the first official description of the B-21's acoustic signature, as well as the performance of the engines. “The B-21 engine noise is expected to be quieter than the B-1B and about the same or quieter than the B-2,” the poster says. Previously, the only detail released by the Air Force about the B-21's engines is that Pratt & Whitney is named as one of seven of Northrop's suppliers. The poster data appears to confirm expectations that the B-21 would use a non-afterburning engine, like the similarly subsonic, flying wing-shaped, B-2. The supersonic B-1B is powered by afterburning engines. The Air Force has selected Ellsworth Air Force Base in South Dakora as the site for the first B-21 operational squadron, followed by Dyess AFB in Texas and Whiteman AFB, Missouri. The environmental impact review is evaluating Ellsworth and Dyess for the main operating beddown 1 location. https://aviationweek.com/defense-space/aircraft-propulsion/new-usaf-materials-hint-high-altitude-role-b-21