Northrop YB-49
| YB-49 | |
|---|---|
 |
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| YB-49 | |
| Role | Strategic bomber |
| Manufacturer | Northrop Corporation |
| Designer | Jack Northrop |
| First flight | 21 October 1947 |
| Status | Prototype only |
| Primary user | United States Air Force |
| Number built | 3 converted from YB-35 two YB-49 one YRB-49A More incomplete examples scrapped |
| Developed from | Northrop YB-35 |
The Northrop YB-49 was a prototype jet-powered heavy bomber aircraft developed by Northrop Corporation shortly after World War II for service with the U.S. Air Force. The YB-49 featured a flying wing design and was a jet-powered development of the earlier, piston-engined Northrop XB-35 and YB-35. The two YB-49s actually built were both converted YB-35 test aircraft.
The YB-49 never entered production, being passed over in favor of the more conventional Convair B-36 piston-driven design. Design work performed in the development of the YB-35 and YB-49 nonetheless proved to be valuable to Northrop decades later in the eventual development of the B-2 stealth bomber, which entered service in the early 1990s.
With the XB-35 program seriously behind schedule by 1944, and the end of piston-engined combat aircraft in sight, the production contract for this propeller-driven type was cancelled in May of that year. Nevertheless, the Flying Wing design was still sufficiently interesting to the Air Force that work was continued on testing a single YB-35A production aircraft.
Among the aircraft later completed were two airframes that the Air Force ordered be fitted with jet propulsion and designated as YB-49s. The first of these new YB-49 jet-powered aircraft flew on 22 October 1947 (from Northrop airfield in Hawthorne, CA) and immediately proved more promising than its piston engined counterpart. The YB-49 set an unofficial endurance record of staying continually above 40,000 ft (12,200 m) for 6.5 hours.
The second YB-49 was lost on 5 June 1948, killing its pilot, Major Daniel Forbes (for whom Forbes Air Force Base was named), Captain Glen Edwards, co-pilot (after whom Edwards Air Force Base is named), and three other crew members, one of whom, Lt. Edward Lee Swindell, was a crew member on the Boeing B-29 that assisted Chuck Yeager in breaking the sound barrier in the Bell X-1 aircraft. Their aircraft suffered structural failure, with both outer wing sections becoming detached from the center section. Speculation at the time was that the YB-49 was lost due to excessive pullout loads imposed on the heavy airframe when a scheduled flight test of the large bomber's stall recovery resulted in a sudden and dramatic high-speed, nose-over dive. The post-stall high-speed dive resulted from the clean, low-drag, all-wing design, which gave the YB-49 a rapid speed increase in any type of dive. Fellow YB-49 test pilot Robert Cardenas later claimed that the YB-49 rotated backwards in stall, and that he warned Edwards about it. Jack Northrop later countered that such a behavior was impossible for the all-wing design.
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