Northrop YB-49
Encyclopedia
The Northrop YB-49 was a prototype jet
-powered heavy bomber aircraft developed by Northrop
shortly after World War II
. Intended for service with the U.S. Air Force
, the YB-49 featured a flying wing
design. It 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 Peacemaker piston-driven design. Design work performed in the development of the YB-35 and YB-49, nonetheless, proved to be valuable to Northrop in the eventual development of the current day B-2 Spirit strategic bomber, which first entered operational service in the 1990s.
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 21 October 1947 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 airframe when a planned stall recovery resulted in a high speed, nose-over dive. The post-stall high speed dive resulted from the clean, low-drag design, which gave the YB-49 a rapid speed increase in any type of dive.
On 4 February 1949, the first YB-49 flew from Muroc Air Force Base
in California
to Andrews Air Force Base
near Washington, D.C.
in 4 hours 25 minutes. The return flight from Andrews was marred when four of the eight engines had to be shut down for oil starvation. Inspection after a successful emergency landing at Winslow Airport, Arizona revealed no oil had been replaced in these engines at Wright after the Muroc-to-Andrews leg, raising a suspicion of industrial sabotage.
The last operational YB-49 prototype was destroyed on March 15, 1950 during high-speed taxi trials at Muroc Field. The nosewheel began to encounter severe vibration problems and finally collapsed. The aircraft was completely destroyed in the ensuing fire. The taxi trials took place with the YB-49's fuel tanks full, an unusual testing procedure, fanning further speculation of industrial sabotage of the aircraft.
The Air Force ordered the remaining uncompleted YB-35 piston-engined airframes be completed as production B-35B aircraft.
Bombing target tests showed a tendency of Flying Wings to "hunt" in yaw after turns and when flying in "disturbed" air, degraded bombing accuracy. It was thought that one of the new Honeywell autopilots, with yaw damping, would correct this flaw.
During early 1950, the remaining YB-35Bs airframes being converted to YRB-49As were scrapped. Flight testing of the sole remaining YB-49 prototype ended 14 March 1950. On 15 March 1950, that program was canceled, and coincidentally, that last YB-49 prototype suffered a high-speed taxiing accident and, as previously noted, was totally destroyed in the ensuing fire.
But only two months later, all Flying Wing contracts were canceled abruptly without explanation by order of Stuart Symington
, Secretary of the Air Force
. Shortly thereafter, also without explanation, Symington turned down a request from the Smithsonian for the Air Force to donate one of these big wings to its collection of pioneering Northrop aircraft designs.
All remaining Flying Wing bomber airframes, except for the sole YRB-49A reconnaissance version, were then ordered chopped up by the Air Force, the materials smelted down with portable smelters brought to Northrop's facility, in plain sight of its employees. Jack Northrop retired from both the company he founded and aviation shortly after he saw his dream of a pure, all-wing aircraft destroyed. His son, John Northrop Jr., later recounted during an interview his father's devastation and life-long suspicion that his Flying Wing project had been sabotaged by political influence and back room wheeling-and-dealing between Convair and the Air Force.
The sole prototype reconnaissance platform, the YRB-49A, first flew on 4 May 1950. After only 13 flights, testing ended abruptly on 26 April 1951. It was then flown back to Northrop's headquarters from Edwards Air Force Base (formally Muroc) on what would be its last flight. There, this remaining Flying Wing sat at edge of Northrop's Ontario airport for more than two years, abandoned. It was finally ordered scrapped on 1 December 1953.
But in a 1979 videotaped news interview, Jack Northrop broke his long silence and said publicly that all flying wing contracts had been canceled because Northrop Aircraft Corporation had refused to merge with competitor Convair
at Stuart Symington's strong suggestion, because according to Jack Northrop, Convair's merger demands were "grossly unfair to Northrop.". A short while later, Symington became president of Convair upon leaving his post as Secretary of the Air Force. Allegations of political influences in the cancellation of the Flying Wing were investigated by the House Armed Services Committee, where Symington publicly denied exerting pressure on Northrup to merge.
Northrop's entire Flying Wing program may have been terminated due to its technical difficulties and the program being behind schedule and over budget. Another possible contributing factor to the program's cancellation may have been the tendency of Northrop to become engaged in other experimental programs, which spread its small engineering staff too wide. While the competing propeller-driven Convair B-36 "Peacemaker"
was an obsolete World War II-era design by this time, and had been having just as many or even more development problems, the Air Force seemed to have greater confidence that its more conventional design and "teething" problems could be overcome, when compared to those of the more radical Flying Wing. While the YB-49 had well-documented performance and design issues, the B-36 program needed more development money.At one time, it appeared the B-36 program might be canceled as well. But the Air Force and the Texas Congressional delegation desired to have a production program for their large Fort Worth aircraft production factory, and Convair had much more effective lobbyists in Washington DC. The Northrop Corporation was always a technological trailblazer, but the independent nature of Jack Northrop often collided with the political wheeling-and-dealing in Washington, which gravitated to massive military appropriations; consequently, the Convair B-36
prevailed. When the YB-49 jet bomber was canceled, Northrop received a much smaller production contract for its F-89 Scorpion
fighter as compensation for the lost Flying Wing contract.
The YB-49 and its modern counterpart, the B-2 Spirit, both built by Northrop, have the same wingspan: 172.0 ft (52.4 m). Flight test data collected from the original YB-49 test flights, including the aircraft's (then) undervalued invisibility to early radar systems, was used in the development of the B-2 bomber.
Thirty years later, in April 1980, Jack Northrop, now quite elderly and wheel chair bound, was taken back to the company he founded. There, he was ushered into a classified area and shown a scale model of the Air Force's forthcoming but still highly classified Advanced Technology Bomber, which would eventually become known as the B-2A; it was a sleek, all-black Flying Wing. Looking over its all-wing design, Northrop, unable to speak due to various illnesses, was reported to have written on a pad: "I know why God has kept me alive for the past 25 years." Jack Northrop died 10 months later, in February 1981, eight years before the first B-2A became the Air Force's most advanced bomber aircraft.
incorporates color footage of a YB-49 test flight, originally used in Paramount's Popular Science
theatrical shorts; in the film the Flying Wing is used to drop an atomic bomb on the invading Martians.
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
-powered heavy bomber aircraft developed by Northrop
Northrop Corporation
Northrop Corporation was a leading United States aircraft manufacturer from its formation in 1939 until its merger with Grumman to form Northrop Grumman in 1994. The company is known for its development of the flying wing design, although only a few of these have entered service.-History:Jack...
shortly after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. Intended for service with the U.S. Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
, the YB-49 featured a flying wing
Flying wing
A flying wing is a tailless fixed-wing aircraft which has no definite fuselage, with most of the crew, payload and equipment being housed inside the main wing structure....
design. It was a jet-powered development of the earlier, piston-engined Northrop XB-35 and YB-35
Northrop YB-35
The Northrop XB-35 and YB-35 were experimental heavy bomber aircraft developed for the United States Army Air Forces during and shortly after World War II by the Northrop Corporation. It used the radical and potentially very efficient flying wing design, in which the tail section and fuselage are...
; 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 Peacemaker piston-driven design. Design work performed in the development of the YB-35 and YB-49, nonetheless, proved to be valuable to Northrop in the eventual development of the current day B-2 Spirit strategic bomber, which first entered operational service in the 1990s.
Design and development
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 21 October 1947 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
Daniel Forbes
Daniel Hugh Forbes, Jr. was an American aviator.-Biography:Born in Carbondale, Kansas, Osage County, the only child of Daniel Sr., and Hattie Forbes of Topeka, Kansas...
for whom Forbes Air Force Base
Forbes Air Force Base
Forbes Field, previously Forbes Air Force Base, is a joint-use civil-military airport operated by the Topeka Airport Authority located approximately south of Topeka, Kansas....
was named, Captain Glen Edwards
Glen Edwards (pilot)
Glen Edwards was a test pilot for the U.S. Air Force, and is the namesake of Edwards Air Force Base.Edwards was born in Medicine Hat, Alberta, Canada, where he lived until 1931. At age 13, his parents moved the family to California, settling in Lincoln, northeast of Sacramento...
, co-pilot (after whom Edwards Air Force Base
Edwards Air Force Base
Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
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
Chuck Yeager
Charles Elwood "Chuck" Yeager is a retired major general in the United States Air Force and noted test pilot. He was the first pilot to travel faster than sound...
in breaking the sound barrier in the Bell X-1
Bell X-1
The Bell X-1, originally designated XS-1, was a joint NACA-U.S. Army/US Air Force supersonic research project built by Bell Aircraft. Conceived in 1944 and designed and built over 1945, it eventually reached nearly 1,000 mph in 1948...
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 airframe when a planned stall recovery resulted in a high speed, nose-over dive. The post-stall high speed dive resulted from the clean, low-drag design, which gave the YB-49 a rapid speed increase in any type of dive.
On 4 February 1949, the first YB-49 flew from Muroc Air Force Base
Edwards Air Force Base
Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
to Andrews Air Force Base
Andrews Air Force Base
Joint Base Andrews is a United States military facility located in Prince George's County, Maryland. The facility is under the jurisdiction of the United States Air Force 11th Wing, Air Force District of Washington ....
near Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
in 4 hours 25 minutes. The return flight from Andrews was marred when four of the eight engines had to be shut down for oil starvation. Inspection after a successful emergency landing at Winslow Airport, Arizona revealed no oil had been replaced in these engines at Wright after the Muroc-to-Andrews leg, raising a suspicion of industrial sabotage.
The last operational YB-49 prototype was destroyed on March 15, 1950 during high-speed taxi trials at Muroc Field. The nosewheel began to encounter severe vibration problems and finally collapsed. The aircraft was completely destroyed in the ensuing fire. The taxi trials took place with the YB-49's fuel tanks full, an unusual testing procedure, fanning further speculation of industrial sabotage of the aircraft.
The Air Force ordered the remaining uncompleted YB-35 piston-engined airframes be completed as production B-35B aircraft.
Bombing target tests showed a tendency of Flying Wings to "hunt" in yaw after turns and when flying in "disturbed" air, degraded bombing accuracy. It was thought that one of the new Honeywell autopilots, with yaw damping, would correct this flaw.
Operational history
One YRB-49A had been completed when, in September 1948, the Air Force ordered the type into full production as the RB-49A reconnaissance aircraft. It was powered by six jet engines, two of them externally mounted in under wing pods, ruining the aircraft's sleek, aerodynamic lines, but extending its range by carrying additional fuel. The use of jet engines had resulted in considerably increased fuel consumption, and decreased its range significantly below that of the rivaling Convair B-36.During early 1950, the remaining YB-35Bs airframes being converted to YRB-49As were scrapped. Flight testing of the sole remaining YB-49 prototype ended 14 March 1950. On 15 March 1950, that program was canceled, and coincidentally, that last YB-49 prototype suffered a high-speed taxiing accident and, as previously noted, was totally destroyed in the ensuing fire.
But only two months later, all Flying Wing contracts were canceled abruptly without explanation by order of Stuart Symington
Stuart Symington
William Stuart Symington was a businessman and political figure from Missouri. He served as the first Secretary of the Air Force from 1947 to 1950 and was a Democratic United States Senator from Missouri from 1953 to 1976.-Education and business career:...
, Secretary of the Air Force
United States Secretary of the Air Force
The Secretary of the Air Force is the Head of the Department of the Air Force, a component organization within the Department of Defense of the United States of America. The Secretary of the Air Force is appointed from civilian life by the President, by and with the advice and consent of the Senate...
. Shortly thereafter, also without explanation, Symington turned down a request from the Smithsonian for the Air Force to donate one of these big wings to its collection of pioneering Northrop aircraft designs.
All remaining Flying Wing bomber airframes, except for the sole YRB-49A reconnaissance version, were then ordered chopped up by the Air Force, the materials smelted down with portable smelters brought to Northrop's facility, in plain sight of its employees. Jack Northrop retired from both the company he founded and aviation shortly after he saw his dream of a pure, all-wing aircraft destroyed. His son, John Northrop Jr., later recounted during an interview his father's devastation and life-long suspicion that his Flying Wing project had been sabotaged by political influence and back room wheeling-and-dealing between Convair and the Air Force.
But in a 1979 videotaped news interview, Jack Northrop broke his long silence and said publicly that all flying wing contracts had been canceled because Northrop Aircraft Corporation had refused to merge with competitor Convair
Convair
Convair was an American aircraft manufacturing company which later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Vultee Aircraft and Consolidated Aircraft, and went on to produce a number of pioneering aircraft, such as the Convair B-36 bomber, and the F-102...
at Stuart Symington's strong suggestion, because according to Jack Northrop, Convair's merger demands were "grossly unfair to Northrop.". A short while later, Symington became president of Convair upon leaving his post as Secretary of the Air Force. Allegations of political influences in the cancellation of the Flying Wing were investigated by the House Armed Services Committee, where Symington publicly denied exerting pressure on Northrup to merge.
Northrop's entire Flying Wing program may have been terminated due to its technical difficulties and the program being behind schedule and over budget. Another possible contributing factor to the program's cancellation may have been the tendency of Northrop to become engaged in other experimental programs, which spread its small engineering staff too wide. While the competing propeller-driven Convair B-36 "Peacemaker"
Convair B-36
The Convair B-36 "Peacemaker" was a strategic bomber built by Convair and operated solely by the United States Air Force from 1949 to 1959. The B-36 was the largest mass-produced piston engine aircraft ever made. It had the longest wingspan of any combat aircraft ever built , although there have...
was an obsolete World War II-era design by this time, and had been having just as many or even more development problems, the Air Force seemed to have greater confidence that its more conventional design and "teething" problems could be overcome, when compared to those of the more radical Flying Wing. While the YB-49 had well-documented performance and design issues, the B-36 program needed more development money.At one time, it appeared the B-36 program might be canceled as well. But the Air Force and the Texas Congressional delegation desired to have a production program for their large Fort Worth aircraft production factory, and Convair had much more effective lobbyists in Washington DC. The Northrop Corporation was always a technological trailblazer, but the independent nature of Jack Northrop often collided with the political wheeling-and-dealing in Washington, which gravitated to massive military appropriations; consequently, the Convair B-36
Convair B-36
The Convair B-36 "Peacemaker" was a strategic bomber built by Convair and operated solely by the United States Air Force from 1949 to 1959. The B-36 was the largest mass-produced piston engine aircraft ever made. It had the longest wingspan of any combat aircraft ever built , although there have...
prevailed. When the YB-49 jet bomber was canceled, Northrop received a much smaller production contract for its F-89 Scorpion
F-89 Scorpion
The Northrop F-89 Scorpion was an early American jet-powered fighter designed from the outset as an all-weather interceptor. Though its straight wings limited its performance, it was among the first USAF jet fighters with guided missiles, and notably the first combat aircraft armed with air-to-air...
fighter as compensation for the lost Flying Wing contract.
The YB-49 and its modern counterpart, the B-2 Spirit, both built by Northrop, have the same wingspan: 172.0 ft (52.4 m). Flight test data collected from the original YB-49 test flights, including the aircraft's (then) undervalued invisibility to early radar systems, was used in the development of the B-2 bomber.
Thirty years later, in April 1980, Jack Northrop, now quite elderly and wheel chair bound, was taken back to the company he founded. There, he was ushered into a classified area and shown a scale model of the Air Force's forthcoming but still highly classified Advanced Technology Bomber, which would eventually become known as the B-2A; it was a sleek, all-black Flying Wing. Looking over its all-wing design, Northrop, unable to speak due to various illnesses, was reported to have written on a pad: "I know why God has kept me alive for the past 25 years." Jack Northrop died 10 months later, in February 1981, eight years before the first B-2A became the Air Force's most advanced bomber aircraft.
Notable appearances in media
Paramount Studios' 1953 film, The War of the WorldsThe War of the Worlds (1953 film)
The War of the Worlds is a 1953 science fiction film starring Gene Barry and Ann Robinson. It was the first on-screen loose adaptation of the H. G. Wells classic novel of the same name...
incorporates color footage of a YB-49 test flight, originally used in Paramount's Popular Science
Popular Science
Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...
theatrical shorts; in the film the Flying Wing is used to drop an atomic bomb on the invading Martians.
Specifications (YB-49)