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135-563: 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

270-558: A 10,000 lb (4,500 kg) bomb-load, a cruising speed between 240 and 300 mph (390 and 480 km/h), and a service ceiling of 40,000 ft (12,000 m) The ceiling in both cases was chosen to exceed the maximum effective altitude of most of Nazi Germany 's anti-aircraft guns. In the Pacific, the USAAF needed a bomber capable of reaching Japan from bases in Hawaii , and

405-415: 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 refused to merge with competitor Convair at Air Force Secretary Stuart Symington's strong suggestion, because, according to Jack Northrop, Convair's merger demands were "grossly unfair to Northrop." Allegations of political influences in

540-476: A 450 mph (720 km/h) top speed, a 275 mph (443 km/h) cruising speed, a service ceiling of 45,000 ft (14,000 m) and a maximum range of 12,000 mi (19,000 km) at 25,000 ft (7,600 m). These requirements were too demanding and far exceeded the technology of the day, so on 19 August 1941, they were reduced, to a maximum range of 10,000 mi (16,000 km), an effective combat radius of 4,000 mi (6,400 km) with

675-568: A B-36 crashed in February 1950. Training missions were typically in two parts, a 40-hour flight—followed by time on the ground for refueling and maintenance—and then a 24-hour second flight. With a sufficiently light load, the B-36 could fly at least 10,000 mi (16,000 km) nonstop, and the highest cruising speed of any version, the B-36J-III, was at 230 mph (370 km/h). Engaging

810-482: A B-36H-20-CF (serial number 51-5712) that had been damaged in a tornado at Carswell AFB on 1 September 1952. This aircraft, redesignated the XB-36H (and later NB-36H ), was modified to carry a 1 MW , air-cooled nuclear reactor in the aft bomb bay, with a four-ton lead disc shield installed in the middle of the aircraft between the reactor and the cockpit. A number of large air intake and exhaust holes were installed in

945-454: A bomb bay. The GRB-36D would ferry the RF-84K to the vicinity of the objective, whereupon the RF-84K would disconnect and begin its mission. Ten GRB-36Ds and 25 RF-84Ks were built and had limited service in 1955–1956. Projects Tip Tow and Tom-Tom involved docking F-84s to the wingtips of B-29s and B-36s. The hope was that the increased aspect ratio of the combined aircraft would result in

1080-528: A closed feedback loop. The pilot may not be fully aware of all the control outputs acting to affect the outcome, only that the aircraft is reacting as expected. The fly-by-wire computers act to stabilize the aircraft and adjust the flying characteristics without the pilot's involvement, and to prevent the pilot from operating outside of the aircraft's safe performance envelope . Mechanical and hydro-mechanical flight control systems are relatively heavy and require careful routing of flight control cables through

1215-589: A combination of both. A "mixed" control system with mechanical backup feedbacks any rudder elevation directly to the pilot and therefore makes closed loop (feedback) systems senseless. Aircraft systems may be quadruplexed (four independent channels) to prevent loss of signals in the case of failure of one or even two channels. High performance aircraft that have fly-by-wire controls (also called CCVs or Control-Configured Vehicles) may be deliberately designed to have low or even negative stability in some flight regimes – rapid-reacting CCV controls can electronically stabilize

1350-717: A crew of 15. War missions would have been one-way, taking off from forward bases in Alaska or Greenland , overflying the USSR, and landing in Europe, Morocco, or the Middle East. Veteran crews recall feeling confident in their ability to fly the missions, but not to survive weapon delivery, as the aircraft were not fast enough to escape the blast. These concerns were confirmed by the 1954 Operation Castle tests, in which B-36s were flown at combat distances from detonations of bombs in

1485-466: A dining galley and led to the tail turret. The tricycle landing gear of the XB-36 featured a single-wheel main landing gear whose tires were the largest ever manufactured up to that time: 9 ft 2 in (2.79 m) tall, 3 ft (0.91 m) wide, and weighing 1,320 lb (600 kg), with enough rubber for 60 automobile tires. These tires placed so much ground pressure on runways that

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1620-525: A further 120 days. Changes in the USAAF requirements added back the weight saved in redesigns, and cost more time. A new antenna system needed to be designed to accommodate a new radio and radar system and the Pratt and Whitney engines were redesigned, adding another 1,000 lb (450 kg). The B-36 was two-thirds longer than the previous "superbomber", the B-29 and its wingspan and height exceeded those of

1755-548: A golf ball from 45,000 ft (14,000 m) and up to 63,600 ft (19,400 m) away. The first RB-36D (44-92088) made its initial flight on 18 December 1949, six months after the B-36D, but initially flew without turbojets. The 28th Strategic Reconnaissance Wing based at Rapid City AFB (later renamed Ellsworth AFB) , South Dakota , received its first RB-36D on 3 June 1950 but due to severe material shortages, they were not operational until June 1951. The 24th and last RB-36D

1890-557: A greater range. Project Tip Tow was cancelled when an EF-84D and a specially modified test EB-29A crashed, killing everyone on both aircraft. This accident was attributed to the EF-84D flipping over onto the wing of the EB-29A. Project Tom-Tom, involving RF-84Fs and a GRB-36D from the FICON project (redesignated JRB-36F), continued for a few months after this crash, but was also cancelled due to

2025-595: A high-speed taxiing accident and, as previously noted, was totally destroyed in the ensuing fire. Only two months later, all Flying Wing contracts were canceled abruptly without explanation by order of Stuart Symington , Secretary of the Air Force . All remaining Flying Wing bomber airframes, except for the sole YRB-49A reconnaissance version, were ordered chopped up by Symington, the materials smelted down using portable smelters brought to Northrop's facility, in plain sight of its employees. Jack Northrop retired from both

2160-499: A higher data transfer rate, immunity to electromagnetic interference and lighter weight. In most cases, the cables are just changed from electrical to optical fiber cables. Sometimes it is referred to as "fly-by-light" due to its use of fiber optics. The data generated by the software and interpreted by the controller remain the same. Fly-by-light has the effect of decreasing electro-magnetic disturbances to sensors in comparison to more common fly-by-wire control systems. The Kawasaki P-1

2295-538: A level partly determined by knowledge of the capability of Soviet air-defense radar . The main Soviet air-defense radar in the 1950s was the American-supplied SCR-270 , or locally made copies, which were only effective up to 40,000 ft (12,000 m) – in theory, and an aircraft cruising above this level likely would remain undetected. The first aircraft to put this theory to

2430-465: A lightweight version of this aircraft, the RB-36-III, could reach 58,000 ft (18,000 m). RB-36s were distinguished by the bright aluminum finish of the camera compartment (contrasting with the dull magnesium of the rest of the fuselage) and by a series of radar domes under the aft fuselage, varying in number and placement. When developed, it was the only American aircraft large enough to carry

2565-498: A piston-driven aircraft, made possible by its huge wing area and six engines, putting it out of range of most interceptors, as well as ground-based anti-aircraft guns . Consolidated Vultee Aircraft Corporation (later Convair) and Boeing Aircraft Company took part in the competition, with Consolidated winning a tender on 16 October 1941. Consolidated asked for a $ 15 million contract with $ 800,000 for research and development, mockup, and tooling. Two experimental bombers were proposed,

2700-454: A prodigious appetite for lubricating oil and each engine required a dedicated 100 US gal (380 L) tank. Normal maintenance consisted of tedious measures, such as changing the 56 spark plugs on each of the six engines which were often fouled by the lead in the 145 octane anti knock fuel required. Thus, each service required changing 336 spark plugs. The B-36 was too large to fit in most hangars . Since even an aircraft with

2835-695: A role in the aircraft's demise, the Flying Wing program was ultimately cancelled for solid technological reasons. In June 1948, the Air Force ordered the type into full production as the RB-49A reconnaissance aircraft (company designations N-38 and N-39 ). 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

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2970-468: A similar design with conventional controls. This is partly due to the lower overall weight of the system components and partly because the natural stability of the aircraft can be relaxed (slightly for a transport aircraft; more for a maneuverable fighter), which means that the stability surfaces that are part of the aircraft structure can therefore be made smaller. These include the vertical and horizontal stabilizers (fin and tailplane ) that are (normally) at

3105-548: A tail turret, or no gunners at all for several years but the development of air-to-air missiles , such as the Soviet K-5 which began test firings in 1951, eliminated remaining justifications for keeping them. In February 1954, the USAF awarded Convair a contract for a new "Featherweight" program, which significantly reduced weight and crew size. The three configurations were: The six turrets eliminated by Featherweight I reduced

3240-531: A trapeze. The concept was tested using a B-29 carrier, but docking was difficult even for experienced test pilots. Moreover, the XF-85 was no match for contemporary foreign powers' interceptors in development or in service and consequently the project was cancelled. The FICON project was more successful and involving a modified B-36 (a GRB-36D "mothership") and the RF-84K , a fighter modified for reconnaissance , in

3375-656: A wired protocol for the physical layer a wireless protocol is employed. In addition to reducing weight, implementing a wireless solution has the potential to reduce costs throughout an aircraft's life cycle. For example, many key failure points associated with wire and connectors will be eliminated thus hours spent troubleshooting wires and connectors will be reduced. Furthermore, engineering costs could potentially decrease because less time would be spent on designing wiring installations, late changes in an aircraft's design would be easier to manage, etc. A newer flight control system, called intelligent flight control system (IFCS),

3510-457: Is an extension of modern digital fly-by-wire flight control systems. The aim is to intelligently compensate for aircraft damage and failure during flight, such as automatically using engine thrust and other avionics to compensate for severe failures such as loss of hydraulics, loss of rudder, loss of ailerons, loss of an engine, etc. Several demonstrations were made on a flight simulator where a Cessna -trained small-aircraft pilot successfully landed

3645-432: Is the first production aircraft in the world to be equipped with such a flight control system. Having eliminated the mechanical transmission circuits in fly-by-wire flight control systems, the next step is to eliminate the bulky and heavy hydraulic circuits. The hydraulic circuit is replaced by an electrical power circuit. The power circuits power electrical or self-contained electrohydraulic actuators that are controlled by

3780-648: Is used in the Lockheed Martin F-35 Lightning II and in Airbus A380 backup flight controls. The Boeing 787 and Airbus A350 also incorporate electrically powered backup flight controls which remain operational even in the event of a total loss of hydraulic power. Wiring adds a considerable amount of weight to an aircraft; therefore, researchers are exploring implementing fly-by-wireless solutions. Fly-by-wireless systems are very similar to fly-by-wire systems, however, instead of using

3915-564: The Airbus A320 , Airbus flight-envelope control systems always retain ultimate flight control when flying under normal law and will not permit pilots to violate aircraft performance limits unless they choose to fly under alternate law. This strategy has been continued on subsequent Airbus airliners. However, in the event of multiple failures of redundant computers, the A320 does have a mechanical back-up system for its pitch trim and its rudder,

4050-719: The Airbus A340 has a purely electrical (not electronic) back-up rudder control system and beginning with the A380, all flight-control systems have back-up systems that are purely electrical through the use of a "three-axis Backup Control Module" (BCM). Boeing airliners, such as the Boeing 777 , allow the pilots to completely override the computerized flight control system, permitting the aircraft to be flown outside of its usual flight control envelope. The advent of FADEC (Full Authority Digital Engine Control) engines permits operation of

4185-611: The B-2 Spirit , both built either by Northrop or Northrop Grumman, have the same wingspan: 172.0 ft (52.4 m). Flight test data collected from the original YB-49 test flights were used in the development of the B-2 bomber. Shortly before his death in February 1981, Jack Northrop learned from the Northrop Corporation of the company's flying wing bid for the future B-2; he remarked: "I know why God has kept me alive for

Northrop YB-49 - Misplaced Pages Continue

4320-557: The B-47 Stratojet . The B-47 was optimized for high-altitude and high-speed flight and, in an era where speed and altitude were becoming increasingly important, the YB-49's thick airfoil could never be maximized for high-speed performance. In the same Discovery Channel documentary, former Air Force Flight Test Center Historian Dr. James Young states his opinion that while political gamesmanship and back room dealing certainly played

4455-719: The Boeing B-29 Superfortress and Boeing B-50 Superfortress , were also too limited in range. Intercontinental ballistic missiles did not become sufficiently reliable until the early 1960s. Until the Boeing B-52 Stratofortress became operational in 1955, the B-36 was the primary nuclear weapons delivery vehicle of the SAC. Convair touted the B-36 as the "aluminum overcast", a so-called " long rifle ", giving SAC truly global reach. During General Curtis LeMay 's tenure as head of SAC (1949–57),

4590-710: The Lockheed F-117 Nighthawk and the Northrop Grumman B-2 Spirit flying wing to fly in usable and safe manners. The United States Federal Aviation Administration (FAA) has adopted the RTCA / DO-178C , titled "Software Considerations in Airborne Systems and Equipment Certification", as the certification standard for aviation software. Any safety-critical component in a digital fly-by-wire system including applications of

4725-539: The United States Air Force (USAF) from 1949 to 1959. The B-36 is the largest mass-produced piston-engined aircraft ever built, although it was exceeded in span and weight by the one-off Hughes H-4 Hercules . It has the longest wingspan of any combat aircraft. The B-36 was capable of intercontinental flight without refueling. Entering service in 1948, the B-36 was the primary nuclear weapons delivery vehicle of Strategic Air Command (SAC) until it

4860-477: The actuators at each control surface to provide the ordered response. Implementations either use mechanical flight control backup systems or else are fully electronic. Improved fully fly-by-wire systems interpret the pilot's control inputs as a desired outcome and calculate the control surface positions required to achieve that outcome; this results in various combinations of rudder , elevator , aileron , flaps and engine controls in different situations using

4995-424: The first Soviet atomic bomb , American military planners sought bombers capable of delivering the very large and heavy first-generation atomic bombs. The B-36 was the only American aircraft with the range and payload to carry such bombs from airfields on American soil to targets in the USSR. The modification to allow the use of larger atomic weapons on the B-36 was called the "Grand Slam Installation". The B-36

5130-530: The pitch, roll and yaw axes . Any movement (from straight and level flight for example) results in signals to the computer, which can automatically move control actuators to stabilize the aircraft. While traditional mechanical or hydraulic control systems usually fail gradually, the loss of all flight control computers immediately renders the aircraft uncontrollable. For this reason, most fly-by-wire systems incorporate either redundant computers (triplex, quadruplex etc.), some kind of mechanical or hydraulic backup or

5265-472: The 15-megaton range. At distances typical of wartime delivery, aircraft suffered extensive flash and blast damage. The B-36 was employed in a variety of aeronautical experiments throughout its service life. Its immense size, range, and payload capacity lent itself to use in research and development programs. These included nuclear propulsion studies, and "parasite" programs in which the B-36 carried smaller interceptors or reconnaissance aircraft. In May 1946,

5400-540: The 1950s, which were first used in regular production for the Convair B-58 Hustler and then when computer-generated artificial stability became available in the 1970s, culminating in the development of the all-wing Northrop Grumman B-2 Spirit Stealth Bomber . The conversion of the long-range XB-35 to jet power essentially cut the effective range of the aircraft in half, putting it in the medium-range bomber category with Boeing 's new swept-winged jet bomber

5535-503: The A330/A340 family, fuel is transferred between the main (wing and center fuselage) tanks and a fuel tank in the horizontal stabilizer, to optimize the aircraft's center of gravity during cruise flight. The fuel management controls keep the aircraft's center of gravity accurately trimmed with fuel weight, rather than drag-inducing aerodynamic trims in the elevators. Fly-by-optics is sometimes used instead of fly-by-wire because it offers

Northrop YB-49 - Misplaced Pages Continue

5670-709: The Air Force began the Nuclear Energy for the Propulsion of Aircraft project, which was followed in May 1951 by the Aircraft Nuclear Propulsion (ANP) program. The ANP program used modified B-36s to study shielding requirements for an airborne reactor to determine whether a nuclear-powered aircraft was feasible. Convair modified two B-36s under the MX-1589 project. The Nuclear Test Aircraft was

5805-442: The B-36 a wide margin between stall speed ( V S ) and maximum speed ( V max ) at these altitudes. This made the B-36 more maneuverable at high altitude than most jet interceptors of the day, which could not maneuver effectively above 40,000 ft (12,000 m). However, the U.S. Navy McDonnell F2H Banshee fighter could intercept the B-36, thanks to its ability to operate at more than 50,000 ft (15,000 m). Later,

5940-444: The B-36 and the carburetor was in front of the engine, where it would not benefit from engine heat and made more existing carburetor heat systems unsuitable. Hence, when intake air was cold and humid, ice gradually obstructed the carburetor intake, which increased the air/fuel mixture richness until unburned fuel in the exhaust caught fire. Three engine fires of this nature led to the first loss of an American nuclear weapon when

6075-504: The B-36 ceased in 1954. Due to problems that occurred with the B-36 in its early stages of testing, development, and later in service, some critics referred to the aircraft as a "billion-dollar blunder". In particular, the United States Navy saw it as a costly bungle, diverting congressional funding and interest from naval aviation and aircraft carriers in general, and carrier–based nuclear bombers in particular. In 1947,

6210-457: The B-36 could match what was arguably its approximate Soviet counterpart, the later Tu-95 . Until the B-52 became operational, the B-36 was the only means of delivering the first generation Mark 17 hydrogen bomb , 25 ft (7.6 m) long, 5 ft (1.5 m) in diameter, and weighing 42,000 lb (19,000 kg), the heaviest and bulkiest American aerial nuclear bomb. The Mark 17 took up

6345-484: The B-36 formed the heart of the Strategic Air Command. Its maximum payload was more than four times that of the B-29 and exceeded that of the later B-52. The B-36 was slow and could not refuel in midair, but could fly missions to targets 3,400 mi (5,500 km) away and stay aloft as long as 40 hours. Moreover, the B-36 was believed to have "an ace up its sleeve": a phenomenal cruising altitude for

6480-533: 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

6615-407: The B-36 slogan of "six turnin' and four burnin ' ". The B-36 had more engines than any other mass-produced aircraft. The jet pods greatly improved takeoff performance and dash speed over the target. In normal cruising flight, the jet engines were shut down to conserve fuel. When the jet engines were shut down, louvers closed off the front of the pods to reduce drag. The two pods with four turbojets and

6750-551: The B-36 to USS United States . The Air Force successfully defended the B-36 project, and United States was cancelled by Secretary of Defense Louis A. Johnson in a cost-cutting move over the objections of both Secretary of the Navy John L. Sullivan and the Navy's senior leadership. Sullivan resigned in protest and was replaced as Secretary of the Navy by Francis P. Matthews , who had limited familiarity with defense issues, but

6885-540: The Muroc-to-Andrews leg, raising a suspicion of industrial sabotage. The last operational YB-49 prototype was destroyed on 15 March 1950, during high-speed taxi trials at Muroc Field. The nose wheel 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

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7020-520: The Navy attacked congressional funding for the B-36, alleging it failed to meet Pentagon requirements. The Navy held to the pre-eminence of the aircraft carrier in the Pacific during World War II, presuming carrier-based aircraft would be decisive in future wars. To this end, the Navy designed USS  United States , a " supercarrier " capable of launching huge fleets of tactical aircraft or nuclear bombers. It then pushed to have funding transferred from

7155-620: The Soviet Union's 1960s Antonov An-22 , the largest turboprop ever produced. Only with the advent of the Boeing 747 and the Lockheed C-5 Galaxy , both designed two decades later, did aircraft capable of lifting a heavier payload enter service. The wings of the B-36 were large even when compared with present-day aircraft, exceeding, for example, those of the C-5 Galaxy, and enabled the B-36 to carry enough fuel to fly

7290-673: The XB-36 was restricted to Carswell Field adjacent to the factory in Texas, Eglin Field in Florida, and Fairfield-Suisun Field in California. The single-wheel gear was soon replaced by a four-wheeled bogie . At one point, a tank-like tracked landing gear was also tried on the XB-36, but it proved heavy and noisy and was soon abandoned. The four bomb bays could carry up to 87,200 lb (39,600 kg) of bombs, more than 10 times

7425-476: The YB-36, flew on 4 December 1947. It had a redesigned, high-visibility, yet still heavily framed greenhouse dome-shaped canopy, which was later adopted for production, and the engines used on the YB-36 were more powerful and more efficient. Altogether, the YB-36 was much closer to the production aircraft. The first 21 B-36As were delivered in 1948 as interim airframes intended for crew training. No defensive armament

7560-449: 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. During flight tests in the 1940s, it was noticed that the aircraft had a small radar cross-section , due to its flying wing design. Decades later, this stealthy detail would prove crucial to the design of Northrop Grumman's advanced, all-wing B-2 bomber . On 9 February 1949,

7695-462: 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 (formerly Muroc AAF) on what would be its last flight. There, this remaining flying wing sat abandoned at the edge of Northrop's Ontario airport for more than two years. It was finally ordered scrapped on 1 December 1953. In

7830-505: The adaptation of the autopilot in this dual function "damped out the directional oscillations to the degree where... I think you would say it met the (military) specifications." Brig. General Robert Cardenas also flew the YB-49 during many of its test flights, praising the aircraft for its marvelous performance, while also noting the YB-49 required a very long bomb run to damp directional oscillations. Many of these challenges would eventually be overcome when fly-by-wire systems were developed in

7965-592: The aircraft available. The United States would need a new bomber to reach Europe and return to bases in North America, necessitating a combat range of at least 5,700 mi (9,200 km), the length of a Gander, Newfoundland – Berlin round trip. The USAAC therefore sought a bomber of truly intercontinental range. The German Reichsluftfahrtministerium 's (RLM) would request the similar ultralong-range Amerikabomber program on 12 May 1942. The USAAC sent out an initial request on 11 April 1941, asking for

8100-422: The aircraft by systems of pulleys, cranks, tension cables and hydraulic pipes. Both systems often require redundant backup to deal with failures, which increases weight. Both have limited ability to compensate for changing aerodynamic conditions. Dangerous characteristics such as stalling , spinning and pilot-induced oscillation (PIO), which depend mainly on the stability and structure of the aircraft rather than

8235-409: The aircraft from being handled dangerously by preventing pilots from exceeding preset limits on the aircraft's flight-control envelope, such as those that prevent stalls and spins, and which limit airspeeds and g forces on the airplane. Software can also be included that stabilize the flight-control inputs to avoid pilot-induced oscillations . Since the flight-control computers continuously feedback

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8370-450: The aircraft's equations of motion to determine the appropriate command signals for the flight controls to execute the intentions of the pilot. The programming of the digital computers enable flight envelope protection . These protections are tailored to an aircraft's handling characteristics to stay within aerodynamic and structural limitations of the aircraft. For example, the computer in flight envelope protection mode can try to prevent

8505-502: The aircraft's electrical wiring to jar loose or the vacuum tube electronics to malfunction, leading to failure of the aircraft controls and navigation equipment, which contributed to the crash of B-36B 44-92035 on 22 November 1950. The Convair B-36 was the only aircraft capable of carrying the T-12 Cloudmaker , a gravity bomb weighing 43,600 lb (19,800 kg) and designed to produce an earthquake bomb effect. Part of

8640-481: The aircraft's two aft bomb bays, while the forward bay could hold a Mark 6 atomic weapon. The defensive armament consisted of six retractable gun turrets, with side-by-side turrets mounted in forward dorsal, aft dorsal and ventral positions, aft dorsal and non-retractable tail and nose turrets. Each turret was fitted with two 20 mm (0.79 in) cannon , for a total of 16, and all turrets were remote controlled. Recoil vibration from gunnery practice often caused

8775-413: The aircraft. Bombing target tests showed a tendency of flying wings to "hunt" in yaw after turns and when flying in "disturbed" air, degrading bombing accuracy. It was thought that one of the new Honeywell autopilots , with yaw damping , would correct this flaw. Northrop chief test pilot on the YB-35 and YB-49 programs Max Stanley contends in the 1992 Discovery Channel documentary "The Wing Will Fly",

8910-594: The appropriate "feel" forces on the manual controls. This was used in Concorde , the first production fly-by-wire airliner. A digital fly-by-wire flight control system can be extended from its analog counterpart. Digital signal processing can receive and interpret input from multiple sensors simultaneously (such as the altimeters and the pitot tubes ) and adjust the controls in real time. The computers sense position and force inputs from pilot controls and aircraft sensors. They then solve differential equations related to

9045-480: The automatic-electronic system, which flared the aircraft, when it was close to the ground. In 1941, Karl Otto Altvater, who was an engineer at Siemens , developed and tested the first fly-by-wire system for the Heinkel He 111 , in which the aircraft was fully controlled by electronic impulses. The first non-experimental aircraft that was designed and flown (in 1958) with a fly-by-wire flight control system

9180-496: The bulky, high-resolution cameras of the day. The standard RB-36D carried up to 23 cameras, primarily K-17C, K-22A, K-38, and K-40 cameras. A special 240 in (6,100 mm) focal length camera (known as the Boston Camera after the university where it was designed) was tested on 44-92088, the aircraft being redesignated ERB-36D. The long focal length was achieved by using a two-mirror reflection system and could resolve

9315-563: The cancellation of the Flying Wing were investigated by the House Armed Services Committee, where Symington publicly denied exerting pressure on Northrop to merge. Northrop's 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 cancellation may have been Northrop spreading its small engineering staff too widely in other experimental programs. While

9450-527: The case of the Tornado this allows rudimentary control of the stabilators only for pitch and roll axis movements. Servo-electrically operated control surfaces were first tested in the 1930s on the Soviet Tupolev ANT-20 . Long runs of mechanical and hydraulic connections were replaced with wires and electric servos. In 1934, Karl Otto Altvater  [ de ] filed a patent about

9585-471: 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

9720-447: The combined system is designed to exclude the results from that computer in deciding the appropriate actions for the flight controls. Depending on specific system details there may be the potential to reboot an aberrant flight control computer, or to reincorporate its inputs if they return to agreement. Complex logic exists to deal with multiple failures, which may prompt the system to revert to simpler back-up modes. In addition, most of

9855-405: 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 lifelong 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,

9990-428: 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,

10125-462: The complexity, fragility and weight of the mechanical circuit of the hydromechanical or electromechanical flight control systems – each being replaced with electronic circuits. The control mechanisms in the cockpit now operate signal transducers, which in turn generate the appropriate commands. These are next processed by an electronic controller—either an analog one, or (more modernly) a digital one. Aircraft and spacecraft autopilots are now part of

10260-430: The control surface until it has moved to where the flight control computer commanded it to. The controllers measure the position of the flight control surface with sensors such as LVDTs . Fly-by-wire control systems allow aircraft computers to perform tasks without pilot input. Automatic stability systems operate in this way. Gyroscopes and sensors such as accelerometers are mounted in an aircraft to sense rotation on

10395-541: The control system itself, are dependent on the pilot's actions. The term "fly-by-wire" implies a purely electrically signaled control system. It is used in the general sense of computer-configured controls, where a computer system is interposed between the operator and the final control actuators or surfaces. This modifies the manual inputs of the pilot in accordance with control parameters. Side-sticks or conventional flight control yokes can be used to fly fly-by-wire aircraft. A fly-by-wire aircraft can be lighter than

10530-420: The crew from 15 to 9. Featherweight III had a longer range and an operating ceiling of at least 47,000 ft (14,000 m), especially valuable for reconnaissance missions. The B-36J-III configuration (the last 14 made) had a single radar-aimed tail turret, extra fuel tanks in the outer wings, and landing gear allowing the maximum gross weight to be increased to 410,000 lb (190,000 kg). Production of

10665-593: The development of the B-36 became a priority. Secretary of War Henry L. Stimson , in discussions with high-ranking officers of the USAAF, decided to waive normal army procurement procedures, and on 23 July 1943, 15 months after the Germans' Amerikabomber proposals, and the same day that the German firm Heinkel began design on a six-engined bomber of their own. The USAAF submitted a "letter of intent" to Convair for an initial production run of 100 , even before testing of

10800-433: The digital flight control computers. All benefits of digital fly-by-wire are retained since the power-by-wire components are strictly complementary to the fly-by-wire components. The biggest benefits are weight savings, the possibility of redundant power circuits and tighter integration between the aircraft flight control systems and its avionics systems. The absence of hydraulics greatly reduces maintenance costs. This system

10935-409: The earlier Silverplate program for the atomic bomb-carrying "specialist" B-29s), resulting in a "featherweight" configuration that increased top speed to 423 mph (681 km/h), and cruise at 50,000 ft (15,000 m) and dash at over 55,000 ft (17,000 m), perhaps even higher. The large wing area, with the four jet engines supplementing the piston engines in later versions gave

11070-407: The early digital fly-by-wire aircraft also had an analog electrical, mechanical, or hydraulic back-up flight control system. The Space Shuttle had, in addition to its redundant set of four digital computers running its primary flight-control software, a fifth backup computer running a separately developed, reduced-function, software flight-control system – one that could be commanded to take over in

11205-594: The early to mid-60s. The program was curtailed when the air-frame ran out of flight time. In 1972, the first digital fly-by-wire fixed-wing aircraft without a mechanical backup to take to the air was an F-8 Crusader , which had been modified electronically by NASA of the United States as a test aircraft ; the F-8 used the Apollo guidance, navigation and control hardware . The Airbus A320 began service in 1988 as

11340-430: The electronic controller. The hydraulic circuits are similar except that mechanical servo valves are replaced with electrically controlled servo valves, operated by the electronic controller. This is the simplest and earliest configuration of an analog fly-by-wire flight control system. In this configuration, the flight control systems must simulate "feel". The electronic controller controls electrical devices that provide

11475-828: 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

11610-449: The environment, pilot's workloads can be reduced. This also enables military aircraft with relaxed stability . The primary benefit for such aircraft is more maneuverability during combat and training flights, and the so-called "carefree handling" because stalling, spinning and other undesirable performances are prevented automatically by the computers. Digital flight control systems (DFCS) enable inherently unstable combat aircraft, such as

11745-475: The era. Data from National Museum of the United States Air Force , and U.S. Standard Aircraft Characteristics General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Related lists Convair B-36 The Convair B-36 "Peacemaker" is a strategic bomber built by Convair and operated by

11880-601: The event that a fault ever affected all of the other four computers. This backup system served to reduce the risk of total flight control system failure ever happening because of a general-purpose flight software fault that had escaped notice in the other four computers. For airliners, flight-control redundancy improves their safety, but fly-by-wire control systems, which are physically lighter and have lower maintenance demands than conventional controls also improve economy, both in terms of cost of ownership and for in-flight economy. In certain designs with limited relaxed stability in

12015-429: The film. The second bomb bay contained up to 80 T-86 photoflash bombs , while the third bay could carry an extra 11,000 L (3,000 US gal) droppable fuel tank. The fourth bomb bay carried electronic countermeasure equipment. The full defensive armament was retained. The extra fuel tanks increased the flight endurance to up to 50 hours and it had an operational ceiling of 50,000 ft (15,000 m). Later,

12150-550: 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, after which President Truman ordered a flyby of Pennsylvania Avenue at rooftop level. The return flight from Andrews was marred when four of the eight engines had to be shut down due to oil starvation. Inspection after a successful emergency landing at Winslow Airport , Arizona, revealed no oil had been replaced in these engines at Wright after

12285-510: The first mass-produced airliner with digital fly-by-wire controls. As of June 2024, over 11,000 A320 family aircraft, variants included, are operational around the world, making it one of the best-selling commercial jets. Boeing chose fly-by-wire flight controls for the 777 in 1994, departing from traditional cable and pulley systems. In addition to overseeing the aircraft's flight control, the FBW offered " envelope protection ", which guaranteed that

12420-477: The first to be delivered in 30 months, and the second within 36 months. Originally designated Model B-35, the name was changed to B-36 to avoid confusion with the Northrop YB-35 piston-engined flying-wing bomber, against which the B-36 was meant to compete for a production contract. Throughout its development, the B-36 program encountered delays. When the United States entered World War II, Consolidated

12555-456: The flight control computer to make the aircraft perform a certain action, such as pitch the aircraft up, or roll to one side, by moving the control column or sidestick . The flight control computer then calculates what control surface movements will cause the plane to perform that action and issues those commands to the electronic controllers for each surface. The controllers at each surface receive these commands and then move actuators attached to

12690-412: The flight control systems and autothrottles for the engines to be fully integrated. On modern military aircraft other systems such as autostabilization, navigation, radar and weapons system are all integrated with the flight control systems. FADEC allows maximum performance to be extracted from the aircraft without fear of engine misoperation, aircraft damage or high pilot workloads. In the civil field,

12825-451: The fuselage to carry spare engines between bases. Each pod could airlift two engines. When the pods were empty, they were removed and carried in the bomb bays. No record exists of the pods being used. As engine fires occurred with the B-36's radial engines, some crews humorously changed the aircraft's slogan from "six turning, four burning" into "two turning, two burning, two smoking, two choking and two more unaccounted for". This problem

12960-449: The high-pressure airflow behind the wings to produce an easily recognizable very-low-frequency pulse at ground level that betrayed approaching flights. Beginning with the B-36D, Convair added a pair of General Electric J47 -19 jet engines suspended near the end of each wing which were also retrofitted to surviving B-36Bs. Consequently, the B-36 was configured to have 10 engines, six radial propeller engines and four jet engines, leading to

13095-523: The independent nature of Jack Northrop often collided with the political wheeling-and-dealing in Washington, which gravitated toward massive military appropriations; consequently, the obsolete Convair B-36 prevailed. When the YB-49 jet bomber was canceled, Northrop was awarded a much smaller, lower profile production contract for its straight-winged F-89 Scorpion fighter as compensation for the canceled Flying Wing. The YB-49 and its modern counterpart,

13230-532: The integration increases flight safety and economy. Airbus fly-by-wire aircraft are protected from dangerous situations such as low-speed stall or overstressing by flight envelope protection . As a result, in such conditions, the flight control systems commands the engines to increase thrust without pilot intervention. In economy cruise modes, the flight control systems adjust the throttles and fuel tank selections precisely. FADEC reduces rudder drag needed to compensate for sideways flight from unbalanced engine thrust. On

13365-440: The intended long missions without refueling. The maximum thickness of the wing, measured perpendicular to the chord , was 7.5 ft (2.3 m), containing a crawlspace that allowed access to the engines. The wing area permitted cruising altitudes well above the operating ceiling of any 1940s-era fighters, at over 40,000 ft (12,000 m). In 1954, the turrets and other nonessential equipment were stripped out (not unlike

13500-456: The jet engines could raise the cruising speed to over 400 mph (640 km/h). Hence, a 40-hour mission, with the jets used only for takeoff and climbing, flew about 9,200 mi (14,800 km). Due to its size, the B-36 was never sprightly or agile. Lieutenant General James Edmundson likened it to "sitting on your front porch and flying your house around". Crew compartments were nonetheless cramped, especially when occupied for 24 hours by

13635-526: The lack of natural stability. Pre-flight safety checks of a fly-by-wire system are often performed using built-in test equipment (BITE). A number of control movement steps can be automatically performed, reducing workload of the pilot or groundcrew and speeding up flight-checks. Some aircraft, the Panavia Tornado for example, retain a very basic hydro-mechanical backup system for limited flight control capability on losing electrical power; in

13770-508: The late 1940s, strategic intelligence on Soviet capabilities and intentions was scarce. Before the development of the Lockheed U-2 high-altitude spy plane and Corona orbital reconnaissance satellites, technology and politics limited American reconnaissance efforts to the borders, of the Soviet Union. One of the essential criteria of the early postwar reconnaissance aircraft was the ability to cruise above 40,000 ft (12,000 m),

13905-440: The laws of aeronautics and computer operating systems will need to be certified to DO-178C Level A or B, depending on the class of aircraft, which is applicable for preventing potential catastrophic failures. Nevertheless, the top concern for computerized, digital, fly-by-wire systems is reliability, even more so than for analog electronic control systems. This is because the digital computers that are running software are often

14040-530: The load carried by the World War II Boeing B-17 Flying Fortress . The B-36 was not designed with nuclear weapons in mind, because the existence of such weapons was top secret during the period when the B-36 was conceived and designed, and the initial B-36A was not capable of accommodating them. Nevertheless, the B-36 stepped into its nuclear delivery role immediately upon becoming operational. In all respects except speed,

14175-524: The location. Special shelters were built to provide the maintenance crews a modicum of protection. Ground crews were at risk of slipping and falling from icy wings. The wing roots were thick enough, at 7 ft (2.1 m), to enable a flight engineer to access the backs of the engines and the landing gear during flight by crawling through the wings but was only possible at lower altitudes. In 1950, Consolidated-Vultee developed streamlined pods that looked like large drop tanks that mounted on each side of

14310-581: The new Secretary of Defense, Louis A. Johnson , who considered the U.S. Navy and naval aviation essentially obsolete in favor of the USAF and SAC, forbade putting the Navy's claim to the test. The propulsion system of the B-36 was unique, with six 28-cylinder Pratt & Whitney R-4360 Wasp Major radial engines mounted in an unusual pusher configuration , rather than the conventional tractor propeller layout of other heavy bombers . The prototypes six R-4360s delivered 18,000 hp (13,000 kW) which resulted in early B-36s needing long takeoff runs, which

14445-703: The only control path between the pilot and aircraft's flight control surfaces . If the computer software crashes for any reason, the pilot may be unable to control an aircraft. Hence virtually all fly-by-wire flight control systems are either triply or quadruply redundant in their computers and electronics . These have three or four flight-control computers operating in parallel and three or four separate data buses connecting them with each control surface. The multiple redundant flight control computers continuously monitor each other's output. If one computer begins to give aberrant results for any reason, potentially including software or hardware failures or flawed input data, then

14580-541: The past 25 years." The new bomber would be publicly displayed for the first time in 1988. Paramount Pictures ' 1953 film, The War of the Worlds , depicts a YB-49 dropping an atomic bomb on the invading Martians . The feature film , produced by George Pal and directed by Byron Haskin , incorporates Northrop color footage of a YB-49 test flight, originally used in Paramount's Popular Science theatrical shorts of

14715-627: The pilot. The first electronic fly-by-wire testbed operated by the U.S. Air Force was a Boeing B-47E Stratojet (Ser. No. 53-2280) The first pure electronic fly-by-wire aircraft with no mechanical or hydraulic backup was the Apollo Lunar Landing Training Vehicle (LLTV), first flown in 1968. This was preceded in 1964 by the Lunar Landing Research Vehicle (LLRV) which pioneered fly-by-wire flight with no mechanical backup. Control

14850-452: The pitch axis, for example the Boeing 777, the flight control system may allow the aircraft to fly at a more aerodynamically efficient angle of attack than a conventionally stable design. Modern airliners also commonly feature computerized Full-Authority Digital Engine Control systems ( FADECs ) that control their engines, air inlets, fuel storage and distribution system, in a similar fashion to

14985-488: The range of the B-36 needed to be stationed as close to enemy targets as possible, this meant the plane was largely based in the extreme weather locations of the northern continental United States, Alaska, and the Arctic . Since the maintenance had to be performed outdoors, the crews were largely exposed to the elements, with temperatures of −60 °F (−51 °C) in winters and 100 °F (38 °C) in summers, depending on

15120-491: The rear of the fuselage . If these structures can be reduced in size, airframe weight is reduced. The advantages of fly-by-wire controls were first exploited by the military and then in the commercial airline market. The Airbus series of airliners used full-authority fly-by-wire controls beginning with their A320 series, see A320 flight control (though some limited fly-by-wire functions existed on A310 aircraft). Boeing followed with their 777 and later designs. A pilot commands

15255-474: The rival Convair B-36. One YB-35 airframe (s/n 42-102369) was chosen as the prototype for the RB-49 and designated YRB-49A . During early 1950, the remaining YB-35Bs airframes, which were being converted to YRB-49As, were ordered scrapped. Flight testing of the sole remaining YB-49 prototype ended 14 March 1950. On 15 March 1950, that program was canceled. Coincidentally, the sole remaining YB-49 prototype suffered

15390-926: The serving Chief of Naval Operations (CNO), Admiral Louis E. Denfeld , following Denfeld's testimony before the House Armed Services Committee . The congressional and media furor over the firing of Admiral Denfeld, as well as the significant use of aircraft carriers in the Korean War , resulted in the Truman administration subsequently ousting both Johnson and Matthews, and procuring Forrestal -class supercarriers, which were similar in size to United States , but geared towards multirole use with air wings of fighter, attack, reconnaissance, electronic warfare , early warning and antisubmarine-warfare aircraft. Simultaneously, heavy manned bombers for SAC were also deemed crucial to national defense and

15525-414: The sides and bottom of the aircraft's rear fuselage to cool the reactor in flight. On the ground, a crane would be used to remove the 35,000 lb (16,000 kg) reactor from the aircraft. To protect the crew, the highly modified cockpit was encased in lead and rubber, with a 1 ft-thick (30 cm) leaded glass windshield . The reactor was operational, but did not power the aircraft as its purpose

15660-433: The six piston engines combined gave the B-36 a total of 40,000 hp (30,000 kW) for short periods of time. The B-36 had a crew of 15. As with the B-29 and B-50, the pressurized flight deck and crew compartment were linked to the rear compartment by a pressurized tunnel through the bomb bay. In the B-36, movement through the tunnel was on a wheeled trolley, pulling on a rope. The rear compartment featured six bunks and

15795-496: The system would step in to avoid accidental mishandling, stalls, or excessive structural stress on the aircraft. The 777 used ARINC 629 buses to connect primary flight computers (PFCs) with actuator-control electronics units (ACEs). Every PFC housed three 32-bit microprocessors, including a Motorola 68040 , an Intel 80486 , and an AMD 29050 , all programmed in Ada programming language. All fly-by-wire flight control systems eliminate

15930-511: The test was the RB-36D specialized photo-reconnaissance version of the B-36D . It was outwardly identical to the standard B-36D, but carried a crew of 22 rather than 15, the additional crew members being needed to operate the reconnaissance equipment carried. The forward bomb bay was filled with a pressurized, manned compartment with 14 cameras and a darkroom , where a photo technician would develop

16065-478: The testing process involved dropping two of them in a single flight, one from 30,000 ft (9,100 m) and the second from 40,000 ft (12,000 m). The first prototype XB-36 flew on 8 August 1946. The speed and range of the prototype failed to meet the standards set out by the USAAC in 1941. This was expected, as the Pratt & Whitney R-4360 engines required were not yet available. A second aircraft,

16200-645: The two prototypes was complete. The first delivery was due in August 1945, and the last in October 1946, but Consolidated (by now renamed Convair after merging with Vultee Aircraft ) delayed delivery. Three months after V-E Day the aircraft was unveiled on 20 August 1945 , and flew for the first time on 8 August 1946. After the start of the Cold War with the 1948 Berlin Airlift , and the 1949 atmospheric test of

16335-546: The two systems would never again be in competition for funding. The B-36, including its GRB-36, RB-36, and XC-99 variants, was in USAF service as part of the SAC from 1948 to 1959. The RB-36 variants of the B-36 were used for reconnaissance during the Cold War with the Soviet Union and the B-36 bomber variants conducted training and test operations and stood ground and airborne alert, but were never flown offensively as bombers against hostile forces. The Wasp Major engines had

16470-433: The violent turbulence induced by the wingtip vortices of the B-36. One of the SAC's initial missions was to plan strategic aerial reconnaissance on a global scale. The first efforts were in photo-reconnaissance and mapping. Along with the photo-reconnaissance mission, a small electronic intelligence cadre operated. Weather reconnaissance was part of the effort, as was long-range detection of Soviet atomic explosions. In

16605-578: The way that FBW controls the flight control surfaces. This allows the engine output to be continually varied for the most efficient usage possible. The second generation Embraer E-Jet family gained a 1.5% efficiency improvement over the first generation from the fly-by-wire system, which enabled a reduction from 280 ft.² to 250 ft.² for the horizontal stabilizer on the E190/195 variants. Airbus and Boeing differ in their approaches to implementing fly-by-wire systems in commercial aircraft. Since

16740-543: Was a close friend of Johnson. Several high-level Navy officials questioned the government's decision in cancelling the United States to fund the B-36, alleging a conflict of interest because Johnson had once served on Convair's board of directors. The uproar following the cancellation of United States in 1949 was nicknamed the " Revolt of the Admirals ", during which time Matthews dismissed and forced into retirement

16875-462: Was ameliorated when power was boosted to 22,800 hp (17,000 kW). Each engine drove a three-bladed propeller, 19 ft (5.8 m) in diameter, mounted in a pusher configuration. This unusual configuration prevented propeller turbulence from interfering with airflow over the wing, but led to engine overheating due to insufficient airflow around the engines, resulting in inflight engine fires . The large, slow-turning propellers interacted with

17010-582: Was delivered in May 1951. Some RB-36Ds were later modified to the featherweight configuration, in which all but the tail guns were removed and the crew reduced from 22 to 19. These aircraft were redesignated as RB-36D-III. Modifications were carried out by Convair from February to November 1954. Fly-by-wire Fly-by-wire ( FBW ) is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals, and flight control computers determine how to move

17145-502: Was exacerbated by the propellers' pusher configuration, which increased carburetor icing . The design of the R-4360 engine tacitly assumed that it would be mounted in the conventional tractor configuration with the air flowing in the order of propeller/air intake/cylinders and to the carburetor. In this configuration, the carburetor is bathed in warm air flowing past the engine, so is unlikely to ice up. However, they were mounted backwards in

17280-709: Was fitted, since none was ready. All surviving B-36As were converted to RB-36E reconnaissance models once later models became available. Deliveries began in November 1948 of the combat-capable B-36B, which finally met the 1941 requirements, but had serious engine reliability and maintenance problems (changing the 336 spark plugs was a task dreaded by ground crews) and with the availability of weapons and spares. Later models had more powerful R-4360 engines, improved radar, and redesigned crew compartments. The jet engines increased fuel consumption and reduced range. Gun turrets were already recognized as obsolete, and newer bombers had only

17415-681: Was lost when it crashed on June 5, 1948, killing its pilot, Major Daniel Forbes (for whom Forbes Air Force Base was named), co-pilot Captain Glen Edwards (for whom Edwards Air Force Base is named), and three other crew members, one of whom, 1st Lieutenant 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

17550-401: Was obsolete from the outset, while it now faced the widespread introduction of opposing jet fighters. The Boeing B-47 Stratojet , its jet engined counterpart, did not become fully operational until 1953, and lacked the range to attack the Soviet Union from North America without aerial refueling and could not carry the huge Mark 16 hydrogen bomb . The other American piston bombers of the day,

17685-470: Was ordered to slow B-36 development to greatly increase Consolidated B-24 Liberator production. The first mockup was inspected on 20 July 1942, following six months of refinements. A month after the inspection, the project was moved from San Diego, California, to Fort Worth, Texas, which set back development several months. Consolidated changed the tail from a twin-tail to a single, thereby saving 3,850 lb (1,750 kg), but this change delayed delivery by

17820-556: Was replaced by the jet-powered Boeing B-52 Stratofortress beginning in 1955. All but four aircraft have been scrapped. The design of the B-36 can be traced to early 1941, prior to the entry of the United States into World War II . At the time, Britain was at risk of falling to the Nazi "Blitz" attacks , making strategic bombing attacks by the United States Army Air Corps (USAAC) against Germany impossible with

17955-609: Was the Avro Canada CF-105 Arrow , a feat not repeated with a production aircraft (though the Arrow was cancelled with five built) until Concorde in 1969, which became the first fly-by-wire airliner. This system also included solid-state components and system redundancy, was designed to be integrated with a computerised navigation and automatic search and track radar, was flyable from ground control with data uplink and downlink, and provided artificial feel (feedback) to

18090-767: Was through a digital computer with three analog redundant channels. In the USSR, the Sukhoi T-4 also flew. At about the same time in the United Kingdom a trainer variant of the British Hawker Hunter fighter was modified at the British Royal Aircraft Establishment with fly-by-wire flight controls for the right-seat pilot. In the UK the two seater Avro 707 C was flown with a Fairey system with mechanical backup in

18225-489: Was to investigate the effect of radiation. Between 1955 and 1957, the NB-36H completed 47 test flights and 215 hours of flight time, during 89 of which the reactor was critical. Other experiments involved providing the B-36 with its own fighter defense in the form of parasite aircraft carried partially or wholly in a bomb bay. One parasite aircraft was the diminutive football-shaped McDonnell XF-85 Goblin , which docked using

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