(North American) XB-70 Valkyrie @·AIRCRAFTUBE

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  • XB-70A - Convair B-58A XB-70A - Convair B-58A
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North American XB-70 Valkyrie

The North American Aviation XB-70 Valkyrie was the prototype version of the proposed B-70 nuclear-armed deep-penetration strategic bomber for the United States Air Force's (USAF) Strategic Air Command. Designed by North American Aviation in the late 1950s, the Valkyrie was a large six-engined aircraft able to fly Mach 3+ at an altitude of 70,000 feet (21,000 m), which would have allowed it to avoid interceptors, the only effective anti-bomber weapon at the time.

Improved high-altitude surface-to-air missiles (SAMs), the change to low-level penetration bombing, the program's high development costs, and the introduction of intercontinental ballistic missile (ICBMs) led to the cancellation of the B-70 program in 1961. Although the proposed fleet of operational B-70 bombers was canceled, two prototype aircraft were built as the XB-70A and used in supersonic test flights from 1964 to 1969. One prototype crashed following a midair collision in 1966; the other is on display at the National Museum of the United States Air Force in Ohio.

Background

As an offshoot of Boeing's MX-2145 manned boost-glide bomber project, the company partnered with RAND Corporation in January 1954 to explore what sort of aircraft would be needed to deliver the various nuclear weapons then under development. Providing for a long range and high payload were obvious requirements, but they also concluded that after bomb-release the plane would need supersonic speed to escape the weapon's critical blast-radius. An aircraft capable of carrying a reasonable bomb load to the Soviet Union from the continental United States had to carry a large fuel load (and thus be very large itself) due to the unrefueled range required. The need for supersonic performance would only increase this, dramatically.

The aviation industry had been examining this problem for some time. There was considerable interest in the use of nuclear-powered aircraft in the bomber role from the mid-1940s. In a conventional jet engine thrust is provided by accelerating air, which is accomplished by heating it with burning jet fuel. In a nuclear engine the heat is supplied by a reactor, although a small amount of jet fuel was carried to add extra energy during high-power portions of flight—take-off and high-speed dashes. Another possibility was the use of boron-enriched "zip fuels", which improved the energy density of the fuel by about 40%, and could be used in versions of existing jet engine designs. Zip fuels appeared to offer just enough of a performance improvement to produce a supersonic strategic bomber.

The U.S. Air Force followed these developments closely, and in 1955 issued General Operational Requirement No. 38 for a new bomber with the payload and intercontinental range of the B-52 and the Mach 2 top speed of the Convair B-58 Hustler. The new bomber was expected to enter service in 1963. Both nuclear and conventional designs would be considered. The nuclear-powered bomber was placed under "Weapon System 125A" and pursued simultaneously with the jet-powered version, "Weapon System 110A".

The USAF Air Research and Development Command's (ARDC) requirement for WS-110A asked for a chemical fuel bomber with Mach 0.9 cruising speed and "maximum possible" speed during a 1,000 nautical miles (1,852 km) entrance and exit from the target. The requirement also called for a 50,000 pound (22,670 kg) payload and a combat radius of 4,000 nautical miles (4,600 mi, 7,400 km). The Air Force formed similar requirements for a WS-110L intercontinental reconnaissance system in 1955, but this was later canceled in 1958 due to better options. In July 1955 six contractors were selected to bid on WS-110A studies. Boeing and North American Aviation (NAA) submitted proposals, and on 8 November 1955 were awarded contracts for Phase 1 development.

In mid-1956, initial designs were presented by the two companies. Zip fuel was to be used in the afterburners to improve range by 10% to 15% over conventional fuel. Both designs featured huge wing tip fuel tanks that could be jettisoned when their fuel was depleted before a supersonic dash to the target. The tanks also included the outer portions of the wing, which would also be jettisoned to produce a smaller wing planform suitable for supersonic speeds.

The two designs had takeoff weights of approximately 750,000 pounds (340,000 kg) with large fuel loads. The Air Force evaluated the designs, and in September 1956 deemed them too large and complicated for operations. The USAF ended Phase 1 development in October 1956 and instructed the two contractors to continue design studies. Curtis LeMay was dismissive, declaiming, "This is not an airplane, it's a three-ship formation."

New designs

During the period that the original proposals were being studied, advances in supersonic flight were proceeding rapidly. The "long thin delta" was establishing itself as a preferred planform for supersonic flight, replacing earlier designs like the swept wing and compound sweep as seen on designs like the Lockheed F-104 Starfighter (and the earlier NAA design for WS-110). Engines able to cope with higher temperatures and widely varying inlet air speeds were also under design, allowing for sustained supersonic speeds. By March 1957, engine development and wind tunnel testing had progressed such that the potential for all-supersonic flight appeared feasible – the cruise-and-dash approach that had resulted in huge designs was no longer needed.

The project decided that the aircraft would fly at speeds up to Mach 3 for the entire mission, instead of a combination of subsonic cruise and supersonic dash of the aircraft designs in the previous year. Zip fuel was to be burned in the engine's afterburner to increase range. Both North American and Boeing returned new designs with very long fuselages and large delta wings. They differed primarily in engine layout; the NAA design arranged its six engines in a semi-circular duct under the rear fuselage, while the Boeing design used separate podded engines located individually on pylons below the wing.

North American had scoured the literature to find any additional advantage. This led them to an obscure report by two NACA wind tunnel experts who wrote a report in 1956 entitled "Aircraft Configurations Developing High Lift-Drag Ratios at High Supersonic Speeds". Known today as compression lift, the idea was to use the shock wave generated off the nose or other sharp points on the aircraft as a source of high-pressure air. By carefully positioning the wing in relation to the shock, the shock's high pressure could be captured on the bottom of the wing and generate additional lift. To take maximum advantage of this effect, they redesigned the underside of the aircraft to feature a large triangular intake area far forward of the engines, better positioning the shock in relation to the wing.

North American improved on the basic concept by adding a set of drooping wing tip panels that were lowered at high speed. This helped trap the shock wave under the wing between the downturned wing tips, and also added more vertical surface to the aircraft to improve directional stability at high speeds. NAA's solution had an additional advantage, as it decreased the surface area of the rear of the wing when the panels were moved into their high-speed position. This helped offset the rearward shift of the center of pressure, or "average lift point", with increasing speeds. Under normal conditions this caused an increasing nose-down trim, which had to be offset by moving the control surfaces, increasing drag. When the wing tips were drooped the surface area at the rear of the wings was lowered, moving the lift forward and counteracting this effect, reducing the need for control inputs.

The buildup of heat due to skin friction during sustained supersonic flight had to be addressed. During a Mach 3 cruise the aircraft would reach an average of 450 °F (230 °C), with leading edges reaching 630 °F (330 °C), and up to 1,000 °F (540 °C) in engine compartments. NAA proposed building their design out of sandwich panels, with each panel consisting of two thin sheets of stainless steel brazed to opposite faces of a honeycomb-shaped foil core. Expensive titanium would be used only in high-temperature areas like the leading edge of the horizontal stabilizer, and the nose. For cooling the interior, the XB-70 pumped fuel en route to the engines through heat exchangers.

On 30 August 1957, the Air Force decided that enough data was available on the NAA and Boeing designs that a competition could begin. On 18 September, the Air Force issued operational requirements which called for a cruising speed of Mach 3.0 to 3.2, an over-target altitude of 70,000–75,000 ft (21,300–22,700 m), a range of up to 10,500 mi (16,900 km), and a gross weight not to exceed 490,000 lb (222,000 kg). The aircraft would have to use the hangars, runways and handling procedures used by the B-52. On 23 December 1957, the North American proposal was declared the winner of the competition, and on 24 January 1958, a contract was issued for Phase 1 development.

In February 1958, the proposed bomber was designated B-70, with the prototypes receiving the "X" experimental prototype designation. The name "Valkyrie" was the winning submission in early 1958, selected from 20,000 entries in a USAF "Name the B-70" contest. The Air Force approved an 18-month program acceleration in March 1958 that rescheduled the first flight to December 1961. But in late 1958 the service announced that this acceleration would not be possible due to lack of funding. In December 1958, a Phase II contract was issued. The mockup of the B-70 was reviewed by the Air Force in March 1959. Provisions for air-to-surface missiles and external fuel tanks were requested afterward. At the same time North American was developing the F-108 supersonic interceptor. To reduce program costs, the F-108 would share two of the engines, the escape capsule, and some smaller systems with the B-70. In early 1960, North American and the USAF released the first drawing of the XB-70 to the public.

The "missile problem"

The B-70 was planned to use a high-speed, high-altitude bombing approach that followed a trend of bombers flying progressively faster and higher since the start of manned bomber use. Anti-aircraft artillery with the ability to reach jet bomber altitudes of 50,000 ft and above was extremely expensive, and had almost no chance of a hit as the aircraft quickly flew out of range. Interceptor aircraft were the only effective anti-bomber weapons by the early 1950s, but high altitudes were an issue for them as well; Soviet interceptors during the late 1950s could not intercept the higher-altitude U-2 reconnaissance aircraft. It was later discovered that flying faster made radar detection much more difficult due to an effect known as the blip-to-scan ratio, and any reduction in tracking efficiency would further interfere with the operation and guidance of fighters.

The introduction of the first effective anti-aircraft missiles by the late 1950s had seriously upset this equation. Missiles could stand ready for immediate launch directly at the bombers, eliminating operational delays like the time needed to get the pilot into the cockpit of a fighter. Guidance did not require wide-area tracking or calculation of an intercept course: a simple comparison of the time needed to fly to the altitude of the target returned the required "lead". Missiles also had greater altitude capability than any aircraft, and improving this to adapt to new aircraft was a low-cost development path. The US was aware of Soviet work in the field, and had reduced the expected operational lifetime of the U-2, knowing that it would become vulnerable to these missiles as they were improved. This eventuality came to pass in the 1960 downing of the U-2 flown by Gary Powers.

Faced with this problem, military doctrine had already started shifting away from high-altitude supersonic bombing toward low-altitude penetration. As radar operates on the line-of-sight, aircraft could dramatically shorten detection distances by flying close to the Earth and hiding behind terrain. Missile sites spaced to overlap in range when attacking bombers at high altitudes would leave large gaps between their coverage for bombers flying at lower levels. With an appropriate map of the missile sites, the bombers could fly between and around the defences. Additionally, early missiles generally flew unguided for a period of time before the radar systems were able to track the missile and start sending it guidance signals. With the SA-2 Guideline missile, this minimum altitude was roughly 2,000 ft. Flying below this would make the bomber effectively invulnerable to the missiles, even if they happened to fly into range.

Flying at low level provided protection against fighters as well. Radars of the era did not have the ability to "look down"; if the radar were aimed down to detect targets at a lower altitude, the reflection of the ground would overwhelm the signal returned from a target. An interceptor flying at normal altitudes would be effectively blind to bombers below it. The interceptor could descend to lower altitudes to increase the amount of visible sky above it, but doing so would limit its radar range in the same way as the missile sites, as well as greatly increasing fuel use and thus reducing mission time. The Soviet Union would not introduce an interceptor with look-down capability until 1972 with the High Lark radar, and even this model had very limited capability.

Strategic Air Command found itself in an uncomfortable position; bombers had been tuned for efficiency at high speeds and altitudes, performance that had been purchased at great cost in both engineering and financial terms. Before the B-70 was to replace the B-52 in the long-range role, SAC had introduced the Convair B-58 Hustler to replace the Boeing B-47 Stratojet in the medium-range role. The Hustler was expensive to develop and purchase, and required enormous amounts of fuel and maintenance in comparison to the B-47. It was estimated that it cost three times as much to operate as the much larger and longer-ranged B-52.

The B-70, designed for even higher speeds, altitudes and range than the B-58, suffered even more in relative terms. At high altitudes the B-70 was as much as four times faster than the B-52, but at low altitudes it was limited to only Mach 0.95, only modestly higher than the B-52 at the same altitudes. It also had a smaller bombload and shorter range. Its only major advantage would be its ability to use high speed in areas without missile cover, especially on the long journey from the USA to USSR. The value was limited; the USAF's doctrine stressed that the primary reason for maintaining the bomber force in an era of ICBMs was that the bombers could remain in the air at long ranges from their bases and were thus immune to sneak attack. In this case, the higher speed would be used for only a short period of time between the staging areas and the Soviet coastline.

Adding to the problems, the zip fuel program was canceled in 1959. After burning, the fuel turned into liquids and solids that increased wear on moving turbine engine components. Although the B-70 was intended to use zip only in the afterburners, and thus avoid this problem, the enormous cost of the zip program for such limited gains led to its cancellation. This by itself was not a fatal problem, however, as newly developed high-energy fuels like JP-6 were available to make up some of the difference. Most of the range lost in the change from zip fuel was restored by filling one of the two bomb bays with a fuel tank. Also, the F-108 program was canceled in September 1959, which ended the shared development that benefited the B-70 program.

Downsizing, upswing, cancellation

At two secret meetings on 16 and 18 November 1959, the Chairman of the Joint Chiefs of Staff, Air Force General Twining, recommended the Air Force's plan for the B-70 to reconnoiter and strike rail-mobile Soviet ICBMs, but the Chief of Staff of the Air Force, General White, admitted the Soviets would "be able to hit the B-70 with rockets" and requested the B-70 be downgraded to "a bare minimum research and development program" at $200 million for fiscal year 1960. President Eisenhower responded that the reconnaissance and strike mission was "crazy" since the nuclear mission was to attack known production and military complexes, and emphasized he saw no need for the B-70 since the ICBM is "a cheaper, more effective way of doing the same thing". Eisenhower also identified that the B-70 would not be in manufacturing until "eight to ten years from now" and "said he thought we were talking about bows and arrows at a time of gunpowder when we spoke of bombers in the missile age." In December 1959 the Air Force announced the B-70 project would be cut to a single prototype, and most of the planned B-70 subsystems would no longer be developed.

Then interest increased due to the politics of presidential campaign of 1960. A central plank of John F. Kennedy's campaign was that Eisenhower and the Republicans were weak on defense, and pointed to the B-70 as an example. He told a San Diego audience near NAA facilities, "I endorse wholeheartedly the B-70 manned aircraft." Kennedy also made similar campaign claims regarding other aircraft: near the Seattle Boeing plant he affirmed the need for B-52s and in Fort Worth he praised the B-58.

The Air Force changed the program to full weapon development and awarded a contract for an XB-70 prototype and 11 YB-70s in August 1960. In November 1960, the B-70 program received a $265 million appropriation from Congress for FY 1961. Nixon, trailing in his home state of California, also publicly endorsed the B-70, and on 30 October Eisenhower helped the Republican campaign with a pledge of an additional $155 million for the B-70 development program.

On taking office in January 1961, Kennedy was informed that the missile gap was an illusion. On 28 March 1961, after $800 million had been spent on the B-70 program, Kennedy canceled the project as "unnecessary and economically unjustifiable" because it "stood little chance of penetrating enemy defenses successfully." Instead, Kennedy recommended "the B-70 program be carried forward essentially to explore the problem of flying at three times the speed of sound with an airframe potentially useful as a bomber." After Congress approved $290 million of B-70 "add-on" funds to the President's 12 May 1960 modified FY 1961 budget, the Administration decided on a "Planned Utilization" of only $100 million of these funds. The Department of Defense subsequently presented data to Congress that the B-70 would add little performance for the high cost.

However, after becoming the new Air Force Chief of Staff in July 1961, Curtis LeMay increased his B-70 advocacy, including interviews for August Reader's Digest and November Aviation Week articles, and allowing a 25 February General Electric tour at which the press was provided artist conceptions of, and other info about, the B-70. Congress had also continued B-70 appropriations in an effort to resurrect bomber development. After Secretary of Defense Robert McNamara explained again to the House Armed Services Committee (HASC) on 24 January 1962 that the B-70 was unjustifiable, LeMay subsequently argued for the B-70 to both the House and Senate committees—and was chastised by McNamara on 1 March. By 7 March 1962, the HASC—with 21 members having B-70 work in their districts—had written an appropriations bill to "direct"—by law—the Executive Branch to use all of the nearly $500 million appropriated for the RS-70. McNamara was unsuccessful with an address to the HASC on 14 March, but a 19 March 1962 11th hour White House Rose Garden agreement between Kennedy and HASC chairman Carl Vinson retracted the bill's language and the bomber remained canceled.

Experimental aircraft

The XB-70s were intended to be used for the advanced study of aerodynamics, propulsion, and other subjects related to large supersonic transports. The crew was reduced to only the two pilots, as a navigator and a bombardier were not needed for this research role. The production order was reduced to three prototypes in March 1961 with the third aircraft to incorporate improvements from the previous prototype. The order was later reduced to two experimental XB-70As, named Air Vehicle 1 and 2 (AV-1 and AV-2). XB-70 No. 1 was completed on 7 May 1964, and rolled out on 11 May 1964 at Palmdale, California. One report stated "nothing like it existed anywhere". AV-2 was completed on 15 October 1964. The manufacture of the third prototype (AV-3) was canceled in July 1964 before completion. The first XB-70 carried out her maiden flight in September 1964 and many more test flights followed.

The data from the XB-70 test flights and aerospace materials development were used in the later B-1 bomber program, the American supersonic transport (SST) program, and via espionage, the Soviet Union's Tupolev Tu-144 SST program. The development of the Lockheed U-2 and the SR-71 Blackbird reconnaissance aircraft, as well as the XB-70, prompted Soviet aerospace engineers to design and develop their high-altitude and high-speed MiG-25 interceptor.

Design

The Valkyrie was designed to be a high-altitude Mach 3 bomber with six engines. Harrison Storms shaped the aircraft with a canard surface and a delta wing, which was built largely of stainless steel, sandwiched honeycomb panels, and titanium. The XB-70 was designed to use supersonic technologies developed for the Mach 3 Navaho, as well as a modified form of the SM-64 Navaho's all-inertial guidance system.

The XB-70 used compression lift, which was generated from a prominent wedge at the center of the engine inlets that created a shock wave below the aircraft. The wing included inboard camber to more effectively use the higher pressure field behind the strong shock wave (the airflow at the XB-70 wing's leading edge was subsonic). The compression lift increased the lift by five percent. Unique among aircraft of its size, the outer portions of the wings were hinged, and could be pivoted downward by up to 65 degrees. This increased the aircraft's directional stability at supersonic speeds, shifted the center of lift to a more favorable position at high speeds, and strengthened the compression lift effect. With the wingtips drooped downwards, the compression lift shock wave would be further trapped under the wings.

The XB-70 was equipped with six General Electric YJ93-GE-3 turbojet engines, designed to use JP-6 jet fuel. The engine was stated to be in the "30,000-pound class", but actually produced 28,000 lbf (124.6 kN) with afterburner and 19,900 lbf (88 kN) without afterburner. The Valkyrie used fuel for cooling; it was pumped through heat exchangers before reaching the engines. To reduce the likelihood of autoignition, nitrogen was injected into the JP-6 during refueling, and the "fuel pressurization and inerting system" vaporized a 700 lb (320 kg) supply of liquid nitrogen to fill the fuel tank vent space and maintain tank pressure.

Operational history

The XB-70's maiden flight was on 21 September 1964. In the first flight test, between Palmdale and Edwards AFB, shortly after take-off one engine had to be shut down, and an undercarriage malfunction warning meant that the flight was flown with the undercarriage down as precaution, limiting speed to 390 mph - about half that planned. On landing, the rear wheels of the port side main gear locked, the tires ruptured, and a fire started.

The Valkyrie first became supersonic (Mach 1.1) on the third test flight on 12 October 1964, and flew above Mach 1 for 40 minutes during the following flight on 24 October. The wing tips were also lowered partially in this flight. XB-70 No. 1 surpassed Mach 3 on 14 October 1965 by reaching Mach 3.02 at 70,000 ft (21,300 m). The first aircraft was found to suffer from weaknesses in the honeycomb panels, primarily due to inexperience with fabrication and quality control of this new material. On two occasions, honeycomb panels failed and were torn off during supersonic flight, necessitating a speed limit of Mach 2.5 being placed on the aircraft.

The deficiencies discovered on AV-1 were almost completely solved on the second XB-70, which first flew on 17 July 1965. On 3 January 1966, XB-70 No. 2 attained a speed of Mach 3.05 while flying at 72,000 ft (21,900 m). AV-2 reached a top speed of Mach 3.08 and maintained it for 20 minutes on 12 April 1966. On 19 May 1966, AV-2 reached Mach 3.06 and flew at Mach 3 for 32 minutes, covering 2,400 mi (3,840 km) in 91 minutes of total flight.

A joint NASA/USAF research program was conducted from 3 November 1966 to 31 January 1967 for measuring the intensity and signature of sonic booms for the National Sonic Boom Program (NSBP). Testing was planned to cover a range of sonic boom overpressures on the ground similar to but higher than the proposed American SST. In 1966, AV-2 was selected for the program and was outfitted with test sensors. It flew the first sonic boom test on 6 June 1966, obtaining a speed of Mach 3.05 at 72,000 ft (21,900 m). Two days later, AV-2 crashed following a mid-air collision with an F-104 while flying in a multi-aircraft formation. Sonic boom and later testing continued with XB-70A #1.

The second flight research program (NASA NAS4-1174) investigated "control of structural dynamics" from 25 April 1967 through the XB-70's last flight in 1969. At high altitude and high speed, the XB-70A experienced unwanted changes in altitude. NASA testing from June 1968 included two small vanes on the nose of AV-1 for measuring the response of the aircraft's stability augmentation system. AV-1 flew a total of 83 flights.

The XB-70's last supersonic flight took place on 17 December 1968. On 4 February 1969, AV-1 took its final flight to Wright-Patterson Air Force Base for museum display (now the National Museum of the United States Air Force). Flight data was collected on this subsonic trip. North American Rockwell completed a four-volume report on the B-70 that was published by NASA in April 1972.

Variants

  • XB-70A : Prototype of B-70. Two were built:
    • AV-1, NAA Model Number NA-278, USAF S/N 62-0001, completed 83 flights spanning 160 hours and 16 minutes.
    • AV-2, NAA Model Number NA-278, USAF S/N 62-0207, flew 46 times over 92 hours and 22 minutes, before it crashed in June 1966.
  • XB-70B : AV-3, NAA Model Number NA-274, USAF S/N 62-0208, was originally to be the first YB-70A in March 1961. This advanced prototype was canceled during early manufacture.
  • YB-70 : Planned preproduction version with improvements based on XB-70s.
  • B-70A : Planned bomber production version of Valkyrie. A fleet of up to 65 operational bombers was planned.
  • RS-70 : Proposed reconnaissance-strike version with a crew of four and in-flight refueling capability.

Incidents and accidents

On 7 May 1965, the divider separating the left and right halves of the engine inlet on XB-70A AV-1 broke off in flight and was ingested into the engines, damaging all six beyond repair.

On 14 October 1965, AV-1 surpassed Mach 3, but heat and stress damaged the honeycomb panels, leaving 2 ft (0.6 m) of the leading edge of the left wing missing. The first aircraft was limited to Mach 2.5 afterwards.

Mid-air collision

On 8 June 1966, XB-70A No. 2 was in close formation with four other aircraft (an F-4, F-5, T-38, and F-104) for a photoshoot at the behest of General Electric, manufacturer of the engines of all five aircraft. After the completion of the photoshoot, the F-104 drifted into contact with the XB-70's right wing, flipped over and rolled inverted over the top of the Valkyrie, striking the vertical stabilizers and left wing of the bomber. The F-104 exploded, destroying the Valkyrie's rudders and damaging its left wing. With the loss of both rudders and damage to the wings, the Valkyrie entered an uncontrollable spin and crashed into the ground north of Barstow, California. NASA Chief Test Pilot Joe Walker (F-104 pilot) and Carl Cross (XB-70 co-pilot) were killed. Al White (XB-70 pilot) ejected, sustaining serious injuries, including one arm crushed by the closing clamshell-like escape capsule moments prior to ejection.

The USAF summary report of the accident investigation stated that, given the position of the F-104 relative to the XB-70, the F-104 pilot would not have been able to see the XB-70's wing, except by uncomfortably looking back over his left shoulder. The report said that Walker, piloting the F-104, likely maintained his position by looking at the fuselage of the XB-70, forward of his position. The F-104 was estimated to be 70 ft (21 m) to the side of, and 10 ft (3 m) below, the fuselage of the XB-70. The report concluded that from that position, without appropriate sight cues, Walker was unable to properly perceive his motion relative to the Valkyrie, leading to his aircraft drifting into contact with the XB-70's wing. The accident investigation also pointed to the wake vortex off the XB-70's right wingtip as the reason for the F-104's sudden roll over and into the bomber.

Aircraft on display

Valkyrie AV-1 (AF Ser. No. 62-0001) is on display at the National Museum of the United States Air Force at Wright-Patterson AFB near Dayton, Ohio. The aircraft was flown to the Museum on 4 February 1969, following the conclusion of the XB-70 testing program. Over the years the Valkyrie became the Museum's signature aircraft, appearing on Museum letterhead, and even appearing as the chief design feature for the Museum's restaurant, the Valkyrie Cafe. As of 2011, the XB-70 was in the Museum's Research & Development Hangar where it is displayed alongside other experimental aircraft in the Museum's collection.

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Specifications (XB-70A)

  • Crew: 2.
  • Length: 189 ft 0 in (57.6 m).
  • Height: 30 ft (9.1 m).
  • Wingspan: 105 ft (32 m).
  • Wing area: 6,297 ft² (585 m²).
  • Wing loading: 84.93 lb/ft² (414.7 kg/m²).
  • Airfoil: Hexagonal; 0.30 Hex modified root, 0.70 Hex modified tip.
  • Empty weight: 253,600 lb (115,030 kg; operating empty weight).
  • Loaded weight: 534,700 lb (242,500 kg).
  • Max. takeoff weight: 542,000 lb (246,000 kg).
  • Internal fuel capacity: 300,000 lb (136,100 kg) or 46,745 US gallons (177,000 L).
  • Maximum speed: Mach 3.1 (2,056 mph, 3,309 km/h).
  • Cruise speed: Mach 3.0 (2,000 mph, 3,200 km/h).
  • Range: 3,725 nmi (4,288 mi, 6,900 km) on combat mission.
  • Service ceiling: 77,350 ft (23,600 m).
  • lift-to-drag: about 6 at Mach 2.
  • Powerplant: Six General Electric YJ93-GE-3 afterburning turbojet.
  • Dry thrust: 19,900 lbf (84 kN) each.
  • Thrust with afterburner: 28,800 lbf[75] (128 kN) each.
  • Thrust/weight: 0.314.

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  • Website : The following provisions apply to a single Website accessible via the www.aircraftube.com, www.aircraftube.org, www.aircraftube.net and www.all-aircraft.com. URL's
  • Service : All free informations and tools contained on the Website.
  • Comments : All text written by users on Blogs and comment pages available on the Website.
  • Media : All media available on or through the Website. One must distinguish the local media (photos, curves, drawings) and the external media (videos) which the Website refers.

    • Purpose of this site

    The purpose of this non-commercial site is purely educational. Reflecting a passion, it is also there to preserve the memory of all those who gave their lives, their health or energy in the name of freedom, aviation safety or simply our passenger comfort.

    Copyright

    Some media may have escaped the vigilance of Administrators with regard to copyrights. If a user reports copyright infringement, he will be asked to prove that he is indeed the rights's owner for the concerned media. If so, his decision on the Administrator's next action will be respected: A total suppression of the Media on the Website, or the addition of some owner's reference. The publication of a media on the internet normally having as a goal to make it visible to many people, the Administrators expect in any case that the second option will be most often chosen.

    Pursuant to the Law on copyright and related rights, the user has the right to download and reproduce information on the Website for personal use and provided that the source is mentionned. They cannot however be used for commercial or advertising purposes.

    Using Blogs and filing comments

  • Moderator : The Administrator reserves the right to prevent the publication of comments that are not directly related to the Service without providing any explanation. Similarly, all insults, out of scope or unethical material will be banned.
  • Identification : Persons wishing to post a comment or use any form of contact are required to provide identification by the means of a valid e-mail address.
  • Responsibilities : Comments are posted on the Website under the unique responsability of their authors and the Administrators may in no case be liable for any statements or claims that the users might have issued.

    • As the comment system is hosted and maintained on servers external to the Website, the Administrators may in no circumstances be held responsible for the use that administrators of these servers or other third parties may have with those comments or filed data.

    Content Liability

    The Administrators carefully check the reliability of the sources used. They cannot, however, guarantee the accuracy of any information contained on the Website, partly because of the multiple sources from which they come.

    JavaScript and cookies - Storing information

    This Website imperatively uses JavaScript and cookies to function properly. Neither of these technologies, or other means shall in no case be used on the Website for the retention or disclosure of personal information about Visitors. Exceptions to this rule will involve storing the Users banned for inappropriate comments they might have given as well as contact information for Users wishing to subscribe to future newsletters.

    When a user accesses the Website, the corresponding servers may automatically collect certain data, such as IP address, date and time of Website access, viewed pages and the type of browser used. This information is kept only for the purpose of measuring the number of visitors to the different sections of the site and make improvements.

    Donations - Advertising

    To continue providing the Service for free, the Webmaster reserves the right to insert advertising or promotional messages on any page of the Site. In the same idea, any donations will only by used to cover the running costs of the site, such as hosting, connection fees, hardware and software necessary for the development and maintenance of the Website.

    Links and other websites

    Administrators shall in no case be liable for the non-availability of websites operated by third parties to which users would access through the Website.

    Administrators assume no liability for any content, advertising, products and/or services available on such third party websites. It is reminded that those sites are governed by their own terms of use.

    Placing a link to third party sites or authorize a third party to include a link on their website refering to this Website does not mean that the Administrators recommend in any way the products or services offered by these websites.

    Modifications

    The Webmaster reserves the right to modify at any time without notification the present terms of use as well as all content or specific functionality that the Website offers.

    The modified terms and conditions immediately apply to the using Visitor when changes come online. Visitors are invited to consult the site regularly on the most current version of the terms and conditions

    Governing Law and Jurisdiction

    These general conditions are governed by Belgian law.

    In case of dispute regarding the interpretation and/or execution of the above terms, the parties agree that the courts of the district of Nivelles, Belgium shall have exclusive jurisdiction power.

    Credits page

    Wikipedia.org

    Wikipedia is a collaboratively edited, multilingual, free Internet encyclopedia.

    Youtube

    YouTube is a video-sharing website on which users can upload, view and share videos.

    Special thanks to all Youtube quality aviation vids providers, specially (Those I forgot, please excuse me or report) :

    Airboyd
    Andys Video
    Aviation videos archives
    Bomberguy
    Classic Aviation TV
    Historical Aviation Film Unit
    Horsemoney
    Jaglavaksoldier
    Joluqa Malta
    Just Planes
    Koksy
    Classic Airliners & Vintage Pop Culture
    Memorial Flight
    Octane130
    Okrajoe
    SDASM archives
    Spottydog4477
    The Aviators TV
    Valentin Izagirre Bengoetxea
    Vexed123
    VonBerlich
    Zenos Warbirds

    Bundesarchiv

    The German Federal Archives or Bundesarchiv are the National Archives of Germany.

    FAQ

    I don't see my comments any more!

    Please note that each page has it's own comment entry. So, if you enter a comment i.e. on the B-747, you will only see it on that related page.

    General comments are accessed via the "BLOG En" button.

    Comments are moderated, so please allow some delay before they appear, specially if you are outside Europe.

    Menus are developing below the page, because they are too long!

    But they remain accessible, for example by scrolling the mouse wheel, or with your finger (on the menu) on a smartphone or tablet.

    I see adds on all videos.

    Use a good free add remover software.

    The site is loading random pages at startup.

    We think it is a good way to bring back the memory of aircraft, persons or events sometimes quite forgotten.

    HELP PAGE

    Why this site?

    Discovery

    This website is dedicated to one's aeronautical passion (which I hope we share) and was realised mainly as an educationnal tool. Knowing that, you'll notice that each new visit brings random topics for the purpose of making new discoveries, some achievements or characters certainly not deserving the oblivion into which they have sometimes fallen.

    By these pages, we also want to pay tribute to all those who gave at one time or another, their lives or health in the name of freedom, aeronautical security or simply our comfort.

    Centralisation

    Internet is full of websites dedicated to aviation, but most are dedicated to subjects or periods that are very limited in space or time. The purpose of this site is to be as general as possible and thus treats all events as well as characters of all stripes and times while putting much emphasis on the most significant achievements.

    The same years saw birth of technologies like photography and cinema, thus permitting illustration of a large part of important aeronautical events from the start. Countless (and sometimes rare) media recently put online by enthousiasts finally give us access to these treasures, but the huge amount of information often makes things a little messy. A centralization effort is obviously most needed at this level.

    All persons who directly or indirectly contributed to the achievement or posting of such documents are here gratefully acknowledged.

    General

    Fluid website

    This site automatically fits the dimensions of your screen, whether you are on a desktop computer, a tablet or a smartphone.

    Bilingual website

    You can change the language by clicking on the flag in the upper left or via "Options" in the central menu. Of course, the videos remain in the language in which they were posted ...

    Browser compatibility

    The site is not optimized, or even designed to run on older browsers or those deliberately deviating from standards. You will most probably encounter display issues with Internet Explorer. In this case, it is strongly recommended installing a modern (and free!) browser that's respecting the standards, like Firefox, Opera, Chrome or Safari.

    Cookies and Javascript

    This site uses cookies and JavaScript to function properly. Please ensure that your browser is configured accordingly. Neither of these technologies, or other means shall in no case be used on the Site for the retention or disclosure of personal information about its Visitors. See the "Legal" page for more on this subject.

    Website layout

    Left menus

    Because of the lack of space on smartphones and small tablets, these menus are hidden. Everything is nevertheless accessible via the main menu option, located between the video and photo sections. This menu is placed there for compatibility reasons with some browsers, which play the videos over the menus.

    "Search" and "Latest" :
    The link "In Titles" restricts the search to the titles of different forms. Use this option if you are looking for a plane, a constructor, a pilot or a particular event that could have been treated as a subject.

    The link "In Stories" will bring you to a search in all texts (the "Story" tab) and will take more time. The search term will appear highlighted in green when opening the corresponding story.

    Would you believe, "Timeline" will show all subjects in chronological order.

    "Random" will reload the entire page with a new random topic.

    The bottom section keeps you abreast of the latest five entries. New topics are added regularly. Don't hesitate to come visit us often : add bookmark.

    Blogs and Comments central section

    Under the photos section comes the comments tabs window :

    You can enter general comments in your own language via one of the two buttons on the left (BLOG EN and BLOG FR). Note that these buttons are accessible regardless of the language to allow some participation in the other language.

    All comments are subject to moderation and will be published only if they comply with the basic rules of decorum, while remaining relevant to the purpose of this site.

    The third tab allows you to enter comments on the shown topic and is bilingual. Personal anecdotes, supplements and other information questions will take place here.

    The "Story" tab shows the explanatory texts. They are most often taken from Wikipedia, a site where we participate regularly.

    The "Data" tab is reserved for list of features and specifications.

    Right menus

    On a smartphone, the lack of space is growing and this menu is moved to the bottom of the page to give priority to videos and pictures.

    The top right icons are links to videos posted by third parties (on their own responsabilities) or by ourselves. The link below these icons will take you to the channel of the one who posted the video. Feel free to suggest other videos if you think they are of some interest (Use the BLOG button or the "Contact" link).