Xb 70 Bomber - The North American XB-70 Valkyrie was the prototype version of the B-70 nuclear-armed supersonic strategic bomber intended for the US Air Force's Strategic Air Command. -United States. Designed in the late 1950s by North American Aviation (NAA), the six-generation Valkyrie was capable of going for thousands of miles at Mach 3+ while flying at 70,000 ft. (21,000 m).
At these speeds, the B-70 was expected to be largely immune to interceptor aircraft, the only effective weapon against bomber aircraft at the time. The bomber would only briefly hover over a particular radar station, flying out of range before the controllers could put their fighters into a suitable position for interception. . Its high speed made the aircraft difficult to see radar displays and its high altitude and high speed capabilities could not be matched by a Soviet spy or contemporary fighter aircraft.
Xb 70 Bomber
The introduction of the first Soviet surface-to-air missiles in the late 1950s cast doubt on the near invulnerability of the B-70. In response, the United States Air Force (USAF) began flying its missions at low level, where the missile's radar line of sight was limited by the terrain. In this low-level artillery role, the B-70 offered little additional performance over the B-52 it was intended to replace, while being much more pronounced with a shorter range. Other missions were proposed, but they didn't have much space. With the advent of intercontinental ballistic missiles (ICBMs) in the late 1950s, manned bombers became increasingly obsolete.
North American Xb 70 Valkyrie Blueprint
The USAF eventually gave up the fight for its production and the B-70 program was canceled in 1961. The development turned into a research program to study the effects of long-range high-speed aircraft. Therefore, two prototype aircraft were built, designated XB-70A; these aircraft were used for supersonic test flights in 1964–69. In 1966, one prototype crashed after colliding with a smaller aircraft while flying in close formation; the remaining Valkyrie bomber is at the National Museum of the United States Air Force near Dayton, Ohio.
As part of Boeing's MX-2145 manned boe-glide project, Boeing partnered with the RAND Corporation in January 1954 to study what type of bomber aircraft would be needed to carry the various nuclear weapons present which was under development to give. At the time, there were several nuclear-armed ducks, and the need to carry solid fuel to fly that payload from the United States to the Soviet Union required large bombs. They also determined that after the bombs were released, the aircraft would need supersonic speed to escape the critical blast radius.
The airline industry had been studying this problem for some time. Since the mid-1940s, there has been interest in using nuclear-powered aircraft in the bomber role.
In a convection jet engine, thrust is provided by heating air with jet fuel and accelerating it through a nozzle. In a nuclear reactor, the heat is provided by a reactor, and its products last for months instead of hours. Most designs also carried a small amount of jet fuel for use during high-power moments of the aircraft, such as high-speed takeoffs and dives.
A F 104 Explodes After Colliding With A Xb 70 Valkyrie Strategic Bomber Prototype On 8 June, 1966, Near Barstow, California. The Xb 70's Left Wing And Rudders Were Destroyed And It Crashed Shortly Afterwards(all
Another possibility that was explored at the time was the use of boron-rich "zip fuels", which improve close to jet fuel by about 40 percent,
The US Air Force (USAF) closely followed these developments, and in 1955 issued Geral Operational Requirement No. 38 for a new bomber, combining the payload and intercept range of the B-52 with the high Mach 2 speed of the Convair B-58 Hustler.
Both nuclear and convectional designs have been considered. The nuclear powered bomber was organized as "Weapon System 125A" and was followed at the same time by the jet version, "Weapon System 110A".
The Boeing design was almost identical, differing mainly in having one vertical stabilizer and two of its gensets in pods at the outer ends of the inner section.
File:north American Xb 70 Valkyrie Usaf.jpg
The USAF Air Research and Development Command (ARDC) requirement for the WS-110A called for a chemically powered bomber with a cruise speed of Mach 0.9 and a "maximum possible" range of ' 1,000 nautical miles (1,200 mi; 1,900 km) trance and depart. from the target. The requirement also called for a payload of 50,000 pounds (23,000 kg) and a combat radius of 4,000 nautical miles (4,600 mi; 7,400 km).
The Air Force created similar requirements for the WS-110L interagency surveillance system in 1955, but it was canceled in 1958 due to better options.
Boeing and North American Aviation submitted proposals, and on November 8, 1955 contracts were awarded for the development of Phase 1.
Zip fuel was to be used in afterburners to improve range by 10 to 15 percent over conventional fuel.
Xb 70 Valkyrie: The Experimental Mach 3 Bomber The Air Force Said 'no' To
Both designs featured large winged fuel tanks that could be jettisoned when their fuel ran low before a supersonic run to the target. The tanks also included the outer parts of the wings, which are also removed to create a smaller wing suitable for supersonic speeds.
Both became trapezoidal wings after launch, at the time the highest performance plane known. They also featured a flush cockpit to maintain the highest productivity ratio despite the impact on visibility.
Both designs had takeoff weights of about 750,000 pounds (340,000 kg) with large fuel loads. The Air Force evaluated the designs, and in September 1956 deemed it too large and too complex to operate.
The USAF completed Phase 1 development in October 1956 and directed both contractors to continue design studies.
Xb 70 Valkyrie: Watch The World's Last Xb 70 Leave Its Hangar
While the original proposals were being investigated, advances in supersonic flight were moving rapidly. The narrow delta was establishing itself as the preferred plan for supersonic flight, replacing earlier designs such as the swept wing and trapezoidal designs on designs such as the Lockheed F-104 Starfighter and the earlier WS-110 concepts. genes able to cope with higher temperatures were also being developed, allowing sustained supersonic speeds.
This work led to an interesting discovery: when a gene was specifically optimized for high speed, it burned perhaps twice as much fuel at that speed than it did at subsonic speeds. However, the plane would fly up to four times faster. So his lowest speed, in terms of fuel per mile, was his highest speed. This was very invisible and meant that the dash concept was useless; if the aircraft can reach Mach 3, it can also fly its tire mission at that speed. The question remained whether such a concept was technologically feasible, but by March 1957, gene development and wind tunnel tests had progressed well enough to suggest that it was.
WS-110 was redesigned to fly at Mach 3 for the tire mission. Zip fuel was reserved.
Both North American and Boeing returned new designs with very long fuselages and large delta wings. They differed mainly in the form of gin; the NAA design arranged its six engines in a semi-circular duct under the rear fuselage, while the Boeing design used individual podded engines located individually on pylons under the wings,
Valkyrie: The North American Xb 70: The Usa's Ill Fated Supersonic Heavy Bomber: Amazon.co.uk: Simons, Graham M.: 9781473822856: Books
North America searched the available literature to find an additional benefit. This led them to a dark report by two NACA wind tunnel experts, who wrote a report in 1956 titled "Aircraft Configurations Developing High Lift-Weight Ratios at High Supersonic Speeds".
Known today as compression lift, the idea was to use the shock wave that came out of the nose or other sharp points on the plane as a source of high pressure air.
By carefully positioning the wing in relation to the shock, the high pressure of the shock can be trapped at the bottom of the wing and build additional lift. To get the most out of this effect, they redesigned the underside of the plane to include a large triangular area well forward of the gensets, and placed a better shock in relation to the wing. The six individually podded genes were repositioned, three in each of two separate ducts, under the fuselage.
North American improved the concept by adding a set of overhanging wing panels that were lowered at high speed. This helped to capture the shock wave under the wing between the collapsed wing tips. It also added more vertical surface to the aircraft to maintain directional stability at high speeds.
Xb 70 Valkyrie
The NAA solution had the added benefit of reducing the rear wing surface area when the panels were moved into position at high speed. This helped counteract the natural backward movement of the cter weight, or "point of average lift", with increasing speed. Under normal conditions this caused nose-down lift, which had to be compensated for by moving the control surfaces, increasing drag. When the wing tips were lowered, the lifting area of the wing was reduced, forward lift and drag reduced.
Heat build-up due to skin friction during sustained supersonic flight had to be addressed. During Mach 3 cruise, the aircraft reaches an average of 450 °F (230 °C), with the leading edges reaching 630 °F (330 °C), and up to 1,000 °F (540 °C ) in no category. NAA proposed to build their design from sandwich panels, with each panel consisting of two thin sheets of stainless steel welded to opposite surfaces to a core of honeycomb-shaped foil. Explosive titanium is only used in
Sig p365 tulster holster, sig p365 iwb holster, sig holsters p365, sig p365 sas holster, sig p365 xl holster, sig p365 hybrid holster, appendix holster sig p365, safariland holster sig p365, sig p365 belt holster, sig p365 holster, sig p365 purse holster, sig sauer p365 holster
0 Comments