XB-70 Valkyrie Photo Gallery
The XB-70 is one of the world's most exotic aircraft that was conceived for the Strategic Air Command in the 1950s as a high-altitude bomber that could fly threetimes the speed of sound. Due to limitations on funding, only two XB-70 aircraft were built for the advanced study of aerodynamics, propulsion, and other related subjectsof large supersonic aircraft. The XB-70 Valkyrie was mainly built of stainless-steel honeycomb sandwich panels and titanium. It was designed to make use of a phenomenonwhen the shock wave generated by the airplane flying at supersonic speeds supports part of the airplane's weight, this is called compression lift. For better stability atsupersonic speeds, the XB-70 could droop its wingtips as much as 65 degrees. The first XB-70 made its first flight on September 21, 1964, and reached a speed of Mach 3flight on October 14, 1965. The second XB-70 first flew on July 17, 1965, but on June 8, 1966, it crashed due to a mid-air collision. The first airplane continued withthe research program until flown to the United States Air Force Museum on February 4, 1969.
With research and development studies beginning in the mid 1950s, the XB-70 was a large, long-range strategic bomber that was planned to be the replacement for theB-52. As in the B-58 program, the Air Force wanted new technology advances. To this end, the Air Force gave the prime contractor total weapon system responsibility.Boeing and North American competed for the contract during the design phase. Then, in 1958, the North American design was chosen and a development contract wasawarded. The Air Force requirement for this replacement was for a Mach 3, high-altitude, long-range bomber capable of carrying nuclear and conventional weapons.Although there was a technological breakthrough in 1957 that made Mach 3 possible, the XB-70 never went into production. The continuing emergence of new SAMs was thekey factor in the demise of the XB-70 Valkyrie, just as it affected the B-47 and B-58.
The XB-70 had a length of about 196 feet, a height at the tail of about 31 feet, and an estimated maximum gross weight of 521,000 pounds. It had a crew of four, whichincluded a pilot, copilot, bombardier, and defensive systems operator. The delta wing had a span of 105 feet with six turbojet engines side by side in a large podunderneath the fuselage. A large canard fore plane near the front of the fuselage with a span of 28 feet, 10 inches was used for stability. In addition to its deltawings, the XB-70 had two large vertical stabilizers. The aircraft was fabricated using titanium and brazed stainless steel honeycomb materials to withstand theheating during the sustained high Mach number portions of flight. The propulsion system consisted of six J93-GE 3 engines with two large rectangular inlet ducts providingtwo-dimensional airflow.
The entire mission was to be flown at Mach 3, but even in the 1960s, the aircraft was vulnerable to SAMs. A high altitude, Mach 3 penetrator cannot maneuver well. Itsstraight and level trajectory would have been an easy course to plot and intercept. Further, the technology that made Mach 3 possible yielded an airframe with alarge radar cross-section that added to the effectiveness of SAMs against the XB-70.
The XB-70 design had payload flexibility but not mission flexibility. In 1959, the XB-70 concept was changed to a reconnaissance/strike aircraft, making it areconnaissance aircraft with a bomber strike capability. However, its reconnaissance capability would not have been as good as the super high altitude aircraft designedto fill the reconnaissance role, the SR-71. The XB-70 is an aircraft which met the criteria it was designed to meet, but whose mission had been eliminated by defensivethreat technology. In 1961, the XB-70 program was to be reduced to research only, citing high cost of over $700 million per prototype and vulnerability. Although twoXB-70 prototypes were built, with the first flight in 1964, the program terminated five years later in 1969.
During the early 1960s, the NASA Flight Research Center was involved in support of the national Supersonic Transport Program. These two aircraft became availablefor SST research with the cancellation of their intended military program. Aircraft serial #62-0207 with its improved wing design, was capable of sustained Mach 3flight at altitudes around 70,000 ft. An attempt to substitute the slower aircraft (serial #62-0001) into the research program met with limited success. Ship #62-0001was flown by the NASA Flight Research Center from March 1967 through early 1969. The XB-70A program produced a significant quantity of information about supersonicflight up to Mach 3 speeds. In many areas, such as noise, clear air turbulence, flight controls, aerodynamics and propulsion system performance and operation problems, itrelated to SSTs.
Contractor | North American Aviation, Inc. |
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Power Plant | Six General Electric YJ-93s of 30,000 lbs. thrust each. |
Length | 192' 2" (with boom) |
Height | 30' 9" |
Wingspan | 105' |
Max. Speed | 2,056 mph. or Mach 3.1 |
Cruising Speed | 2,000 mph. or Mach 3.0 |
Ceiling | 77,350' |
Weight | 534,700 lbs. |
Range | 4,288 miles |