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Cancelled U.S. Aircraft Programs

A look at what might have been

Aviation is one of the most competitive industries in history. Competitive fly-offs – head-to-head battles like that of the recent Joint Strike Fighter – have been used to determine which aircraft is best. All too often, the winners in these competitions were only marginally better (if at all) than the “losers,” who never gained a place in history. There were also aircraft that were passed over in decisions made on requests for proposals or unsolicited proposals. Like Canada’s CF-105 Arrow or the British TSR 2, some cancelled U.S. aircraft programs still arouse strong feelings among those serving at the time as well as those who worked in the aerospace industry. Sometimes projects were cancelled despite showing great promise. All of these make it interesting to look back on history and see “What Might Have Been.”

All too often, the winners in these competitions were only marginally better (if at all) than the “losers,” who never gained a place in history.

 

North American F-107A Ultra Sabre

Vivid images of the U.S. Air Force Republic F-105 flying missions during the Vietnam War have solidified the “Thud” forever in the annals of history. However, there could easily have been a different aircraft operating in its place. The North American Aviation (NAA) YF-107 competed against the existing F-105B for an Air Force nuclear-capable, Mach 2 fighter/bomber. During August 1954, NAA was awarded a contract for nine YF-107 flight test vehicles and one static test airframe. However, in January 1957 this was reduced to three aircraft.

A North American F-107A in flight. U.S. Air Force photo

A North American F-107A in flight. U.S. Air Force photo

During the YF-107’s first flight on Sept. 10, 1956 Mach 1.03 was achieved, and on Nov. 3, 1956, Mach 2 was added to the log. To accommodate the XMA-12 integrated fire control system, the 107’s unique intake was located above and behind the cockpit. In early 1957, zoom climb tests reached an altitude of 69,000 ft., achieved with a pull-up at Mach 2.1, and climbing vertically above Mach 1. However, there would be no publicity for the F-107’s feat, since the Lockheed F-104 was concurrently performing speed and zoom climb flights in pursuit of new “official” records. By early 1957 the performance of the F-107 seemed to give it a chance at production.

The Air Force terminated the NAA F-107 contract in March 1957, but the prototypes continued test flying under the auspices of NACA (now NASA) until August 1959.

The Republic F-105 incorporated an internal bomb bay. In contrast NAA designed a semi-recessed area in the 107’s lower fuselage that fit a wide variety of external stores. Ironically, after the F-105 won the competition that “all important” bomb bay would be used mainly to carry internal fuel. The Air Force terminated the NAA F-107 contract in March 1957, but the prototypes continued test flying under the auspices of NACA (now NASA) until August 1959. If things had worked out differently, the F-107 might have done great work in Vietnam.

 

North American F-108 Rapier

XF-108 Rapier

Rendering of a notional U.S. Air Force F-108A interceptor. The big North American Aviation aircraft was intended to intercept Soviet bombers at long range. Artists conception by Erik Simonsen

Capitalizing on know-how acquired from the canceled F-107, NAA was awarded a contract on June 1, 1957, for what was known as Weapon Systems 202A. On Jan. 20, 1959, a full-scale mockup of the F-108, named Rapier in May 1959, was presented to the Air Force. NAA considered the F-108 long-range interceptor a major technological leap. Operating at Mach 3 and 75,000 feet throughout the 1960s and 70s, the Rapier would have provided U.S. air defenses outstanding dash speed, look-down-shoot-down capability, and the range to keep potential nuclear-armed adversaries well away from our borders. However, budgets favored ICBM development, for in 1959 no one foresaw that the Soviet Union would eventually develop supersonic bombers.

NAA’s fighter legacy came to an end with a Sept. 23, 1959, statement from the Air Force announcing that the F-108 was being canceled.

NAA’s fighter legacy came to an end with a Sept. 23, 1959, statement from the Air Force announcing that the F-108 was being canceled. The cancellation had an adverse impact on the NAA XB-70, because the F-108 was no longer able to share the cost of their common technologies. No Rapiers would be built, but its advanced AN/ASG-18 radar system would move on to the Lockheed YF-12A.

 

North American XB-70 Valkyrie

XB-70A Valkyrie

A North American XB-70A Valkyrie in flight with wingtips in 25 percent (transitional) drooped position. U.S. Air Force photo

The legendary XB-70 was a bomber that would cruise at Mach 3-plus at 75,000 ft. – powerful performance for the 1960s. The dream began back on Dec. 23, 1956, with a $360 million development contract award to NAA to begin work on three prototypes. Powered by six General Electric YJ-93-GE-3 engines, the 500,000 pound bomber rode on its own shock wave, a widely acclaimed aerodynamic advance. However, as former president of NAA Lee Atwood quipped over four decades later, “compression lift was definitely a factor, but overplayed by so-called experts. It was the variable-geometry-inlet designed that provided Mach 3-plus cruise.” NAA as usual, was ahead of its time.

Unfortunately, in April 1961, only three months after the Kennedy Administration took office, newly appointed Secretary of Defense Robert McNamara ordered that the three prototypes would be used for research only, and the XB-70 would not be carried forward as a full-scale weapon system. Despite the repeated promises before Congress that the three airframes would be built, he cut plans for the third XB-70.

McNamara also took exception to the XB-70’s not being compatible with the Skybolt and Hound Dog air-to-ground missiles – weapons that had been designed for the subsonic B-52 and not a new-generation Mach 3 bomber.

McNamara’s testimony before the Senate Armed Services Committee in early 1962 indicated that he did not understand how a B-70 would perform. In operation, the B-70 would have been equipped for a quick scramble, operate well on airborne alert well below Mach 3 to save fuel, and would conduct air-to-air refueling just as the B-47 and B-52 did.

McNamara also took exception to the XB-70’s not being compatible with the Skybolt and Hound Dog air-to-ground missiles – weapons that had been designed for the subsonic B-52 and not a new-generation Mach 3 bomber.

XB-70A Valkyrie

A North American XB-70A Valkyrie just after collision. Note the F-104 is at the forward edge of the fireball and most of both XB-70A vertical stabilizers are gone. U.S. Air Force photo

The program continued with two aircraft. The first XB-70 flew on Sept. 21, 1964, followed by number two on July 23, 1965. DoD budget cuts forced changes that severely limited NAA’s original test plans. When XB-70 number two was lost in a midair accident on June 8, 1966, the program was in trouble. The remaining aircraft flew 22 research missions for NASA before retiring on Feb. 4, 1969. A great chance for future research was lost when the XB-70 program was canceled.

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