XB-70 Ship Number 1 in her permanent home at the National Air and Space Museum in Dayton, Ohio.
8 June 1966, a day of horror depending on where you were sitting. Fireballs and explosions would have rained down from the heavens as an angel fell from the sky. Cast out from her domain where she knew no equals, this was the fate of one of the most monumental achievements in aviation history. Today was the day that Ship Number 2 in the Valkyrie program came crashing down after a mid-air collision with an F-104 Starfighter. Less than three years later, the project was terminated for a number of different reasons. Regardless of its cancellation, the XB-70 Valkyrie would fuel the imagination of aviation engineers and designers for decades to come. The folly would cause its creators, North American Aviation, to be absorbed into Rockwell Aviation who would go on to create one the three major bomber aircraft in the American Nuclear Triad Program and the Air Force's Global Strike Command.
Even so, the XB-70 program and its history remains relatively limited in explanation. A brainchild of the Atomic Space Age, the XB-70 lives on today only as a memory and Ship Number 1 remains an anchor in her permanent dwelling in Dayton, Ohio. So goes the known fate of the grand chief of the skies, the Valkyrie.
The YB-52 prototype in a demonstration flight.
Much like today, the U.S. Air Force (USAF) in the 1950s was focusing on the future of aeronautical warfare. After all, as technology was rapidly developing and being deployed, the military had a requirement to meet any new threats that may arise on the battlefield. However, unlike today, the Air Force was also charged with building its own pool of new resources. By 1952, the Department of the Air Force was just a fledgling at the age of five years, having been born in 1947 from the Army Air Force (USAAF). When the Air Force was established, it inherited many of the USAAF resources, such as the B-17 Flying Fortress, the B-25 Mitchell, and the B-29 Super Fortress. Each of these bombers were inherited warbirds from the days of World War II just two years earlier. The designs were tried and true, with the B-17 having the most bombing sorties of any in the Air Force. The B-29 provided coverage for the deployment of atomic weaponry in the new Atomic Space Age as well, but only so much as a modified airframe would allow. The requirement immediately was issued for the development and deployment of a bomber that was natively capable of carrying an atomic payload.
This requirement resulted in the B-36 Peacemaker that was fielded in 1948, just months after the establishment of the Air Force. The B-36 would fulfill the immediate need, but a long term solution to the nuclear problem required that of a jet powered aircraft - the way of the future. The same year that the B-36 was delivered, the Air Force tasked Boeing with the mission of designing and developing a jet bomber that would be capable of carrying a large payload at higher altitudes and higher speeds. By 1952, the Air Force had in their possession what would become the worlds longest serving aircraft: the B-52 Stratofortress. In spite of the venture, the Air Force began examining additional means of nuclear deployment methods and a variation on airframes. This included a wide assortment of aircraft modifications, such as the NB-36, the XB-46, and the YB-49.
However, by the mid to late 1950s, the imaginations and dreams of an engineer slowly began to bleed into the very fabric of reality.
The first revision of North American's submission for the WS-110 Project. Note the inclusion of canards and the use of four engines juxtaposed to the B-52's eight and the XB-70's six.
"Catch Me If You Can"
"General Operational Requirement 38" was the name of the demand that called for the need of a long range, intercontinental bomber to replace the B-52 in 1955. The Air Force had growing concerns over the vulnerabilities of its aircraft against Soviet missile technology. This worry was only amplified in May of 1960, when a Soviet missile system shot down a U-2 reconnaissance plane piloted by USAF pilot Gary Powers. The ensuing after-action review resulted in programs that would include the SR-71 Blackbird, the F-15 Eagle, and eventually both the B-1 Lancer (Bone) and the B-2 Spirit bombers. The Air Force wanted aircraft that could outrun Soviet missiles (and if it couldn't outrun them, hide from the Soviets altogether).
The Air Force had already been satisfied with the deployment of the B-58 Hustler, and interest continued to grow in aircraft capable of doubling the threshold of the "Mach." By this time, designs were beginning to be presented for mesospheric and even orbital weapons platforms, notably presented by both Boeing and Lockheed. The introduction of Intercontinental Ballistic Missiles (ICBMs) earlier had made the notion of orbital weapon systems viable. In addition, perpetual power sources were being experimented with to eliminate the need for risky in-flight refuelling. Notably, this included the experimentation with nuclear powered aircraft (such as the NB-36), and other proposed aircraft frames such as the WS-110.
However, the original WS-110 design presented by North American in 1956 was specified to fly just below Mach 1. The USAF, by the time this proposition was received, already had a long-range deep penetration bomber in the B-58, and its fighter and interceptors were all capable of anywhere from Mach 1.5 to Mach 2. Not to be outdone, the North American version of WS-110 returned to the drawing board to be presented again in 1957 - this time with a proposed top speed of around Mach 3. By 23 December, the Air Force had decided that North American would be awarded the contract over Boeing's proposal.
Artists depiction of XB-70, Ship Number 1.
Drawing of the XF-108 Rapier as originally planned in 1958.
The Struggle for Funding
At the onset of the project, the program was hit with a number of monetary cutbacks which set back the forward motion of development. By 1958, financial allocation had only been presented to complete one ship. Subsequently in 1960, an additional $265 million (~$2.3 billion 2019 dollars) was provided to the North American corporation for the construction and development of Ship 2. The justification for the new monies came in the form of the procurement of hand-me-down technology from the XB-70. Various components that were scheduled to be wrapped into the package of the Valkyrie would also be used on the proposed XF-108 - a complementary project being worked on in addition to the XB-70.
The intent, as North American Aviation had it, was to produce a full suite of aircraft for the next generation of warfare. The XF-108 borrowed more than just a few components. In the final mockup and subsequent production model of the aircraft, the airframe borrowed heavily from the Valkyrie. Much like it's parent, the XF-108 featured a delta wing design with folding wing tips. The aircraft was to be powered with two General Electric J93 turbojet engines, juxtaposed to the Valkyrie's six. With the variation in scale and size meant the two J93's could operate for the XF-108, codenamed Rapier, much in the same capacity as the six would for the Valkyrie - sporting a maximum speed of Mach 3.
However, much like it's parent, the Rapier was destined to fall short of the mark in the USAF's organization and the project was cannibalized by the North American A-5 Vigilante. Despite the failure of the project, many elements of the Rapier were carried over into the Vigilante, and development on the Valkyrie was scheduled to continue. The XB-70 had overcome it's first obstacle, survival in a Department of Defense that was seeking to cut the budget.
President Eisenhower had been a proponent to terminate the Valkyrie program, and had justified his stance on the basis that ICBM deployment was cheaper and more unpredictable. When John F. Kennedy ran for election in 1960, he did so on the platform that the XB-70 was an absolute necessity to enhance the strike capabilities of the Air Force. The USAF had walked back it's planned restriction of the XB-70 by late 1960, allocating funds for a total of twelve Valkyrie ships to be constructed (1 XB-70 testbed, and 11 YB-70 prototypes). However, Kennedy's stance on the program was built upon the foundations and perceptions of the controversial "missile gap." When Kennedy entered office and learned the true nature - or lack thereof - of the missile gap, he reduced the program to a research and development platform that would be used to experiment with higher supersonic flight. Despite a boisterous and upset Chief of Staff of the Air Force, Curtis LeMay, the Valkyrie's bomber role had effectively been canceled.
When the final funding was secured in 1962, the Valkyrie had fallen from having twelve airframes, to three, and finally resting on the two ships that were constructed.
Ship Number 1 takes to the skies at Edwards Air Force Base, California. This is the same ship that is now on display at the National Air and Space Museum. Note the steep departure angle.
Have You Ever Seen an Angel?
The XB-70, for all intents and purposes, was truly of its own age when the first testbed ship was completed in 1964. It was a large white bird that demanded the attention of those in its presence. At 30 feet tall and 185 feet long, the towering aircraft's central axis took on the form of a swan's neck. The wings spanned 105 feet and were a very radical delta-wing design with adjustable and foldable wing-tips. Just behind the cockpit, forward canards were used to increase the stability of the aircraft. Two vertical stabilizers flanked the engine cluster at the rear which featured six J93 turbojet engines, each capable of producing up to 28,000 lbs of thrust - a total of 168,000 lbs with the afterburners on. The engine air intakes jetted out entirely under the delta-wings. The loud-and-proud white color scheme was only interrupted on the nose-cone, which was painted black to aid with the issue of sunlight reflection in the pilots vision.
The Valkyrie, much like many other aircraft in this era that were capable of higher Mach speeds, deployed the use of an escape capsule over a simple ejector seat. The escape capsule allowed the pilot to safely eject entirely enclosed to protect them from the extreme forces incurred at this high speed. Unlike most aircraft today, the capsule was deployed forward and under the aircraft.
The plane was a hefty one, maintaining a lean 253,000 lb weight empty and able to carry up to 300,000 lbs of fuel. In spite of the capacity, the XB-70 was spec'd to only weigh up to 530,000 lbs on takeoff. By comparison, the aircraft the Valkyrie was originally slated to replace, the B-52, weighed 185,000 lbs empty, and had a takeoff weight of 488,000 lbs.
This article is part of an ongoing research project on the Valkyrie program. New information will be periodically updated as it is uncovered. When an update to this article is published, the article will move back to the top of the recent post list. Articles specifically related to the program may be posted in other sections, but will be included here in the comments section or in a further reading section - depending on what the content is.