The surviving prototype is now part of an exhibition at the National Museum of USAF (National Aviation Museum USA), in Dayton, Ohio. It stands in one of the hangars, along with many other experimental structures from the Cold War period. In early November, as part of the reorganization of the exhibition, the large bomber was briefly rolled outside, which was an opportunity to make a number of photos and recordings.
Although more than half a century has passed since the last flight of the XB-70 Valkyrie (X is the designation for experimental), the aircraft is still impressive. The giant machine still looks futuristic and remains one of those that invariably evokes great emotions among aviation enthusiasts. Despite the passage of time. The exceptional fame of the XB-70 is the result of the combination of a unique appearance, still impressive performance and a confusing and tragic story.
Ambitious but unsuccessful plans
The plane, rolled from a hangar in Ohio, is similar to the much better known passenger Concorde, or its lesser known Soviet counterpart Tu-144 (which I described earlier). It also has a lot to do with even less known Soviet counterpart, the T-4. The resemblance to these three machines is the result of the immutable laws of physics. Simply put, they are / were all large jet airplanes designed to develop great speeds at high altitudes. Such a requirement imposed specific solutions on their designers: an elongated, thin fuselage, large delta wings and massive engines located at the bottom of the machine.
The XB-70 was the most extreme of the above-mentioned designs. And the greatest. It was assumed to develop and maintain three times the speed of sound, that is over three thousand km / h. In addition, fly very high, at an altitude of 21-23 kilometers (passenger planes currently fly about 10 km). All this is supplemented with an intercontinental range, which meant the ability to fly up to 16,000 kilometers without additional refueling. And the ability to take several tons of nuclear bombs. Although the expectations were great, it turned out later, during test flights, that most of them were met.
Work on the XB-70 began in the mid-1950s, when the main defense against Soviet fighters was seen at altitude and flight speed. The big bomber was just supposed to leave them behind and down, going towards its target. However, even before the first prototype was built, it turned out that in the USSR it was possible to create anti-aircraft missiles with very good performance surprisingly quickly. Height and speed no longer afford immunity. Additionally, intercontinental ballistic missiles appeared, which were not only incomparably more difficult to shoot down, but also cheaper. As a result, strategic bombers lost their importance significantly. Dark clouds have gathered over the XB-70 program.
In 1959, the military themselves concluded that the bomber had become redundant. The program was about to close. But politics has entered the game. Both civil and military. The XB-70 had a great believer in the form of the highly influential longtime U.S. Strategic Aviation Commander, General Curtis LeMay. He was also briefly supported by John F. Kennedy when he tried to be elected the president and played the arms fan card. However, when he sat in the White House and the problem with the XB-70 was explained to him, he also began to insist on closing the program. Ultimately, both sides were reconciled. In 1961, it was agreed that three planes (eventually two) would be built, not as prototypes of bombers, but as experimental planes. Their task was to develop technology in the field of large aircraft flying at high supersonic speeds. Mainly for the planned American supersonic passenger plane, which was to be built as part of the great SST program, supported by order.
Expensive research program with a tragic accident
The first prototype was completed by North American Aviation in May 1964. During his first flights, a number of shortcomings came to light. For example, when flying at high speed, the machine had a problem with stability and parts of the skin fell off it. The XB-70’s fuselage was mostly made of steel, not aviation standard aluminum. Steel can withstand high temperatures much better, and the machine’s fuselage, during flight at a speed of 3000 km / h, heated up to several hundred degrees C. However, it is much heavier than aluminum, so in order to maintain the appropriate proportions of strength and weight, it was formed into honeycomb structure. It was a new technology that had to be learned.
After a series of modifications, the second prototype was completed six months later. And it turned out that it meets most of the requirements initially set in the 1950s. He developed a speed of 3250 km / h, held it for over half an hour and climbed 23 kilometers. Both planes provided a lot of valuable information for engineers working on other machines flying at high speeds. However, it was hardly an effective research program. The development and construction of both machines cost the American taxpayer about ten billion modern dollars. Five billion a copy.
In 1966 there was a disaster. At the request of General Electric, with the support of friendly USAF officers, a semi-official flight photo shoot was organized with the participation of the second XB-70 prototype and four other smaller aircraft. They were all powered by GE engines. The session turned out very well and a number of beautiful photos were taken. Unfortunately, a moment later, one of the smaller aircraft, the F-104 fighter flying at the tip of the right wing of the XB-70, was sucked in by a powerful vortex caused by them. At that time, this phenomenon had not yet been well researched and the danger was not realized. The F-104 pilot couldn’t do anything when his machine turned upside down, cut down one XB-70 tailplane and crashed into its back. He died instantly. The crippled bomber flew straight ahead for a moment, then fell into a spin and fell to the ground, killing one of its pilots. The second catapulted and survived despite serious injuries. The whole tragic event was recorded by photographers who were just taking a photo session for the planes.
The second prototype flew until 1969. In recent years, in the colors of NASA. Both machines made a total of 129 research flights. While many new technologies were developed and a great deal of valuable information was obtained, they ultimately turned out to be impressive but dead ends in the history of aviation development. Two years after the last XB-70 flight, the SST program was also canceled, the intricate history of which is another subject for text.
In the 1970s, attempts were made to revive the concept of a high-speed bomber in the form of the B-1A. During the work on this machine, the knowledge from the XB-70 program was used. However, the latter approach also ended in a flop. Only after serious changes, the B-1, marked with the letter B, went into production and are still flying today. However, they are not among those American planes that can be described as successful.
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