(XB-70A-2 image). The bomb bay or weapons bay of the XB-70 measured about 10 meters long and had a sliding doors system designed by North American Aviation to facilitate bombing at supersonic speed. This bomb bay had capacity for 25 tons of nuclear or conventional free fall bombs, however, this space was used in both prototypes to house various test equipment. It was considered to install underwing hardpoints for launching air-to-surface missiles, but this bomber was designed to carry out attacks at high supersonic speeds, something totally unsuitable for the proper launch of missiles. Currently, the concept of “high-altitude supersonic bombing” has been replaced by “low-altitude high subsonic bombing”, which is much more accurate and effective.(XB-70A Minuteman Mating variant image). During the height of the XB-70 Valkyrie program, a good number of variants were studied for different uses of this aircraft. Proposals were studied for a supersonic cargo aircraft, a supersonic personnel transport (SST), a supersonic tanker, a reusable orbital vehicle launcher, a recoverable launch booster, an upward launcher for technology research vehicles, a high speed launch vehicle, a general purpose missile carrier (GPM) and a LGM-30 Minuteman II CBM launcher (Minuteman Mating). (XB-70A transport variant image). Of all the previous proposals, only studies began for the cargo / personnel transport variant under the heading SST or supersonic transport. In the personnel transport variant the aircraft could carry 80 passengers, expandable to maximum of 107. In addition, a medicalized variant was studied in which up to 48 stretchers with wounded people were transported. The cargo variant (C-70) with a slightly modified fuselage was also studied. In this version, a swinging nose similar to that of the C-5 Galaxy would have been installed or the possibility of installing a detachable cargo pod under the fuselage was even considered.(XB-70A-1 image). Despite the spectacular appearance of the XB-70 bomber, the plane was stillborn, since in addition to fighting against the supporters of ICBM missiles and the very high costs, it was later discovered that it was fighting against a secret rival. This rival was the Lockheed YF-12 aircraft, developed in total secrecy, and which had the same features, but which flew 2 years earlier. This circumstance was the final straw for the B-70 program and even led to the Secretary of Defense at that time, Robert McNamara, refusing to allocate the funds already approved by Congress to keep the B-70 program alive.(XB-70A-1 image). On September 21, 1964, XB-710A-1 headed toward one of the runways at Edwards Air Force Base (AFB), California. Three years later than planned, and almost 10 years after starting its program, the Valkyrie took flight. At the controls were North American’s chief engineering test pilot Alvin S. (Al) White and USAF project pilot Colonel Joseph F. Cotton. The planned 1 hour 45 minute flight that was to end with a pass at Mach 1 at 11,700 meters had to be changed for another secondary flight test plan at low speed. During this flight, engine number 3 had to be shut down due to turbine overspeed, but the flight continued for 67 minutes with only 5 engines. During landing, two of the rear wheels of the left main landing gear locked and blew, leaving a trail of sparks and smoke. Unfortunately, it wasn’t a great start for the Valkyrie.Although the maiden flight did not go as brilliantly as everyone expected, the pilots commented that the aircraft went well in flight and that despite the bursting of the two wheels of the landing gear, they never lost control of the aircraft. The second test flight was not much better than the first since the landing gear had to be deployed in emergency conditions using the electrical auxiliary system and the Valkyrie ended up landing on the lakebed with only two braking parachutes open instead of the corresponding three. Anecdotally, it should be said that after this second flight North American Aviation had to pay a contract penalty to the USAF of 125,000 dollars for not meeting the objective of reaching Mach 1.(XB-70A-1 image). Finally, during the third test flight, Mach 1 (1,225 km/h) was reached at 10,760 meters of altitude, and this speed was maintained for 15 minutes, reaching a maximum speed of Mach 1.11 (1,359 km/h). The fourth test flight completed the first phase of testing, reaching the XB-70A-1 Mach 1.42 (1,739 km/h) at 14,075 meters altitude. After this flight the plane spent 4 months performing structural stress tests. During the eighth test flight, Mach 2.14 (2,621 km/h) was reached at 17,000 meters altitude and during test flight 14, Mach 2.85 (3,491 km/h) was reached at 20,670 meters, it seemed that Valkyrie was beginning to demonstrate its excellent capabilities.(XB-70A-2 image). On July 17, 1965 the second prototype, XB-70A-2 joined the test program. This aircraft had some improvements incorporated such as greater fuel capacity, computerized AICS system, small modification to the wings and installation of instrumentation to collect data for the future SST supersonic transport aircraft. On October 14, 1965 during the 17th test flight, the XB-70A-1 reached Mach 3.02 (3,699 km/h) at 21,280 meters (70,000 feet) altitude. On January 3, 1966, also during its 17th test flight, it was the XB-70A-2 aircraft that it reached Mach 3.05 (3,736 km/h) at 21,888 meters altitude and on May 19, 1966 this aircraft maintained a speed of Mach 3 for 32 minutes, crossing eight states in this time. During this flight, the highest speed ever achieved by the XB-70 was reached, Mach 3.08 (3,773 km/h) at 22,040 meters (72,500 feet).(XB-70A-2 image). During the test program, it was decided that the XB-70A-1 would not exceed Mach 2.5 speed due to the problems detected with fuel leaks, tearing of parts of the external skin during flight and problems with the internal hydraulic fluid. Therefore, the XB-70A-2 remained as the main aircraft to develop the entire XB-70 program. In this period the test flights were developing normally after somewhat problematic first phase, but unfortunately this soon changed. On June 8, 1966, flight number 46 of the XB-70A-2 had been scheduled, which in turn made flight number 95 of the B-70 program. On this occasion, a series of subsonic calibration test flights and a single supersonic flight would be carried out. Afterwards, a photo session would be held with other jet aircraft equipped with GE engines. General Electric had organized this event to celebrate having obtained USAF approval for the B-70 Flight Test Operations a few days earlier. The formation would be completed with a McDonnell Douglas F-4B Phantom II, a Northrop T-38 Talon, a Northrop F-5A, and a Lockheed F-104N belonging to NASA. In addition, a Gates Lear Jet loaded with photographers and a Lockheed F-104D loaded with an USAF photographer were in charge of taking the photos and recorded the event at a certain distance.(XB-70A-2 image). The aircraft was piloted by Al White, who was going to make his 49th flight in the XB-70, and with him, a new co-pilot, USAF Major Carl S. Cross, who was making his first flight within the test program. After successfully completing the daily tasks, it was time for the photo session and at 8:43 a.m. a V-formation was formed with the 5 aircraft, with the XB-70 leading it. To its right was the F-104N, and to the right of it the F-5. To the left of the XB-70 was the F-4B and to the right of it the T-38. The formation ascended to 25,000 feet (8,200 meters) and at 8:45 the cameras went into action. The session lasted until 9:25 a.m. , and at 9:26, suddenly… disaster struck.(XB-70A-2 image). At 9:26 the radios began to desperately broadcast: “Mid-air, Mid-air!”, announcing that an explosion had occurred in the air. Suddenly, the F-104N rammed the XB-70, crashing the tail of the fighter into the right wingtip of the bomber. This caused the F-104N to turn upside down and roll to its left, passing over the XB-70, destroying its vertical fins. It then hit the left wing of the XB-70 and ended up exploding in the air. In less than 3 seconds the F-104N was destroyed, causing the death of its pilot. However, the XB-70A-2 continued flying without realizing its damage for 16 more seconds, after which the plane turned on its back, went nose down and then made a violent turn due to the lack of its vertical fins. At this point, the fate of the XB-70A-2 was sealed.(XB-70A-2 image). It seems that the pilots of the XB-70A-2 heard the explosion in the air, but did not know which aircraft had exploded or that their own plane had been seriously damaged despite some radio warnings from other pilots in the formation indicating that they had lost their “tails” (vertical fins) and would probably start to spin. Al White managed to survive by activating his escape capsule and ended up falling about 15 km from where the Valkyrie crashed, but suffered serious injuries due to the impact of the capsule against the ground. Unfortunately, the co-pilot, Major Carl S. Cross, was unable to activate his capsule and died in the accident. After the horrific accident that caused the loss of two lives and two aircrafts, Congress initiated two investigative commissions. The fact that the accident had occurred during a photo session organized by a private company (General Electric) was not liked at all and some heads rolled. The blame fell on three USAF colonels and a civilian who did not inform higher authorities or prevent this event.(XB-70A-1 image). At the beginning of 1966, NASA wanted to join the XB-70 flight research program, for which it contributed 50 million dollars in test equipment that was installed in the fuselage and bomb bay of the XB-70A-2. The joint USAF/NASA research flight program would last 18 months and was to begin in June 1966, but the unfortunate accident of the XB-70A-2 ruined everything and finally only NASA remained interested in continuing with the research flights. Since all the equipment was lost in the XB-70A-2 accident, a new batch was installed in the XB-70A-1 and an improved emergency capsule system and the computerized AICS system were also installed.(XB-70A-1 image). On November 1, 1966, the XB-70A-1 was ready to begin the series of NASA research flights, initially dedicated to the study of controlled sonic booms and various maneuvers carried out with a view to the development of the future supersonic SST. transportation The first 11 flights of this phase remained a joint USAF/NASA program, but NASA was subsequently left in sole charge. The first flight carried out exclusively by NASA took place on April 25, 1967 and subsequently 22 more flights were made. The last one took place on February 4, 1969 when the XB-70A-1 took off from Edwards AFB, California bound for Wright-Patterson AFB, Ohio, where the Valkyrie would be part of the Air Force Museum. This 3 hour 18 minutes trip was also the last of this impressive aircraft.(XB-70A-1 image). Despite the efforts and hopes placed in both the “B-70” program and the “SST” program, both projects were finally canceled due to their difficulty and extreme cost. The two XB-70 Valkyrie performed a total of 129 test flights, 83 for the XB-70A-1 and 46 for the XB-70A-2 in which they flew for 252 hours and 38 minutes. Of this amount, 145 hours 28 minutes were subsonic (- Mach 1), 55 hours 50 minutes supersonic (+ Mach 1), 49 hours 32 minutes doublesonic (+ Mach 2) and 1 hour 48 minutes triplesonic (+ Mach 3). The total cost of the B-70 (XB-70) program was 1.5 billion dollars, so each of the 129 flights cost an average of 11.6 million dollars at the time.(XB-70A-1 image). Since its retirement in February 1969, the XB-70A-1 Valkyrie rests and can be seen at the Air Force Museum located in Ohio. This beautiful aircraft has been known as “Pterodactyl” for its folding wingtips, “The Thing” for its enormous size, “Cecil” for its resemblance to a TV character, “The Great White Bird” for its beauty and Valkyrie for its enormous destructive capacity within such a beautiful form. There will be those who simply call it “bluff” or “disappointment”, and do not understand the enormous amount of effort and money wasted on it. The B-70 project cannot really be judged with the perspective of the 21st century, but rather with that of being in the middle of the Cold War, with a real fear that an attack by the Soviet Union could be unleashed at any moment. Perhaps this aircraft wanted to represent the hope that a weapon of these characteristics could make them think twice before starting it, only in this way can the construction of this beautiful bomber be understood.
