Flying at 70,000 feet above the world at three times the speed of sound floats the future of combat – so much so that the US air force called it the last manned bomber.Its platform was so versatile that the military planned a range of future versions, from supersonic refueling, medical evac to even passengers!But this 1950s miracle plane would never enter production, and the what if only remains on paper. This is the lost future we never had, the legendary XB-70 Valkyrie Super Bomber.The XB-70 Valkyrie was an experimental high-speed, delta-wing aircraft that was developed by the North American Aviation, or NAA, Los Angeles Division of the United States Air Force. The XB-70 was a plane full of amazing features but its two most-distinguishing features were these: Firstly, it was designed to fly at three times the speed of sound, which meant attaining Mach 3 speed. Secondly, it was designed to fly at an altitude higher than 70,000 feet, which is approximately 21,000 kilometers. It was to be a very, very fast plane that could fly very, very high.The Air Force had first dreamt up the concept for the XB-70 in 1954, with the contract for its Air Force Weapon System 110A competition being between two American aircraft manufacturers: Boeing and NAA. It was the NAA proposal that was awarded the contract on December 23rd, 1957. The intent was for the XB-70 to be a very large, very fast strategic bomber meant to replace the legendary and hugely successful Boeing fighter bomber, the B-52. The new super bomber would need to be capable of carrying nuclear and conventional weapons. Interestingly, a key aspect of the Air Force contract was that NAA as the prime contractor would have total responsibility over weapon systems as well. This Valkyrie would have a crew of four, namely a pilot, co-pilot, bombardier and defensive systems operator. The XB-70 was 196 feet or 59,7 metres in length and its tail stood at a height of 31 feet or 9.4 metres. The plane would weigh in at an estimated maximum gross weight of 521,000 pounds or 235,868 kilograms. The delta wing spanned an impressive 105 feet or 32 metres, with the wing swept at just over 65 degrees. The plane also had two large vertical tails.Its engines could push the plane to a decent range of 4,288 miles or 6,900 kilometres, which, although not a huge range, would still be considerable given the incredible cruising speed the plane could attain. Its service ceiling was especially attractive – an incredibly high altitude of 77,350 feet or 23,576 metres, which equated to 14.64 miles or 23.57 kilometres up in the air.Also noteworthy and downright impressive were the plane’s braking gears, which weighed more than 6 tons in total. Each main gear had four wheels, whilst the nose gear had two wheels. To give an idea of just how much aircraft had to be stopped by the braking system, consider this: a single stop for the XB-70 Valkyrie would absorb kinetic energy equivalent to that needed to suddenly stop 800 medium-sized cars travelling at a speed of about 100 miles or 161 kilometres per hour.The XB-70 was full of new and experimental technologies. These included an exotic new type of boron-based fuel, known colloquially as zip fuel. It was more energy-dense than gasoline or jet fuel and its advantage, so the thinking at the time went, was that it would offer jets greater range and speed advantages. Six General Electric J93-GE 3 turbojet engines that produced a massive 28,000 pounds of thrust each would be needed to burn this special fuel and attain such blistering speed. Each of the engines would also have an afterburner, with the six engines located side by side in a large pod underneath the fuselage. There would also be two large rectangular inlet ducts that provided two-dimensional airflow and thus improved aerodynamic efficiencies for the XB-70.The plane would also feature what’s been dubbed a retractable “wind screen” for when the plane attained Mach 3 flight. This movable screen was comprised of a wind shield and ramp that would be raised during supersonic flight in order to reduce drag. The assembly would be lowered once the plane needed to land so that both the pilot and co-pilot would have a clear view of the runway. In effect, the B-70 was designed to “ride” its own shock wave, akin to how a surfer rides an ocean wave. That’s quite a ride!There were such hopes for this super-fast super bomber that many different variations regarding its potential were proposed for the XB-70 Valkyrie and they’re worth looking into.