While the Sr-71 Blackbird is considered to be the fastest manned plane of all time, it is actually only the fastest manned airbreathing jet plane to ever see active service. The record for the fastest flying object every flown by a human goes to the X-15, an experimental plane which reached the edge of space and set altitude and speed records. This rocket powered aircraft reached a top speed of an amazing 7274 km/h or Mach 6.7. 13 of the X-15's flights actually went into space by going over 80000 metres, and the pilots immediately became astronauts. (Above right): An X-15 in flight.
The X-15 was based on a concept for a hypersonic research plane. North American Aviation and Reaction Motors were contracted to build the fuselage and engines respectively. The plane looks like an oversized missile with thick fins at the rear to provide stability during hypersonic flight, and indeed, it was launched just like a missile. Almost all of the X-planes were dropped from the bomb bay of a modified B-52 mother ship. (Right): An X-15 after being dropped.
Early X-15 variants used two Reaction Motors XLR11 liquid propellant rocket engines, which were then replaced by a single Reaction Motors XLR99 rocket engine capable of producing a massive 57000 pounds of thrust. It used anhydrous ammonia and liquid oxygen propellant, while hydrogen peroxide was used to drive the high-speed pump that pumped the fuel to the engine. (Left): A XLR99 on the tail of an X-15.
The X-15 was more like a space aircraft than a normal plane, and used rocket thrusters to steer unlike a normal plane which manoeuvres by altering the flow of air around its wings and tail. The reason for this method of manoeuvrability was that the air at the edge of space was too thin for normal mechanisms to work. Automatic systems controlled the rocket thrusters to keep the plane steady at high altitudes, although this could be overridden by the pilot. Pilots had to wear a spacesuit-like pressurized suit with an independent oxygen supply. Ejection was possible at speeds below Mach 4. (Above left): The cockpit of an X-15.
Although the X-15 was never mass-produced, the insights it gave into flight at hypersonic speeds at the edge of space were invaluable, and were used to further develop space planes and next-generation hypersonic spacecraft.