X-51 Waverider – the US Air Force Hypersonic Jet

X-51 Waverider program

The U.S. Air Force Research Laboratory came together with the Defense Advanced Research Projects Agency (DARPA), Pratt & Whitney Rocketdyne and Boeing to build an aircraft with extraordinary hypersonic flight capability. The X-51 WaveRider consortium is focused on developing a free-flying vehicle that is able to fly longer at hypersonic speeds than all of it predecessors combined. Hypersonic speed means over Mach 5 (five times the speed of sound). If you would like to read more about the fastest flying vehicles click here.
The X-51A Waverider is an unmanned flight test demonstrator for a scalable, robust endothermic hydrocarbon-fueled scramjet propulsion system, high temperature materials, airframe/engine integration and additional key technologies. It is intended to reach the hypersonic speeds range from Mach 4.5 to 6.5. It is called “WaveRider” as it uses its shockwaves to add lift.
Here is a short video about X-51 Waverider. Have you ever thought it could be possible to fly from London to New York in an hour?


How does the X-51 Waverider reach hypersonic speed?

X-51A WaveriderDuring flight demonstrations, the X-51Waverider is carried under the wing of a mothership B-52 to an altitude of about 50,000 feet (15.2 km) and then launched over the Pacific Ocean. The aircraft is propelled by an MGM-140 ATACMS solid rocket booster to about Mach 4.5 at first. And then the booster jettisoned and the vehicle’s Pratt & Whitney Rocketdyne SJY61 scramjet accelerates it to reach a flight speed of Mach 6. The X-51 Waverider uses JP-7 fuel for the SJY61 scramjet, carrying approximately 270 lb (120 kg) onboard.

General Characteristics:

  • Crew: None
  • Length: Full stack 25 feet; Cruiser 14 feet; Interstage 5 feet; Solid rocket booster 6 feet
  • Power Plant: JP-7 fueled/cooled SJY61 supersonic combustion ramjet
  • Weight: Approx. 4,000 pounds (1814 kg)
  • Fuel Capacity: Approx. 270 pounds JP-7
  • Speed: 3,600+ miles per hour (Mach 6)
  • Range: 400+ nautical miles (740 km)
  • Ceiling: 70,000 + feet (21,300 m)

Although hypersonic flights are possible nowadays, the average person cannot experience such a flight. However, another supersonic jet offers a great “speed ride”. It is possible with MiG-29 in Russia. Actually the last option for a commercial supersonic flight.

Waverider’s flight trials

X-51A Waverider under the wing of a B-52The X-51 Waverider hypersonic aircraft failed during the test over the Pacific Ocean in the late morning of August 14th, 2012. The aircraft was supposed to exceed 6 times the speed of sound but seconds into the test “a fault was identified with one of the cruiser control fins” – as Air Force officials stated.
The X-51 Waverider was successfully launched by a mothership B-52 Bomber. The rocket booster was fired as intended. But faulty control fin prevented testers to be in command of the aircraft which was lost after 15 seconds, even before its scramjet engine was lighted. The machine disintegrated and the remains crashed into an area of the Pacific Ocean north-west of Los Angeles at Point Mugu. And although all the conditions for the scramjet engine ignition were met the test unfortunately failed. Air Force program officials will work towards determining the exact cause and all factors at play. And since there is only one X-51 Waverider left it hasn’t been decided yet whether the final model of the jet will fly.
Hypersonic technologies were tested by the Pentagon in anticipation of reaching any place on the globe within minutes. The X-51 Waverider had its first experimental flight on 26 May 2010. It was largely successful when the aircraft reached a velocity of five times the speed of the sound (Mach 5 at an altitude of 70,000 feet or 21 km) for over 200 seconds (the flight of 300 seconds was actually planned). The flight had the longest scramjet burn time of 140 seconds. During the second flight trial last year the Waverider fell into the sea as it encountered a problem with the rocket booster not separating from the main craft.

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