Military Factory logo

Boeing X-51 (Waverider)

United States (2010)
Picture of Boeing X-51 (Waverider) Scramjet Technology Demonstrator

The Boeing X-51 Waverider product is a pioneering effort in the realm of SCRAMJET engines.


Detailing the development and operational history of the Boeing X-51 (Waverider) Scramjet Technology Demonstrator.  Entry last updated on 4/25/2016. Authored by Staff Writer. Content ©www.MilitaryFactory.com

The Boeing X-51 "Waverider" is an unmanned technology demonstrator designed to further develop the concept of shockwave-assisted, high-speed flight by way of an internal scramjet engine. The product was born from the 1990s-era Scramjet Engine Demonstrator program in which the SJX61 hydrocarbon-fueled engine was originally developed for the X-43, a NASA-sponsored unmanned hypersonic technology demonstrator (the "Hyper-X" program). While the X-43 eventually fell to naught, the research was later rolled into the Boeing X-51. Following a steady stream of ground tests beginning in 2006, the X-51 prototype recorded its first flight on May 26th, 2010 to which the test vehicle reached speeds of 4,000 miles per hour (Mach 6) when launched from a Boeing B-51 Stratofortress mothership. As of this writing (2013), the X-51 has been produced in four development examples.

A scramjet engine ("Supersonic Combustion RAMJET") - a concept initially developed in the technology evolution of the 1950s - makes use of incoming air (via an air intake) through extremely high-speed flight, the air being slowed prior to combustion . An inlet body manages the supersonic compression to which fuel is then injected during the combustion process and a nozzle manages the outgoing supersonic exhaust, therefore producing the required thrust. A scramjet, therefore, is related to a "ramjet" in its general approach though, in a ramjet engine, combustion occurs in subsonic airflow as oppose to supersonic. A scramjet can provide speeds rated in Mach values - even as high as Mach 12 - and is a future alternative to the conventionally-powered turbofan engines in wide-scale use today. One of the key limitations of modern scramjet technology is the lack of low-altitude, low-powered capabilities which require the airframe to be airlifted though use of a "host" / "mother" ship for its launching. From there, the scramjet must also be first brought to speed by way of a rocket booster.

The X-51's scramjet powerplant makes use of the same fuel as in the Lockheed SR-71 Blackbird, designated in the USAF inventory as "JP-7". The X-51 is hauled into the air by the host ship (B-52) and then air-launched. The X-51 initially utilizes the power of a modified Lockheed Martin MGM-140 ATacMS (Army Tactical Missile System) solid rocket booster to help clear the host ship and reach initial speeds (approximately Mach 4.5). Once the booster system is spent, the assembly is jettisoned, allowing the Pratt & Whitney Rocketdyne SJY61 scramjet to take over in helping the airframe reach speeds nearing Mach 6. The aerodynamic principles involved in the X-51 fuselage design then react to the naturally-occurring shockwaves to add required lift (hence the nickname of "Waverider"). The fuselage consists of a well-sloped nose cone assembly, streamlined nearly-rectangular fuselage and short stubby wings about the design. An air intake is identified under the fuselage with the scramjet exhausting through the rear of the design in a conventional fashion. In essence, the X-51's configuration is similar to that of a streamlined cruise missile ala the "Tomahawk". Despite its unmanned design, the X-51's project data may very well be applied to all manner of future aircraft still to come - such as a scramjet-powered civilian airliner.

The X-51 sports a running length of 25 feet with an empty weight of 4,000lbs. Its presented operational range is 460 miles with a service ceiling of 70,000 feet.

As of 2013, the X-51 is still in active testing.

Any available statistics for the Boeing X-51 (Waverider) Scramjet Technology Demonstrator are showcased in the areas immediately below. Categories include basic specifications covering country-of-origin, operational status, manufacture(s) and total quantitative production. Other qualities showcased are related to structural values (namely dimensions), installed power and standard day performance figures, installed or proposed armament and mission equipment (if any), global users (from A-to-Z) and series model variants (if any).






Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.

Image of collection of graph types

Relative Maximum Speed Rating
Hi: 5000mph
Lo: 2500mph
    This entry's maximum listed speed (3,604mph).

    Graph average of 3750 miles-per-hour.
City-to-City Ranges
NYC
 
  LON
LON
 
  PAR
PAR
 
  BER
BER
 
  MOS
MOS
 
  TOK
TOK
 
  SYD
SYD
 
  LAX
LAX
 
  NYC
Graph showcases the Boeing X-51A (Waverider)'s operational range (on internal fuel) when compared to distances between major cities.
Aviation Era
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
4
4


  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.


Altitude Visualization
Small airplane graphic
  Compare this entry against other aircraft using our Comparison Tool  
National Flag Graphic
Origin: United States
Year: 2010
Type: Scramjet Technology Demonstrator
Manufacturer(s): Boeing - USA
Production: 4
Global Operators:
United States
Historical Commitments / Honors:

Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.
Measurements and Weights icon
Structural - Crew, Dimensions, and Weights:
Unless otherwise noted the presented statistics below pertain to the Boeing X-51A (Waverider) model. Common measurements, and their respective conversions, are shown when possible.

Operational
CREW


Personnel
0


Dimension
LENGTH


Feet
25.00 ft


Meters
7.62 m


Weight
EMPTY


Pounds
3,968 lb


Kilograms
1,800 kg

Engine icon
Installed Power - Standard Day Performance:
1 x Pratt & Whitney SJX61 hydrocarbon fuel scramjet engine.

Performance
SPEED


Miles-per-Hour
3,604 mph


Kilometers-per-Hour
5,800 kph


Knots
3,132 kts


Performance
RANGE


Miles
460 mi


Kilometers
740 km


Nautical Miles
400 nm


Performance
CEILING


Feet
69,882 ft


Meters
21,300 m


Miles
13.24 mi

Armament - Hardpoints (0):

None.
Variants: Series Model Variants
• X-51 - Base Series Designation
• X-51A - Initial Demonstration vehicle; 4 examples produced.