The XLR11, company designation RMI 6000C4, was the first

liquid-propellant rocket A liquid-propellant rocket or liquid rocket uses a rocket engine burning liquid rocket propellant, liquid propellants. (Alternate approaches use gaseous or Solid-propellant rocket , solid propellants.) Liquids are desirable propellants because th ...

engine developed in the United States for use in aircraft. It was designed and built by Reaction Motors Inc., and used

ethyl alcohol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an alcohol, with its formula also written as , or EtOH, where Et is the pseudoelement symbol ...

and

liquid oxygen Liquid oxygen, sometimes abbreviated as LOX or LOXygen, is a clear cyan liquid form of dioxygen . It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an application which is ongoing. Physical ...

as propellants to generate a maximum

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

of . Each of the four

combustion chamber A combustion chamber is part of an internal combustion engine in which the air–fuel ratio, fuel/air mix is burned. For steam engines, the term has also been used for an extension of the Firebox (steam engine), firebox which is used to allow a mo ...

s produced of thrust. The engine was not

throttle A throttle is a mechanism by which fluid flow is managed by construction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ha ...

able but each chamber could be turned on and off individually.

Development

Development of the engine began in 1943. Reaction Motors called the engine "Black Betsy", though informally it was referred to as "The Belching Black Bastard". Its first official designation was the 6000C4, and it was later given the military designation XLR11.

Operational history

The XLR11-RM-5 engine was first used in the

Bell X-1 The Bell X-1 (Bell Model 44) is a rocket engine–powered aircraft, designated originally as the XS-1, and was a joint National Advisory Committee for Aeronautics– U.S. Army Air Forces– U.S. Air Force supersonic research project built by B ...

. On October 14, 1947, the X-1 became the first aircraft to fly faster than the

speed of sound The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elasticity (solid mechanics), elastic medium. More simply, the speed of sound is how fast vibrations travel. At , the speed of sound in a ...

(Mach 1). The XLR11-RM-5 was also used in the X-1A and X-1B, and as a booster engine in the U.S. Navy's D-558-2 Douglas Skyrocket turbojet (where it was designated the XLR8-RM-5). In 1959 and 1960, while development of a more powerful engine was still under way, a pair of XLR11-RM-13's were used as an interim power plant for the initial flights of the

X-15 The North American X-15 is a Hypersonic speed, hypersonic rocket-powered aircraft which was operated by the United States Air Force and the National Aeronautics and Space Administration (NASA) as part of the List of X-planes, X-plane series of ...

research aircraft. These engines were boosted to of thrust per chamber for a total of . In comparison, the thrust of the X-15's XLR99 engine could be varied from . After 24 powered flights, the XLR11 engines were replaced by the new XLR99 engine in November 1960. The XLR11-RM-13 was also used in the Dryden lifting bodies, and as a booster engine in the Republic XF-91 Thunderceptor turbojet.

Variants

;RMI 6000C4:Company designation of the LR11 family. ;XLR8-RM-5: ;XLR8-RM-6: (RMI A6000C4-2) ;XLR11-RM-5: ;XLR11-RM-13:

Specifications (XLR11-RM-5)

Data from:Aircraft engines of the World 1959/60

References

External links

Reaction Motors XLR11 Rocket
–

National Museum of the United States Air Force The National Museum of the United States Air Force (formerly the United States Air Force Museum) is the official museum of the United States Air Force located at Wright-Patterson Air Force Base, northeast of Dayton, Ohio. The NMUSAF is ...

Dryden Flight Research Center

X-Planes at Edwards AFB
{{DEFAULTSORT:XLR11 Aircraft rocket engines Rocket engines using alcohol propellant