LR-87
Encyclopedia
The LR-87 was a liquid-propellent rocket engine
Rocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...

, which was used to propel the first stages of Titan
Titan (rocket family)
Titan was a family of U.S. expendable rockets used between 1959 and 2005. A total of 368 rockets of this family were launched, including all the Project Gemini manned flights of the mid-1960s...

 intercontinental ballistic missile
Intercontinental ballistic missile
An intercontinental ballistic missile is a ballistic missile with a long range typically designed for nuclear weapons delivery...

s and launch vehicles
Titan (rocket family)
Titan was a family of U.S. expendable rockets used between 1959 and 2005. A total of 368 rockets of this family were launched, including all the Project Gemini manned flights of the mid-1960s...

. Though this powerful engine used two discrete combustion chambers, it is considered a single unit owing to both chambers using common turbomachinery not unlike later Russian engines such as the RD-170. The LR-87 first flew in 1959.
The LR-87 rocket engine
Rocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...

 was developed in the late 1950s by Aerojet
Aerojet
Aerojet is an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California with divisions in Redmond, Washington, Orange, Gainesville and Camden, Arkansas. Aerojet is owned by GenCorp. They are the only US propulsion company that provides both solid rocket...

. It is the world's first production rocket engine capable (with modifications) of burning the three most common liquid rocket propellant combinations, liquid oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 and RP-1
RP-1
RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...

, liquid oxygen and hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

, and nitrogen tetroxide and aerozine 50
Aerozine 50
Aerozine 50 is a 50/50 mix of hydrazine and unsymmetrical dimethylhydrazine . Originally developed in the late 1950s by Aerojet General Corporation as a storable, high-energy, hypergolic fuel for the Titan II ICBM rocket engines, Aerozine continues in wide use as a rocket fuel, typically with...

 (mixture of 50% MMH
Monomethylhydrazine
Monomethylhydrazine is a volatile hydrazine chemical with the chemical formula CH3 NH2. It is used as a rocket propellant in bipropellant rocket engines because it is hypergolic with various oxidizers such as nitrogen tetroxide and nitric acid...

 and 50% UDMH
UDMH
Unsymmetrical dimethylhydrazine is a toxic volatile hygroscopic clear liquid, with a sharp, fishy, ammoniacal smell typical for organic amines. It turns yellowish on exposure to air and absorbs oxygen and carbon dioxide. It mixes completely with water, ethanol, and kerosene. In concentration...

). The engine operates on an open gas-generator cycle and utilizes a regenerative cooled nozzle and combustion chamber. Later versions have additional ablative-cooled flanges. LR-87 served as a template for the LR-91, which is used in the second stage of the Titan missile.

It was a fixed-thrust engine, which could not be throttled or restarted in flight. The LR-87 delivered approximately 1,900 kilonewtons (430,000 pounds) of thrust. When used on the Titan I
Titan I
The Martin Marietta SM-68A/HGM-25A Titan I was the United States' first multistage ICBM . Incorporating the latest design technology when designed and manufactured, the Titan I provided an additional nuclear deterrent to complement the U.S. Air Force's SM-65 Atlas missile...

, early LR-87 engines were fuelled by RP-1
RP-1
RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...

 and liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...

. Because the liquid oxygen was cryogenic, it could not be stored in the missile for long periods of time, and had to be loaded before the missile could be launched. For the Titan II
Titan II
The Titan II was an intercontinental ballistic missile and space launcher developed by the Glenn L. Martin Company from the earlier Titan I missile. Titan II was originally used as an ICBM...

, it was converted to use Aerozine-50 and nitrogen tetroxide, which were hypergolic, and were storable at room temperature, so they could remain in their tanks for long periods, allowing Titan II missiles to be launched quickly if a threat was detected.

LR-87-3

The first version used on the Titan I
Titan I
The Martin Marietta SM-68A/HGM-25A Titan I was the United States' first multistage ICBM . Incorporating the latest design technology when designed and manufactured, the Titan I provided an additional nuclear deterrent to complement the U.S. Air Force's SM-65 Atlas missile...

, burned liquid oxygen and RP-1
RP-1
RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...

. Following the retirement of the Titan missile program, these engines saw no further use.

Operating parameters
  • Pull
    Pull
    A pull is a force that acts in the direction of the origin of the force.Pull may also refer to:* Muscle pull, a strain injury* Drawer pull* Pull , impression from a handstamp or die- Sports :...

     (sea level
    Sea level
    Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

    ): 647 kN
  • Move (vacuum
    Vacuum
    In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...

    ): 733 kN
  • Specific impulse
    Specific impulse
    Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...

     (vacuum): 2840 Ns / kg (290 s
    Second
    The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....

    )
  • Specific impulse (sea level
    Sea level
    Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

    ): 2510 Ns / kg (256 seconds)
  • Ignition time: 139 seconds

Weight: 839 kg
  • Length: 3.13 m
  • Diameter: 1.53 m
  • Number of chambers: 1
  • Chamber pressure: 4000 kPa
  • Temperature in the chamber: ~ 3300 °C
  • Expansion Ratio: 8:1
  • Ratio of LOX
    Oxygen
    Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

    /RP-1
    RP-1
    RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...

    : 1,91:1
  • Thrust / weight: 87.2

LR-87-5

A modified version for the Titan II
Titan II
The Titan II was an intercontinental ballistic missile and space launcher developed by the Glenn L. Martin Company from the earlier Titan I missile. Titan II was originally used as an ICBM...

 used new propellants, nitrogen tetroxide and aerozine-50. The engine was generally lighter and simpler than its predecessor, partly due to the propellants being hypergolic (pyrophoric), which did not need an independent ignition system.

Operating parameters
  • Pull
    Pull
    A pull is a force that acts in the direction of the origin of the force.Pull may also refer to:* Muscle pull, a strain injury* Drawer pull* Pull , impression from a handstamp or die- Sports :...

     (sea level
    Sea level
    Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

    ): 956.5 kN
  • Move (vacuum
    Vacuum
    In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...

    ): 1096.8 kN
  • Specific impulse
    Specific impulse
    Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...

     (vacuum): 2910 Ns / kg (297 sec)
  • Specific impulse (sea level
    Sea level
    Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

    ): 2540 Ns / kg (259 sec)
  • Ignition time: 155 seconds

Weight: 739 kg
  • Length: 3.13 m
  • Diameter: 1.14 m
  • Number of chambers: 1
  • Chamber pressure: 5.4 MPa
  • Temperature in the chamber: ~ 3000 °C
  • Expansion Ratio: 8:1
  • Fuel consumption of 750 kg / s
  • Ratio N2O4/Aerozine 50
    Aerozine 50
    Aerozine 50 is a 50/50 mix of hydrazine and unsymmetrical dimethylhydrazine . Originally developed in the late 1950s by Aerojet General Corporation as a storable, high-energy, hypergolic fuel for the Titan II ICBM rocket engines, Aerozine continues in wide use as a rocket fuel, typically with...

    : 1,93:1
  • Thrust / weight: 151.34

LR-87-7

Modified versions of LR-87-5 adapted to the needs of the Gemini program
Project Gemini
Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966....

. The performance was similar to the previous version, only reducing the chamber pressure and nozzle thrust to meet man-rating requirements. This version was only used on the Titan GLV 2.
  • LR-87-9 - the use of early versions of Titan 3
  • LR-87-11 - the later version of the Titan IIIB Titan 4

LR-87 LH2

Version burning liquid oxygen and hydrogen. The development coincided with other variants of the late 1950s. Compared to the -3, it had a number of changes associated with the use of lighter and colder liquid hydrogen. The fuel injector turbo was changed along with the fuel turbopump among other things. A total of 52 static tests were performed without serious issue. Aerojet
Aerojet
Aerojet is an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California with divisions in Redmond, Washington, Orange, Gainesville and Camden, Arkansas. Aerojet is owned by GenCorp. They are the only US propulsion company that provides both solid rocket...

 took part in the selection process for a new engine for the second stage of the Saturn IB
Saturn IB
The Saturn IB was an American launch vehicle commissioned by the National Aeronautics and Space Administration for use in the Apollo program...

 and Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...

. Though LR-87 LH2 was the best in 10 out of 11 criteria, NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 selected Rocketdyne's J-2. Lessons learned were used during development of the Aerojet M-1
M-1 (rocket engine)
Aerojet's M-1 was the largest and most powerful liquid hydrogen-fueled rocket engine to be designed and built. The M-1 offered a baseline thrust of 6.67 million N and 8 million N as its immediate growth target...



The intended parameters
  • Move (vacuum
    Vacuum
    In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...

    ): 667 kN
  • Specific impulse
    Specific impulse
    Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...

    (vacuum): 4420 Ns / kg (~ 450 sec)
  • Weight: ~ 700 kg

Length: 4 m
  • Diameter: 1.13 m
  • Number of chambers: 1

External links

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