The
F-1 is a
rocket engineA 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...
developed by
RocketdyneRocketdyne was a Rocket engine design and production company headquartered in Canoga Park, California, United States. The company was related to North American Aviation for most of its history. NAA merged with Rockwell International, which was then bought by Boeing in December, 1996...
and used in the
Saturn VThe 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...
. Five F-1 engines were used in the
S-ICThe S-IC was the first stage of the Saturn V rocket. The S-IC first stage was built by The Boeing Company. Like the first stages of most rockets, most of its mass of over two thousand metric tonnes at launch was propellant, in this case RP-1 rocket fuel and liquid oxygen oxidizer...
first stage of each Saturn V, which served as the main launch vehicle in the Apollo program. The F-1 is still the most powerful single-chamber liquid-fueled rocket engine ever developed. The
RD-170The RD-170 is the world's most powerful liquid-fuel rocket engine, designed and produced in the USSR by NPO Energomash for use with Energia launch vehicle...
has slightly more thrust, using a cluster of four smaller combustion chambers and nozzles.
History
The F-1 was originally developed by Rocketdyne to meet a 1955
US Air ForceThe United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
requirement for a very large rocket engine. The eventual result of that requirement was two different engines, the
E-1Rocketdyne's E-1 was a liquid propellant rocket engine originally built as a backup design for the Titan I missile. While it was being developed, Heinz-Hermann Koelle at the Army Ballistic Missile Agency selected it as the primary engine for the rocket that would emerge as the Saturn I...
and the much larger F-1. The E-1, although successfully tested in static firing, was quickly seen as a technological dead-end and was abandoned for the larger, more powerful F-1. The USAF eventually halted development of the F-1 because of a perceived lack of requirement for such a large engine. However, the recently created
NASAThe 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...
appreciated the usefulness of an engine with so much power and contracted Rocketdyne to complete its development. Test firings of F-1 components had been performed as early as 1957. The first static firing of a full stage developmental F-1 was performed in March 1959.
For seven years of development F-1 tests revealed serious combustion instability problems which would sometimes cause
catastrophic failureA catastrophic failure is a sudden and total failure of some system from which recovery is impossible. Catastrophic failures often lead to cascading systems failure....
. Progress on this problem was initially slow, as the problem onset was intermittent and unpredictable. Oscillations of 4 kHz with harmonics to 24 kHz were noticed. Eventually engineers developed a technique of detonating small explosive charges (which they called "bombs") outside the combustion chamber through a tangential tube (RDX, C4 or Black Powder were used) while the engine was firing, which allowed them to determine exactly how the running chamber responded to variations in pressure and to determine how to nullify these oscillations. The designers could then quickly experiment with different co-axial fuel-injector designs to obtain the one most resistant to instability. These problems were addressed from 1959 through 1961. Eventually the engine's combustion was so stable it would
self-damp[[Image:Damped spring.gif|right|frame|Underdamped [[spring–mass system]] with ζ 1 , and is referred to as overdamped.*Underdamped:If s is a complex number, then the solution is a decaying exponential combined with an oscillatory portion that looks like \exp...
artificially induced instability within 1/10 of a second.
Design
The
RocketdyneRocketdyne was a Rocket engine design and production company headquartered in Canoga Park, California, United States. The company was related to North American Aviation for most of its history. NAA merged with Rockwell International, which was then bought by Boeing in December, 1996...
-developed
F-1 engine is the most powerful single-nozzle
liquid fueled rocket engineA liquid-propellant rocket or a liquid rocket is a rocket engine that uses propellants in liquid form. Liquids are desirable because their reasonably high density allows the volume of the propellant tanks to be relatively low, and it is possible to use lightweight pumps to pump the propellant from...
ever used in service. The RD-170 produces slightly more thrust through a cluster of four combustion chambers and four nozzles. The
M-1 rocket engineAerojet'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...
was designed to have more thrust, and was ground tested, but was never put into service. The F-1 was a liquid-fueled rocket motor, burning
RP-1RP-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...
(
keroseneKerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
) as fuel, and using
liquid oxygenLiquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
(LOX) as the oxidizer. A
turbopumpA turbopump is a gas turbine that comprises basically two main components: a rotodynamic pump and a driving turbine, usually both mounted on the same shaft, or sometimes geared together...
was used to inject fuel and oxygen into the combustion chamber.
The heart of the engine was the thrust chamber, which mixed and burned the fuel and oxidizer to produce thrust. A domed chamber at the top of the engine served as a
manifoldA manifold, in systems for moving fluids or gases is a junction of pipes or channels, typically bringing one into many or many into one.-Applications:*Heated-manifold direct-injection die casting for zinc die casting....
supplying liquid oxygen to the injectors, and also served as a mount for the
gimbalA gimbal is a pivoted support that allows the rotation of an object about a single axis. A set of two gimbals, one mounted on the other with pivot axes orthogonal, may be used to allow an object mounted on the innermost gimbal to remain immobile regardless of the motion of its support...
bearing which transmitted the thrust to the body of the rocket. Below this dome were the injectors, which directed fuel and oxidizer into the thrust chamber in a way designed to promote mixing and combustion. Fuel was supplied to the injectors from a separate manifold; some of the fuel first travelled in 178 tubes down the length of the thrust chamber—which formed approximately the upper half of the exhaust nozzle—and back in order to cool the nozzle.
A
gas-generatorThe gas generator cycle is a power cycle of a bipropellant rocket engine. Some of the propellant is burned in a gas-generator and the resulting hot gas is used to power the engine's pumps. The gas is then exhausted...
was used to drive a
turbineA turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
which in turn drove separate fuel and oxygen pumps, each feeding the thrust chamber assembly. The turbine was driven at 5,500 RPM by the gas generator, producing 55,000 brake horsepower (41 MW). The fuel pump produced 15,471
gallonThe gallon is a measure of volume. Historically it has had many different definitions, but there are three definitions in current use: the imperial gallon which is used in the United Kingdom and semi-officially within Canada, the United States liquid gallon and the lesser used United States dry...
s (58,564
litrepic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
s) of RP-1 per minute while the oxidizer pump delivered 24,811 gal (93,920 l) of liquid oxygen per minute. Environmentally, the turbopump was required to withstand temperatures ranging from input gas at 1,500 °F (816 °C), to liquid oxygen at −300 °F (−184 °C). Structurally, fuel was used to lubricate and cool the turbine
bearingsA bearing is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can...
.
Below the thrust chamber was the
nozzle extensionNozzle extension — nozzle expander of reaction/rocket engine. The application of nozzle extensions improves efficiency of rocket engines in vacuum by increasing nozzle ratio. As a rule, their modern design assumes use of carbon-carbon materials without regenerative cooling...
, roughly half the length of the engine. This extension increased the
expansion ratioThe expansion ratio of a liquefied and cryogenic substance is the volume of a given amount of that substance in liquid form compared to the volume of the same amount of substance in gaseous form, at a given temperature and pressure....
of the engine from 10:1 to 16:1. The exhaust from the turbopump was fed into the nozzle extension by a large, tapered manifold; this relatively cool gas formed a film which protected the nozzle extension from the hot (5,800 °F, 3,200 °C) exhaust gas.
The F-1 burned 3945 pounds (1,789.4 kg) of liquid oxygen and 1738 pounds (788.3 kg) of RP-1 each second, generating 1500000 pound-forces (6.7 MN) of thrust. This equated to a flow rate of 413.5 gallons (1,565.3 l) of LOX and 257.9 gallons (976.3 l) RP-1 per second. During their two and a half minutes of operation, the five F-1s propelled the Saturn V vehicle to a height of 42 miles (67.6 km) and a speed of 6164 miles per hour (9,920 km/h). The combined propellant flow rate of the five F-1s in the Saturn V was 3357 gallons (12,707.6 l) per second. Each F-1 engine had more thrust than three
Space Shuttle Main EngineThe RS-25, otherwise known as the Space Shuttle Main Engine , is a reusable liquid-fuel rocket engine built by Pratt & Whitney Rocketdyne for the Space Shuttle, running on liquid hydrogen and oxygen. Each Space Shuttle was propelled by three SSMEs mated to one powerhead...
s combined.
Designer of the pump for the E-1/F-1 for Rocketdyne was Ernest A. Lamont. His hand written original calculations are part of the family archives and available for display. He stated that the design of the rocket engine hinged on the question of whether the pump design was viable.
Specifications
|
Apollo 4, 6, and 8 |
Apollo 9 on |
ThrustThrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....
(sea level): |
1,500,000 lbf The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...
(6.67 MN) |
1,522,000 lbf The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...
(6.77 MN) |
| Burn time: |
150 s |
165s |
Specific impulseSpecific 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 ,...
: |
260 s (2.55 kN·s/kg) |
263 s (2.58 kN·s/kg) |
| Chamber pressure: |
70 bar |
70 bar |
| Engine weight dry: |
18,416 lb (8,353 kg) |
18,500 lb (8,391 kg) |
| Engine weight burnout: |
20,096 lb (9,115 kg) |
20,180 lb (9,153 kg) |
| Height: |
19 ft (5.79 m) |
| Diameter: |
12.3 ft (3.76 m) |
| Exit to throat ratio: |
16 to 1 |
| Propellants: |
LOXLox is salmon fillet that has been cured. In its most popular form, it is thinly sliced—less than in thickness—and, typically, served on a bagel, often with cream cheese, onion, tomato, cucumber and capers...
& RP-1RP-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...
|
| Mixture ratio: |
2.27:1 oxidizer to fuel |
| Contractor: |
NAA/Rocketdyne |
| Vehicle application: |
Saturn V / S-ICThe S-IC was the first stage of the Saturn V rocket. The S-IC first stage was built by The Boeing Company. Like the first stages of most rockets, most of its mass of over two thousand metric tonnes at launch was propellant, in this case RP-1 rocket fuel and liquid oxygen oxidizer...
1st stage - 5-engines |
Sources:
Improvements to F-1
F-1 thrust and efficiency were improved between
Apollo 8Apollo 8, the second manned mission in the American Apollo space program, was the first human spaceflight to leave Earth orbit; the first to be captured by and escape from the gravitational field of another celestial body; and the first crewed voyage to return to Earth from another celestial...
(SA-503) and
Apollo 17Apollo 17 was the eleventh and final manned mission in the American Apollo space program. Launched at 12:33 a.m. EST on December 7, 1972, with a three-member crew consisting of Commander Eugene Cernan, Command Module Pilot Ronald Evans, and Lunar Module Pilot Harrison Schmitt, Apollo 17 remains the...
(SA-512). This was necessary for Saturn V payload capacity to meet the increasing demands of the later
ApolloThe Apollo program was the spaceflight effort carried out by the United States' National Aeronautics and Space Administration , that landed the first humans on Earth's Moon. Conceived during the Presidency of Dwight D. Eisenhower, Apollo began in earnest after President John F...
missions. There were small performance variations between engines on a given mission, and variations in average thrust between missions. For
Apollo 15Apollo 15 was the ninth manned mission in the American Apollo space program, the fourth to land on the Moon and the eighth successful manned mission. It was the first of what were termed "J missions", long duration stays on the Moon with a greater focus on science than had been possible on previous...
, F-1 performance was:
- Thrust (average, per engine, sea level liftoff): 1,553,200 lbf
The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...
(6.909 MN)
- Burn time: 159 s
- 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 ,...
: 264.72 s
- Mixture ratio: 2.2674
- S-IC
The S-IC was the first stage of the Saturn V rocket. The S-IC first stage was built by The Boeing Company. Like the first stages of most rockets, most of its mass of over two thousand metric tonnes at launch was propellant, in this case RP-1 rocket fuel and liquid oxygen oxidizer...
total sea level liftoff thrust: 7,766,000 lbfThe pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...
(34.55 MN)
Measuring and making comparisons of rocket engine thrust is more complicated than it first appears. Based on actual measurement the liftoff thrust of
Apollo 15Apollo 15 was the ninth manned mission in the American Apollo space program, the fourth to land on the Moon and the eighth successful manned mission. It was the first of what were termed "J missions", long duration stays on the Moon with a greater focus on science than had been possible on previous...
was 7.823 million lbf (34.8 MN), which equates to an average F-1 thrust of 1.565 million lbf (6.962 MN) - significantly more than the specified value. For more information, see S-IC thrust comparisons
After Apollo
There was an uprating redevelopment of the F-1 undertaken by Rocketdyne during the 1960s which resulted in a new engine specification known as the F-1A. While outwardly very similar to the F-1, the F-1A was lighter yet 33% more powerful (2 million lbf compared to F-1's 1.5 million) and would have been used on future Saturn V vehicles in the post-
ApolloThe Apollo program was the spaceflight effort carried out by the United States' National Aeronautics and Space Administration , that landed the first humans on Earth's Moon. Conceived during the Presidency of Dwight D. Eisenhower, Apollo began in earnest after President John F...
era. However, the Saturn V production line was closed prior to the end of Project Apollo and no F-1A engine ever flew on a launch vehicle.
There were proposals to use eight F-1 engines on the first stage of the
Nova rocketNova was a series of proposed rocket designs, originally as NASA's first large launchers for missions similar to the production-level Saturn V, and later as larger follow-ons to the Saturn V intended for missions to Mars. The two series of designs were essentially separate, but shared their name...
. Numerous proposals have been made from the 1970s on to the present day to develop new expendable boosters based around the F-1 engine design, but none have proceeded beyond the initial study phase.
The F-1 remained the most powerful liquid-fuel rocket engine at 6.7 MN of thrust at sea level until overshadowed by the RD-170 from the Soviet Union. The RD-170 is actually a cluster of four separate combustion chambers and nozzles driven by a single turbopump. It visually appears to be and is considered by some a cluster of four engines, not a single engine. Viewed as a single engine it is the most powerful liquid-fuel rocket engine ever developed. The F-1 still holds the crown of largest single-chamber, single-nozzle liquid fuel engine ever flown. However among
solid-fuelA solid rocket or a solid-fuel rocket is a rocket engine that uses solid propellants . The earliest rockets were solid-fuel rockets powered by gunpowder; they were used by the Chinese in warfare as early as the 13th century and later by the Mongols, Arabs, and Indians.All rockets used some form of...
engines, more powerful engines exist, such as the
Space Shuttle Solid Rocket BoosterThe Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
, with a sea-level liftoff thrust of 12.45 MN.
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