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Air Force Museum Foundation

Aerospace Propulsion

Aerospace PropulsionPropulsion constitutes a critical element of air power. The history of military propulsion systems follows the quest to attain faster speeds, greater range and higher altitudes. Without advances in propulsion systems, military aviation would not have grown from the first captive observation balloons into today's flexible, powerful and dominant U.S. Air Force.

Propulsion means to push forward or drive an object forward. This word is derived from two Latin words: pro meaning "forward" and pellere meaning "to drive." Thus, a propulsion system produces the necessary thrust to push an object forward. On an aerospace vehicle, the propulsion system creates thrust by accelerating a gas, or "working fluid," which can be either air moved by a propeller or exhaust from a jet or rocket engine. Propulsion system designers apply Sir Isaac Newton's Third Law of Motion -- for every action there is an equal and opposite reaction -- to drive an aerospace vehicle forward.

Note: This online exhibit is continually being developed and more content will be added as we move forward. Please revisit this page often for updates.

(Photo courtesy of Tom Reynolds)

Early Years Engines

Early aircraft used various types of liquid and air cooled engines. One of the more interesting was the rotary engine, such as the Gnome N-9. These small engines produced relatively with low horsepower, but World War I spurred the development of larger and more powerful engines, like the famous Liberty.

Wright 6-60
Gnome N-9
Liberty 12-Cylinder
Curtiss D-12
Wright R-1820 Cyclone

WWII Engines

During WWII, designers and manufacturers produced aircraft engines far more powerful than could have been imagined during WWI. With the addition of turbo superchargers, the liquid and air cooled engines reached higher power and altitudes, and jet engines appearing at the end of the war took aerospace propulsion to a new level.

Packard V-1650 Merlin
Pratt & Whitney R-1830-90C
Allison V-1710
Pratt & Whitney R-2800
Wright R-3350 Duplex-Cyclone
General Electric I-16/J-31
Junkers Jumo 004 Turbojet
Allison J33 Turbojet

Korean War Engines

Propeller driven combat aircraft gave way to the newer and more powerful jet engines after World War II. As a result, the Korean War became known as the first jet war as American and communist jet fighters fought for aerial supremacy over Korea.

Allison J35-A-35A Turbojet
Russian VK-1

SEA War Engines

The more powerful engines available during the Southeast Asia War allowed aircraft to carry heavier loads and fly twice as fast as during the Korean War.

General Electric J79 Turbojet

Cold War Engines

Aerospace propulsion advanced during the Cold War to make supersonic fighters and large airlift aircraft commonplace.

Pratt & Whitney J57 Turbojet
Williams International F-121 Fanjet
Williams International F107-WR-101 Turbofan
Pratt & Whitney F100-PW-220
Pratt & Whitney YF119-PW-100L Augmented Turbofan

R&D Engines

Creating new propulsion systems and airframe improvements have been associated with aerospace advances since the beginning of powered flight. Not every engine is successful, and even the successful ones do not always go into production. Nevertheless, research and development (R&D) remains a vital element of aerospace propulsion.

Allison T-40-A-10
General Electric T-31 Turboprop
General Electric YF120
General Electric YJ93-G-3 Turbojet
Pratt & Whitney JT15D-5

Missile & Space Engines

Some aircraft, like the Messerschmitt Me 163 Komet in World War II or the North American X-15A, used rocket propulsion, but the exploration of space and the development of intercontinental ballistic missiles required increasingly powerful rocket engines.

Walter HWK 509A
Walter HWK 509B-1 Rocket
V-2 Rocket
Thiokol TE-M-364-4 Solid Rocket
Rocketdyne LR79
Reaction Motors XLR99 Rocket

Lectures

Airpower in the Korean War: America's First Jet-Age Air War
Dr. Richard Hallion
Dr. Hallion discusses the aircraft and aerospace advancements during America's first jet-age air war.
Hallion Transcript

The Jet Race and the Second World War
Dr. S. Mike Pavelec
This lecture discusses the three major competing propulsion programs -- German, British and American -- and its quest to develop jet aircraft technology during World War II.
Pavelec Transcript

Note: These materials are directed to an adult audience and may contain visual material or language which may be considered inappropriate for young viewers. The museum strongly suggests videotapes be previewed prior to student viewing in the classroom. Additionally, the expressed comments and opinions presented by guest speakers are solely those of the speaker and do not necessarily reflect the views of the museum or the U.S. Air Force.