Although the terms jet engine and gas turbine engine are sometimes used interchangeably, they actually refer to distinct types of engine designs.
The jet engine family encompasses rocket jets, ramjets, pulsejets, and gas turbine–powered jets. Within the gas turbine category, the primary types are the turbojet, turboprop, turboshaft, and turbofan—engines that dominate modern aviation.
Hero’s Aeolipile
The foundation of today’s modern turbine engine can be traced back to an ancient concept, the reaction principle.
One of the earliest recorded demonstrations of this principle comes from the Egyptian mathematician and philosopher Hero (or Heron), who invented a device known as the aeolipile. This ingenious machine converted steam pressure into mechanical motion. Historians estimate its creation between 100 and 200 B.C. By heating water inside a sealed vessel and channeling the resulting steam through opposing nozzles attached to a rotating sphere, Hero effectively showcased the reaction principle in action. However, it remains uncertain whether the aeolipile was ever put to practical use.
Figure 1 presents an artist’s interpretation of Hero’s aeolipile, though the original device may have appeared quite different.
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| Figure 1. Hero’s aeolipile |
Chinese Rocket
Another early use of the reaction principle appeared in China around 1200 A.D., with the development of solid-fuel rockets. Using black powder, a mix of charcoal, sulfur, and saltpeter (potassium nitrate), —the Chinese built rockets capable of propulsion. Historical records suggest that by 1230 A.D., these rockets were already being used in battle as military weapons. [Figure 2]
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| Figure 2. Chinese rocket |
Branca’s Turbine Device
In 1629, Italian engineer Giovanni Branca introduced what is considered the first gas turbine device, a steam-driven impulse turbine. His design featured a closed, water-filled vessel heated by solid fuel, with steam directed through a nozzle onto an impulse wheel. The wheel powered a simple cogwheel reduction system, an early concept that foreshadowed the modern turbosupercharger used in reciprocating engines. Today, Branca’s device is preserved in the British Museum. [Figure 3]
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| Figure 3. Branca’s turbine |
Newton’s Horseless Carriage
In 1687, Sir Isaac Newton introduced his third law of motion, every action has an equal and opposite reaction, establishing the principle that underpins jet propulsion. Inspired by this concept, scientist Gravensade later constructed a model of a steam-powered carriage. His design used a watertight sphere mounted on wheels, expelling steam rearward to create thrust. Though inventive, the vehicle was far too heavy and underpowered, and no evidence suggests it ever operated successfully. [Figure 4]
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| Figure 4. Newton’s horseless carriage |
Moss Turbo-Supercharger
In 1900, Dr. Sanford A. Moss published a thesis on the gas turbine engine while pursuing an advanced engineering degree, a study that laid the groundwork for his later innovations. By 1918, as an engineer with General Electric, he oversaw the development of the first gas turbine–driven turbo-supercharger for aircraft piston engines. This breakthrough not only advanced aviation performance but also spurred the creation of lightweight, high-strength, heat-resistant materials essential for further gas turbine research in both Europe and the United States. [Figure 5]
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| Figure 5. Turbo-supercharger |
Sir Frank Whittle – British Development
As a cadet at the Royal Air Force College, Frank Whittle wrote a thesis proposing the use of the gas turbine for aircraft propulsion. Aware of industrial turbine applications, he argued that if the engine could be made light enough, the ram effect of incoming air in flight would provide sufficient power for practical aviation use. In 1930, he patented the first turbojet aircraft engine, drawing on ideas from his thesis and incorporating a compressor impeller similar to Dr. Moss’s design, driven by a turbine wheel.
During the early 1930s, Whittle served as both design engineer and test pilot in the RAF, flying piston-powered aircraft. Despite improvements in reciprocating engines, he remained convinced of their limitations in altitude and speed. Between 1930 and 1935, he worked on his turbojet concept but received little government or private backing, many dismissed his idea as impractical. Discouraged, he let his patent lapse.
By 1936, however, with rising political tensions in Europe, Whittle’s supporters encouraged him to resume his work. This led to the creation of Power Jets, Ltd., a privately funded company formed to build a prototype engine. Their design was a pure reaction turbojet, producing thrust entirely from the exhaust gases expelled through a nozzle. The engine featured an impeller-type compressor, multiple combustion chambers, and a single-stage turbine.
On April 12, 1937, Whittle’s prototype ran successfully on a test stand, producing nearly 3,000 horsepower, a milestone unmatched by similar German efforts at the time. By 1939, the Air Ministry contracted Power Jets to develop a flight-ready version. [Figure 6]
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| Figure 6. W-IX, first experimental turbojet |
One of Whittle’s greatest challenges, as he later explained in his book Jet – The Story of a Pioneer (1953), was finding high-temperature, high-strength metals for the combustor and turbine. It took three years of trial and error to build a working combustion system, eventually using ten separate chambers.
In May 1941, the Whittle W-1 engine powered the Gloster E.28/39, achieving 400 mph on its maiden flight and generating 1,000 pounds of thrust. This success led to the development of the W-2, which by 1943 powered the twin-engine Gloster Meteor, Britain’s first operational jet fighter. The Meteor later intercepted Germany’s V-1 “buzz bomb,” marking the first jet-versus-jet encounters of World War II.
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| Figure 7. Whittle’s reverse-flow combustion chamber (A), the Gloster E28/39 experimental airplane (B) |
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| Figure 8. Whittle W-1 turbojet engine |
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| Figure 9. Gloster Meteor |
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| Figure 10. Whittle W2/700 turbojet engine |
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| Figure 11. Frank Whittle and the Whittle W-2/200 turbojet engine |
Whittle also pioneered beyond the turbojet. In 1936, he patented the first turbofan engine, proposed turbine-driven propellers, and even worked on a prototype supersonic axial-flow design. Lacking financial and government support, he could not complete these projects, but all were later developed into practical engines, testament to the remarkable foresight of his work.
German and Italian Developments
While Whittle struggled to gain government support, German engineer Hans von Ohain successfully demonstrated a gas turbine model in 1936 and received nearly unlimited funding for research. Partnering with the Heinkel Company, von Ohain designed the powerplant for the Heinkel He-178, which, in August 1939, became the first aircraft to achieve a purely jet-powered flight. Only one He-178 was built, completing just three flights. [Figure 12]
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| Figure 12. German Heinkle He-178 |
The He-178 was powered by von Ohain’s HeS-3B centrifugal-flow turbojet, producing around 1,100 pounds of thrust. Developed independently, it did not rely on Whittle’s early work. Von Ohain later advanced the axial-flow engine, which has since become the standard for large gas turbine engines. [Figure 13]
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| Figure 13. Hans von Ohain next to his original flight engine, the HeS-3b, which powered the first turbojetpowered plane |
By 1942, Germany introduced the Messerschmitt Me-262, a twin-engine jet powered by axial-flow turbojets from the Junker and BMW companies. Each engine produced roughly 2,000 pounds of takeoff thrust, enabling the aircraft to reach speeds up to 500 mph. However, the hot sections (combustor and turbine) of these engines were less advanced than Whittle’s W-1, requiring disassembly for inspection and part replacement every 10–15 flight hours. [Figures 14, 15]
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| Figure 14. The first operational jet fighter, the Messerschmidtt Me 262 Schwalbe (Swallow) |
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| Figure 15. Junkers Jumo 004 turbojet engine |
Meanwhile, in Italy, the Caproni Company and engineer Secondo Campini developed a jet-powered aircraft during the same period. Their designs relied on a liquid-cooled piston engine to drive the compressor, rather than a turbine wheel in the hot gas path as in Whittle’s patent. Flying in late 1939 at a maximum speed of 205 mph, these aircraft were limited by the piston-driven compressor, and the design was eventually abandoned. [Figure 16]
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| Figure 16. The Caproni-Campini “jet propelled” monoplane |
Early American Gas Turbine Development
In 1941, while visiting England, General H.H. “Hap” Arnold was impressed by the potential of gas turbine-powered aircraft as tactical weapons. He acquired a Whittle engine and helped secure an Air Force contract with General Electric for research and development. Between October 1, 1941, and April 2, 1942, GE had a redesigned engine successfully running in a test cell.
General Electric was selected due to its expertise in high-temperature metals from turbo-supercharger production and its connections to Whittle’s work in Britain. GE went on to develop the first American prototype turbojet, the GE I-A.
The Bell Aircraft Company of Buffalo, New York, was tasked with building the first jet airplane. Driven by wartime urgency, Bell quickly designed an aircraft to use GE’s engine. In October 1942, at Muroc Field, California, the Bell XP-59 (Airacomet) made its maiden flight, powered by two GE I-A engines producing 1,250 pounds of thrust each. While the Airacomet never saw combat due to its limited 30-minute flight time, it became an important trainer for the later P-80 jet. A total of 30 XP-59A aircraft were built. [Figures 17, 18]
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| Figure 17. The Bell Airacomet, a twin turbojet fighter powered by two Whittle-type G.E. gas turbines |
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| Figure 18. The General Electric I-16 (J-31-GE-1 military designation) production model of the GE-1-A turbojet |
Although the United States did not deploy jet aircraft during World War II, the work of Whittle and General Electric laid the foundation for future military, commercial, and industrial gas turbine development.
Commercial Aircraft Development
The British led the way in early commercial jet and turboprop aviation. In 1948, they tested the Vickers Viscount, the first turboprop-powered passenger liner, which remains in service in some regions today. A year later, the De Havilland Comet, the first turbojet-powered airliner, made its debut. Entering service in 1952, the Comet initially suffered structural fatigue and high-altitude decompression issues, leading to catastrophic crashes and grounding in 1954. Following extensive redesign and testing, it returned to service and operated for many years. [Figure 19]
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| Figure 19. Vickers Viscount (top), de Havilland DH 106 Comet 1 (bottom) |
In the United States, Boeing pioneered commercial jet aviation using Pratt & Whitney engines originally developed for military aircraft. Investing roughly a quarter of their net worth, Boeing developed the 707, which, after years of testing, entered service in 1958. Boeing went on to produce numerous narrow-body airliners and the iconic wide-body 747, still the largest passenger aircraft flying today. [Figure 20]
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| Figure 20. Boeing 707 (top), Boeing 747 (bottom) |
In 1966, Boeing attempted to introduce supersonic airline service with the Boeing 2707, a Mach 2.8, 300-passenger aircraft powered by four GE-4 turbojet engines producing 68,000 pounds of thrust each. Environmental concerns over potential ozone layer damage and congressional opposition halted the project in the late 1960s, and work officially ceased in 1971. [Figure 21]
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| Figure 21. The American SST design, Boeing 2707-300 |
Meanwhile, in 1976, the British and French introduced the Concorde, a smaller supersonic jetliner powered by Rolls-Royce Olympus turbojets. Capable of carrying 100 passengers at speeds up to Mach 2.2, Concorde’s service cruising speed was limited to around Mach 2.0 to reduce airframe stress. First flight-tested in 1969, it remained in service until 2003. Modern research indicates that high-flying aircraft like the Concorde have minimal impact on the ozone layer, which is largely affected by industrial and agricultural pollution. [Figure 22]
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| Figure 22. The British-French Concorde SST |
Two recent advancements in gas turbine technology are notable: the Europrop TP400, an advanced eight-bladed turboprop (or propfan) producing 11,000 shaft horsepower, the largest turboprop to date, and the General Electric Unducted Fan (UDF) engine, designed to replace mid-range engines in narrow-body airliners [Figure 23].
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| Figure 23. Advanced swept-back eight-bladed turboprop (top), General Electric unducted fan engine on an MD-80 (bottom) |
The aviation industry continues to adapt to EPA and FAA regulations on noise and emissions. While the future of supersonic commercial flight remains uncertain, history suggests the industry will develop the innovations necessary to meet these challenges and advance aviation further.
Commuter and Business Jets
Since the 1970s, the use of gas turbine engines in commuter aircraft, business jets, and general aviation has grown significantly, a trend that continues into the 21st century.
The commuter airline industry, once dominated by small turboprop aircraft, is increasingly adopting turbofan-powered regional jets. These high-bypass fan airplanes, seating 50 to 100 passengers, offer greater efficiency and speed and are meeting growing market demand.
Business jets have also expanded in popularity. No longer reserved for Fortune 50 or 100 companies, many smaller businesses now operate jets through fractional ownership programs. A new category of very light jets (VLJs), sometimes called “affordable jets”—has emerged. Initially intended to cost around $1 million, current models range from $2 to $5 million. These VLJs typically feature two small turbofan engines, seat 4 to 6 passengers, cruise at 400–500 mph, and produce 800–1,500 pounds of thrust per engine. Some manufacturers are even developing single-engine VLJs.
A number of U.S. and international companies now supply the majority of gas turbine engines for fixed-wing and rotary-wing aircraft used in commercial, commuter, business, and military aviation:
U.S. Companies:
- United Technologies (Pratt & Whitney)
- General Electric Engines
- Honeywell-Lycoming
- Teledyne
- Williams International
International Companies:
- Rolls-Royce, UK
- CFM International (GE, USA & Snecma, France)
- Europrop International, France
- International Aero Engines (Pratt & Whitney, Rolls-Royce, MTU Germany)
- Klimov, Russia
- Safran-Turbomeca, France
These manufacturers have leveraged earlier military and commercial engine technologies to create reliable, high-performance turbine engines for today’s aviation market. Much of the early civil aviation technology originated from military research funded by governments, but today, commercial and business engine development is largely driven by private investment.
Milestones in Gas Turbine Aviation
- 1948 – First commercial turboprop airliner: The British Vickers Viscount made its maiden flight on July 16, 1948, becoming the world's first turboprop-powered airliner. It entered service in 1953 and was retired in 2009 .
- 1949 – First commercial turbojet airliner: The de Havilland Comet 1 prototype first flew on July 27, 1949. It entered commercial service in 1952, marking the beginning of the jet age in civil aviation .
- 1959 – First commercial turbofan airliner: The British Vickers VC10, featuring turbofan engines, first flew in 1959. It entered service in 1964 and was known for its excellent short-field performance .
- 1968 – First supersonic commercial airliner: The Soviet Tupolev Tu-144 made its first flight on December 31, 1968. It became the world's first commercial supersonic transport aircraft, entering service in 1975 .
- 1986 – First propfan engine flight: The General Electric GE36 unducted fan (UDF) engine was flight-tested on a Boeing 727 aircraft in 1986, marking a significant step in propfan engine development .
- 1994 – First propfan in service: The Antonov An-70, powered by four Progress D-27 propfan engines, first flew in 1994. It became the first aircraft to take off using only propfan engines.
