The History of the Jet Engine

Jet engine testing facility, Kadena AFB, Japan

 U.S. Air Force photo/Airman 1st Class Justin Veazie

Although the invention of the jet engine can be traced back to the aeolipile made around 150 B.C., Dr. Hans von Ohain and Sir Frank Whittle are both recognized as being the co-inventors of the jet engine as we know it today, even though each worked separately and knew nothing of the other's work.

Jet propulsion is defined simply as any forward movement caused by the backward ejection of a high-speed jet of gas or liquid. In the case of air travel and engines, jet propulsion means that the machine itself is powered by jet fuel.

While Von Ohain is considered the designer of the first operational turbojet engine, Whittle was first to register a patent for his schematics of a prototype, in 1930. Von Ohain obtained a patent for his prototype in 1936, and his jet was the first to fly in 1939. Whittle's took off for the first time in 1941.

While von Ohain and Whittle may be the acknowledged fathers of modern jet engines, many grandfathers came before them, guiding them as they paved the way for the jet engines of today.

Early Jet Propulsion Concepts

The aeolipile of 150 B.C. was created as a curiosity and never used for any practical mechanical purpose. In fact, it wouldn't be until the invention of the fireworks rocket in the 13th century by Chinese artists that a practical use for jet propulsion was first implemented.

In 1633, Ottoman Lagari Hasan Çelebi used a cone-shaped rocket powered by jet propulsion to fly up into the air and a set of wings to glide it back to a successful landing. However, because rockets are inefficient at low speeds for general aviation, this use of jet propulsion was essentially a one-time stunt. In any event, his effort was rewarded with a position in the Ottoman Army.

Between the 1600s and World War II, many scientists experimented with hybrid engines to propel aircraft. Many used one of the piston engine's forms—including air-cooled and liquid-cooled inline and rotary and static radial engines—as the power source for aircraft.

Sir Frank Whittle's Turbojet Concept

Sir Frank Whittle was an English aviation engineer and pilot who joined the Royal Air Force as an apprentice, later becoming a test pilot in 1931.

Whittle was only 22 when he first thought to use a gas turbine engine to power an airplane. The young officer tried unsuccessfully to obtain official support for study and development of his ideas but was ultimately forced to pursue his research on his own initiative.

He received his first patent on turbojet propulsion in January 1930.

Armed with this patent, Whittle again sought funding to develop a prototype; this time successfully. He began construction of his first engine in 1935 -- a single-stage centrifugal compressor coupled to a single-stage turbine. What was meant to be only a laboratory test rig was successfully bench-tested in April 1937, effectively demonstrating the feasibility of the turbojet concept.

Power Jets Ltd. -- the firm with which Whittle was associated -- received a contract for a Whittle engine known as the W1 on July 7, 1939. In February 1940, the Gloster Aircraft Company was chosen to develop the Pioneer, the small engine aircraft the W1 engine was earmarked to power; the historic first flight of the Pioneer took place on May 15, 1941.

The modern turbojet engine used today in many British and American aircraft is based on the prototype invented by Whittle.

Dr. Hans von Ohain's Continuous Cycle Combustion Concept

Hans von Ohain was a German airplane designer who obtained his doctorate in physics at the University of Göttingen in Germany, later becoming the junior assistant to Hugo Von Pohl, director of the Physical Institute at the university.

At the time, von Ohain was investigating a new type of aircraft engine that did not require a propeller. Only 22 years old when he first conceived the idea of a continuous cycle combustion engine in 1933, von Ohain patented a jet propulsion engine design in 1934 very similar in concept to that of Sir Whittle, but different in internal arrangement.

Upon the mutual recommendation of Hugo von Pohl, Von Ohain joined German aircraft builder Ernst Heinkel, at the time seeking assistance in new airplane propulsion designs, in 1936. He continued development of his jet propulsion concepts, successfully bench-testing one of his engines in September 1937.

Heinkel designed and constructed a small aircraft known as the Heinkel He178, to serve as a testbed for this new propulsion system, which flew for the first time on August 27, 1939.

Von Ohain went on to develop a second, improved jet engine known as the He S.8A, which was first flown on April 2, 1941.