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Hans von Ohain

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Hans von Ohain
File:Ohain.jpg
Hans von Ohain during the 1970s
Born
Hans Joachim Pabst von Ohain

Template:Birth date
Dessau, Duchy of Anhalt, German Empire
Died13 March 1998(1998-03-13) (aged 86)
Melbourne, Florida, U.S.
EducationUniversity of Göttingen
OccupationEngineer (jet propulsion)
SpouseHanny von Ohain
Children4

Hans Joachim Pabst von Ohain (14 December 1911Template:Spaced ndash13 March 1998) was a German physicist and engineer credited with designing the first aircraft powered by a turbojet engine. Alongside Frank Whittle and Anselm Franz, he is recognized as a co-inventor of the turbojet engine. Nevertheless, timeline evidence indicates that von Ohain was still a university student when Whittle filed his initial patent for a turbojet in January 1930 and successfully tested his first engine in April 1937—approximately six months prior to von Ohain’s first engine test. Furthermore, before constructing his own engine and submitting his patent in 1935, von Ohain reviewed and critiqued Whittle’s patents.[1][2][3][4][5][6][7] In his autobiography, von Ohain recalled, "My interest in jet propulsion began in the fall of 1933 when I was in my seventh semester at Göttingen University. I didn't know that many people before me had the same thought."[2] Unlike Whittle, von Ohain benefited significantly from support by an aircraft manufacturer—Heinkel—who financed his research.

When von Ohain developed his initial engine design in 1935, he opted for a compact arrangement utilizing a centrifugal impeller (centrifugal or radial compressor) combined with a radial inflow turbine.[8]

Although this design exhibited several limitations preventing mass production, the extensive resources provided by Heinkel Aircraft Company allowed for refinement. Consequently, a functional version powered the He 178, marking on 27 August 1939 the historic achievement of creating the world’s first gas turbine to power an aircraft.

Von Ohain continued focusing on centrifugal compressor designs, contributing to Heinkel’s subsequent projects such as the hybrid centrifugal/axial HeS8 and HeS011 engines,[9] although none reached production status. Meanwhile, rival German engineers at Junkers and BMW pursued axial compressor layouts; their engines entered production despite unresolved challenges related to power output and durability. Nevertheless, von Ohain initiated Germany’s first jet engine industry with numerous prototypes and series models manufactured until 1945.

Although von Ohain began turbojet development later than Whittle, both men worked on their respective engines during overlapping periods when Whittle was constructing his WU engine in Britain. Their simultaneous efforts have been cited as examples of independent invention.[10] Von Ohain recounts that in 1935—while preparing his own patent application but prior to building an engine—his attorney provided him with a copy of Whittle’s patent for review. This prompted adjustments to his patent to avoid infringement.[11]

The heart of von Ohain’s inaugural jet engine—the Heinkel HeS 1, which he referred to as his "hydrogen test engine"—was operational "in March or early April," according to von Ohain himself (though Ernst Heinkel’s diaries indicate September 1937).[12][13]

Development on this hydrogen-powered test engine progressed further; it required modifications to address overheating issues and to incorporate a fuel system capable of running independently on liquid fuel—a milestone achieved by September 1937.[14][15] Supported heavily by Heinkel's backing, von Ohain’s jet engine became the first to power an aircraft—the Heinkel He 178—in 1939. This was followed by Whittle’s engine powering the Gloster E.28/39 in 1941.[16] Operational turbojet fighter aircraft appeared nearly simultaneously in July 1944: Germany’s Messerschmitt Me 262 on July 26 and Britain’s Gloster Meteor on July 27.[17][18][19][20] The Me 262 became the inaugural operational jet fighter with extensive combat deployment involving hundreds of units; meanwhile, only limited numbers of Meteors saw action.

Despite knowledge of axial flow compressors by both von Ohain and Whittle, they remained committed to enhancing centrifugal compressor engines throughout World War II for powering respectively the Heinkel He 178 and Gloster E.28/39 aircraft. In contrast, axial flow compressor designs were simultaneously advanced by Anselm Franz at Junkers and Hermann Oestrich at BMW through development of engines such as the Jumo 004 and BMW 003,[21][22] which were widely adopted by manufacturers during the following decade.[23][24]

Following World War II, von Ohain and Whittle met personally, forged a friendship, and jointly received the prestigious Charles Stark Draper Prize for Engineering recognizing their independent invention of the turbojet engine.[25][26]

Early years and jet engine innovation

Hans von Ohain was born in Dessau, Germany. He completed his secondary education in 1930 at the Arndt-Gymnasium located in Dahlem and went on to earn a doctorate in physics from the University of Göttingen in 1935. His dissertation, titled An Interference Light Relay for White Light, focused on an optical microphone designed to capture sound directly onto film, which subsequently led to his initial patent. At that time, the University of Göttingen was a leading institution for aeronautical research, where Ohain attended lectures by notable figures such as Ludwig Prandtl. While still a student in 1933, he envisioned what he described as "an engine that did not require a propeller."

Following the completion of his PhD in 1935, Ohain became a junior assistant to Robert Wichard Pohl, who was then heading the university’s Physical Institute. In 1936, during his tenure with Pohl, Ohain filed a patent for his jet engine concept titled Process and Apparatus for Producing Airstreams for Propelling Airplanes. Unlike Frank Whittle’s Power Jets WU design, which utilized an axial flow turbine, Ohain’s approach employed a radial in-flow turbine paired with a centrifugal compressor, arranged back-to-back and encircled by an annular combustion chamber.

While working at the university, Ohain frequented a local garage named Bartles and Becker for servicing his sports car. There, he met Max Hahn, an automotive mechanic, whom he persuaded to construct a demonstration version of his engine for Template:Reichsmark. The resulting prototype was wider in diameter than Whittle’s fully operational 1937 engine but significantly shorter. Upon testing at the university, Ohain encountered issues with combustion; fuel ignition predominantly occurred downstream of the turbine, causing flames to erupt from the exhaust outlet. This delayed combustion prevented the engine from operating independently without electric motor assistance, which eventually overheated.

File:Hans von Ohain test engine engine-with Max Hahn.jpg
Mechanic Max Hahn alongside key components of Hans von Ohain's experimental engine

Von Ohain later reflected on his motivation: "My fascination with jet engines began around 1933. I realized that the smoothness of flight was marred by intense vibrations and noise from piston engines coupled with propellers. I concluded that a continuous cycle—constant compression, combustion, and expansion—would offer significant benefits. Therefore, I opted for a straightforward design featuring a radial compressor paired with a radial turbine."

Despite this innovative approach, the prototype developed with Max Hahn demonstrated that the combustion chamber required further refinement. Consequently, Pohl and von Ohain decided to seek collaboration with Heinkel, recognizing him as an individual who "embraces new ideas without hesitation."

Heinkel

In February 1936, Pohl reached out to Ernst Heinkel to inform him about Ohain's innovative design and its potential applications. Heinkel subsequently organized a meeting between his engineering team and Ohain, during which he expressed skepticism about the current "garage engine" prototype but affirmed the validity of the underlying concept. The engineers were persuaded by this reasoning, leading to Ohain and Hahn joining Heinkel's team in April, working at the Marienehe airfield near Rostock, in Warnemuende.

Collaborating with Engineer Gundermann and Hahn within Special Development, von Ohain recalled: "Faced with the challenge of rapidly developing a combustion chamber with unknown durability, I conceived the idea of isolating the turbine issue from the combustion chamber by utilizing hydrogen fuel. As a physicist, I was aware that gaseous hydrogen's diffusion and combustion rates were significantly faster than those of petrol."[27]

Over a two-month period, analysis of the model’s airflow led to multiple enhancements. Motivated by these results, Ohain created a new prototype designed to operate on hydrogen gas supplied from an external pressurized source. This engine, named Heinkel-Strahltriebwerk 1 (HeS 1), meaning Heinkel Jet Engine 1 in German, was handcrafted by carefully selected top machinists from the company—a decision that displeased some shop-floor supervisors. Meanwhile, Hahn focused on resolving combustion challenges, an area where he had prior expertise.

The engine’s design was notably straightforward, primarily constructed from sheet metal. The build process began late summer 1936 with a village blacksmith and was finished by March 1937. Two weeks later, the engine successfully ran on hydrogen; however, the high exhaust temperatures caused significant metal scorching. Despite this issue, testing was largely successful. By September, after replacing the combustor, the engine was operated on gasoline for the first time. Gasoline use led to clogging within the combustor. Although not intended as a flight-ready model, the engine definitively demonstrated that the fundamental concept was viable—marking Ohain's breakthrough in matching Whittle’s progress. With considerably greater financial backing and industrial support, Ohain would soon surpass Whittle and advance further.

Unaware of Whittle?

Template:Original research section There has been frequent assertion that Ohain had no knowledge of Whittle’s efforts.[28] Strictly speaking, this may hold true insofar as he was not aware of Whittle's experiments at Lutterworth—where the RAF engineer successfully ran the world’s first jet engine on April 12, 1937—but Ohain had received copies of Whittle’s patents through his lawyer while preparing his own patent application and prior to commencing engine construction.

In his autobiography, Ohain offered a candid evaluation of Whittle’s design:[29]

"When I reviewed Whittle’s patent, I initially thought it involved boundary layer suction combinations. It featured a two-flow, dual entrance radial compressor that appeared cumbersome from an engineering perspective. Its flow reversal seemed undesirable to us; however, it ultimately proved manageable despite causing some minor instability issues... Our patent claims had to be narrowed relative to Whittle’s because he disclosed certain elements." He then reasonably justified their awareness of Whittle's work by stating: "We believed it represented a patent on an idea... We assumed it was not being actively developed."

Engine Development

By February 1937, the turbine section had been successfully operated on a test rig. Von Ohain recalled, "At this stage, we were developing a device capable of powering an aircraft, the precursor to the He-S3B. Initially, I planned to position the combustion chamber between the compressor and turbine, as was done in the hydrogen-powered unit, but Hahn proposed locating it ahead of these components, which proved to be an excellent suggestion." The He-S3 turbine underwent flight testing by Erich Warsitz and Walter Künzel aboard a Heinkel He 118, where it provided supplementary throttled thrust alongside the conventional engine.[27]: 120 

While continuing work on the HeS 1, the Pohl-Ohain team advanced toward creating a flight-capable engine known as the HeS 3. Key improvements included replacing the bent and folded sheet metal with precision-machined compressor and turbine stages, and redesigning the layout to minimize engine cross-sectional area by situating an annular combustor within an extended gap between compressor and turbine. The initial turbine design was insufficiently sized for efficient operation.

Early in 1939, the He-S3A was installed in the He 178 airframe for static display at Roggentin on 3 July 1939. However, this turbine still lacked adequate power for flight. Von Ohain explained, "We tested various configurations to modify the compressor diffuser and turbine nozzle vanes to boost thrust enough to qualify the aircraft for its inaugural flight demonstration. We discovered that a small diffuser positioned behind the engine with a collar and splitter to redirect airflow performed better than high-speed flow through the entire duct. These modifications culminated in the He-S3B."[27]: 122–123 

File:NASM-A19810039000cp05.jpg
Hans von Ohain's centrifugal compressor and radial inflow turbine design of the HeS3B

A subsequent iteration, designated HeS 3b, was introduced,[30] extending the combustor by placing its forward section ahead of the compressor's outer rim. Although not as compact as the original HeS 3, the 3b remained relatively small. The first run of the 3b occurred in July 1939 (some sources cite May), followed by airborne testing beneath the Heinkel He 118 dive bomber prototype. The initial 3b engine failed due to burnout; however, a second unit was nearing completion concurrently with a new test airframe, the Heinkel He 178, which achieved its maiden flight on 27 August 1939—the first jet-powered aircraft flight—piloted by test pilot Erich Warsitz. On May 31, 1939, Heinkel filed a patent for an 'Aircraft power plant' (US2256198), credited to inventor Max Hahn; its original German application dated back to May 1938.

File:Heinkel He 178 050602-F-1234P-002.jpg
Heinkel He 178 jet aircraft
File:Hans von Ohain and Ernst Heinkel celebrate the first jet flight.jpg
Hans von Ohain toasts following the successful flight of the Heinkel He 178; Ernst Heinkel is visible raising his glass on the left.

Development efforts promptly shifted toward larger engines: initially, the HeS 6—a scaled-up version of the HeS 3b—and subsequently a novel design known as the HeS 8, which once again reconfigured the layout. This model connected compressor and turbine via a large-diameter drum sufficiently long to accommodate an annular combustion chamber between them. The intention was to equip this engine on the Heinkel He 280 fighter, but while airframe development progressed smoothly, engine development lagged, forcing use of gliding tests during continued engine refinement. A flight-ready HeS 8 was installed by late March 1941, culminating in its first flight on April 2. Three days later, it was demonstrated before a group of Nazi and RLM officials who expressed strong approval, resulting in prompt allocation of full development funding.

At this juncture, multiple turbojet projects were underway across Germany. Impressed by their potential, Heinkel facilitated Adolph Müller's transfer from Junkers, where Müller had been developing an axial compressor-driven engine renamed as the Heinkel HeS 30. Müller departed Junkers following their acquisition of Junkers Motoren, which maintained their own project known as the Junkers Jumo 004. Concurrently, BMW advanced its own design with the BMW 003.

By early 1942, progress on the HeS 8—officially designated as model 109-001 (HeS 001)—remained sluggish. In contrast, Müller's HeS 30 (109-006 or HeS 006) advanced more rapidly. Nevertheless, both engines were still some distance from production readiness, whereas both BMW's 003 and Junkers' Jumo 004 appeared closer to operational status. Consequently, RLM’s jet development director Helmut Schelp withdrew funding for both designs early that year and instructed Heinkel to focus on a new "pet project," which evolved into the Heinkel HeS 011. Although this became Schelp’s first "Class II" engine to demonstrate promising performance, production had not commenced before war’s end. Work on the HeS 8 persisted for some time but was ultimately discontinued in spring 1943.

Final outcome

One of the key difficulties von Ohain faced was his method of creating a feasible turbojet engine suitable for development. His initial concept featured a centrifugal compressor paired with a radial inflow turbine, a configuration that ultimately proved unworkable and, despite extensive efforts, never reached production.

In contrast, Whittle’s centrifugal flow engines—available in both straight-through and reverse flow designs and further refined by Rolls Royce—powered all Allied jets during World War II and most early post-war fighter aircraft. These engines were produced under license in several countries such as Australia, France, and the United States, while Soviet and Chinese manufacturers replicated them to power the MiG-15 and MiG-17 fighters. Whittle’s fundamental reverse flow layout remains the predominant gas turbine design in current production, with over 80,000 units manufactured globally in the form of the Allison (RR) 250/300 and Pratt & Whitney PT6 engine families.

Nonetheless, von Ohain’s development of the HeS 011 introduced a standard approach combining axial and radial components—a principle now widely applied in most business jets, turboprop aircraft, and helicopters.

Post-World War II

In 1947, von Ohain was brought to America through Operation Paperclip and began working for the United States Air Force at Wright-Patterson Air Force Base. By 1956 he had been appointed Director of the Air Force Aeronautical Research Laboratory, and by 1975 he served as Chief Scientist of the Aero Propulsion Laboratory at the same facility.

While at Wright-Patterson, von Ohain pursued various independent research projects. In the early 1960s, he extensively explored designs for gas core reactor rockets intended to contain nuclear fuel while utilizing the working fluid as exhaust. The engineering principles from these efforts were adapted for terrestrial applications such as centrifuges and pumps. Building on these mass-flow concepts, von Ohain later devised an innovative jet engine devoid of moving parts, where airflow within the engine formed a stable vortex functioning simultaneously as compressor and turbine.

His fascination with mass-flow phenomena also led him to investigate magnetohydrodynamics (MHD) for electricity generation. He recognized that hot gases exiting coal-fired plants could be harnessed for their velocity to generate power before remaining sufficiently hot to drive conventional steam turbines. This approach promised improved efficiency by extracting additional energy from coal combustion. However, practical implementation has been hindered by the absence of suitable high-temperature, non-magnetic materials capable of resisting chemically aggressive exhaust gases. Von Ohain also explored other power-generation technologies during his career.

Among his inventions was the "jet wing" concept, which involved diverting compressed air from a jet engine into large augmented vents on wings to enhance lift for VTOL aircraft. A small quantity of high-pressure air is forced into a venturi, inducing a much larger airflow and thereby increasing thrust. This principle was applied in the experimental Rockwell XFV-12, although commercial interest in VTOL designs waned shortly thereafter. Von Ohain contributed to numerous additional patents throughout his career.

He notably influenced Paul Bevilaqua, one of his students at Wright-Patterson Air Force Base, steering him from pure mathematics toward engineering—a shift that enabled Bevilaqua to develop the Rolls-Royce LiftSystem used in the JSF F35B STOVL. Bevilaqua remarked that while formal education taught him how to move pieces on a board, von Ohain taught him how to play chess. Additionally, von Ohain helped Bevilaqua understand the practical significance of TS diagrams.

Von Ohain retired from Wright-Patterson in 1979 and accepted an associate professorship teaching propulsion and thermodynamics at the nearby University of Dayton. Between 1981 and 1983, he also taught these subjects during winter terms at the University of Florida. He remained at Dayton until 1992 when health concerns prompted him and his wife Hanny to relocate to Melbourne, Florida.

Awards

Throughout his professional journey, Ohain received numerous accolades in both engineering and leadership fields. Among these honors were the American Institute of Aeronautics and Astronautics (AIAA) Goddard Astronautics Award, the United States Air Force Exceptional Civilian Service Award, the Systems Command Award for Exceptional Civilian Service, the Eugene M. Zuckert Management Award, the Air Force Special Achievement Award, and shortly before retiring, the Citation of Honor. Between 1984 and 1985, he held the prestigious Charles A. Lindbergh Chair in Aerospace History, a competitive senior fellowship at the National Air and Space Museum. In 1991, Ohain and Whittle were jointly recognized with the Charles Stark Draper Prize for their pioneering work on turbojet engines. Additionally, Ohain was inducted as a member of the U.S. National Academy of Engineering (NAE).

In 1992, he was honored with the Ludwig-Prandtl-Ring by the Deutsche Gesellschaft für Luft- und Raumfahrt (German Society for Aeronautics and Astronautics) in recognition of his "exceptional contributions to aerospace engineering."

Ohain’s achievements also led to his induction into the International Air & Space Hall of Fame at the San Diego Air & Space Museum in 1982.

Further acknowledgment came in 1990 when he was inducted into the National Aviation Hall of Fame.

Death

Ohain passed away in Melbourne, Florida, in 1998 at the age of 86. He left behind his wife and four children. One of his sons, Christopher von Ohain, served in the United States Marine Corps (USMC). Christopher’s son, Hans Christopher von Ohain, also enlisted in the USMC but tragically died in a car accident in 2022.

See also

References

  1. ↑ Golley,John-Genesis of the Jet Airlife Publishing 1995 p 86
  2. ↑ 2.0 2.1 Margaret Conner, Hans von Ohain: Elegance in Flight (Reston, Virginia: American Institute for Aeronautics and Astronautics, Inc., 2001), page 31
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  8. ↑ Margaret Conner, Hans von Ohain: Elegance in Flight (Reston, Virginia: American Institute for Aeronautics and Astronautics, Inc., 2001), pages 131–133
  9. ↑ Margaret Conner, Hans von Ohain: Elegance in Flight (Reston, Virginia: American Institute for Aeronautics and Astronautics, Inc., 2001), pages 124–131
  10. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  11. ↑ Conner, Margaret (2001). hans von Ohain – Elegance in Flight. American Institute for Aeronautics and Astronautics, Inc. ISBN 1563475200.
  12. ↑ Margaret Conner, Hans von Ohain: Elegance in Flight (Reston, Virginia: American Institute for Aeronautics and Astronautics, Inc., 2001), page 62
  13. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  14. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  15. ↑ Margaret Conner, Hans von Ohain: Elegance in Flight (Reston, Virginia: American Institute for Aeronautics and Astronautics, Inc., 2001), page 63
  16. ↑ Koehler 1999, p. 173.
  17. ↑
  18. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
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  20. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
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  22. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  23. ↑ Experimental & Prototype US Air Force Jet Fighters, Jenkins & Landis, 2008
  24. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  25. ↑ Klooster 2009, p.459.
  26. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  27. ↑ 27.0 27.1 27.2 Cite error: Invalid <ref> tag; no text was provided for refs named lw
  28. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  29. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  30. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named SNAaSM

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Sources

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External links

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