Who invented jet propulsion

After receiving his degree in , he became a junior assistant to Robert Wichard Pohl, director of the university's Physical Institute. Granted a patent for his turbojet engine in , Ohain joined the Heinkel Company in Rostock, Germany. By he had built a factory-tested demonstration engine and, by , a fully operational jet aircraft, the He Soon after, Ohain directed the construction of the He S.

This engine was installed in the He airplane, which made the world's first jet-powered aircraft flight on August 27, Ohain developed an improved engine, the He S. This engine design, however, was less efficient than one designed by Anselm Franz, which powered the Me , the first operational jet fighter aircraft.

During his 32 years of U. In Ohain was honored by the U. Ohain died on March 13, , at his home in Melbourne, Florida. The committee as a whole, Bush reminded him, "on account of British wishes," could not be privy to full information about the Whittle engine.

Bush now qualified his support for the Jacobs project. If the Whittle engine was as advanced as it appeared, it deserved to be expedited, regardless of the promise of the Jacobs project over the long term:. Lyon, the Army's technical liaison officer in Great Britain.

In August Colonel Donald Keirn, the engineer from Wright Field who brought the news to the Cleveland laboratory two years later, took off for England to bring back the Whittle engine. Later Keirn joined the Special Committee so that he was fully informed of all the jet propulsion projects, both the "most secret" Whittle project and the "secret" projects of the Special Committee. His letter to Colonel Lyon, 2 October , reveals the first discussions of a possible future Army effort to preempt the jet propulsion field and thereby end the NACA hegemony over basic aeronautical research.

However, with characteristic restraint, he refused to commit himself on this issue. Clearly, he saw the turbojet as a possible answer to the problem of obtaining higher speeds for pursuit aircraft, but he stopped short of predicting that the piston engine would be obsolete in ten years.

The letter reveals Arnold's astute assessment of the possible dawning of a new era of jet propulsion. Although not privy to the full Whittle story, the Durand committee had enough information on the Whittle engine to see the potential of the compressor-turbine combination. It should be noted that Jacobs and his team were obviously informed of the conclusion of the panel, but persisted in their belief that the hybrid scheme would work.

A letter to the panel from Henry Reid, Engineer-n-Charge at Langley, indicated that "jet propulsion can better be accomplished at present with the use of the conventional engine". Whether the simpler centrifugal compressor was considered at all is difficult to determine, since all the minutes for the compressor-turbine panel have not been found. The axial compressor, because of its smaller frontal area and higher potential pressure ratio, looked more promising on paper.

However, if the axial compressor was lighter and more compact, it demanded knowledge of aerodynamics. The complex movement of air across the blades of several stages presented a challenge to the designer. The fabrication of the complicated compressor was a nightmare. Vibrations created the danger that compressor blades might fly off in all directions. The simpler solution found by Whittle and von Ohain-the centrifugal compressor-eluded the steam turbine experts on the committee.

The same month that the compressor panel was formed, representatives of Allis-Chalmers visited Langley. Lewis revealed that the results of a joint investigation with General Electric would be made available, This was obviously a reference to the eight-stage axial-flow compressor of Jacobs and Wasielewski. All three of the companies selected axial-flow compressors, but they decided not to attempt as many stages. The Westinghouse design team may have decided to use a Brown-Boveri compressor as its model.

In any case, the company was familiar with the axial configuration through experience with axial compressors in Navy surface vessels. When the Durand Committee met at Langley Field in September, they recommended that Jacobs begin design studies to explore "the most suitable means for applying this system of jet propulsion to actual aircraft".

They also decided that the preliminary studies of the companies could be made into actual proposals for submission to the Army or Navy. The Army agreed to support General Electric's proposal for a turboprop. Up to the time of the submission of the proposals, the committee had allowed considerable cooperation and exchange of information among the three companies, and the NACA was a clearinghouse for information.

After the September meeting each company began to work independently, and although the upper management of each company represented on the Special Committee was aware of the parallel development of General Electric's Whittle turbojet, the design teams actually working on the respective projects were kept in the dark, Moreover, they were not allowed to exchange information with designers working on the other projects sponsored by the Special Committee until Durand wrote to General O.

Echols for permission for greater cooperation. In recalling the "helpful attitude regarding mutual conference and interchange of data and suggestions" that the companies had enjoyed prior to the awarding of specific design contracts, he urged that it be allowed to continue.

While the members of the Special Committee knew about the "Whittle matter," as did selected high-level individuals at General Electric, Arnold would not allow the Whittle engine to be tested at Langley Field because of the British "most secret" classification. In a memorandum addressed to General Arnold, 13 November , he wrote: "As we get deeper into the Bell XPA and GE Type I Supercharger Projects, we find that [ 53 ] in order to exploit the fullest possibilities of this engine-airplane combination Echols suggested either the foot tunnel at Moffet Field Ames or the foot pressure tunnel at Langley.

Noted in large letters on the memo was "Decision is NO" with the appended note: "General Echols advised that he had discussed this matter with Gen. A, this date, and that Gen. A did not wish to tunnel test at NACA in view of the "secrecy" of project. Therefore it will be necessary to proceed without tunnel tests planning on testing for 2nd attack if first attempt is a "bust".

If the committee had encouraged at least one American design based on the centrifugal compressor, more rapid progress would have been apparent. Kept in the dark, those making the initial decisions did not know that part of the success of the Whittle engine depended on its simple centrifugal compressor. Progress on all four of the projects of Durand's Special Committee was slow. In June , Vannevar Bush raised doubts about the wisdom of exclusive reliance on the axial compressor. Referring to "the secret development being carried on by the General Electric Company on compressors for use in jet propulsion," he wanted to know whether the special panel that "had previously provided for the interchange of information on compressor design" should be reconvened.

Durand responded that A. Stevenson, Jr. These "troubles" were directly related to the compressor: "We are becoming quite worried about vibration of the blades on the axial-flow compressor". He reported that their experimental four-stage compressor, like the one at Langley, had lost its blades. Although a turboprop provides more efficient propulsion at modest speeds, the gearing to connect the gas turbine to the propeller adds mechanical complexity.

Nevertheless, its tricky axial compressor made significant progress slow. Support for the Allis-Chalmers design for a ducted fan with double paths of cool and hot air was dropped by the Navy in , when the company obtained the license to build a British Havilland-Halford jet propulsion unit.

Centrifugal compressor. Of the three designs submitted by the steam turbine manufacturers, only the Westinghouse 19B turbojet actually reached flight-testing before the end of World War II. The company proudly called it the "Yankee" because it was the product of American engineering.

It appears that R. Kroon, head of the team that actually built the "Yankee," did not know of the British developments prior to However, even in the Westinghouse unit, a British idea for a ring of individual combustors around the central shaft of the [ 54 ] engine did find its way into the design. The "Yankee" engine had 24 combustor "cans". A company history relates that in July , during the time that Westinghouse was struggling with its design, Stuart Way mentioned their problems in a meeting of a NACA combustion subcommittee.

At some point the engineers at West Lynn and Schenectady may have exchanged information, because the TG, the General Electric project at Schenectady, also used multiple combustor cans.

Glenn Warren, one of its designers, called the idea one of the most important aspects of British-American cooperation. Jacobs never had the benefit of the British solution to the combustion problem. Unaware that turbojets had already passed their bench tests in England and Germany, Langley engineers struggled to perfect Jacobs's hybrid scheme. The problem of achieving stable combustion in a continuous airstream without creating a flame that was so hot it would melt the metal sides of the apparatus was particularly recalcitrant.

Jacobs tried to get the fuel to vaporize within a tubular boiler. However, he could not get his system to operate satisfactorily, and he agreed to enlist the assistance of Kemper's Power Plants Division.

Durand strongly supported the idea that a series of fuel jets should be tried. Pinkel assigned Kervork Nahigyan the task of redesigning the burner.

Durand noted on a visit to Langley in March that both Jacobs's approach and that of the Power Plants Division appeared promising. He encouraged the rivalry between the two groups and set a deadline for an actual demonstration to the entire committee for July As the first test flight of the General Electric 1-A engine neared, he became apprehensive.

If Jake's jeep failed, it would seriously affect the prestige of his committee, perhaps that of the entire NACA. In a letter to Lewis from California, written several days before he was to witness the flight over Muroc Dry Lake, Durand urged Lewis to "feel quite free to take hold of and direct the work of Jacobs along the lines agreed upon earlier".

There was not a great deal that they could do about the projects that were in the hands of the private companies, but, he wrote, I have, There can be no question that once the Whittle engine was successfully flown, it became clearer that the outlines of future development would favor the far simpler compressor and turbine combination over the unwieldy piston engine and fan combination of Jacobs's conception.

Durand was enthusiastic about the "splendid results" of the tests at Muroc. He wrote to Keirn, "It really begins to look as though a definite start has been made along the lines we have been thinking about so long". Durand informed members of the Special Committee that "resulting from entirely different causes" a meeting had been called "on the initiative of Army aviation" to take place in Washington, D. Although no direct reference was made to the Whittle project, there could have been no question in any member's mind as to what Durand was talking about when he wrote that representatives of the Army, Navy, the Chairman of NACA, and the Chairman of the Special Committee on jet Propulsion "take a broad general view, with an attempt to evaluate its significance as a factor in our present war effort, and, if possible, to reach some decision as to the extent to which the subject merits immediate support and development".

He revealed that a report on the Langley project would be presented at that time. Obviously, the Whittle turbojet was the winner because it was at a point of development well beyond that of the NACA project. Although it was not clear at the time, ultimately the complexity and the excessive amount of weight in comparison to its low thrust meant that the ducted fan could not compete with the simplicity, efficiency, and low maintenance of future turbojets.

The jeep, nevertheless, played an important role in future American turbojet development because it stimulated both axial-compressor research and pioneering work on afterburners work that was continued after the move of the Power Plants Division to Cleveland.

The failure of the jeep to win the continuing support of the Army directly affected the research program of the Cleveland laboratory.

Ben Pinkel recalled that some time prior to his departure for Cleveland in December , he was called to Henry Reid's office, where George Lewis reported that "officers of the military echelon" had informed him that "the war would be fought" with five reciprocating engines currently under production and "that all work on jet propulsion should be stopped in order that all effort should be directed toward those reciprocating engines".

Even after the Army's decision, Jacobs continued to believe in his ducted-fan design. In January , after his transfer to Cleveland, Nahigyan perfected his design for a burner employing a series of liquid-injection spray nozzles, located within bell-shaped flame holders.

In a memorandum written after this visit, Reid noted the apparent lack of general overview of the jet propulsion situation. It was impossible to compare the various schemes to decide which ones were worthy of vigorous development A technician uses a micrometer to determine possible distortion of the turbine blades of General Electric's I turbojet engine. The ring of combustor cans, immediately behind the turbine, was Whittle's solution to the combustion problem.

However, the successful test flight of the General Electric 1-A engines in the Bell Airacomet the previous fall had sealed the fate of the Jacobs project.

On 15 April the Special Committee officially resolved to drop "without prejudice" the project they had so wholeheartedly supported. Viewed in the context of the abortive effort to develop the jeep at Langley, Arnold's decision to assign the Cleveland laboratory the task of solving the mechanical problems of existing piston engines takes on new meaning.

He had lost confidence in the NACAs technical leadership in the propulsion field. The cancellation of the jeep took the creative, experimental work on jet propulsion away from the NACA for the duration of the war. Arnold chose to promote General Electric, a company previously only marginally involved in the development of aircraft engines, to a place on the cutting edge of jet propulsion development in the United States.

Although the piston engine companies bore the brunt of Arnold's wrath for the dismal engine situation, he also punished the NACA for its belated and rather minimal efforts prior to to develop a jet propulsion scheme.

Arnold's decision to focus on developing existing piston engines to fight the war was a gamble. By the Germans were mass-producing a turbojet with an axial-flow compressor, the Jumo for the Messerschmitt Fortunately, Hitler did not appreciate the strategic importance of the superior speed of the turbojet, and production of the Jumo came too late to make a difference in the outcome of the war.

The Germans made only limited use of jet aircraft to shoot down Allied reconnaissance planes and to attack bomber missions. How close the jet engine came to making the difference in the war is revealed by a remark in a memo from Arnold in May "The jet propelled airplane has one idea and mission in life and that is to get at the bombers, and he is going by our fighters so fast that they will barely see him, much less throw out a sky hook and slow him up".

This visit, however, clearly underscored the Army's intention to limit this involvement to the testing of engines already developed by private companies such as General Electric and Westinghouse. Jacobs's jeep briefly gave the NACA license to develop a jet prototype. The Cleveland laboratory would continue to feel the repercussions of its cancellation. By August it was clear to the leaders of the Cleveland laboratory that jet propulsion would play an increasingly important role in the future.

After a survey of existing facilities, George Lewis pointed out that "when the Committee's Cleveland laboratory was laid out, no thought was given to the provision of facilities for testing jet propulsion units". Jacobs himself spent several months at the laboratory in and made such an impression on several clean-shaven young engineers that they grew beards in his honor.

The precise nature of Jacobs's work in Cleveland is not clear. It appears that he continued work on his jet propulsion scheme despite the Army's cancellation.

It was now "bootleg" work, carried on without official sanction. He was told that Jacobs designed the engine from information gathered by two agents in a German Bavarian Motor Works plant. Melzer recalled that Jacobs often came to the shop to watch his painstaking labor, cutting the blades to conform to the so-called German configurations. One afternoon Jacobs called Meltzer to let him know that they were going to start the unit in a test cell.

About a year later, we heard that another engine had exploded, and the blades had gone off in all directions. We were lucky taking that chance". By March Lewis reported on the "change in character of the Committee's research program" brought about by the "success of the Whittle jet-propulsion engine".

Staff working under Kervork Nahigyan in the special jet Propulsion Static Test Laboratory built and tested the first afterburner in October , a direct result of the earlier work on the burner for Jake's jeep. Abe Silverstein's group adapted the Altitude Wind Tunnel to test the new jet propulsion units.

General Electric and Westinghouse sent experimental models of their engines for tests in the new tunnel. Although denied work on their own experimental engine of NACA design, the staff of the Cleveland laboratory acquired a unique, hands on, experience in jet technology. They would build on this early experience to become the government's experts in jet propulsion in the early postwar years.

Letter from Ben Pinkel to V. Dawson, 2 September This consists of Army correspondence and contains a wealth of information waiting to be mined. Also, Leslie E. Neville and Nathaniel F. Ben Pinkel to V. Oscar W. Schey, Benjamin Pinkel, and Herman H. Ellerbrock, Jr. Proceedings In addition to studies mentioned in note 5, for the history of jet propulsion, see Edward W.

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