Frank Whittle
Sir Frank Whittle, was an English engineer, inventor and Royal Air Force air officer. He is credited with co-creating the turbojet engine. A patent was submitted by Maxime Guillaume in 1921 for a similar invention which was technically unfeasible at the time. Whittle's jet engines were developed some years earlier than those of Germany's Hans von Ohain, who designed the first-to-fly turbojet engine as well as Austria’s Anselm Franz.
Whittle demonstrated an aptitude for engineering and an interest in flying from an early age. At first he was turned down by the RAF but, determined to join the force, he overcame his physical limitations and was accepted and sent to No. 2 School of Technical Training to join No 1 Squadron of Cranwell Aircraft Apprentices. He was taught the theory of aircraft engines and gained practical experience in the engineering workshops. His academic and practical abilities as an Aircraft Apprentice earned him a place on the officer training course at Cranwell. He excelled in his studies and became an accomplished pilot. While writing his thesis he formulated the fundamental concepts that led to the creation of the turbojet engine, taking out a patent on his design in 1930. His performance on an officers' engineering course earned him a place on a further course at Peterhouse, Cambridge, where he graduated with a First.
Without Air Ministry support, he and two retired RAF servicemen formed Power Jets Ltd to build his engine with assistance from the firm of British Thomson-Houston. Despite limited funding, a prototype was created, which first ran in 1937. Official interest was forthcoming following this success, with contracts being placed to develop further engines, but the continuing stress seriously affected Whittle's health, eventually resulting in a nervous breakdown in 1940. In 1944 when Power Jets was nationalised he again suffered a nervous breakdown, and resigned from the board in 1946.
In 1948, Whittle retired from the RAF and received a knighthood. He joined BOAC as a technical advisor before working as an engineering specialist with Shell, followed by a position with Bristol Aero Engines. After emigrating to the U.S. in 1976 he accepted the position of NAVAIR Research Professor at the United States Naval Academy from 1977 to 1979. In August 1996, Whittle died of lung cancer at his home in Columbia, Maryland. In 2002, Whittle was ranked number 42 in the BBC poll of the 100 Greatest Britons.
Early life
Whittle was born in a terraced house in Newcombe Road, Earlsdon, Coventry, England, on 1 June 1907, the eldest son of Moses Whittle and Sara Alice Garlick. When he was nine years old, the family moved to the nearby town of Royal Leamington Spa where his father, a highly inventive practical engineer and mechanic, purchased the Leamington Valve and Piston Ring Company in Clinton Street, which comprised a few lathes and other tools and a single-cylinder gas engine, on which Whittle became an expert. Whittle developed a rebellious and adventurous streak, together with an early interest in aviation.After two years attending Milverton School, Whittle won a scholarship to a secondary school which in due course became Leamington College for Boys, but when his father's business faltered there was not enough money to keep him there. He quickly developed practical engineering skills while helping in his father's workshop, and being an enthusiastic reader spent much of his spare time in the Leamington reference library, reading about astronomy, engineering, turbines, and the theory of flight. At the age of 15, determined to be a pilot, Whittle applied to join the RAF.
Entering the RAF
In January 1923, having passed the RAF entrance examination with a high mark, Whittle reported to RAF Halton in Buckinghamshire as an Aircraft Apprentice. He lasted only two days: just five feet tall and with a small chest measurement, he failed the medical. He then put himself through a vigorous training programme and special diet devised by a physical training instructor at Halton to build up his physique, only to fail again six months later, when he was told that he could not be given a second chance, despite having added three inches to his height and chest. Undeterred, he applied again under an assumed name and presented himself as a candidate at the No 2 School of Technical Training RAF Cranwell. This time he passed the physical and, in September that year, 364365 Boy Whittle, F, started his three-year training as an aircraft mechanic in No. 1 Squadron of No. 4 Apprentices Wing, RAF Cranwell, because RAF Halton No. 1 School of Technical Training was unable to accommodate all the aircraft apprentices at that time.Whittle hated the strict discipline imposed on apprentices and, convinced there was no hope of ever becoming a pilot, he at one time seriously considered deserting. However, throughout his early days as an aircraft apprentice, he maintained his interest in model aircraft and joined the Model Aircraft Society, where he built working replicas. The quality of these attracted the eye of the Apprentice Wing commanding officer, who noted that Whittle was also a mathematical genius. He was so impressed that in 1926 he recommended Whittle for officer training at RAF College Cranwell.
For Whittle, this was the chance of a lifetime, not only to enter the commissioned ranks but also because the training included flying lessons on the Avro 504. While at Cranwell he lodged in a bungalow at Dorrington. Being an ex-apprentice amongst a majority of ex-public schoolboys, life as an officer cadet was not easy for him, but he nevertheless excelled in the courses and went solo in 1927 after only 13.5 hours’ instruction, quickly progressing to the Bristol Fighter and gaining a reputation for daredevil low flying and aerobatics.
A requirement of the course was that each student had to produce a thesis for graduation: Whittle decided to write his on potential aircraft design developments, notably flight at high altitudes and speeds over 500 mph. In Future Developments in Aircraft Design he showed that incremental improvements in existing propeller engines were unlikely to make such flight routine. Instead he described what is today referred to as a motorjet; an air compressor using a conventional piston engine to provide compressed air to a combustion chamber whose exhaust was used directly for thrust – essentially an afterburner attached to a piston engine driven air compressor. The idea was not new and had been talked about for some time in the industry, but Whittle's aim was to demonstrate that at increased altitudes the lower outside air density would increase the design's efficiency. For long-range flight, using an Atlantic-crossing mailplane as his example, the engine would spend most of its time at high altitude and thus could outperform a conventional powerplant. According to Whittle, "...I came to the general conclusion that if very high speeds were to be combined with long range, it would be necessary to fly at very great height, where the low air density would greatly reduce resistance in proportion to speed."
Of the few apprentices accepted into the Royal Air Force College, Whittle graduated in 1928 at the age of 21 and was commissioned as a pilot officer in July. He ranked second in his class in academics, won the Andy Fellowes Memorial Prize for Aeronautical Sciences for his thesis, and was described as an "exceptional to above average" pilot. However, his flight logbook also showed numerous red ink warnings about showboating and overconfidence, and because of dangerous flying in an Armstrong Whitworth Siskin he was disqualified from the end-of-term flying contest.
Development of the turbojet engine
Whittle continued working on the motorjet principle after his thesis work but eventually abandoned it when further calculations showed it would weigh as much as a conventional engine of the same thrust. Pondering the problem he thought: "Why not substitute a turbine for the piston engine?" Instead of using a piston engine driven compressor to provide the compressed air for the burner, a turbine could be used to extract some power from the exhaust and drive a compressor, similar as in a turbocharger. The remaining exhaust thrust would power the aircraft.On 27 August 1928, Pilot Officer Whittle joined No. 111 Squadron, Hornchurch, flying Siskin IIIs. His continuing reputation for low flying and aerobatics provoked a public complaint that almost led to his being court-martialled. Within a year he was posted to the Central Flying School, then at RAF Wittering, for a flying instructor's course. He became a popular and gifted instructor, and was selected as one of the entrants in a competition to select a team to perform the "crazy flying" routine in the 1930 Royal Air Force Air Display at RAF Hendon. He destroyed two aircraft in accidents during rehearsals but remained unscathed on both occasions. After the second incident an enraged Flight Lieutenant Harold W. Raeburn said furiously, "Why don't you take all my bloody aeroplanes, make a heap of them in the middle of the aerodrome and set fire to them – it's quicker!"
Whittle showed his engine concept around the base, where it attracted the attention of Flying Officer Pat Johnson, formerly a patent examiner. Johnson, in turn, took the concept to the commanding officer of the base. This set in motion a chain of events that almost led to the engines being produced much sooner than actually occurred.
Earlier, in July 1926, A. A. Griffith had published a paper on compressors and turbines, which he had been studying at the Royal Aircraft Establishment. He showed that such designs up to this point had been flying "stalled", and that by giving the compressor blades an aerofoil-shaped cross-section their efficiency could be dramatically improved. The paper went on to describe how the increased efficiency of these sorts of compressors and turbines would allow a jet engine to be produced, although he felt the idea was impractical, and instead suggested using the power as a turboprop. At the time most superchargers used a centrifugal compressor, so there was limited interest in the paper.
Encouraged by his commanding officer, in late 1929 Whittle sent his concept to the Air Ministry to see if it would be of any interest to them. Whittle was invited to the Ministry and met an officer of the Ministry's Department of Scientific and Industrial Research and Griffith. Afterwards, Whittle received a letter from Griffith, who was of the opinion that Whittle's "simple" design could not achieve the sort of efficiencies needed for a practical engine. After pointing out an error in one of Whittle's calculations, Griffith went on to comment that the centrifugal design would be too large for aircraft use and that using the jet directly for power would be rather inefficient. Griffith called the design "impracticable," as current materials could not achieve the high temperatures. Griffith did say "the internal combustion turbine will almost certainly be developed into a successful engine, but before this can be done the performance of both compressors and turbines will have to be greatly improved. However it has been of real interest to investigate your scheme and I can assure you that any suggestion submitted by people in the Service is always welcome."
Whittle received a report noting the limitations of his concept. The report said "the internal combustion turbine will not be rendered practical by the revolutionary design of some lucky inventor. The steam turbine engineer and the metallurgist... are the people with whom the future development of the turbine rests" Whittle recorded that he found the response depressing.
Pat Johnson remained convinced of the validity of the idea, and had Whittle patent the idea in January 1930. Since the RAF was not interested in the concept they did not declare it secret, meaning that Whittle was able to retain the rights to the idea, which would have otherwise been their property. Johnson arranged a meeting with British Thomson-Houston, whose chief turbine engineer seemed to agree with the basic idea. However, BTH did not want to spend the £60,000 it would cost to develop it, and this potential brush with early success went no further.
In January 1930, Whittle was promoted to flying officer. In Coventry, on 24 May 1930, Whittle married his fiancée, Dorothy Mary Lee, with whom he later had two sons, David and Ian. Then, in 1931, he was posted to the Marine Aircraft Experimental Establishment at Felixstowe as an armament officer and test pilot of seaplanes, where he continued to publicise his idea. This posting came as a surprise for he had never previously flown a seaplane, but he nevertheless increased his reputation as a pilot by flying some 20 different types of floatplanes, flying boats, and amphibians.
While at Felixstowe, Whittle met with the firm of Armstrong Siddeley, and their technical advisor W.S. Farren. The firm rejected Whittle's proposal, doubting material was available to sustain the required very high temperatures. Whittle's turbojet proposal required a compressor with a pressure ratio of 4:1, while the best current supercharger had only half that value. Besides publishing a paper on superchargers, Whittle wrote The Case for the Gas Turbine. According to John Golley, "The paper contained example calculations which showed the big increase in efficiency which could be obtained with the gas turbine at great height due to the beneficial effects of low air temperature. It also contained calculations to demonstrate the degree to which range would depend on height with turbojet aircraft."
Every officer with a permanent commission was expected to take a specialist course, and as a result Whittle attended the Officers School of Engineering at RAF Henlow in 1932. He obtained an aggregate of 98% in all subjects in his entrance exam, which allowed him to complete a shortened one-year course. Whittle received a Distinction in every subject, except mechanical drawing, where he was described as "a very able student. He works hard and has originality. He is suitable for experimental duties."
His performance in the course was so exceptional that in 1934 he was permitted, though the scheme for RAF officers had been ended the year before, to take a two-year engineering course as a member of Peterhouse, the oldest college of Cambridge University, graduating in 1936 with a First in the Mechanical Sciences Tripos. The Ministry gave him permission to spend a further year after graduation working with the aerodynamicist Melvill Jones. On 1 February 1934, he was promoted to the rank of flight lieutenant.