Editing Frank Whittle (section)

==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.<ref>''[http://www.warbirdforum.com/whittle.htm Gentlemen, I give you the Whittle engine]'' {{webarchive |url=https://web.archive.org/web/20080516164256/http://www.warbirdforum.com/whittle.htm |date=16 May 2008 }}</ref>

On 27 August 1928, Pilot Officer Whittle joined [[No. 111 Squadron RAF|No. 111 Squadron]], Hornchurch, flying [[Armstrong Whitworth Siskin|Siskin IIIs]]. His continuing reputation for low flying and aerobatics provoked a public complaint that almost led to his being court-martialled.<ref name="RAF2" >{{cite web |url=http://www.raf.mod.uk/history_old/whittle2.html |title=Sir Frank Whittle – Flying Career |work=Royal Air Force History |archive-url=https://web.archive.org/web/20070713020750/https://www.raf.mod.uk/history_old/whittle2.html |archive-date=13 July 2007}}</ref> 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 [[Hendon Aerodrome|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!"<ref name="RAF2" />

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.<ref name=tele/>

Earlier, in July 1926, [[Alan Arnold Griffith|A. A. Griffith]] had published a paper on compressors and turbines, which he had been studying at the [[Royal Aircraft Establishment]] (RAE). 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 (DSIR) and Griffith (at the time a member of the Aeronautical Research Committee).<ref name="WhittleInvent" /> 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.<ref name=tele/><ref name="WhittleInvent" /> 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."<ref name="WhittleInvent" />

Whittle received a report noting the limitations 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"<ref name=WhittleInvent> Nahum, Andrew 2004 ''Frank Whittle Invention of the Jet Engine'' p 18-20</ref> Whittle recorded that he found the response depressing.<ref name="WhittleInvent" />

Pat Johnson remained convinced of the validity of the idea, and had Whittle patent<ref>{{cite web |url=http://www.frankwhittle.co.uk/content.php?act=viewDoc&docId=4&docFatherId=1&level=sub |title=Welcome to the Frank Whittle Website |access-date=22 October 2016 |archive-url=https://web.archive.org/web/20120213182253/http://www.frankwhittle.co.uk/content.php?act=viewDoc&docId=4&docFatherId=1&level=sub |archive-date=13 February 2012 |url-status=dead  }}</ref> 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]] (BTH), 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.<ref name=tele/>



In January 1930, Whittle was promoted to [[flying officer]].<ref>{{London Gazette|issue = 33591|date = 25 March 1930|page=1896}}</ref> In Coventry, on 24 May 1930, Whittle married his fiancée, Dorothy Mary Lee, with whom he later had two sons, David and Ian.<ref name="RAF2"/> 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.<ref name="MAM"/><ref>{{cite web|url=http://www.flightglobal.com/pdfarchive/view/1951/1951%20-%200881.html|title=power jets – frank whittle – gloster – 1951 – 0881 – Flight Archive|access-date=20 April 2020}}</ref>

While at Felixstowe, Whittle met with the firm of [[Armstrong Siddeley]], and their technical advisor [[William Farren (engineer)|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#Aircraft|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."{{sfn|Golley|1987|pp=51–54}}

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."{{sfn|Golley|1987|pp=58–59}}

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, Cambridge|Peterhouse]], the oldest college of [[University of Cambridge|Cambridge University]], graduating in 1936 with a [[British undergraduate degree classification#First Class Honours|First]] in the Mechanical Sciences [[Tripos]].<ref name=tele /> The Ministry gave him permission to spend a further year after graduation working with the aerodynamicist [[Melvill Jones]].<ref>Nahum 2004 p22</ref> On 1 February 1934, he was promoted to the rank of [[flight lieutenant]].<ref>{{London Gazette|issue = 34023|date = 13 February 1934|page=1004}}</ref>

===Power Jets Ltd===<!-- This section is linked from [[Gloster Meteor]] -->
Still at Cambridge, Whittle could ill afford the £5 renewal fee for his jet engine patent when it became due in January 1935, and because the Air Ministry refused to pay it the patent was allowed to lapse. Shortly afterwards, in May, he received mail from [[Sir Rolf Dudley-Williams, 1st Baronet|Rolf Dudley-Williams]], who had been with him at Cranwell in the 1920s and Felixstowe in 1930. Williams arranged a meeting with Whittle, himself, and another by-then-retired RAF serviceman, [[James Collingwood Tinling]]. The two proposed a partnership that allowed them to act on Whittle's behalf to gather public financing so that development could go ahead.<ref name=tele/><ref name="Eminent Petreans"/>  Whittle thought improvements to his original idea could be patented, noting, "Its virtue lies entirely in its extremely low weight, and that it will work at heights where atmospheric density is very low." This led to three provisional specifications being filed, as the group sought to develop a jet-propelled aeroplane.{{sfn|Golley|1987|pp=65–66}} The arrangement was that Williams and Tinling would have a quarter share each of the commercial rights but they would not approach any existing company in the aircraft industry.<ref>Nahum 2004 p25</ref>

The agreement soon bore fruit, and in 1935, through Tinling's father, Whittle was introduced to Mogens L. Bramson, a well-known independent consulting aeronautical engineer and patent engineer.{{sfn|Golley|1987|p=66}} Bramson was initially sceptical but after studying Whittle's ideas became an enthusiastic supporter.<ref name = ASAEE>{{cite report |url= https://archive.org/details/ECL-172|title= ECL 172: This Must Be Done!|last1= Kardos|first1= Geza|year= 1971|publisher= [[American Society for Engineering Education]] | series = Engineering Case Library|access-date= 16 July 2015}}</ref> Bramson introduced Whittle and his two associates to the investment bank [[Oswald Toynbee Falk|O.T. Falk]] & Partners, where discussions took place with [[Lancelot Law Whyte]] and occasionally Sir [[Maurice Bonham-Carter]].<ref name=tele/>{{sfn|Golley|1987|p=67}} The firm had an interest in developing speculative projects that conventional banks would not touch. Whyte was impressed by the 28-year-old Whittle and his design when they met on 11 September 1935:
{{blockquote|The impression he made was overwhelming, I have never been so quickly convinced, or so happy to find one's highest standards met... This was genius, not talent. Whittle expressed his idea with superb conciseness:  'Reciprocating engines are exhausted.  They have hundreds of parts jerking to and fro, and they cannot be made more powerful without becoming too complicated.  The engine of the future must produce 2,000&nbsp;hp with one moving part: a spinning turbine and compressor.' |Lancelot Law Whyte<ref name=airf>Lee Payne, ''[http://www.afa.org/magazine/jan1982/0182race.html The Great Jet Engine Race... And How We Lost]'', Air Force Magazine, Vol. 65, No. 1 (January 1982) {{webarchive |url=https://web.archive.org/web/20120515152255/http://www.afa.org/magazine/jan1982/0182race.html |date=15 May 2012 }}</ref>}}

However O.T. Falk & Partners specified they would only invest in Whittle's engine if they had independent verification that it was feasible.<ref name = Bramson/> They financed an independent engineering review from Bramson (the historic{{sfn|Golley|1987|p=67}} "Bramson Report"<ref name = Bramson>{{cite journal |last= Meher-Homji|first= Cyrus&nbsp;B. |year= 2002|title= Enabling the Turbojet Revolution – The Bramson Report|url= http://files.asme.org/IGTI/News/25224.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://files.asme.org/IGTI/News/25224.pdf |archive-date=9 October 2022 |url-status=live |publisher= American Society of Mechanical Engineers|volume= 42|issue= 1|pages= 16–20|access-date=16 July 2015}}</ref><ref>{{cite journal |last= Bramson|first= Mogens |date= February 1979|title= Report on the Whittle System of Aircraft Propulsion (Theoretical Stage) – 8 October 1935|journal= Journal of the Royal Aeronautical Society}}</ref>), which was issued in November 1935.  It was favourable and together with a letter of support for Whittle and the engine from [[Henry Tizard]] (chair of the Engine sub-committee of the Aeronautical Research Committee) in response to Whyte Falk then agreed to finance Whittle.{{sfn|Nahum|2004|p=28}}<ref>Nahum 2004 p29,32</ref> With that the jet engine was finally on its way to becoming a reality.

On 27 January 1936, the principals signed the "Four Party Agreement", creating "[[Power Jets]] Ltd" which was incorporated in March 1936. The parties were O.T. Falk & Partners, the Air Ministry, Whittle and, together, Williams and Tinling. Falk was represented on the board of Power Jets by Whyte as chairman and Bonham-Carter as a director (with Bramson acting as alternate{{sfn|Golley|1987|p=70}}).{{sfn|Nahum|2004|pp=34–35}} Whittle, Williams and Tinling retained a 49% share of the company in exchange for Falk and Partners putting in £2,000 with the option of a further £18,000 within 18 months.<ref name=trust>[http://www.frankwhittle.co.uk/content.php?act=viewDoc&docId=6&docFatherId=1&level=sub Power Jets – A brief biography] {{Webarchive|url=https://web.archive.org/web/20111004135944/http://www.frankwhittle.co.uk/content.php?act=viewDoc&docId=6&docFatherId=1&level=sub |date=4 October 2011 }}, ''The Sir Frank Whittle Commemorative Trust''</ref>{{sfn|Golley|1987|p=69}} As Whittle was still a full-time RAF officer and currently at Cambridge, he was given the title "Honorary Chief Engineer and Technical Consultant". Needing special permission to work outside the RAF, he was placed on the Special Duty List and allowed to work on the design as long as it was for no more than six hours a week.{{sfn|Nahum|2004|p=35}} However he was allowed to continue at Cambridge for a year doing post-graduate work which gave him time to work on the turbojet.{{sfn|Golley|1987|p=77}}

The Air Ministry still saw little immediate value in the effort (they regarded it as long-range research{{sfn|Golley|1987|pp=71, 77}} and set up work on an axial flow turbine at the RAE  with [[Hayne Constant]] in 1937<ref>Nahum 2004 p20</ref>), and having no production facilities of its own, Power Jets entered into an agreement with steam turbine specialists [[British Thomson-Houston]] (BTH) to build an experimental engine facility at a BTH factory in [[Rugby, Warwickshire]].{{sfn|Nahum|2004|p=53}} Work progressed quickly, and by the end of the year 1936 the prototype detail design was finalised and parts for it were well on their way to being completed, all within the original £2,000 budget.<ref name=trust/>{{sfn|Golley|1987|p=82}} However, by 1936, Germany had also started working on jet engines ([[Herbert A. Wagner]] at [[Junkers]] and [[Hans von Ohain]] at [[Heinkel]]) and, although they too had difficulty overcoming conservatism, the [[Ministry of Aviation (Nazi Germany)|German Ministry of Aviation]] (Reichsluftfahrtministerium) was more supportive than their British counterpart.{{sfn|Golley|1987|pp=77, 80}} Von Ohain applied for a patent for a turbojet engine in 1935 but having earlier reviewed and critiqued Whittle's patents,  had to narrow the scope of his own filing.<ref>Conner, Margaret (2001). hans von Ohain – Elegance in Flight P 34. American Institute for Aeronautics and Astronautics, Inc. {{ISBN|1563475200}}.</ref> In Spain, air-force pilot and engineer [[Virgilio Leret Ruiz]] had been granted a patent for a jet engine in March 1935, and [[Second Spanish Republic|Republican]] president [[Manuel Azaña]] arranged for initial construction at the [[Hispano-Suiza]] aircraft factory in Madrid in 1936, but Leret was executed months later by [[Francoist Spain|Francoist]] [[Spanish protectorate in Morocco|Moroccan]] troops after commanding the defence of his seaplane base near [[Melilla]] at the onset of the [[Spanish Civil War]]. His plans were hidden from the Francoists and secretly handed to the British embassy in Madrid a few years later when his wife, [[Carlota O'Neill]], was released from prison.<ref>{{cite web|url=https://english.elpais.com/elpais/2014/05/27/inenglish/1401200493_016805.html|title=Spain's forgotten jet-engine genius|website=english.elpais.com|date=29 May 2014|access-date=2 September 2021}}</ref><ref>{{cite web|url=https://www.aerotendencias.com/cultura-aviacion/23225-el-museo-del-aire-acoge-una-replica-del-motor-a-reaccion-que-diseno-virgilio-leret/|title=El Museo del Aire acoge una réplica del motor a reacción que diseñó Virgilio Leret|website=www.aerotendencias.com|date=9 June 2014|access-date=2 September 2021}}</ref>

Despite lengthy delays in their own programme, the [[Luftwaffe]] beat the British efforts into the air by nine months. A lack of [[cobalt]] for high-temperature steel alloys meant the German designs were always at risk of overheating and damaging their turbines. The low-grade alloy production versions of the [[Junkers Jumo 004]], designed by Dr. [[Anselm Franz]] and which powered the [[Messerschmitt Me 262]] would typically last only 10–25&nbsp;hours (longer with an experienced pilot) before burning out; if it was accelerated too quickly, the compressor would stall and power was immediately lost, and sometimes it exploded on their first startup.  Over 200 German pilots were killed during training.  Nevertheless, the Me 262 could fly far faster than allied planes and had very effective firepower.  Although Me 262s were introduced late in the war they shot down 542<ref>{{cite book |last=Green |first=William |year=1970 |title=Warplanes of the Third Reich |location=New York |publisher=Galahad Books |isbn=0883656663 |pages=634–638}}</ref> or more<ref>{{cite book |last=Boyne |first=Walter&nbsp;J. |author-link=Walter J. Boyne |year=1994 |title=Clash of Wings |location=New York |publisher=Simon & Schuster |isbn=0684839156 |page=325}}</ref> allied planes and in one allied bombing raid downed 32 of the 36 [[Boeing B-17 Flying Fortress]]es.{{sfn|Golley|1987|pp=222–223}}

===Financial difficulty===
Earlier, in January, when the company formed, [[Henry Tizard]], the rector of [[Imperial College London]] and chairman of the [[Aeronautical Research Committee]] (ARC), had prompted the Air Ministry's Director of Scientific Research to ask for a write-up of the design. The report was once again passed on to Griffith for comment, but was not received back until March 1937 by which point Whittle's design was well along. Griffith had already started construction of his own turbine engine design and, perhaps to avoid tainting his own efforts, he returned a somewhat more positive review. However, he remained highly critical of some features, notably the use of jet thrust. The Engine Sub-Committee of ARC studied Griffith's report, and decided to fund Griffith's effort instead.<ref name=trust/> Given this astonishing display of official indifference, Falk and Partners gave notice that they could not provide funding beyond £5,000.<ref name=trust/>

Nevertheless, the team pressed ahead, and the [[Power Jets WU]] (Whittle Unit, or W.U.) engine began test runs on 12 April 1937. Initially, the W.U. showed an alarming tendency to race out of control, due to issues with the fuel injection, before stable speeds were reached.  However, by August, Whittle acknowledged a major reconstruction effort was needed to solve the combustion problem and compressor efficiency.{{sfn|Golley|1987|pp=86–91}}

On 9 July, Falk & Partners gave the company an emergency loan of £250. On 27 July, Falk's option expired, but they agreed to continue financing Power Jets by loan. Also in July, Whittle's post-graduate stay at Cambridge was over, but then he was placed on the Special Duty List so he could work full-time on the engine. On 1 November, Williams, Tinling and Whittle took control of Power Jets.<ref name=trust/> Whittle was promoted to [[squadron leader]] in December.<ref>{{London Gazette|issue = 34461|date = 7 December 1937|page=7661}}</ref>{{sfn|Golley|1987|pp=94–96}} Tizard pronounced it "streaks ahead" of any other advanced engine he had seen, and managed to interest the [[Air Ministry]] enough to fund development with a contract for £5,000 to develop a flyable version.{{sfn|Nahum|2004|pp=37–38}}  However, it was not until March 1938 that a contract was signed, when Power Jets became subject to the [[Official Secrets Act]], limiting the ability to raise additional funds.  In January 1938, BTH invested £2,500.{{sfn|Golley|1987|pp=92–95, 109}}

In December 1937, Victor Crompton became Power Jets’ first employee, as an assistant to Whittle.  Because of the hazardous nature of the work being carried out, development was moved largely from Rugby to BTH's lightly used Ladywood foundry at nearby [[Lutterworth]] in Leicestershire in 1938.  Tests with a reconstructed W.U. engine commenced on 16 April 1938, and proceeded until a catastrophic failure of the turbine on 6 May.  Yet, the engine ran for 1 hour and 45 minutes, and generated a [[thrust]] of {{convert|480|lbf|N}} at 13,000 [[rpm]].  Another W.U. engine reconstruction was started on 30 May 1938, but using ten combustion chambers to match the ten compressor discharge ducts.  Avoiding a single large combustion chamber made the engine lighter and more compact.  Tests commenced with this third W.U. on 26 October 1938.{{sfn|Golley|1987|pp=96–108,114}}

[[File:Gloster E28-39 first prototyp lr.jpg|thumb|The [[Gloster E.28/39]], the first British aircraft to fly with a turbojet engine]]
These delays and the lack of funding slowed the project. In Germany, [[Hans von Ohain]] had filed for a patent in 1935, which in 1939, led to the world's first flyable [[jet aircraft]], the [[Heinkel He 178]], powered by the [[Heinkel HeS 3]].{{sfn|Golley|1987|p=80}} There is little doubt that Whittle's efforts would have been at the same level or even more advanced had the Air Ministry taken a greater interest in the design. When [[World War II|war]] broke out in September 1939, Power Jets had a payroll of only 10 and Griffith's operations at the RAE and [[Metropolitan-Vickers]] were similarly small.

Whittle's smoking increased to three packs a day and he suffered from various stress-related ailments such as frequent severe headaches, indigestion, insomnia, anxiety, [[eczema]] and heart palpitations,{{sfn|Golley|1987|pp=149, 150}} while his weight dropped to nine&nbsp;stone (126&nbsp;lb / 57&nbsp;kg). To keep to his 16-hour workdays, he sniffed [[benzedrine]] during the day and then took tranquillisers and sleeping pills at night to offset the effects and allow him to sleep. He admitted later he had become addicted to benzedrine.{{sfn|Golley|1987|pp=149, 150}} Over this period he became irritable and developed an "explosive" temper.{{sfn|Nahum|2004|pp=79–80, 89}}

===Changing fortunes===
On 30 June 1939, Power Jets could barely afford to keep the lights on when yet another visit was made by Air Ministry personnel. This time Whittle was able to run the third reconstructed W.U. at 16,000 rpm for 20&nbsp;minutes without any difficulty. One of the members of the team was the Director of Scientific Research, [[David Randall Pye]], who walked out of the demonstration utterly convinced of the importance of the project. The Ministry agreed to buy the W.U. and then lend it back to them, injecting cash, and placed an order for a flyable version of the engine, referred to as the [[Power Jets W.1]] and [[Power Jets W.2]].  By then, the Ministry had a tentative contract with the [[Gloster Aircraft Company]] for a simple aircraft specifically to flight-test the W.1, the single-engine [[Gloster E.28/39]].{{sfn|Nahum|2004|pp=37–38}}{{sfn|Golley|1987|pp=119–124, 128}}

Whittle had already studied the problem of turning the massive W.U. into a flyable design, with what he described as very optimistic targets, to power a little aeroplane weighing 2,000 lb with a static thrust of 1,389 lb.<ref>"The Early History of the Whittle Jet Propulsion Gas Turbine" Air Commodore F. Whittle, James Clayton Memorial Lecture 1945, Institution of Mechanical Engineers, p. 423, Fig. 4</ref>  The designed maximum thrust for the W.1 was {{convert|1240|lbf|N}}, while that for the W.2, was {{convert|1600|lbf|N}}  The W.2 was to be flown in the twin-engine [[Gloster Meteor]] fighter, at the time known by its Air Ministry specification as the F.9/40, but the engine was replaced with the W.2B, having a designed static thrust of {{convert|1800|lbf|N}}.  An experimental version of the W.1, designated W.1X, was used as a mock-up for the E.28 installation.  A second E.28 was powered by the W.1A, that incorporated W.2 features such as air cooling of the turbine and a different compressor intake.  On 26 March 1940, the jet engine was listed as a potential war winner by [[Air marshal|Air Marshal]] [[Arthur Tedder, 1st Baron Tedder|Tedder]], and given the associated priority.{{sfn|Golley|1987|pp=132, 139, 143, 154–156}}

Power Jets also spent some time in May 1940 drawing up the W.2Y, a similar design with a "straight-through" airflow that resulted in a longer engine and, more critically, a longer driveshaft but having a somewhat simpler layout. To reduce the weight of the driveshaft as much as possible, the W.2Y used a large diameter, thin-walled, shaft almost as large as the turbine disc, "necked down" at either end where it connected to the turbine and compressor.

In April, the Air Ministry issued contracts for W.2 production lines with a capacity of up to 3,000 engines a month in 1942, asking BTH, [[Vauxhall Motors|Vauxhall]] and the [[Rover Company]] to join. However, the contract was eventually taken up by Rover only.{{sfn|Nahum|2004|p=61}} In June, Whittle received a promotion to [[Wing commander (rank)|wing commander]].<ref>{{London Gazette|issue = 34866|date = 7 June 1940|page=3437}}</ref>

On 19 July 1940, Power Jets abandoned effort to vaporize fuel, and adopted the controlled atomising burner for the combustion chamber, developed by Isaac Lubbock of [[Asiatic Petroleum Company]] (a joint venture of  [[Shell plc|Shell]] and Royal Dutch)   In the words of Whittle, "the introduction of the Shell system may be said to mark the point where combustion ceased to be an obstacle to development." The size of Power Jets also increased with the war effort, increasing from 25 employees in January 1940 to 70 in September 1940.{{sfn|Golley|1987|pp=125, 152–153}}

===Rover===
Meanwhile, work continued with the W.U., which eventually went through nine rebuilds in an attempt to solve the combustion problems that had dominated the testing. On 9 October the W.U. ran once again, this time equipped with Lubbock or "Shell" atomising-burner combustion chambers.<ref>Developed by Isaac Lubbock of the Shell combustion laboratories in Fulham.{{harvnb|Nahum|2004|pp=80–81}}</ref> Combustion problems ceased to be an obstacle to development of the engine although intensive development was started on all features of the new combustion chambers.<ref>"The early history of the Whittle jet propulsion Gas Turbine" Air Commodore F. Whittle, James Clayton Memorial Lecture 1945, Institution of Mechanical Engineers, pp. 428–430</ref>

By this point it was clear that Gloster's first airframe would be ready long before Rover could deliver an engine. Unwilling to wait, Whittle cobbled together an engine from spare parts, creating the W.1X ("X" standing for "experimental") which ran for the first time on 14 December 1940.{{sfn|Nahum|2004|p=89}} Shortly afterwards an application for a US patent was made by Power Jets for an "Aircraft propulsion system and power unit"<ref>{{cite web|url=https://patents.google.com/patent/US2404334A/en|title=Aircraft propulsion system and power unit|access-date=20 April 2020}}</ref>

The W.1X engine powered the E.28/39 for taxi testing on 7 April 1941 at Brockworth near the factory in Gloucester, where it took to the air for two or three short hops of several hundred yards at about six feet from the ground.<ref name ="Whittle quantal DVD"/>

The definitive W.1 of 850&nbsp;[[lbf]] (3.8&nbsp;[[kilonewton|kN]]) thrust ran on 12 April 1941, and on 15 May the W.1-powered E.28/39 took off from Cranwell at 7:40&nbsp;pm, flying for 17&nbsp;minutes and reaching a maximum speed of around 340&nbsp;mph (545&nbsp;km/h). At the end of the flight, Pat Johnson, who had encouraged Whittle for so long said to him, "Frank, it flies."  Whittle replied, "Well, that's what it was bloody well designed to do, wasn't it?"<ref name=tele/><ref>[https://web.archive.org/web/20040508125109/http://businessweek.com/magazine/content/04_18/b3881044_mz072.htm Frank Whittle: A Daredevil Who Built Jets], ''Bloomberg BusinessWeek''</ref>

Within days the aircraft was reaching 370&nbsp;mph (600&nbsp;km/h) at 25,000&nbsp;feet (7,600&nbsp;m), exceeding the performance of the contemporary [[Supermarine Spitfire]] fighters. Success of the design was now evident, and in 1941, [[Rolls-Royce Holdings|Rolls-Royce]], [[Hawker Siddeley]], the [[Bristol Aeroplane Company]], and [[de Havilland]] became interested in gas turbine aircraft propulsion.{{sfn|Golley|1987|pp=171, 178}} Under [[Roxbee Cox, Baron Kings Norton|Harold Roxbee Cox]], the Gas Turbine Collaboration Committee was created to give a forum for all the companies for exchange of information.<ref>Nahum 2004 p 66-67</ref>

The stress on Whittle was expressed in a 27 May 1941 letter to [[Henry Tizard]]:
{{cquote|The responsibility that rests on my shoulders is very heavy indeed. We are faced with two alternatives – either we place a powerful weapon in the hands of the Royal Air Force or, if we fail to get our results in time, we may have falsely raised hopes and caused action to be taken which may deprive the Royal Air Force of hundreds of aeroplanes that it badly needs.{{sfn|Nahum|2004|p=57}}{{sfn|Golley|1987|p=173}}}}

[[File:Whittle Jet Engine W2-700.JPG|thumb|left|The [[Power Jets W.2|W2/700]] engine, or W.2B/23 as it was known to the Air Ministry. It was the first British production jet engine, powering early models of the [[Gloster Meteor]].]]
In mid-1941, relations between Power Jets and Rover had continued to deteriorate.  Rover had established a version of Power Jet's set-up at Waterloo Mill, associated with their [[Barnoldswick]] factory, near [[Clitheroe]]. Rover was working on an alternative to Whittle's "reverse-flow" combustion chambers, by developing a "straight-through" combustion chamber and turbine wheel.  Rover referred to the engine as the B.26, sanctioned by the Directorate of Engine Development, but kept secret until April 1942, from Power Jets, the Controller of Research and Development, and the Director of Scientific Research.{{sfn|Golley|1987|pp=174, 189–191}}

===Rolls-Royce===
Earlier, in January 1940, Whittle had met Dr [[Stanley Hooker]] of [[Rolls-Royce Limited|Rolls-Royce]], who in turn introduced Whittle to Rolls-Royce board member and manager of their Derby factory, [[Ernest Walter Hives, 1st Baron Hives|Ernest Hives]] (later Lord Hives). Hooker was in charge of the supercharger division at Rolls-Royce Derby and was a specialist in [[fluid dynamics]].  He had already increased the power of the [[Rolls-Royce Merlin|Merlin]] piston engine by improving its supercharger.{{sfn|Hooker|2002|p=52}} Such a speciality was naturally suited to the aero-thermodynamics of jet engines in which the optimisation of airflow in compressor, combustion chambers, turbine and jet pipe, is fundamental. Hives agreed to supply key parts to help the project. Also, Rolls-Royce built a compressor test rig which helped Whittle solve the [[Compressor stall|surging]] problems (unstable airflow in the compressor) on the W.2 engine.{{sfn|Hooker|2002|p=68}}

On 10 December 1941 Whittle suffered a [[nervous breakdown]], and left work for a month.{{sfn|Nahum|2004|p=89}}  However, by the end of January 1942, Power Jets had three W.2B engines, two built by Rover. In February 1942, flight trials of the W.1A engine began in the E.28, which reached 430&nbsp;mph (690&nbsp;km/h) at 15,000&nbsp;feet (4,600&nbsp;m).  On 13 March 1942, Whittle started work on a redesign of the W.2B, referred to as the W.2/500. 
On 13 September 1942, W.2/500 performance tests matched predictions, showing a thrust of {{convert|1750|lbf|N}} at full speed. In October 1941, the Ministry approved a new factory to be built outside [[Whetstone, Leicestershire]].{{sfn|Golley|1987|pp=183–185, 188–189, 200}}

From 3 June until 14 August 1942 Whittle visited the United States.  At the [[General Electric]]'s Lynn Factory, Whittle reviewed the Type I Supercharger, GE's code name for their jet engine, based on Power Jets' W.1X.  An improved version of the W.2B would also be built, called the [[General Electric J31|I-16]], incorporating features of the W.2/500.  Whittle also toured the [[Bell Aircraft]], and the three [[Bell XP-59A Airacomet]]s, a twin-engine fighter powered by the [[General Electric I-A]] jet engines. This fighter took flight in October 1942, one year and one day after GE received Power Jets' W.1X.{{sfn|Golley|1987|pp=182–183, 192–199}}

On 11 December 1942 Whittle had a meeting with the chief executive of the  [[Ministry of Aircraft Production]] Air Chief Marshal [[Wilfrid Freeman]] and Air Marshal Francis Linnell, Controller of Research and Development at MAP, According to Whittle, "He made it clear that he had definitely decided to transfer Barnoldswick and Clitheroe to Rolls-Royce management." [[Spencer Wilks]] of Rover met with Hives and Hooker at the "Swan and Royal" pub, in Clitheroe, near the Barnoldswick factory. By arrangement with the Ministry of Aircraft Production<ref>{{cite web |url=https://www.flightglobal.com/pdfarchive/view/1946/1946%20-%200235.html |title=Archived copy |access-date=21 February 2016 |archive-date=5 March 2016 |archive-url=https://web.archive.org/web/20160305070802/https://www.flightglobal.com/pdfarchive/view/1946/1946%20-%200235.html |url-status=dead }}</ref> they traded the jet factory at Barnoldswick for Rolls-Royce's [[Rolls-Royce Meteor|tank engine]] factory in Nottingham.Testing and production ramp-up was immediately accelerated. [[Adrian Lombard]] Rover's supervising engineer on the Whittle engines transferred to Rolls Royce to continue the role. By January 1943, Rolls-Royce had achieved 400 hours of run time, ten times Rover's number of the previous month, and in May 1943, the W.2B passed its first 100-hour development test at {{convert|1600|lbf|N}} of thrust.{{sfn|Golley|1987|pp=202–205}}

When Rolls-Royce became involved, Ray Dorey, the manager of the company's Flight Centre at [[Hucknall Aerodrome|Hucknall Airfield]] on the north side of Nottingham, had a Whittle W.2B engine installed in the rear of a [[Vickers Wellington]] bomber.{{sfn|Hooker|2002|p=106}}{{sfn|Golley|1987|p=206}}<ref>Verbal evidence from Flight Test Engineer W R (Bill) Grose who operated the Whittle engine in the Wellington and had previously been involved in ground test running of the Whittle engine at either Lutterworth or Rugby</ref> The installation was done by Vickers at Weybridge.<ref>Men Of Power, Robert Jackson, Pen % Sword Aviation, Barnsley 2006, {{ISBN|1844154270}}, p. 85</ref>

From the end of 1937, when a Squadron Leader, he lived at 'Broomfield' on Bilton Road, in Rugby. Both sons were at school in the town.<ref>''Rugby Advertiser'' Friday 14 June 1940, page 8</ref> He later briefly lived at 'Laurelcroft', 1 North Street, [[Kilsby]] until 1949.<ref>''Rugby Advertiser'' Friday 28 May 1948, page 6</ref><ref>''Rugby Advertiser'' Friday 23 December 1949, page 6</ref> His two sons went to [[Rossall School]] in Blackpool. Ian later joined the RAF.<ref>''Birmingham Post'' Thursday 16 October 1952, page 5</ref>

===Continued impact===
[[File:GE J-31 Turbojet Engine.jpg|thumb|A cutaway [[General Electric J31]] (I-16) turbojet engine based on the [[Power Jets W.1|W.1]]/[[Power Jets W.2|W.2B]]]]

Whittle wanted to improve the efficiency of the jet engine at lower speeds.  According to Whittle, "I wanted to 'gear down the jet', ie to convert a low-mass high-velocity jet into a high-mass low-velocity jet. The obvious way to do this was to use an additional turbine to extract energy from the jet and use this energy to drive a low-pressure compressor or fan capable of 'breathing' far more air than the jet engine itself and forcing this additional air rearwards as a 'cold jet'. The complete system is known as a '[[turbofan]]'."  The first embodiment was referred to as a No 1 Thrust Augmentor, which consisted of an "aft fan", or additional turbine, in the exhaust of the main engine. In 1942, No 2 Augmentor, a conventional two-stage system with the fan blades external to the turbine blades, was used by GE in the [[Convair 990 Coronado]]. A No 3 Augmentor, known as the "tip turbine", had the turbine blades outside the fan. A No 4 Augmentor, in combination with the W2/700, included an [[afterburner]] and was the design powerplant for the [[Miles M.52]] project.  According to Whittle, "The first attempt at the turbofan proper, ie having the fan ahead of and supercharging the core engine, was the LR1 intended as the power plant of a four-engined bomber for operations in the Pacific. The mass flow through the fan of the LR1 was to have been 3–4 times that through the core engine, ie the '[[bypass ratio]]' was 2–3."  Filed in March 1936, Whittle's main turbofan patent 471368, expired in 1962.{{sfn|Golley|1987|pp=262–264}}

Whittle's work had caused a minor revolution within the British engine manufacturing industry and, even before the E.28/39 flew, most companies had set up their own research efforts. In 1939, [[Metropolitan-Vickers]] set up a project to develop an axial-flow design as a [[turboprop]] but later re-engineered the design as a pure jet known as the [[Metrovick F.2]].{{sfn|Golley|1987|p=180}} Rolls-Royce had already copied the W.1 to produce the low-rated WR.1 but later stopped work on this project after taking over Rover's efforts.{{sfn|Golley|1987|p=187}} In 1941, de Havilland started a jet fighter project, the Spider Crab&nbsp;– later called [[de Havilland Vampire|Vampire]]&nbsp;– along with their own engine to power it,{{sfn|Golley|1987|p=179}} [[Frank Halford]]'s [[de Havilland Goblin|Goblin]] (Halford H.1). [[Armstrong Siddeley]] also developed a more complex axial-flow design with an engineer called Heppner,{{sfn|Golley|1987|p=180}} the [[Armstrong Siddeley ASX|ASX]] but reversed Vickers' thinking and later modified it into a turboprop instead, the [[Armstrong Siddeley Python|Python]]. The [[Bristol Aeroplane Company]] proposed to combine jet and piston engines but dropped the idea and concentrated on propeller turbines instead.{{sfn|Golley|1987|p=180}}

===Nationalisation===
During a demonstration of the E.28/39 to [[Winston Churchill]] in April 1943, Whittle proposed to [[Stafford Cripps]], Minister of Aircraft Production, that all jet development be nationalised. He pointed out that the company had been funded by private investors who helped develop the engine successfully, only to see production contracts go to other companies. Nationalisation was the only way to repay those debts and ensure a fair deal for everyone, and he was willing to surrender his shares in Power Jets to make this happen. In October, Cripps told Whittle that he decided a better solution would be to nationalise Power Jets only.<ref name=trust/>
Whittle believed that he had triggered this decision, but Cripps had already been considering how best to maintain a successful jet programme and act responsibly regarding the state's substantial financial investment, while at the same time wanting to establish a research centre that could use Power Jets' talents, and had come to the conclusion that national interests demanded the setting up of a Government-owned establishment.{{sfn|Nahum|2004|pp=101, 105}} Within the MAP there was a feeling that Power Jets was effectively a research unit funded by the Treasury and that management within the company was non-existent, the latter was also expressed by workers at Power Jets.<ref>Nahum 2004 p97</ref>{{Efn|Whyte had resigned as Chairman and Managing Director in July 1941}} On 1 December Cripps advised Power Jets' directors that the Treasury would not pay more than £100,000 for the company.<ref name=trust/>
[[File:MiG-15 USAF.jpg|thumb|right|[[No Kum-sok]]'s MiG-15 on display at the [[National Museum of the United States Air Force]].]]
In January 1944 Whittle was appointed a [[Commander of the Order of the British Empire]] in the [[1944 New Year Honours|New Year Honours]].<ref>{{London Gazette |issue = 36309 |date = 31 December 1943 |page=17 |supp=y }}</ref> By this time he was a [[group captain]], having been promoted from [[Wing commander (rank)|wing commander]] in July 1943.<ref>{{London Gazette |issue=36092 |date=13 July 1943 |supp=y |page=3200}}</ref> Later that month after further negotiations the Ministry made another offer of £135,500 for Power Jets, which was reluctantly accepted after the Ministry refused arbitration on the matter. Since Whittle had already offered to surrender his shares he would receive nothing at all, while Williams and Tinling each received almost £46,800 for their stock, and investors of cash or services had a threefold return on their original investment.{{sfn|Nahum|2004|p=102}} Whittle met with Cripps to object personally to the nationalisation efforts and how they were being handled, but to no avail. The final terms were agreed on 28 March, and Power Jets officially became Power Jets (Research and Development) Ltd, with [[Roxbee Cox, Baron Kings Norton|Roxbee Cox]] as chairman, [[Hayne Constant|Constant]] of RAE Head of Engineering Division, and Whittle as Chief Technical Advisor.{{Efn|The board of directors included Sir [[William Stanier]], [[Harry Ricardo]], and [[Edwin Plowden, Baron Plowden|Edwin Plowden]]<ref>Nahum 2004 p110</ref>}} On 5 April 1944, the Ministry sent Whittle an award of only £10,000 for his shares.<ref name=trust/>

Whittle and other Power Jets staff still held the view that they would be the sole designers of jet engines; they would build prototypes and industry would actually produce them. This view was in conflict with that of the engine companies, which in engine design had already achieved competence similar or superior to that of Power Jets. The engine companies stated they would not work with Power Jets if Power Jets were the sole designers.<ref>Nahum 2004 p114</ref> The government scientists from RAE who had been moved to Power Jets were against it also and within MAP there was a feeling that Power Jets was publicly financed but not under public administration.   From the end of March, Whittle spent six months in hospital recovering from nervous exhaustion; he resigned from Power Jets (R and D) Ltd in January 1946. In July the company was merged with the gas turbine division of the RAE to form the [[National Gas Turbine Establishment]] (NGTE) at Farnborough. Sixteen Power Jets engineers, following Whittle's example, also resigned.{{sfn|Nahum|2004|pp=118–119}} The [[Rolls-Royce_Nene]] (designed by Hooker,  Lombard, Pearson and Morley) would be licensed and made in two different countries: in the United States as the Pratt & Whitney J42 jet engine, later incorporated into the [[Grumman F9F Panther]] and in the USSR Soviet as the [[Klimov VK-1]] jet engine, later incorporated into the [[MiG-15]]; the Panther vs the MiG-15 would meet in air battles during the Korean war.