4
With the exception of a few ‘specials’ like the Fairey long-range monoplane and the Supermarine Schneider Trophy seaplanes, the only monoplane in service with the R.A.F. in 1934 was the Saro Cloud amphibian trainer, of which there were seventeen. The rest were biplanes. The Air Defence of Great Britain depended on the Bristol Bulldog, the Hawker Fury and Demon fighters, and a variety of bombers ranging from the small Hawker Hart, the Vickers Vildebeest and the Fairey Gordon, to the larger Boulton Paul Overstrand, Vickers Virginia and Handley Page Heyford.
Restrictions during the 1920s severely rationed the resources which the R.A.F. and the aircraft industry devoted to research and development. Progress, which also lacked the stimulus of any change in the basic conceptions of air warfare, was therefore slow. Because there was no financial margin for error, novelties could not be ordered until they had been so thoroughly tested that they were practically obsolescent.
Few advances were made in aerodynamics during the period, and improved performances were derived from increases in engine power. A remarkable exception did appear in 1925, however: the Fairey Fox light bomber whose lines were so clean that it was able to outperform the single-seater fighters of the day. Its secret lay in the American Curtiss D.12 liquid-cooled, in-line engine which lent itself to streamlining impossible to achieve with the popular air-cooled radiais employed in contemporary aircraft design.
Although Rolls-Royce had already produced many thousands of liquid-cooled engines during and after the First World War, notably Eagles and Falcons, it was the Fox and its D.12 which accelerated development of the liquid-cooled type in preference to air-cooled engines. In this respect it may be said to have had a relationship with the Rolls-Royce Kestrel which was the parent of the Merlin engine used in the Battle of Britain Hurricanes and Spitfires.
Kestrels powered the Hawker biplanes which were the backbone of the R.A.F. during the 1930s. The first of the breed was the single-engined Hart day-bomber, built to a specification which lifted the speed of this type of machine from the 120 m.p.h. rut and put it up by a good 60 m.p.h.
Hawkers also developed the Fury interceptor. Chosen for delievery in 1931, it was the first R.A.F. fighter to exceed 200 m.p.h.
In the next ten years the Air Ministry adapted the Hart for many different roles and hung it with many attachments. To maintain its performance it had to be boosted with more power, but this was always available from the Kestrel which Rolls-Royce steadily developed from 480 to 765 h.p. Only in the Hawker Hector was the Kestrel replaced by another engine, the air-cooled Napier Dagger.
Within eighteen months of the Kestrel’s first bench test a supercharger was boosting its power. Then an automatic boost control was developed which pilots hard pressed in combat were to find a boon. Linked to the throttle, the auto-boost mechanism relieved the pilot of the need to nurse his engine. He could open the throttle to full power with the assurance that the engine would not blow up.
From the Kestrel Rolls-Royce developed the Buzzard and then the ‘R’ engine, the latter specially for the Schneider Trophy float planes.
The story of the Schneider Trophy’s effect on British aircraft design and development of the Spitfire goes back to the sixth contest held in Naples in 1922 when the Supermarine Company deprived the Italians of a third and outright win with a Sea Lion flying-boat of their own design. Without that victory there would never have been the incentive to defend the title and in consequence none of the development work that was to have such repercussions eighteen years later.
The Sea Lion was sturdy and reliable but it was obviously not good enough for the 1923 contest. Something radically new was needed. The late Mr. Reginald Mitchell, Supermarine’s chief designer, was convinced a small monoplane built around a 700 h.p. engine was the answer. In the absence of anything better Supermarines entered Sea Lion once more. It performed well but General James Doolittle, then a young lieutenant, won the race and the trophy for America.
Mitchell learned much from the winning Curtiss float-planes, particularly their streamlined engine installations and floats which reduced the frontal area. However, he believed a monoplane could do much better than the Curtiss biplanes.
By August 1925 Mitchell’s S.4 was in the air, and on September 13th it set up a new seaplane record of 226 miles an hour. Even land-planes had not yet achieved such a speed, but it crashed as a result of wing-flutter and was unable to join the two Gloster III biplanes representing Britain. America won again.
Despite the fact that all foreign entries were heavily subsidised, the British Government displayed no official interest in the Schneider Trophy. The entire cost of representing Britain fell on Supermarine, Gloster Aircraft and D. Napier and Son. When national prestige began to be involved, however, it no longer stood aloof. In 1925 the Air Ministry placed an order for seven special high-speed seaplanes, three each from Supermarine and Gloster and one from Short Brothers and Harland. All were powered by 875 h.p. Napier Lion engines except for the Short Crusader, which was fitted with a closely cowled 960 h.p. Bristol Mercury air-cooled radial.
None of the seaplanes was ready for the 1926 contest but the Italians won and gave the trophy a new lease of life by forestalling a third successive win by the Americans and preventing them from taking it back to the United States permanently.
By 1927 Britain had a strong team. Similar in most respects to the S.4, the two Supermarine S.5s then in the contest were low-wing monoplanes with externally braced wooden wings and tailplanes. Duralumin was used elsewhere, including the compact fuselages slimly tailored to fit the cross-section of the Napier Lion engines. Radiators were built into the wing skin, and the fuel was carried in one float so that its weight would counteract the vicious torque delivered by the very coarse pitch propeller and powerful engine.
First and second places were taken by the S.5s flown by Flight Lieutenant Webster and Flight Lieutenant Worsley.
The next Schneider Trophy contest was set for 1929, but the Assistant Director for Engine Development at the Air Ministry, Major G. P. Bulman, did not think enough extra power could be obtained from the Lion to guarantee victory a second time. Napiers had done nothing towards the development of a supercharged version of the engine and Bulman therefore turned to Rolls-Royce.
By August 1929 the Rolls-Royce R engine was developing 1,800 h.p., but during the endurance tests it was found that power dropped off after twenty minutes’ running. Fuel troubles were suspected and Air Commodore F. R. Banks, then with the Associated Ethyl Company, was called in for consultations. Instead of pure benzol, Banks suggested the use of several other fuels and finally concocted a suitable blend.
Though similar in overall design as the S.5s the Supermarine S.6s for the 1929 race were all-metal aeroplanes. Mitchell found ingenious answers to problems of streamlining and engine heat dissipation by building the oil cooler into the surface of the tail-fin.
Again the contest was an Anglo-Italian affair and again the Supermarine plane, powered by the 1,900 h.p. Rolls-Royce engine and flown by Flight Lieutenant Waghorn, won at 328.6 m.p.h.
The 1929 competition was one of the most dramatic for Britain, for in addition to international rivalry there was competition between the Supermarine and Gloster aircraft companies and between Rolls-Royce and Napier whose engines powered the planes. Unfortunately for Glosters, who had by this time abandoned the biplane formula, last-minute troubles with the Napier engine forced the withdrawal of their Mk VI Golden Arrow.
Britain now had to win only the 1931 competition to achieve the three successive victories needed to keep the trophy for good. The Government, however, was suddenly struck with one of the bouts of ‘economy fever’ that nearly killed the aircraft industry altogether ten years earlier. They withdrew support.
Supermarine could not carry on unsubsidised and consequently little was done until eight months before the race when the late Lady Houston, incensed by the Socialist Government’s parsimony, put up £100,000 to cover the cost of development and participation.
There was no time to design anything radically different from the S.6s, but Supermarine built two improved versions designated S.6Bs. The R engine was amenable to further development and Rolls-Royce therefore went to work to build up its power. Banks advised in the matter of fuels.
Banks’ pioneer work in this field had important repercussions. From 1929 on the evolution of fuels went hand in hand with engine development and can be conservatively credited with having doubled the power of engines.
After months of feverish activity the Rs developed a maximum 2,300 h.p. for a guaranteed duration of only a few minutes. They also developed so much heat that cooling radiators for the water and oil had to be built into the double skins of wings, floats and fuselage.
The Italians worked desperately under orders from their government to produce an engine to beat the R. Their engines would not stand up to the demands made on them and they were forced to withdraw. The French contender, a Bernard-Hispano, crashed near Marseilles on July 31st, 1931, killing the pilot, M. Bougault. On September 13th, in the absence of any other contenders, it remained only for Air Chief Marshal Sir John Boothman, then a flight lieutenant, to cover the course at 340 m.p.h. to win the Trophy for Britain outright. On the same day Flight Lieutenant Stainforth raised the world speed record to 378 m.p.h. On the 29th, using a different blend of fuel, the R gave 2,530 h.p. and Stainforth achieved 407.8 m.p.h., a speed unexceeded by any other British aircraft until fourteen years later.
Mitchell’s seaplane designing days were over but he applied the lessons in aerodynamic efficiency to other types of aircraft. Similarly the Gloster seaplanes were of inestimable value to their designers. The R engines were also of great importance in their effect on the attitude of the Government and the aircraft industry, and Rolls-Royce in particular, towards liquid-cooled engines. They established that only liquid-cooled engines allowed the clean aerodynamic design required for fast planes, especially fighters, and that far greater power could be obtained from them than from any comparable air-cooled types. It was not until 1940 that an air-cooled engine anywhere in the world equalled the 2,783 h.p. maintained during a bench test for an hour by a Rolls-Royce R in 1931.
About the middle of 1932 Rolls-Royce decided on their own initiative that future fighters about the same size as existing types would require a larger engine than the Kestrel. The PV–12 was an almost identical but larger 750 h.p. version of the Kestrel with a 1,649 cubic inches capacity instead of 1,295. It was at first to be inverted, but inverted engines were not popular with aircraft designers. After criticism of the mock-up late in 1932, Rolls-Royce reverted to the V arrangement of cylinders.
The TV in the designation indicated that the project was a private venture. Detailed design work on the PV–12 started as Hitler became Chancellor of Germany. A year and a half later it was named the Merlin.
In the meantime the Air Ministry were speculating about the possibilities of applying the experiences of the 1929 Schneider Trophy races to a military aircraft. In 1930 a specification, F7/30, was issued for a plane. This was based on the Rolls-Royce Goshawk engine.
Sir Sydney Camm (then Mr. Sydney Camm), chief engineer for the Hawker Aircraft Company and responsible for the Hart and Fury aircraft, was heavily committed to the development of variants of these types for the R.A.F. and foreign air forces when he received the specification. He responded with a monoplane design based on the Fury then entering service. As originally planned the Fury monoplane was to have a fixed undercarriage and four guns, two in the fuselage and two in the wings, like Mitchell’s independent answer to F7/30 based on the S.6B.
Mitchell found the specification restrictive and insufficiently advanced in concept to produce an aircraft of the highest possible performance. It reflected the uncertain atmosphere of the era in which hindsight ruled any arguments on air warfare and foresight was hemmed in by economics and disarmament. Nevertheless an aircraft was tailored to the specification, but long before it flew Mitchell’s dissatisfaction with it led to a design he believed the R.A.F. should have. It was a heat monoplane with retractable undercarriage, an enclosed cockpit and four machine-guns. Beneath the starboard wing it could carry four small bombs.
The tempo of production quickens as war draws near. Here, in 1939, a production Vickers Wellington 1 twin Pegasus-engined bomber takes off from Brooklands, while in the foreground stands the prototype Mk. 2 Wellington with Merlin engines. The Wellington employed a special criss-cross lattice structure developed by Barnes Wallis, later to become famous as the inventor of the spinning bomb which broke the Mohne and Eder dams
Although Camm’s preliminary designs never materialised, studies progressed, and when the Merlin came into the picture the geometry began to diverge so sharply from the Fury’s that the term ‘interceptor monoplane’ gained currency. The Merlin also altered Mitchell’s plans, which, like the Hawker design, was further modified by a fresh specification following an important conference on armament at the Air Ministry on July 19th, 1934.
The specification was based on the premises that the modern fighter’s speed over contemporary bombers was so great that repeated attacks could not be maintained. Decisive results must, therefore, be obtained on the first attack during which a fighter pilot would have the target in the gunsight for only two seconds.
Captain F. W. Hill, senior ballistics officer at the Aeroplane and Armament Experimental Establishment, Martlesham Heath, Suffolk, was at the conference. He showed that at least eight guns firing one thousand rounds a minute each were needed to destroy a bomber in two seconds. The results of his experiments convinced Air Marshal Sir Ralph Sorley, then a comparatively junior squadron leader at the Air Ministry’s Operational Requirements Branch, who set about ‘selling’ the eight-gun concept to higher authority. This created a furore, particularly among older officers like Air Chief Marshal Sir Robert Brooke-Popham, Commander-in-Chief Air Defence of Great Britain, who thought ‘eight guns was going a bit too far’. Brooke-Popham was also against enclosed cockpits.
Sorley pleaded the case vigorously and in 1935 specification F5 34, drawn up round the fast-firing American Browning machine-gun, was issued. It called for a monoplane fighter capable of catching the fastest bomber and destroying it with a two-second burst of gunfire. An enclosed cockpit, eight Brownings with 300 rounds per gun giving a total firing time of roughly fifteen seconds, a reflector sight, retractable undercarriage with wheel-brakes and oxygen for the pilot were specified. No particular engine was called for but the designers were asked to aim for a speed of 275 m.p.h. at 15,000 feet, ninety minutes’ endurance, a seven-and-a-half minute climb to 20,000 feet, a ceiling of 33,000 feet, and a landing run of 250 yards. These ideas combined so well with the Camm and Mitchell plans that the Air Ministry, freed of the Government’s financial restraint by the 1934 expansion programme, ordered both aircraft.
Mitchell’s health, meanwhile, deteriorated following a partially successful lung operation in 1933. He was persuaded to take a holiday on the Continent. There he ran into members of the Deutscher Luftsportverband (German Aviation Sport Association), in whose drive, aggressive spirit and shapely gliders he recognised the menace of the future.
Back in Britain Mitchell was profoundly influenced by another German product—a Heinkel He 70 bought by Rolls-Royce and tested by the R.A.F. at Martlesham Heath. It had eliptical wings, a shape that made those of the Spitfire so distinctive in the air.
Camm and Mitchell worked their way into relatively unexplored territory. Monoplane production, retractable undercarriages, wheel-brakes, wing-flaps, stressed skin construction, blind-flying instruments and radio, all needed detailed attention.
The Hawker prototype, K 5083, was built in eleven months at Kingston, Surrey, and was named the Hurricane. Hawker’s chief test pilot, Mr. P. W. S. Bulman, flew it for the first time from Brooklands on November 6th, 1935. He reported remarkable manoeuvrability and docility.
Seven months later, on May 5th, 1936, the Spitfire prototype took off on its maiden flight from Eastleigh airfield, Southampton, with Mr. J. ‘Mutt’ Summers at the controls. Summers was chief test pilot for Vickers-Armstrong, which company had acquired the entire share capital of the Supermarine Company in 1928. He reported enthusiastically on the performance of the small cream-coloured plane.
With the same armament and the same engine the Hurricane and the Spitfire represented two totally different approaches to the same problem. The Spitfire’s stressed-skin metal construction was a new and more complex concept based on specialised experience. The Hurricane’s fabric-covered tubular steel and duralumin structure was tradition compromising with a modern world. The simplicity of the latter allowed quantity production to start without delay. It also had the advantage of being easily repairable. This allowed battle-scarred aircraft to be back in combat often within hours of being damaged.
Because of the success of the initial trials of the Hurricane, Hawkers felt justified in preparing to tool-up and order material for 1,000 aircraft, although the first Air Ministry contract placed in June 1935 was for no more than 600. A further 400 were ordered in November 1938. Later the Canadian Car and Foundry Company, of Montreal, and the Gloster Aircraft Company were licensed to build the Hurricane. Further contracts were placed with them.
The first production Hurricane made its maiden flight on October 12th, 1937, and in December the type replaced the Gauntlet biplanes of No. 111 Squadron at Northolt. In January 1938 Hurricanes replaced Gloster Gladiators of No. 3 Squadron at Kenley, Surrey. In February Squadron Leader J. E. Gillan, commanding officer of No. 111 Squadron, flew a Hurricane from Edinburgh to Northolt at an average speed of 408 m.p.h.
Sensational though this performance was, a strong tail-wind at 17,000 feet helped to mask the Hurricane’s true capabilities. With the 1,030 h.p. Merlin II engine and a wooden, fixed-pitch two-bladed propeller the fighter had a 2,420 feet a minute rate of climb and a maximum speed of 320 m.p.h. at 18,500 feet.
Production Hurricanes differed from the prototype in a number of details in addition to having the Merlin II. In 1939 metal-covered wings began to be fitted on the production line instead of fabric-covered wings.
By the outbreak of war 400 Hurricanes were delivered and eighteen squadrons equipped with them. By August 7th, 1940, 2,309 had been built and the number of Hurricane squadrons had risen to thirty-two.
Supermarine’s first production contract for 310 Spitfires placed at the same time as the Hurricane order was due for completion in March 1939. Early manufacturing difficulties, due to the late delivery of wings made by sub-contractors, delayed this, however, until August. A year after the initial contract 200 more were ordered. On April 12th, 1938, the Nuffield Organisation was contracted to build 1,000 at the newly erected Castle Bromwich shadow factory. By October 1939 Spitfire orders increased to 4,000.
Like the early Hurricanes, the first Spitfires to come off the assembly lines had Merlin II engines, two-bladed fixed-pitch wooden propellers and numerous other detailed refinements. No variable-pitch propellers were available for either of the fighters, a position which was characteristic of a period of rapid expansion. The older Spitfires and Hurricanes continued in service until only a few weeks before the invasion of Poland. Even then only the two-pitch propeller was available. A limited number of variable-pitch propellers were being made before the war but they were reserved for the new bombers which, fully loaded, would never have taken off without them.
A fixed-pitch propeller’s main drawback is that the angle at which the blades are set is a compromise. A propeller is literally an airscrew, and like a wood-screw it goes forward a certain amount with each turn. An airscrew designed to travel at 200 miles an hour has coarse pitch blades and moves a long way forward in one revolution. It must therefore be very inefficient at lower speeds.
In 1925 Dr. Hele-Shaw invented a hydraulic variable-pitch propeller which was test flown in Gloster fighter biplanes. It was not only the first variable-pitch propeller, it also had a constant-speed control like the propellers hurriedly fitted to all Merlin-engined fighters in the Battle of Britain. Instead of the pilot selecting his pitch, a governor automatically maintained the engine revolutions at a chosen setting, whatever the speed or attitude of the plane.
Glosters tried to sell the idea, pointing out that pilots would no longer have to watch their engine speed. The authorities were apathetic, however, and development was dropped. This apathy was still in evidence in 1934 when de Havillands asked the Government for support to acquire the rights to make the variable-pitch propeller put into production in 1933 by the American Hamilton-Standard Corporation. De Havillands went ahead on their own and began manufacture in 1935.
Spitfires reached the R.A.F. in June 1938 and in August No. 19 Squadron at Duxford, Cambridgeshire, received the first. Another Duxford Gauntlet squadron, No. 66, was re-equipped with Spitfires in October. By the beginning of September 1939 there were nine Spitfire squadrons.
The capabilities of the Spitfire were not appreciated outside the service or the industry until January 1939 when Mr. Geoffrey Quill, the Supermarine test pilot, flew from Le Bourget to Croydon in forty-one minutes —290 m.p.h.—which started the Press speculating. On March 8th an official release gave its maximum speed as 362 m.p.h. at 18,500 feet and its rate of climb to 11,000 feet with full war load as 4.8 minutes. The speed quoted exaggerated the true performances by seven miles an hour.
The type 142M Bristol Blenheim as rolled out in 1936, the first flight taking place on June 25th. The Blenheim, with its two Mercury radiais, was fast for its day but not fast enough or suitably protected for the air fighting of World War 2. Nevertheless it bore the brunt of light bombing operations in 1940 and 1941 and served with distinction all over the world
Mitchell did not live to see the first production Spitfire in the air. In March 1937 his tubercular condition was pronounced incurable. On June nth he died at the age of forty-two.
Mitchell’s name will always be linked with the Spitfire, although in the last year of his life he spent most of his creative energy on a bomber. Its lines promised a brilliant future, but the two prototypes were destroyed when the Supermarine factory at Woolston, Hants, was bombed on September 26th, 1940.
The air expansion scheme authorised in Parliament at the end of July 1934 was a step in the right direction, but it failed to satisfy Churchill. Scheme A, as the programme was called, was designed more to impress the Germans than to equip the R.A.F. for early action. Everything ordered was intended for the ‘shop-window’ behind which there were no reserves.
Throughout the autumn Churchill, reiterating the warnings of early summer, was regarded as ‘a bit of a crank about this air business’. Unbeknown to anyone, however, he was being kept thoroughly informed by a private ‘intelligence system’.
With the New Year an increase in tempo began with the unveiling of the Luftwaffe on February 15th and Germany’s conscription proclamation on March 16th. Eleven days later Hitler in Berlin startled Sir John Simon, the Foriegn Secretary, with a blunt announcement that Germany had already reached air parity with Britain and intended to go on building until she had an air force equal to that of France.
Hitler’s claim was certainly not justified. It was contradicted by reliable secret information at the Air Ministry’s disposal and by German officials, including General Erhard Milch, the Secretary of State for Air. Germany, in fact, had 1,888 aircraft, mainly trainers.
There was little reason to doubt that Hitler would fulfil his aims, however All available evidence pointed to a rapidly accelerating aircraft production programme in Germany. Doubts about the Luftwaffe’s capacity to meet the targets Hitler set for it were, nevertheless, entertained by the Air Ministry in London. To reach air parity with France, whose air force numbered 1,500 front-line aircraft, would take the Germans until 1937. It was also considered that although the Luftwaffe might possess a front-line strength of 1,500 first-line aircraft by 1937, two more years at least must elapse before it could be ready for war. The British, therefore, had until 1939 to complete the expansion programme.
The Supermarine S.6.B, winner of the Schneider Trophy in 1931. From this seaplane Vickers-Supermarine gained invaluable know-how for the Spitfire and Rolls-Royce for the Merlin engine
Hitler’s warning, however, roused the Government, which called for further expansion and for completion of the new programme by March 1937.
This was Scheme C announced by the Air Minister, Lord Londonderry, on May 22nd, 1935. It required the establishment of 49 squadrons of 588 aircraft more than the earlier programme. This represented an air force with a first-line strength of 20 heavy bomber, 18 medium bomber, 30 light bomber, two torpedo bomber and 35 fighter squadrons, with 18 reconnaissance and other units. This was a total of 122 squadrons, containing 1,512 aircraft.
Despite the improvement it achieved little more than to dress the shop-window. There was still no provision for adequate reserves. Only one-third of the squadrons of the home defence force were to be fighter squadrons. The ratio reflected the Air Staff’s view that in the long run only offensive power could give the superiority required for safety.
A bomber force would be of scant value if the fighters and the rest of the air defences proved too weak to repulse a succession of surprise attacks by the enemy. Even if the thirty-five fighter squadrons were equipped with the best aircraft available they would not have time to reach combat height before the attacking force crossed the coast or reached the target. The fighter pilots also did not know where to intercept the attackers.
Detection by acoustic means was useless but no one knew whether the experiments in radiolocation beginning at Orfordness on the east coast would be successful. In the light of these circumstances, therefore, it was not surprising that the big bomber enthusiasts held sway.
Unlike the French who, by striving after numbers rather than performance, found themselves near the outbreak of war saddled with a large number of obsolete types, Air Chief Marshal Sir Edward Ellington, Chief of the Air Staff, stressed quality as well as quantity. To minimise the effects of the delay in bringing in new aircraft, squadrons were formed with existing types. Most of these were biplanes like the Gloster Gauntlet, Gloster Gladiator and Hawker Fury fighters, and bombers such as the Hawker Hind and the Handley Page Heyford.
Among the new bombers ordered by the Air Ministry in 1935 was the Bristol Blenheim, whose performance created a stir when it reached the squadrons in 1937.
Like so many of the aircraft that formed the backbone of the R.A.F. in the first two years of the war the Blenheim started as a private venture. In 1933 the Bristol Aeroplane Company had the idea of making an all-metal eight-seater civil transport that would outperform the fastest of the new American airliners. It was backed by Lord Rothermere, the newspaper proprietor.
In 1935 the prototype was named ‘Britain First’, and service pilots were so enthusiastic about its performance that Lord Rothermere presented the aircraft to the nation. As the Bristol 142 it became the first of the new bombers.
Like the contracts for the production of the Wellesley, Harrow and Whitley bombers and the fighters, the Blenheim order was small—150 aircraft. The Royal Air Force was kept in check by financial considerations dictated by the Government’s hope that further rearmament would be rendered unnecessary.
The Abyssinian crisis and the failure of Germany to modify her aims forced the Government to revise their plans. In February 1936 another new air expansion policy was sanctioned. Compared with Scheme C, the new Scheme F strengthened the first line of home defence by substituting medium bombers for light bombers and by placing greater emphasis on fighters. It also had the merit of making better provision for reserves.
Disarmament and the failure of civil aviation to develop rapidly caused the British aircraft industry to dwindle to a shadow of its wartime strength. For fifteen years it survived on repair and overhaul contracts doled out piecemeal by the Air Ministry and an occasional order for new R.A.F. or civil aircraft.
Although designers were filled with inventiveness and ingenuity they were forced to confine designs to the conservative requirements of the Air Ministry.
When Britain began to rearm, therefore, a huge task faced a very small industry employing about 35,000 people. Production techniques did not match the advances made in privately sponsored research. Fabric, wood and tubular metal construction in many cases had to give way to all-metal designs. This presented numerous problems, including those associated with the supply of material. The total British production of aluminium was only 15,000 tons in 1935. Germany and Austria were producing 200,000 tons. Plant, machinery and the output of the industries making vital accessories were also inadequate. The quality of such as was made was good and there were plenty of ideas.
On June 7th, 1935, Sir Philip Cunliffe-Lister became Lord Swinton and replaced Lord Londonderry as Secretary of State for Air. The great significance of the appointment was not subsequently fully appreciated. Swinton brought with him a clear understanding, drive, audacity and imagination which the expansion of the R.A.F. needed. He was chairman of a small Cabinet committee on air armament set up by Mr. Baldwin, the Prime Minister, in 1934. Swinton’s initiative did not always meet with the approval of the Prime Minister or the Board of Trade, however, and until the invasion of Austria they were against gearing the industry for war production in peacetime. The result of this and the Treasury’s tight-fistedness was that the R.A.F. did not have enough aircraft soon enough.
On taking over the Air Ministry Swinton found that the regular procedure was to build a prototype and test it. When it had been fully tested a number of aircraft were ordered. The result was that even with comparatively simple biplanes five years elapsed between ordering the prototype and the re-equipment of a squadron with the new type. The Air Ministry placed orders only with established firms. They had no reason to do otherwise as the small quantities required were barely sufficient to keep even these aircraft companies fully employed.
It was obvious to Swinton that all this had to be changed if the 1939 deadline for the completion of the 1936 programme was to be met. This called for 124 home-based squadrons, 1,376 first-line aircraft and a 225 per cent reserve. One of his first moves to reduce the time lag before aircraft reached the production stage was to by-pass the long-winded prototype procedure by ordering planes straight off the drawing-board. This meant incorporating essential modifications on the production line, but with time in short supply the practice over-rode all disadvantages.
To ensure that modifications did not disrupt the flow of production only those impinging on safety and essential performance were introduced. Complete aircraft had to be returned immediately for alteration. If the modification was an improvement which was not essential to safety or performance it had to wait until it could be embodied without interrupting the production flow.
The availability of several early models obviated the delay an accident to a prototype might have induced, and enabled several kinds of necessary tests to be made simultaneously. It was impossible to judge accurately how a new type would turn out, however, and it was therefore necessary to insure against failure by ordering more than one type for each specification before choice was made.
Each company preferred to make the aircraft of its own design but in the national interest it was necessary to override any prejudices for one type or another. The final choice rested with the Air Council. Once their minds were made up the manufacturers had to be prepared to build the chosen type whether or not they had designed it. Some mistakes were made in the circumstances. Perhaps the most striking was the choice of the Fairey Battle and the subsequent dismissal of the Hawker Henley as a bomber.
The Fairey Battle day bomber carrying a pilot and a gunner was handicapped by being almost as big as the Blenheim but with no more engine power than the Hurricane. Of extremely simple and clean shape it could carry 1,000 lb. of bombs twice as far as the Harts and Hinds it replaced. The Battle failed in war because the Air Staff did not see the anomaly of ordering multi-gun fighters and a large day bomber with only one fixed gun firing forward and a single Vickers gun firing aft.
The Hawker Henley was intended as a fast monoplane replacement for the Hart biplane bomber series. Its wings were interchangeable with those of the Hurricane, an ingenious way of assisting production, maintenance and repair. The wavering attitude of the Air Ministry in 1936 towards light bombers precluded the Henley from quantity production. Numbers of these fast, heavily armed close-support aircraft might have made all the difference to events in early 1940. The Henley was easily capable of conversion to a two-seat twelve-gun fighter-bomber with a 2,000 lb. bomb load. With a top speed of 290 m.p.h. it was nearly fifty miles an hour faster than the Battle and its range of 950 miles was only 100 miles shorter than that of the Battle.
Two of the Air Staff’s re-equipment decisions stand out. The first, taken in 1934, was that the Spitfire and the Hurricane should carry eight guns each instead of two. Without this change the Battle of Britain might well have been lost.
The other, taken in 1938, was the choice of ultra-heavy bombers specified two years earlier as standard aircraft of the home-based striking force. This led to the Short Stirling, Handley Page Halifax and Avro Lancaster bomber offensives against Germany which followed up the battle.
In the Browning gun used in the Hurricane and Spitfire, the R.A.F. had a first-class weapon. It was so reliable that it could be remotely controlled and it had the extremely high rate of fire of 1,260 rounds a minute. The first orders were for American-made guns, but manufacturing rights were soon acquired by the Vickers Company to make them in Britain. It was obvious, however, that heavier armament would replace the rifle calibre Browning. In 1937 Hispano-Suiza were granted facilities to open a factory in Britain for the manufacture of the 20 mm. Oerlikon cannon. These were first tried out during the Battle of Britain on two Hurricanes and thirty Spitfires.
While Swinton was Air Minister, provision was made for engine mountings that were interchangeable. New types of engine could be earmarked provisionally for new aircraft. With the introduction of common mountings alternative engines could be installed if the type of engine originally intended failed to perform as expected and was not available in time. There was in consequence no risk of delaying the output of urgently wanted aircraft.
It became clear that after fifteen lean years the aircraft companies could not be expected to finance unaided the expansion of their productive capacity to meet the later requirements.
To remedy this Lord Swinton devised the ‘shadow factory’ scheme announced in March 1936. It called for the building of state-owned plants to create a reserve productive capacity. Firms not normally aircraft or component manufacturers, but with experience in a similar field, were given the job of equipping and managing these factories to turn out products designed by an aircraft firm. The motor industry was the most suited to make aircraft engines. Thereby arose the situation in which a shadow factory owned by the state and managed by a motor manufacturer produced aero engines or aircraft designed by other firms.
The industry was required to expand and produce to the limit, and to abandon many of the principles of competitive business. Under the scheme the ‘parent’ firm in the aircraft industry had to furnish its shadow with drawings, specifications of plant, jigs, tools, processes, test equipment, layout and other technical information, educate key men and give every sort of advice and assistance.
For airframe production the Government built and equipped two large factories at Birmingham and at Speke, Lancashire, both on existing airfields. The first was entrusted to the Austin Motor Company to build Fairey Battle bombers and the second to the Rootes Organisation for the production of Bristol Blenheims.
Swinton invited the Austin, Daimler, Humber (Rootes), Wolseley (Nuffield), Rover and Standard Companies to co-operate in the manufacture of Bristol engines. They received jointly an immediate order for 4,000 engines. For various technical reasons it was decided that each firm would make components for assembly elsewhere rather than complete engines.
Mr. Leonard Lord, a strong supporter of the plan, represented the Nuffield Organisation. It came as a surprise, therefore, when Lord Nuffield refused to let his firm participate unless each company built complete engines. He did not believe that satisfactory results could be obtained with parts manufactured by different firms. That Rolls-Royce relied on seventy or eighty sub-contractors for the production of their engines failed to impress him, although his own lieutenant insisted that the proposal was justified.
The engine shadow scheme went ahead without the aid of the Wolseley Company, but to fill the gap the Bristol Aero Engine Company erected an assembly plant in addition to supervising the whole team. Lord later joined Austins to take charge of airframe production and the engine assembly work.
The February 1936 programme governed expansion until 1939 but by the end of the first year it was clear to the Air Staff that its scope would have to be widened if the strength of the R.A.F. was to keep pace with German rearmament. A fresh plan was drawn up but this was rejected by the Cabinet in February 1937. It was still before the Cabinet when the Germans annexed Austria. Within a few days the original version was approved and the time scales advanced.
It was decided to apply the shadow factory principle within the aircraft industry itself, firms being selected to equip and manage their own shadows. The Rolls-Royce and Bristol engine companies were duplicated. Swinton wished to entrust a very large new factory at Castle Bromwich to Vickers. This was capable of the tremendous output of 1,500 Spitfires by the spring of 1940. Sir Kingsley Wood replaced Lord Swinton as Air Minister in March 1938, and Castle Bromwich was entrusted to the Nuffield Organisation, a decision which was to have far-reaching consequences.
One of the main ways in which increased output was obtained as the threat of war increased and expansion plans grew was the system of farming out component manufacture to smaller firms. Work was spread over more than 15,000 sub-contractors, including small garages and engineering works throughout the country, with the result that rearmament acquired a peculiarly national character.
After the outbreak of war sub-contracting invaded even homes, where it was not uncommon to find women past the age where they could play a more active part holding ‘filing parties’ to smooth down the rough edges of mysteriously shaped pieces of metal ‘for an hour or two after tea’. School workshops were also filled with small boys diligently lipping the sharp edges of stamped-out aircraft seats with fibre-headed hammers that seemed too big for some. It was everyone’s war and this work gave a sense of participation.
There were of course mistakes. When the first batch of wings built by the Pobjoy Company under subcontract was delivered for assembly it was discovered that none would fit the Spitfire fuselages for which they were intended. The error created serious bottlenecks all along the production lines and delayed re-equipment of many squadrons.
Britain relied on the overseas purchase of many raw materials. It was necessary therefore to build up sufficient stocks to meet emergencies. To ensure maximum self-sufficiency manufacturers were encouraged to make goods normally imported. High octane aviation fuel was such a commodity imported before the war but later refined in satisfactory quantities in Britain.
The two vital prototypes from which came the fighters that won the Battle of Britain. Above, the K 5054, the prototype Spitfire which was first flown on March 5th, 1936, and which soon achieved 349 m.p.h. during tests. Below the first Hurricane which flew on November 6th, 1935, and attained 315 m.p.h. while on trial at Martlesham Heath
As it turned out, aviation spirit was to prove no worry for the R.A.F. By July nth, 1940, the day after the Battle of Britain opened, stocks of 100 octane petrol used in the Merlin engine stood at 343,000 tons. On October 10th, twenty-one days before the battle closed, and after 22,000 tons had been issued, stocks had risen to 424,000 tons. With other grades of aviation spirit total stock available on October 10th, 1940, was 666,000 tons. Oil reserves were 34,000 tons.
The last two pre-war schemes L and M saw production expanded to the limits of peacetime capacity, the chief financial restrictions abandoned and industry much accelerated. The. final programme was prepared after the Munich crisis and hurriedly approved following German occupation of Czechoslovakia. It proposed extensions in nearly every direction, but chiefly in the number of fighter aircraft and in bombers of the latest heavy long-range type, such as the Avro Manchester, the Short Stirling and the Handley Page Halifax. By this time the air estimates had risen to a total of £220,626,000.
Meanwhile, in April 1938, a British air mission went to the United States to discuss the purchase of aircraft. The mission visited the entire American aircraft industry and found it in a worse state of depression than Britain’s before the expansion programme.
The mission ordered 200 Hudsons and 200 North American advanced trainers, the latter known as the Harvard by the R.A.F.
Three months after the first visit to America another British mission went to Canada to discuss manufacture there of the Hampden bomber, and subsequently the Hawker Hurricane and the Fairey Battle. In May 1939 a joint order for aircraft to be built in Australia was placed by the British and Australian Governments.
Before its new planes could be brought into service the R.A.F. had to build new airfields, training units, camps, bombing and gunnery ranges and other ground installations.
Until 1934 the R.A.F. had found fifty-two airfields adequate for its needs. The bomber squadrons organised in the western area of the Air Defence of Great Britain were, apart from those at Bircham Newton, Norfolk, centred on Wiltshire, Hampshire, Berkshire and Oxfordshire. The fighters of Fighting Area were disposed for the defence of London at airfields in Middlesex, Surrey, Sussex, Kent, Essex and Cambridgeshire.
The position of all these airfields, with the exception of those built during the First World War, was dictated in 1932 by the assumption that any attack on Britain would come from France. With Hitler’s rise to power and the possibility of a war, in alliance with France, against Germany the situation was radically changed. By 1939 short-range bombers, intended for continental bases in the event of war, occupied the central airfields. For the long-range bombers a string of new airfields spread across East Anglia, Lincolnshire and Yorkshire.
The dispositions of the fighter bases were determined by a plan recommended in 1935 by the Air Ministry Re-orientation Committee under Air Chief Marshal Sir Robert Brooke-Popham, then commanding A.D.G.B. They stretched as a continuous system of fighter defence from Southampton east and north as far as Newcastle.
Fighters also guarded the Clyde-Forth area and Bristol. An additional eighty-six new airfields were added, bringing the total in 1939 to 186 excluding civil aerodromes.
Surveying sites, clearing the fields and building hangars, work-shops and living quarters was a complex task. Each had to be strategically placed, fighter airfields where they could best defend probable targets, bomber bases conveniently located for offensives.
Meteorological records had to be studied for those intended for all-weather use. In addition to the fully equipped airfields more than fifty satellite and emergency landing grounds were established. Cleared of obstacles and properly drained they were sown with good grass and leased to farmers.
By early 1940, aircraft production was, nevertheless, causing anxiety. Not enough planes were rolling off the assembly lines. Accordingly, on May 14th, four days after the start of the German offensive in France, the Ministry of Aircraft Production was formed out of the Air Ministry’s research and production departments.
A taskmaster was appointed in the person of Lord Beaverbrook to press forward the production of new aircraft. As the head of the new Ministry of Aircraft Production he produced results.
By June 28th, 1940, there were 170 Hurricanes, 97 Spitfires and 20 Defiants in storage units ready for immediate issue to the squadrons. By July 5th the figure rose to 222 Hurricanes, 119 Spitfires and 32 Defiants. These reserves dropped sharply at the height of the Battle of Britain but never to danger point.
Hurricane reserves reached a rock-bottom figure of seventy-eight ready for immediate issue on August 30th. But even then only four days’ work was needed to prepare a further seventeen planes for delivery and about a week for another 113. Spitfire reserves were lowest on September 20th when thirty-eight were available for immediate issue.
When the Battle of Britain began on July 10th Fighter Command had 666 aircraft ready for action. They were of high quality, backed by a unique control and reporting system, and flown by pilots trained to the high standards Lord Trenchard decreed essential when he laid the foundations of the R.A.F. in 1919. The one serious defect was a disturbing shortage of trained pilots.