by Greg Baughen
The Air Ministry continued to do this long after the Foreign Office had made it very clear to all three services that there was no possibility of war with France and the French threat should not be a factor in their planning.4 The Air Ministry had its reasons for ignoring this instruction: they were determined to prove that long-range bombing would decide future wars and needed an enemy that was close enough. However, as the Admiralty and War Office took delight in pointing out, and perhaps deep down the Air Ministry was aware, France was the only major power that Britain could threaten with a bomber strategy. At the time, the Soviet Union and Japan were far more likely enemies, but the former was too vast and the latter too remote to be vulnerable to RAF bombing.
A new generation of high-speed light bombers reinforced the idea that single-engined bombers were best. The Fairey Fox, powered by an American Curtiss engine, astounded all with its speed. It was almost as fast as the best British fighter, but was scarcely a long-range bomber: it could only carry 336 lb of bombs and it had to refuel at the coast just to reach a target as close as Paris. After coming in for some severe criticism for equipping the RAF with a plane powered by an American engine, Hugh Trenchard, the Chief of Air Staff, ordered a British-powered replacement, the Hawker Hart. When it entered service, it could match the speed of the fastest British fighter at low level, but it could only just reach Paris, and only carried 500 lb of bombs.
By the end of the decade, it seemed that there was no place for a twin-engined day bomber. The Air Staff felt that it fell between two stools; planes like the Sidestrand lacked the bomb load of the heavy night bomber and the speed of the single-engined day bomber.5 It seemed only two types of bomber were required—the heavy twin-engined night bomber and the high-speed single-engined day bomber. When the time came to reequip the single squadron of medium Sidestrands, many in the Air Ministry thought it was a waste of time bothering. They did eventually release Specification B.9/32, which asked for a twin-engined medium bomber, but only to keep an eye on what such machines might be capable of. The specification required a bomb load of 1,000 lb and a range of 600 miles at maximum speed, which was sufficient to reach Paris comfortably from airfields behind the main defensive fighter belt. The range was later increased to 720 miles at a lower and more economical cruising speed, a technical adjustment that was to cause confusion further down the line. This specification led to the development of the Vickers Wellington and Handley Page Hampden, but few in the Air Ministry believed they would be needed. The next important bomber would be a single-engined machine to replace the Hart.
In April 1932, the Air Ministry decided the time had come to find that replacement, and this is where the Fairey Battle’s story begins. Specification P.27/32 laid down what would be required. The plane was not to be a like-for-like replacement for the Hart, and the aim was not maximum speed at any price. The requirements were deliberately in line with B.9/32’s twin-engined Sidestrand replacement, so that a fair comparison could be made between the single-engined and twin-engined approach. The only major difference was that the larger twin-engined plane had to carry more fuel so that it could fly to bases around the Empire—the single-engined bomber did not need to because smaller planes were easier to ship abroad.6
The Air Staff wanted the plane to carry twice as many bombs as the Hart (1,000 lb) and have a range of 600 miles at maximum speed, again so that the plane could reach Paris comfortably. The new plane was to be a twoseater, with pilot and observer as close as possible, and the rear gunner would have to be able to reach a prone bomb aiming position in the floor of the plane. Level and dive-bombing were required. Bombs would be carried internally, but for dive-bombing the bombs would have to extend from the bomb bay hydraulically. The Air Ministry was not expecting a huge increase in performance: they only required a top speed of 195 mph. This was only 15 mph faster than the original Hawker Hart specification issued six years before.7
Unlike the Hart, provisions would have to be made for an autopilot and some night flying equipment. They had no plans to operate the plane by night, but during short winter days, it might have to start or finish its missions in darkness. A much bigger bomber than the Hart was always the idea; the Air Ministry wanted a medium bomber, not a light one.8 Early calculations suggested it might be twice the weight of the Hart—which would make it bigger than the Horsley, the RAF’s previous single-engined medium bomber9—and a weight approaching 10,000 lb, once fully fuelled and armed. This was a substantial load for a single engine to haul through the air.
The predicted weight was also a problem for political reasons. Disarmament talks were taking place in Geneva and the British government had proposed a three-ton weight limit on all military aircraft. The Air Ministry felt obliged to build this requirement in to both their B.9/32 and P.27/32 specifications. This scarcely seemed necessary, as the weight limit was only a proposal. No other country had agreed to it and even if they had, Britain would need to continue investigating heavier designs, in case a potential enemy changed its mind. Britain had not taken this attitude with its chemical weapons policy—the government had signed an international agreement banning their use, but this did not stop Portland Down continuing to develop them. With bomber design, a mere proposal immediately became a key feature of Air Ministry requirements. The Air Staff almost seemed to be hoping that they would not be allowed to build large expensive bombers that they knew the country could not afford. Aircraft companies were told the empty weight of their designs could not exceed 6,300 lb, which was slightly less than three tons and gave them at least some leeway for improvements and modifications.
Even with this weight limitation, the plane was still going to be much larger than the Hart and would need far more power than the Hart’s 21-litre Kestrel engine. The power plant the Air Ministry had in mind was the mighty 37-litre Griffon, which Rolls-Royce were developing from their Schneider Trophy R engines and was expected to generate more than 1,000 hp.10 However, the Air Staff did not want to be too prescriptive; the final specification did not specify any particular power plant. There was also no mention of whether it should be a monoplane or incorporate innovations like a retractable undercarriage. Enclosing the pilot and observer was merely mentioned as a possible alternative to simple windscreens. As the modest speed requirement suggested, the Air Ministry was not expecting a revolutionary advance in aircraft design.
In truth, neither the Air Ministry nor the designers realised that there was about to be a revolution in aircraft performance. Below 175 mph, the biplane, with its low weight and high strength, was ideal. Above that speed, reducing drag becomes more important than keeping weight low, and trying to make biplane bombers with fixed undercarriages go faster than around 175 mph would be trying to defy the laws of aerodynamics. Cantilever monoplanes with retractable undercarriages had become essential for reducing drag. Even the uneven surface of the traditional fabric covered structure became an unacceptable source of drag, and designers began to use more easily contoured metal stressed skin construction. All these innovations meant more weight, but speeds suddenly lurched forward in a way that took everyone by surprise. American designers were leading the way with civil airliners like the Boeing 247 and Douglas DC-1. These would soon be carrying their passengers at speeds higher than the Air Ministry was expecting from their P.27/32 bomber.
No-one would be more surprised by the revolution that was about to occur than Charles Fairey. His company, led by their Belgian chief designer Marcel Lobelle, had established a reputation for advanced, elegant designs with their streamlined Fairey Fox light bomber and its Fairey Firefly fighter offspring. Far from being on the brink of a revolution in aircraft design, Fairey believed an era of rapid progress had come to an end and it was a time for consolidation.11
The P.27/32 specification was finalised in April 1933 and released to the industry in June, with twelve companies invited to come up with proposals by September. Fairey’s initial ideas on how to meet the specification were very conservative—one of their ea
rly efforts was a biplane. Fairey soon switched to monoplanes, but he was aware that designs like the Fairey Fox had not been ideal. He felt that the pendulum had swung too far in the direction of aerodynamic finesse and high performance at the expense of operational usefulness.12 He was determined not to make this mistake with the P.27/32. Unfortunately, the pendulum was about to swing too far in the opposite direction.
His initial monoplane entries had undercarriages that retracted neatly outwards into the wings, but aerodynamic refinement ended there. The observer was close to the pilot, as required by the Air Ministry but, to make sure he could see down, Lobelle cut large chunks out of the rear of the wing near the junction with the fuselage. To compensate for the weakened wing root, the wing had to be supported by struts. This, along with a rather angular crew cabin, ensured the end result was not particularly elegant.
The P.27/32 project very nearly got no further. A month after the specification was released, Air Vice-Marshal Ludlow-Hewitt, the newly appointed Deputy Chief of Air Staff, was suddenly very anxious to abandon the entire idea. He had no problem with the single-engined approach to bomber design, but he did not see how the relatively large P.27/32 was what the RAF needed. It was not a high-speed Hart replacement by any stretch of the imagination, nor did it carry a large bomb load. Ludlow-Hewitt was convinced that the RAF needed something along the lines of the original Fox/Hart concept—the fastest possible short-range bomber carrying just a 500-lb bomb load. Air Chief Marshal Edward Ellington, the recently appointed Chief of Air Staff, agreed. A new requirement for a light bomber was drawn up (P.4/34), which would lead to the Hawker Henley and a design from Fairey, known simply by its P.4/34 specification number. The P.27/32 bomber was on the brink of being cancelled before the companies even had the chance to finalise their proposals.
It was saved because Ludlow-Hewitt was worried that companies would not be too happy about the Air Ministry cancelling the project so soon after releasing the specification. ‘To avoid the odium which would be incurred’, Ludlow-Hewitt suggested the P.27/32 should be brought in line with the twin-engined B.9/32 requirement.13 Possibly because he was new to the post, he did not seem to realise that this had always been the intention, and the range requirements had only got out of kilter because the original 600 miles at maximum speed for B.9/32 had become 720 miles at cruising speed. The companies were told about the change in the range requirement and the deadline to tender designs was extended to October 1933.
Seven companies submitted designs: Armstrong Whitworth, Bristol, Fairey, Gloster, Hawker, Vickers, and Westland. These were assessed in November 1933, and a conference held in February the following year made the final decision. The 37-litre Griffon engine was never a serious option, as Rolls-Royce were focusing their efforts on the smaller 27-litre Merlin. All the proposed designs made use of 21 to 27-litre engines like the Napier Dagger, or the Rolls-Royce Goshawk and Merlin, all of which were expected to generate around 800 hp. Fairey wanted to use their own 26-litre Prince engine.
Fairey put forward several proposals. Unfortunately, many of the original files have been lost, so it is not entirely clear what these were. It has been suggested that one of them was an October 1933 twin-engined low-wing monoplane, but there is no mention of a low-wing monoplane for this date in the Fairey G.A. Drawings Register.14 It also seems strange that a twin-engined design should be proposed for P.27/32 when the parallel B.9/32 existed for twin-engined bombers. Fairey did indeed draw up proposals for B.9/32, but there were none after February 1933, so the October 1933 proposal remains a mystery.15
Whatever the options, the Air Ministry chose the Fairey ‘B’ proposal.16 This was a rather ungainly low-wing monoplane with a semi-cantilever braced wing. However, the predicted top speed of 223 mph was far more than the Air Ministry was asking for, and the Fairey proposal was judged the best on offer, with the Armstrong Whitworth entry next best. Formal contracts for both were issued in June 1934, with the delivery of the Fairey prototype expected by September 1935 and Armstrong Whitworth promising theirs by December.17
While the Air Ministry was deciding which prototypes to order, it was changing its mind about what was required. Ludlow-Hewitt decided that he wanted the P.27/32 single-engined bomber to have the same ferry range as the twin-engined B.9/32. In October 1933 ferry range was set at 1,250 miles,18 but this had been increased to 1,500 miles by August 1934.19 By this time, the prospect of war with Germany was becoming a real danger and bombing Paris was no longer good enough. Bombers had to reach Berlin, if not from Britain, then at least from the airfields of a likely ally like France. Companies were told their designs would have to carry a minimum of a 500-lb bomb load with the additional ferry tanks.20 Over the longer ranges the plane was now expected to operate, it was even more likely it would have to take off or land in darkness and night flying equipment and the autopilot became permanent fixtures rather than optional attachments in the spring of 1934.21 All these requirements were pushing up the load the single engine would have to lift.
The revised requirements were also causing delays. With Hitler’s rise to power, the political situation in Europe was deteriorating rapidly and Ludlow-Hewitt urged Air Marshal Dowding, in charge of research and development, to chivvy aircraft companies along. The RAF’s current aircraft were ‘considerably inferior’ to those they might have to face and more modern planes, especially bombers, were needed as quickly as possible.22 Companies should be told any delays would not be tolerated. Dowding suggested that it would help if Ludlow-Hewitt’s staff stopped changing their minds about what they wanted.
Incorporating everything the Air Ministry wanted within a design that weighed only 6,300 lb was almost impossible. The collapse of the Geneva disarmament talks in 1934 therefore came as a great relief to the aircraft industry. The weight restriction could now be dropped, but this meant further delays as designers upgraded their proposals. In the early summer of 1934 Fairey came up with four new versions of the Fairey P.27/32, which seemed still some way from its graceful final form. One proposal was based on the monoplane version of their G.4/31 multipurpose colonial plane.23 Like the earlier proposals, this was a semi-cantilever design with cut-outs at the wing root trailing edge and struts supporting the wing.24
Ideas about the form the bomber should take were transformed by a visit to the United States in the summer of 1934. Both Lobelle and Fairey were taken aback by how advanced the latest American designs were and rather embarrassed by how clumsy their own P.27/32 proposals were by comparison. On their return, Fairey found a threatening letter from the Air Ministry waiting for him, warning the company that if their first prototype was not delivered on time in September 1935, their design would probably not even be looked at.25 Despite this, Fairey and Lobelle felt the company had to ask the Air Ministry for an extension. Fairey explained that they had come up with a more advanced fully-cantilever monoplane with the bomb bays and fuel tanks moved to the wings, the former outboard and the latter inboard of the undercarriage. There was now no space for the undercarriage to retract sideways and so it had to retract backwards instead. This meant the wheels were no longer totally enclosed in the wing, which was actually a step backwards aerodynamically. Fairey asked the Air Ministry for an extra four months to incorporate these changes.26 Fortunately for Fairey, this was the target date for the rival Armstrong Whitworth proposal anyway, and so Fairey got their extension.
It seemed to be worth the delay. Lobelle’s new design was an extremely clean low-wing cantilever, stressed-skin monoplane, with wing bomb bays which held four 250-lb bombs, and two more bombs mounted externally. The observer acted as gunner and bomb aimer but, with no cut-outs in the wing, he could no longer see down. Fairey therefore moved the rear cockpit to the trailing edge of the wing, although this created a gap between observer and pilot. Initially the pilot and gunner were housed in their own streamlined cockpits, but this was changed at some stage to a single, continuous canopy that covered both positions. Rather oddly, this also covered the ori
ginal fuselage, presumably because there was no time for more extensive changes to the design. The space where the fuel tank and bomb bay had been now become an internal cabin connecting the pilot and observer’s position, although some of this space was soon taken up by an auxiliary fuel tank to meet the new Air Ministry range requirements.
For his bomb aiming duties, the gunner took up a prone position in a bathtub-shaped compartment in the floor of the fuselage, which was, by all accounts, rather cramped for anybody above average height. There was a sliding panel through which the bomb aiming equipment protruded in the run in to the target. This was literally just an opening in the floor of the plane, which made the position draughty to say the least, although with the radiator bath immediately ahead, it was a rather warm draught. Much later, Sholto Douglas, the Assistant Chief of Air Staff, happened to come across a Battle that Fairey was building for the Belgian Air Force with a Perspex cover and he immediately ordered that this simple modification be applied to the British version.27 The power plant was now the Rolls-Royce Merlin, an extremely efficient engine that offered more power than the 800 hp the early proposal had been based on. Even so, with the weight of the design increasing rapidly, the plane was still looking a little underpowered. However, there was nothing more powerful available, and the expected performance was impressive. Fairey were soon predicting a speed in excess of 250 mph, far more than the 195 mph the Air Ministry had originally expected.
For Fairey, the stakes were high. If their design was chosen, they could expect substantial orders: the first RAF expansion scheme in 1934 had seen the Air Ministry order large numbers of single-engined Hawker Hinds, an upgraded version of the Hawker Hart. Single-engined bombers were still very much the preferred option. If the Air Ministry decided that it wanted light rather than medium single-engined bombers, Fairey had their P.4/34 scaled-down version of the Battle waiting in the wings.