History

The Bristol 135

On the main up departure platform at Temple Meads Station in Bristol, early one morning in February 1934, the most devastating blow to Britain’s pre-war air defenses started to emerge. Robert Lewis, the editor of the Bristol Evening World, and a member of the Rothermere group of national and regional newspapers was one of the passengers boarding the Great Western Railway express bound for London Paddington. He was present in a meeting of editors being presided over by Lord Rothermere. Rothermere was very interested in aviation and had served on Lloyd George’s Air Council during World War One.

The requirement for a high-speed aircraft to rival the 12-seat Lockheed monoplane lately ordered by Lord Beaverbrook, chairman of the competing Express group of papers, was on the agenda. Lewis noticed Roy Fedden, the Bristol Aircraft Company’s principal engine designer, on the packed platform. Fedden had given a lecture at the Spa Hotel in Clifton, and Lewis was a member of the Bristol Yacht Club, where the men had first met. Fedden’s talk covered the Bristol 135 twin-engined monoplane, his company’s most recent effort.

Lewis encouraged Fedden to sit at his table when they entered the restaurant car for breakfast because he knew Rothermere would be curious to learn about it. They spoke for a while about their shared love of fishing before Lewis changed the topic to the 135, asking Fedden for additional details so he could give Rothermere more information during the London meeting. Fedden was happy to comply. Bristol had experienced rough years in the early 1930s.

The Bristol Fighter biplane, a popular two-seater that became a mainstay of the Royal Flying Corps during World War I, helped the company prosper, and by 1918, more than 5000 had been constructed. But after the war ended, commerce slowed, orders stopped coming in, and Bristol was only able to stay in business by producing designs created by other companies under license. The Bristol 135 was a valiant attempt at a revolutionary new design to revive the market for the company. Sadly, startling new concepts and designs were not readily accepted in aviation.

The Bristol Fighter was still being used in New Zealand’s front-line military service when Fedden and his crew started working on the 135 project. Lewis had all the information regarding the 135 by the time both guys had completed their meal and the train was rolling into Paddington Station. Though he brought a good proposal to the table, he was utterly unaware of how threatening the project would be to military aviation’s stability and Britain’s capacity to repel air attacks. Military aircraft had become powerful weapons during the conflict, but the Armistice had halted the development.

Stories of daring single battles between fighter aces high above the muck, blood, and squalor of the trenches continued to influence the public’s perception of military aviation. The Armistice had prevented the bomber’s full potential from being seen, but it still posed a serious threat going forward. When commercial airliners were originally being developed, aircraft engineers were excited. Fedden has concentrated on the main issue impeding the development of aero-engines.

An engine needed to turn over more quickly to provide more power. Although the first sleeve valve engine was still in its infancy, these promised increased reliability, particularly at higher speeds and power settings. The 135 would have two of the Bristol Aquilas, a smaller six-cylinder radial based on the current Bristol Mercury. Steel would be used for the flanges of the wing-spar webs and the frames on which the engines would be mounted.

To generate some curiosity and even an order for the new aircraft, Fedden maintained his appointment at the Yacht Club. Lewis informed Rothermere about the 135 later that day. Lewis was instructed to speak with Fedden and his colleagues again for more information after Rothermere, who had served on the Air Council during the war, became confident that he could spot good news when he heard it. When he did, Barnwell and Fedden displayed the 135 sketches to him.

The Bristol 142

Later, on March 26, 1934, Rothermere placed an order for the 135 for a total of £18,500, with the stipulation that it be delivered within a year. The Aquila engines’ power output was still somewhat low, and they wouldn’t be ready for bench testing for another six months. However, by prioritizing speed over the economy, Rothermere created a distinct scenario. His aims led Bristol to switch from the smaller and less powerful Aquila engines to the bigger and more powerful supercharged Bristol Mercury engines.

This revised design was renamed the Bristol 142 and work began on the necessary changes. Ironically, Brigadier General P., an ex-Royal Flying Corps officer and former secretary-general of the Air League of the British Empire, served as Rothermere’s own aviation adviser. On April 12, 1935, Bristol test pilot Cyril Uwins started the 142’s two Mercury engines and took flight from the company’s Filton airport. Roy Fedden made a wise proposal in the interim.

Fedden advised adopting the significantly more effective three-bladed variable-pitch airscrews produced by the American Hamilton-Standard Corporation to take full advantage of the low drag factor. This was more than 100 mph faster than Beaverbrook’s Lockheed, much to Rothermere’s pleasure. Even more quickly than any of the RAF’s current fighters was Rothermere’s new aircraft. Rothermere was completely unaware of this issue and considered his purchase as a triumphant confirmation of his expectations that Britain could compete with the most modern aviation designs from outside.

Therefore, calling it the Bristol 142 was inadequate to convey the message the aircraft was carrying. He had the phrase “Britain First” painted on his nose instead. Others referred to it as the “Rothermere Bomber” because they saw the more deadly implications of such a swift aircraft that appeared impervious to fighter attack. Early in the 1930s, the excitement over the victory in 1918 had given way to rising unease regarding the long-range bomber’s growing menace.

Britain should have this capability as soon as possible if “Britain First” could be evolved into a swift, contemporary medium bomber that could outrun enemy aircraft. But others might be able to duplicate Barnwell and Fedden’s success. Rothermere agreed that the aircraft could be sent to the Aeroplane and Armament Experimental Establishment at Martlesham Heath, close to Ipswich, for RAF experts to inspect and test it before they decided to take a closer look at what “Britain First” could do. Britain First joined a group of aircraft waiting for service evaluation in June 1935.

The plane in front of it in the test lineup highlighted just how significantly better it was compared to current military designs. The Boulton Paul Overstrand, a huge and unwieldy biplane with a massive fixed undercarriage and a vast network of bracing struts and wires, was the most recent bomber to be accepted for RAF service. Meeting something like the Bristol 142 would make RAF fighters entirely useless as this slowest of targets was the threat they were built to handle. Although the Air Ministry had been as surprised by the Bristol 142’s performance as its new owner had been, Barnwell and Fedden kept them fully informed.

The 142M

A modern machine for a civilian owner without informing them and without keeping them updated on engine developments was the last thing they wanted to do in a down market for airplanes. Then they created the Bristol 143, a second prototype outfitted with the original Aquila sleeve-valve engines. The plane’s top speed, albeit with engines that were smaller than those of Rothermere’s machine, was a heartening 250 mph. However, Rothermere’s aircraft appeared to be the greatest option for future British bomber development, and Rothermere himself declared he would give it to the RAF if doing so would enable it to acquire the most advanced equipment.

When he touched down, it collapsed after failing to lock into position, seriously damaging the aircraft. The RAF felt this to be extremely embarrassing and insisted on paying Rothermere the original purchase price for “Britain First” as compensation. The 142M, an updated version of the 142 that was better suited to military requirements, had already been created by this point by Barnwell and Fedden.

With the 142M in mind, they created the official medium bomber specification 28/35. They ordered 150 of the new bombers within a month, nearly a year before the 142M prototype actually took to the air. With updated carburetor air intakes and cooling gills around the engine cowlings that the pilot could regulate to ensure the engines functioned at the ideal temperature under various loads, this model left the Bristol facility in June 1936. In reaction to German attacks on Allied towns by huge Gotha biplanes and Zeppelin airships during the closing months of World War One, the public had called for intensifying bombing strikes on Germany.

The Royal Flying Corps of the Army and the Royal Naval Air Service were combined to become the RAF on April 1, 1918, with the goal of improving air defenses for the British Isles and launching a strategic bombing campaign against Germany. To do this, the Independent Force of heavy Handley Page biplane bombers was established in June 1918. Future military victories need an increasing number of bombers carrying bigger bomb loads to annihilate and demoralize the enemy. At its most fervent, the bomber lobby maintained that funding for fighters was entirely unnecessary and took resources away from bombers, which were the only vehicles capable of bringing victory.

Germany

The enormous performance difference between bombers and fighters appeared to be supporting their position. While Rothermere’s aircraft was being built, the newly installed Nazi regime in Germany had started a massive rearmament program that was oriented toward starting a new world war but was being kept secret for the time being under a tight security net. Hitler, therefore, gave Rothermere information on the creation of the new Luftwaffe on March 8, 1935, as soon as he felt secure enough to reveal Germany’s growing military prowess in order to ensure maximum publicity in national newspapers like Rothermere’s Daily Mail. Although the notion of a mail plane was marginally more plausible, it became increasingly clear that this aircraft was a bomber in all but name.

Tank and bomber crews were closely clustered according to German military psychology for mutual assistance. Performance was lacking at first since aero-engine development had just recently been made possible by the Versailles Treaty. The Dornier 17 prototype had a top speed of 225 mph thanks to two BMW engines, each producing 750 bhp. This would be superior to the majority of biplane fighters, but advancements would soon follow.

Heinkel provided perhaps the strongest evidence that Barnwell, Fedden, and Dornier were making the right decisions. With the Heinkel He 70 monoplane’s inaugural flight on December 1, 1932, Heinkel had already begun to catch up to Lockheed by the time of this flight. It was a small, precisely streamlined monoplane with a retractable undercarriage, similar to the Orion. It had a single BMW V12 engine, seated the pilot and radio operator in front of four passengers who were seated in pairs with their backs to the cabin sides.

Its performance was nearly comparable to that of the Orion, although it had a stressed magnesium alloy skin to reduce weight. Fortunately, Lockheed had the twin-engined Electra, their first all-metal stressed-skin monoplane, ready for the new specifications. Boeing’s 247, which had its first flight in 1933 and had a similar capacity and performance, and Douglas’ DC2, which made its debut on May 11, 1934, and could carry 14 passengers at a top speed of 210 mph, were examples of other US aircraft manufacturers working in a similar vein. These American designs, in contrast to their German counterparts, were sincere attempts to address a rapidly expanding need for secure, long-distance travel for passengers and freight throughout their vast country.

These would be entirely different designs when the Americans began to produce their own bombers as the war drew closer. Heinkel’s attempt to follow Lockheed’s lead in converting from a single-engine monoplane to a twin would serve a more nefarious purpose in Nazi Germany, however, where the military tail wagged the aviation dog. The Heinkel 111 was commissioned as a prospective airliner, similar to the Dornier 17, but again, its design only made sense as a bomber. Although it was built up to twin-engine dimensions, it was officially capable of carrying ten passengers at a top speed of 225 mph and had beautiful elliptical wings and tail surfaces akin to the Heinkel 70.

The Junkers 88, which debuted as a military aircraft from the start, would be the second bomber design after the Heinkel 111, which made its first flight on February 24, 1935. The aircraft industry was undergoing rapid change, with performance increasing month over month. The murders of his erstwhile accomplices served as unmistakable evidence that Hitler was a dangerous megalomaniac for many people inside and outside of Germany, and he now considered them as a threat to the consolidation of that authority. In fact, each of these new bombers rendered existing fighters less efficient.

The RAF’s current fighter biplanes were set to be replaced by a completely new generation of fighter biplanes by the time the Blenheim ultimately reached service in the summer of 1937. Front-line fighter units from countries like France, Germany, and the USA continued to rely on aircraft that 1918 pilots were all too familiar with. They desired a fixed undercarriage for its extreme simplicity and dependability as well as the well-known armament of two machine guns that were conveniently located on the engine cowling in front of them. This was the reason why the new metal-skinned monoplane bombers were so immune to fighter interception.

Early 1930s aero engines had a maximum output of about 600 bhp. This allowed a top speed of about 150 mph with a conventional fighter design with all the added drag, which is far too slow to catch and take down one of the new bombers. Even if designers resorted to the retractable undercarriage and all-metal stressed skin construction, their aircraft would still be lucky to achieve 250 mph, which is still too slow to catch a twin-engine bomber. Even with 600 horsepower each, two contemporary engines fitted into a streamlined monoplane provided enough power to outrun aircraft.

Even the most advanced fighter aircraft could never overcome enough weight and drag to provide a high enough top speed and rate of climb from a single, similar engine. Even worse, any fighter that managed to down one of the new bombers would probably not be able to keep it in its gunsight for more than a few seconds. Failure was inevitable due to the preferences of fighter pilots. The drag caused by an open cockpit meant the only view it was likely to give was of a monoplane bomber disappearing into the distance.

The inherent maneuverability of a biplane, according to pilots, is crucial in fighter-to-fighter combat. Designers had little reason to test out novel concepts as long as fighters were evenly matched, but the game was now officially over. Manoeuvrability became less important with the advent of quicker twin-engine monoplanes like the “Britain First.” A speedier opponent could decide the terms of the fight, charge in, and execute a swift hit, taking out his opponent without any maneuvering at all.

It was obvious that the quick monoplane fighter would be in the shape of the future just five years before the second world war. However, fighter performance seemed destined to remain unachievable without significantly more potent engines. It could be equipped with two more machine guns in the wings in addition to the two mounted on the engine cowling. 501’s 690 horsepower Hispano engine was only capable of 250 mph.

Its weaponry was enhanced by an engine-mounted cannon that fired through the propeller hub, but it would never approach an adversary closely enough to pose a threat. Due to its poor performance, it was only suitable for training purposes when the conflict started. The most important takeaway from Lewis and Fedden’s breakfast talk on the train to London was that the balance between fighter and bomber, so disrupted by the Bristol 142 and its contemporaries, could only be restored if engine makers could increase power output beyond 1000 bhp. This required starting from scratch after such engines were made accessible because there wasn’t enough money for fighter development.

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