Finch Neville - United Kingdom
Background
Since 1903 and the Wright brothers’ inaugural heavier-than-air flight at Kitty Hawk, aircraft have been reaching progressively greater altitudes. In the interwar years, gentlemanly one-upmanship between the Italians, British, Americans, French, and Germans intensified, producing a series of impressive achievements. From a scientific perspective, the predominant goal was to observe the effects on pilots and engines. But veiled behind this was the recognition of the military applications of high-altitude flight.
As a result of military sanctions imposed following the First World War, Germany placed the greatest emphasis on the façade of scientific endeavour. In 1931, the seemingly unstable Junkers Ju 49, the second pressurised aircraft in history, reached 13,015 m (42,700 ft). Just seven years later, on October 22, 1938, Italy’s Lieutenant Colonel Mario Pezzi of the Regia Aeronautica reached 17,083 m (56,047 ft) in a Caproni Ca.161 powered by a Piaggio P.XI 750 hp radial engine. [1]While the Ca.161’s pressurisation technology was less sophisticated than that of the Ju 49, meaning Pezzi was somewhat uncomfortable, the Italian record still stands for piston-engined, propeller-driven aircraft.
War begins: reconnaissance becomes paramount.
While national pride was important in driving the achievements of the 1930s, all the major powers understood the military potential of high-altitude flight. Foremost among these – at least at the outbreak of the Second World War on September 1, 1939, was the vital need for information regarding the location and activity of enemy forces, factories, and shipyards. This issue became yet more prominent once the Battle of Britain began over the Channel and England’s southern shores in July 1940.
In the early part of the war, Germany’s Junkers Ju 86P reconnaissance aircraft, which first flew in February 1940, was the most capable high-altitude aircraft in the world. It was the successor to the Ju 86 medium bomber, a lacklustre design that was phased out in favour of the Heinkel He 111 as the Luftwaffe turned its attention towards France, and faced superior British and French fighters.
While the Ju 86 was outclassed, the requirement for observation above the altitude ceiling of British interceptors meant it was selected for an extensive redesign to increase service life. The wings were elongated and took on a shape more akin to a glider; the nose was radically altered with more streamlined glazing and a pressurisation system; and the notoriously unreliable and underpowered Jumo 205C engines were replaced by Jumo 207A engines equipped with dual centrifugal superchargers. The defensive armament was also removed to save weight, improving range and handling characteristics.
Rising above the swirling dogfights and relentless streams of bombers, the Ju 86P could operate effectively above 12,000 m (39,370 ft) over a range of 621 miles while carrying three automatic cameras in place of the conventional bomb load. Its immense service ceiling made it completely invulnerable to interception by enemy fighters or attack from anti-aircraft guns on the ground. A pale grey-blue camouflage and slender silhouette also made it practically impossible to detect before the advent of specialised radar systems situated along the English coastline. One of the few aircraft that could reach similar altitudes was the Supermarine Spitfire PR Mk IV, a photo-reconnaissance version of the famous fighter. However, since its armament had been similarly removed, it posed no threat.
The arms race is on: high-altitude interception
The Ju 86P’s high-altitude dominance unsettled Britain’s top brass. The RAF High Command and the Air Ministry quickly decided there was a need for a high-altitude interceptor. Specification F.4/40 called for just this. Westland Aircraft Company, which had split from its parent company in 1935, submitted the Westland Welkin as an attempt to wrestle stratospheric superiority from the Luftwaffe.
The Welkin was an odd-looking but extremely innovative aircraft designed by William “Teddy” Petter, who had already created the Westland Lysander, an excellent liaison and covert operations aircraft, and would go on to design the English Electric Canberra, which was the RAF’s first jet-bomber in the 1950s and set a series of records.
The Welkin had a slender fuselage joined to two streamlined nacelles containing Rolls-Royce Merlin engines by markedly long, narrow wings—like those of the Ju 86P—that were more akin to those of a glider than a fighter aircraft. This wing shape produced so much lift that the decision was made not to equip the aircraft with flaps. However, a high thickness-to-chord ratio—the measure of how thick the wing is at the base versus its span—caused serious compressibility problems around the limiting Mach number (the speed at which part of the air moving over the airframe reaches the sound barrier). This caused the flight controls to become sluggish and sometimes even fail to operate.
The design’s pressurisation, supplied by a supercharger connected to the port engine, created an apparent cabin altitude of 7,300 m (24,000 ft) when the aircraft was actually flying at 14,000 m (45,000 ft), its standard operating altitude for interception. This meant that the pilot still had to take oxygen through a mask and wear a high-altitude suit in case he needed to bail out. Like a number of British twin-engine fighter aircraft, the design fitted four 20 mm Hispano cannon in a bay under the short nose—enough firepower to turn a Ju 86P into a flaming wreckage of tracer-riddled metal with a short burst.
Outclassed by a Spitfire: Bowing out before service
The Welkin was potentially a capable fighter, possessing moderately heavy armament and high survivability thanks to its twin engines. [2] Its fate was sealed, however, when a Ju 86P was downed by a specially modified Spitfire Mk V at 12,800 m (42,000 ft) over Cairo on the 24th of August 1942, thanks to the higher troposphere boundary caused by the warmer weather, which enabled the wings to continue to produce lift at a higher altitude than would otherwise be the case. Given this success and the enormously high stakes, the Welkin almost immediately lost its role, as the Air Ministry did not see value in pursuing such a complicated design that only offered minor improvements in performance; the electrical systems alone required four hours of checks before a flight. A night-fighter variant with a crew of two subsequently gained a specification but was never built as other aircraft were developed to fill the role.
The success of the Spitfire attack prompted the installation of a defensive machine gun on the Ju 86P. More importantly, it proved that the era of invulnerability was over. Pilot Officer Emanuel Galitzine, a Czarist prince who had emigrated to England, of the Special Service Flight based at RAF Croydon intercepted a Junkers over the Channel on September 12, 1942. He wrote that his Spitfire Mk IX “had been lightened in almost every possible way,” with “all equipment not strictly necessary for high-altitude combat [having been] removed." (Multiple versions of the Spitfire were in service simultaneously, with some of the oldest seeing action in Africa due to the paramount importance of the Western theatre.)
At 9:27 am, the skies over southern England reverberated with the roar of a Merlin engine as Galitzine climbed towards a radar signature high over the Channel. This was the Ju 86P reconnaissance bomber commanded by Sergeant Horst Götz, a veteran of many failed interceptions by Spitfires. He noted the British aircraft a few thousand feet below and was shocked to see that it was still climbing aggressively towards him. Immediately, he jettisoned his bomb load and boosted the Jumo engines to try and escape. Galitzine responded by detaching his drop tank and opening fire with his two 20-mm cannons at close range.
Issues caused by the Junkers’ contrails fogging Galitzine’s cockpit and one of his cannons becoming jammed forced him to descend after three attack passes that lasted 45 minutes. Moreover, the damage Galitzine had inflicted was insignificant—a single hole in the port wing. Nevertheless, the event was enough to stop the Luftwaffe from operating Ju 86Ps over the Channel again. Combined with the removal of the type from reconnaissance duties in the African theatre in the face of increased interception by even unmodified Spitfires at a critical time in the war, this amounted to a massive blow to the German High Command. No longer could they receive information about Allied movements deep into hostile territory.
The Junkers Ju 86P was withdrawn from service in May 1943, having been so critical to Germany’s aerial strength for over three years. The rapid removal of the type served to highlight the remarkable speed of technological innovation during this period. While the unorthodox-looking Blohm & Voss BV 141 superseded the role of tactical reconnaissance, the Ju 86P’s retirement left the niche of high-altitude reconnaissance aircraft with glider-type wings empty for many years until the first flight of the famous American Lockheed U-2 in 1955.
Bibliography
The British Fighter since 1912 by Francis K. Mason (1992)
The British Bomber since 1912 by Francis K. Mason (1994)
The Encyclopaedia of Aircraft of World War II by Paul Eden (2017) https://www.airandspaceforces.com/article/0799altitude/ The Race for the Stratosphere
by Robert E. van Patten (1999) (Accessed 28th of April)
https://www.aviastar.org/air/england/west_welkin.php The Westland Welkin (Accessed
26th of April) [1]
Italian Civil and Military Aircraft 1930-1945 by Jonathan W. Thompson (1963) [2]
British Secret Projects: Fighters and Bombers 1935–1950 by Tony Buttler (2004)
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