Junkers Ju 52/3m, Polish Aviation Museum, Kraków, Lesser Poland, Poland, Europe

The Junkers Ju 52 was a German trimotor transport aircraft manufactured from 1932 to 1945. It saw both civilian and military service during the 1930s and 1940s. In a civilian role, it flew with over twelve air carriers including Swissair and Deutsche Luft Hansa as an airliner and freight hauler. In a military role, it flew with the Luftwaffe as a troop and cargo transport and briefly as a medium bomber. The Ju 52 continued in postwar service with military and civilian air fleets well into the 1980s. The Ju 52 was similar to the company's previous Junkers W33, although larger. In 1930, Ernst Zindel and his team designed the Ju 52 at the Junkers works at Dessau. The aircraft's unusual corrugated duralumin metal skin, pioneered by Junkers during World War I, strengthened the whole structure. The Ju 52 had a low cantilever wing, the midsection of which was built into the fuselage, forming its underside. It was formed around four pairs of circular cross-section duralumin spars with a corrugated surface that provided torsional stiffening. A narrow control surface, with its outer section functioning as the aileron, and the inner section functioning as a flap, ran along the whole trailing edge of each wing panel, well separated from it. The inner flap section lowered the stalling speed and the arrangement became known as the Doppelflügel, or "double wing". The outer sections of this operated differentially as ailerons, projecting slightly beyond the wingtips with control horns. The strutted horizontal stabilizer carried horn-balanced elevators which again projected and showed a significant gap between them and the stabilizer, which was adjustable in-flight. All stabilizer surfaces were corrugated. The fuselage was of rectangular section with a domed decking, all covered with corrugated light alloy. There was a port side passenger door just aft of the wings, with windows stretching forward to the pilots' cabin. The main undercarriage was fixed and divided; some aircraft had wheel fairings, others not. There was a fixed tailskid, or a later tailwheel. Some aircraft were fitted with floats or skis instead of the main wheels. In its original configuration, designated the Ju 52/1m, the Ju 52 was a single-engined aircraft, powered by either a BMW or Junkers liquid-cooled engine. However, the single-engine model was underpowered, and after seven prototypes had been completed, all subsequent Ju 52s were built with three radial engines as the Ju 52/3m (drei motoren - "three engines"). Originally powered by three Pratt & Whitney Hornet radial engines, later production models mainly received 574 kW (770 hp) BMW 132 engines, a licence-built refinement of the Pratt & Whitney design. Export models were also built with 447 kW (600 hp) Pratt & Whitney Wasp R-1340 and 578 kW (775 hp) Bristol Pegasus VI engines. The two wing-mounted radial engines of the Ju 52/3m had full-chord cowlings and diverted noticeably, being mounted at an almost perpendicular angle to the tapered wing's receding leading edge. The central engine had a half-chord cowling like a Townend ring as the fuselage behind it was increasing in diameter, though some later aircraft had deeper cowlings. Production Ju 52/3m aircraft flown by Luft Hansa before World War II, as well as Luftwaffe-flown Ju 52s flown during the war, usually used an air start system to turn over their trio of radial engines, using a common compressed air supply that also operated the main wheels' brakes. Hitler used a Deutsche Luft Hansa Ju 52 for campaigning the 1932 German election, preferring flying to transport by train. After he became German Chancellor in 1933, Hans Baur became his personal pilot, and Hitler was provided with a personal Ju 52. Named Immelmann II after the World War I ace Max Immelmann, it carried the registration D-2600. As his power and importance grew, Hitler's personal air force grew to nearly 50 aircraft, based at Berlin Tempelhof Airport and made up of mainly Ju 52s, which also flew other members of his cabinet and war staff. In September 1939 at Baur's suggestion, his personal Ju 52 Immelman II was replaced by the four-engined Focke-Wulf Fw 200 Condor, although Immelman II remained his backup aircraft for the rest of World War II. The first major operation for the aircraft was in Operation Weserübung, the attack on Denmark and Norway on 9 April 1940. Fifty-two Ju 52s from 1. and 8. Staffel in Kampfgeschwader 1 transported a company of Fallschirmjäger and a battalion of infantry to the northern part of Jutland, and captured the airfield at Aalborg, vital to support the operation in southern Norway. Several hundred Ju 52s were used to transport troops to Norway in the first days of this campaign. Later, Ju 52's participated in the attack on the Netherlands on 10 May 1940, where they were deployed in the first large-scale air attack with paratroops in history during the Battle for The Hague.