Junkers Ju 52/3m

The Junkers Ju 52/3m (nicknamed Tante Ju ("Aunt Ju") and Iron Annie) is a transport aircraft that was designed and manufactured by German aviation company Junkers.

Development of the Ju 52 commenced during 1930, headed by German aeronautical engineer Ernst Zindel. The aircraft's design incorporated a corrugated duralumin metal skin as a strengthening measure, which was very unusual at the time. The Ju 52's maiden flight was performed on 13 October 1930. It was initially designed with a single engine, however, it was produced in quantity as a trimotor. The primary early production model, the Ju 52/3m, was principally operated as a 17-seat airliner or utility transport aircraft by various civil operators during the 1930s. Following the rise of Nazi Germany, thousands of Ju 52s were procured as a staple military transport of the nation. The Ju 52/3mg7e was the principal production model.

The Ju 52 was in production between 1931 and 1952. In a civilian role, it flew with over 12 airlines, including Swissair and Deutsche Luft Hansa, as both a passenger carrier and a freight hauler. In a military role, large numbers flew with the Luftwaffe, being deployed on virtually all fronts of the Second World War as a troop and cargo transport; it was also briefly used as a medium bomber. Additionally, the type was deployed by other nation's militaries in conflicts such as the Spanish Civil War, the Chaco War, and the Portuguese Colonial War. During the postwar era, the Ju 52 had a lengthy service life with numerous military and civilian operators; large numbers were still in use by the 1980s. Even in the 21st century, several aircraft have remained operational, typically used for purposes such as heritage aviation displays and aerial sightseeing.

The Ju 52 was similar to the company's previous Junkers W 33, although larger. In 1930, German aeronautical engineer Ernst Zindel and his team designed the Ju 52 at the Junkers works at Dessau. According to aviation author J. Richard Smith, the Ju 52 directly drew upon the company's First World War-era Junkers J 1 - the world's first all-metal aeroplane.

On 13 October 1930, the first prototype designated Ju 52ba, performed the type's maiden flight; it was initially powered by a single Junkers-built liquid-cooled V-12 engine, capable of generating up to 800 hp. During the aircraft's extensive trials, it was re-engined with a 755 hp BMW IV water-cooled inline-6 powerplant. The second prototype, designated Ju 52de, featured an increased wing span and was powered by the BMW IV engine at first; it was soon re-engined with the 750 hp 14-cylinder twin-row air-cooled radial Armstrong Siddeley Leopard and re-designated Ju 52di. Later on, the Ju 52di was again reengined with the 750 hp Junkers Jumo 204 air-cooled inverted inline-6, after which it was re-designated Ju 52do. The third prototype, designated Ju 52ce, had a strengthened structure, a modified leading edge, and was fitted with both wheeled and float undercarriages.

During May 1931, one of the prototypes, designated Ju 52cai, was written off after a crash. While these initial aircraft had been powered by a single engine, Junkers decided to develop the Ju 52 into a trimotor configuration. Accordingly, the Ju 52/3m (drei motoren—"three engines") was developed, being powered by an arrangement of three radial engines. According to Smith, the earliest known Ju 52/3m was delivered to Bolivian airline Lloyd Aéreo Boliviano during 1932. During its initial production years, airlines were the type's most common customers. By the mid-1930s, the Ju 52/3mce and Ju 52/3fe, were the two primary production variants, both being powered by the BMW 132 radial engine.

During 1934, work commenced on a militarised model of the Ju 52/3m, designated Ju 52/3mg3e, on behalf of the then-secret Luftwaffe. This model could function as a medium bomber, being furnished with a pair of defensive gun turrets and operated by a crew of four. Between 1934 and 1935, a total of 450 Ju 52/3mg3e aircraft were delivered to the Luftwaffe.

Numerous improved models would be introduced prior to and during the Second World War. The dominant production model was the Ju 52/3mg7e, featuring advances such as an autopilot, enlarged doors to the cabin, and other general enhancements. It was configured as a pure transport aircraft, being capable of carrying up to 18 fully-equipped troops. Defensive armaments comprised a dorsal-mounted 13 mm MG 131 machine gun and a pair of sideways-mounted 7.9mm MG 15 machine guns. Successive models saw other improvements, such as revised glazing, newer engines, undercarriage strengthening, and increased take-off weight. The final wartime model to be developed, designated Ju 52/3mg14e, featured improved armour protection for the pilot and a bolstered defensive armament.

From mid-1943 onwards, the Luftwaffe began to make less use of the Ju 52, interest having waned in the type. German officials were interested in procuring a successor to the type; at one stage, the Reich Air Ministry showed enthusiasm for the Junkers Ju 352, a larger transport aircraft somewhat resembling the Ju 52. Actions were taken to convert Junkers' Ju 52 production lines to instead manufacture Ju 352s; however, the conflict's end in May 1945 led to the effort being abandoned in an unfinished state. As such, German production of the Ju 52 was terminated during 1944; Smith claims that a total of 3,234 aircraft of various models were constructed during the conflict.

In the postwar era, manufacture of the Ju 52 resumed, albeit in foreign countries. It was constructed in France by Avions Amiot as the Amiot AAC.1 Toucan; it was also produced in Spain by Construcciones Aeronáuticas SA (CASA) as the CASA 352. A handful of captured wartime aircraft were also rebuilt by Short Brothers of Northern Ireland for civilian service.