Shortly before dawn on May 20, 1941, a flight of 500 transport planes took off from seven airstrips on mainland Greece. As they climbed upward, the tri-motor aircraft emerged from reddish-orange clouds of dust into blue sky. The dust clouds were generated by the propeller wash from hundreds of engines sitting on unpaved runways as the planes prepared for takeoff. Inside each aircraft, a dozen German paratroopers sat hunched on canvas benches sweating profusely inside their heavy uniforms. Each one welcomed the cool air that swept through the cabins once the aircraft were aloft.
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The planes lumbered in tightly packed formations at low altitude over the pale blue waters of the Aegean Sea toward their objective. Once they crossed the coast of enemy-held Crete, they were greeted by a storm of flak that rocked the planes as if they were trees in the wind. Ignoring the turbulence, the veteran paratroopers stood up, shuffled toward the cargo door, and flung themselves spread eagle toward the ground below. Once the flight crews had delivered their human cargo to its destination, they turned their aircraft back toward the mainland to load the next wave. Operation Mercury, the largest airborne invasion the world had yet seen, was without doubt the finest hour of the Junkers Ju-52 transport, known to its crews as “Tante Ju,” or Auntie Junkers.
The Ju-52: A Commercial Aircraft
The Ju-52 was originally envisioned as a commercial venture in 1925 by Deutsche Lufthansa. The concept moved from paper to production when the project was turned over to Junkers in 1928. Its chief designer, Ernst Zindel, oversaw work on two concepts. One was a single-engine freight aircraft (Ju-52/1m) and the other was a three-engine commercial passenger plane (Ju-52/3m) built to carry 17 passengers.
The first single-engine Ju-52 made its maiden flight on October 13, 1930. It was followed six months later by the three-engine version’s maiden flight in April 1931. After just a few years in service, production of the single-engine version came to an abrupt halt in 1934, but the three-engine version, which offered better safety and considerably more power, captured the interest of Lufthansa as well as international customers that used the aircraft for both passenger and freight purposes.
The Ju-52/3m had a wing span of 29.5 meters and measured 18.9 meters from nose to tail. The all-metal plane (80/20 magnesium/ aluminum) was easily recognized not only by its three-engine configuration but also by a box-like, corrugated fuselage that gave it an almost unfinished appearance.
Deutsche Lufthansa began flying the Ju-52/3m on heavily traveled commercial routes, such as Berlin to London and Berlin to Rome in late 1932. Twenty-five countries throughout Europe and North and South America purchased the aircraft for commercial use during the 1930s. For 13 years from 1932 to 1945, the Junkers German factories produced Ju-52 variants. It was during its first few years in operation that the Ju-52 earned the endearing nicknames “Tante Ju” and “Eisen Annie” (Iron Annie) because of its reliability and performance that resulted in few forced landings and the need for minimal repair work.
Militarizing the Ju-52
When Adolf Hitler was elected chancellor of Germany in 1933, the future German dictator instructed the Air Ministry to put a plan into action to build a 1,000-plane air force. He did this despite the fact that Germany was prohibited from having any military aircraft through the Treaty of Versailles. Rather than develop an entirely new transport aircraft, the ministry ordered the conversion of a large number of existing aircraft from civilian to military use.
Minimal alteration was required. The Ju-52/3m freight version had a hatch in the roof for loading by crane, a large cargo door on the starboard side just behind the wing, and a door for passengers on the port side. A new hole was cut into the roof to accommodate a dorsal machine gun, and the interior was reconfigured for different missions.
The Ju-52/3m began its military service as a bomber during the Spanish Civil War. During the blitzkrieg period of World War II from 1939 to 1941 it served in a support role by delivering paratroopers to their targets, towing gliders carrying assault troops, and transferring air landing troops to captured airfields. After the invasion of Crete in May 1941, the airplane was used primarily for delivering fuel, ammunition, and supplies to troops in forward areas or isolated pockets and evacuating wounded.
A military version of Eisen Annie, designated the Ju-52/3mg3e was ready for service in 1934. While a version designated the Ju-52/3m Sa3 was already operating for the Reichswehr in the role of personnel transport, cargo carrier, and pilot trainer, the g3e was intended as an interim bomber before more sophisticated bombers were available in 1936. The military version was powered by three 660hp BMW 132A radial engines and armed with dorsal and ventral 7.92 MG 15 machine guns, the latter of which was affixed to the aircraft’s underside with a retractable dustbin attachment. When fully loaded, whether with troops or supplies, the aircraft had a top speed of 171 miles per hour and a cruising speed of about 120 miles per hour. The Ju-52/3m’s round-trip range carrying a 1,984-pound load was 720 miles. This range increased to 900 miles with a lighter load (992 pounds) or decreased to 450 miles with a heavier load (3,306 pounds).
The Ju-52/3m was equipped with robust landing gear that enabled it to take off and land on dirt or grass strips as short as 400 meters that other aircraft could not use. What is more, the metal structure could withstand considerable punishment, which enabled the crews to complete their missions and limp back to safety when damaged.
First Combat in Spain
Shortly after the Spanish Civil War broke out in July 1936, Hitler sent 20 Ju-52/3ms in September to support Nationalist General Francisco Franco in his struggle against the Republican forces on the Iberian peninsula. During the conflict, Eisen Annie served in a dual role of troop transport and interim bomber. Two years before, the Reichswehr (the Luftwaffe was not reconstituted until 1935) had requested that the Junkers plant at Dessau convert the Ju-52/3m to a bomber configuration (the g3e), and Junkers engineers had installed vertical magazines in its lower cargo bay to accommodate 3,306 pounds of explosives. The makeshift bombers operated with crews of five handling the positions of pilot, co-pilot, radio operator, dorsal gunner, and bombardier/ventral gunner.
Early in the conflict, the Ju-52/3ms played a key role in transporting 13,900 Moorish troops and their heavy weapons to Spain. Lt. Col. Rudolf Moreau established the first official bomber squadron numbering 10 Ju-52/3mg3es in November 1936 to support the Nationalist ground forces. During the course of the conflict, the Moreau squadron dropped more than 6,000 tons of bombs on enemy positions and enemy-held territory. However, the Ju-52/3m’s bomber days were numbered not only because of its lack of speed and maneuverability but because it could not accommodate the horizontal bomb racks that were being installed on newer medium-range bombers in production. As the fighter threat grew more severe in the following months, the Ju-52/3mg3e’s were replaced with more advanced bombers, such as the Dornier Do-17 and the Heinkel He-111. While the Spanish Civil War raged on into its third year, the Ju-52/3ms functioning as bombers were converted back to transports.
Paratroopers in the North: Ju-52s in Operation Weserübung
The invasion of Denmark and Norway on April 9, 1940, known as Operation Weserübung, heralded the use of Ju-52/3ms to deliver paratroopers and air landing forces to the battlefield. During Weserübung, the transports performed a number of key roles, including dropping paratroopers, ferrying air landing troops to captured airfields, and delivering heavy weapons and supplies to paratroopers and other ground forces.
Weserübung involved the first paratrooper attacks in military history. On the first day of the invasion, the paratroopers seized the Vordingborg Bridge linking Copenhagen with its ferry terminal and two airfields at Aalborg in Denmark. The Ju-52/3ms also dropped paratroopers at three key airfields in southern Norway at the cities of Oslo, Stavanger, and Kristiansand.
As the battle progressed over the following days, the Ju-52/3ms played a crucial role delivering weapons and supplies to the German troops fighting Allied forces at the North Sea port of Narvik. A particularly daring mission involved the ferrying of a fully equipped mountain battery to a frozen lake 15 miles north of Narvik with little chance of their returning due to the extreme conditions. The planes took off from Hamburg, refueled at Oslo, and proceeded to their destination. They remained on the frozen lake until they sank in the spring thaw. The lost planes, however, were only a small part of the Ju-52/3m losses incurred during the overall operation. The Luftwaffe counted about 150 transports destroyed or damaged beyond repair by the end of the affair. It was a taste of the heavy losses to come in campaigns ahead.