Messerschmitt Me 323

The Me 323 was the result of a 1940 German requirement for a large assault glider in preparation for Operation Sea Lion, the projected invasion of Great Britain. The DFS 230 light glider had already proven its worth in the Battle of Fort Eben-Emael in Belgium (the first ever assault by gliderborne troops), and would later be used successfully in the invasion of Crete in 1941.

However, in order to mount an invasion across the English Channel, the Germans would need to be able to airlift vehicles and other heavy equipment as part of an initial assault wave. Although Operation Sea Lion was cancelled, the requirement for a heavy air transport capability still existed, with the focus now on the forthcoming Operation Barbarossa, the invasion of the Soviet Union.

[Source: Bundesarchiv]

On 18 October 1940, Junkers and Messerschmitt were given just 14 days to submit a proposal for a large transport glider. The emphasis was still very much on the assault role: the ambitious requirement was to be able to carry either an 88 mm gun and its half-track tractor, or a Panzer IV medium tank. The Junkers Ju 322 Mammut reached prototype form but was eventually scrapped due to difficulties in procuring the necessary high-grade timber for its all-wood construction and, as was discovered during the Mammut's only test flight, an unacceptably high degree of instability inherent in the design. The proposed Messerschmitt aircraft was originally designated Me 261w — partly borrowing the designation of the long-range Messerschmitt Me 261 long-range aircraft, then changed to Me 263 (later re-used for Messerschmitt's improved rocket fighter design) and eventually became the Me 321. Although the Me 321 saw considerable service in Russia as a transport, it was never used for its intended role as an assault glider.

Early in 1941, as a result of feedback from Transport Command pilots in Russia, the decision was taken to produce a motorized variant of the Me 321, to be designated Me 323. It was decided to use French Gnome et Rhône GR14N radial engines rated at 1,180 PS (1,164 hp, 868 kW) for take-off as used in the Bloch MB.175 aircraft; using French engines was thought to place no burden on Germany's overstrained industry.

Initial tests were conducted using four Gnome engines attached to a strengthened Me 321 wing, which gave a modest speed of 210 km/h (130 mph) – 80 km/h (50 mph) slower than the Ju 52 transport aircraft. A fixed undercarriage was fitted, which comprised four small wheels in a bogie at the front of the aircraft with six larger wheels in two lines of three at each side of the fuselage, partly covered by an aerodynamic fairing. The rear wheels were fitted with pneumatic brakes, and could stop the aircraft within 200 m (660 ft).

The four-engined Me 323C was considered merely a stepping stone to the six-engined D series; it still required the five-engined Heinkel He 111Z Zwilling or the highly dangerous, "vic-style" Troika-Schlepp formation of three Messerschmitt Bf 110 heavy fighters and underwing-mounted Walter HWK 109-500 Starthilfe rocket assisted takeoff units to get airborne when fully loaded, but it could return to base under its own power when empty. This was clearly not much better than the Me 321, so the V2 prototype became the first to have six engines and flew for the first time in early 1942, becoming the prototype for the D series aircraft.

The selection of the six engines, and their specific placement on the wing's leading edge, were fitted to reduce torque – a trio of counterclockwise rotation engines mounted on the port wing, and a trio of clockwise rotation engines on the starboard wing as seen forward from "behind" each engine, resulting in the props rotating "away" from each other at the tops of their arcs, as did the counter-rotating twin propellers on the Heinkel He 177.

Source: Wikipedia