Germany · Interwar (1919–1938)
The Heinkel He 118 was a German two-seat dive bomber prototype — the Heinkel rival to the Junkers Ju 87 lacked. Japan acquired the He 118 licence in 1937 + used the design as basis for the Yokosuka D4Y Suisei naval dive bomber that entered Japanese service in 1942. About 0 He 118 airframes survive.
The Heinkel He 118 was a German dive bomber prototype from the mid-1930s. It was Heinkel's competitor to the Junkers Ju 87 Stuka in a Luftwaffe design contest. The Ju 87 won the contest, so the He 118 never entered German service.
Although Germany did not buy the He 118, Japan loved the design. In 1937, Japan bought the license to build the He 118. Japanese engineers used it as the basis for the Yokosuka D4Y Suisei naval dive bomber. The D4Y entered Japanese service in 1942.
The He 118 was a single-engine plane with retractable landing gear. It had two seats — a pilot and a rear gunner. The plane is about as long as a small school bus.
No He 118 airframes survive today. The Japanese D4Y Suisei was used in the Pacific war against the Allies, and many were lost in combat. The He 118 itself is mostly remembered for the planes that came from its design rather than for its own short history.
Japan was modernizing its navy in the 1930s and needed a good dive bomber for its carriers. Buying a German design was much faster than building one from scratch. The Japanese Yokosuka D4Y Suisei used many ideas from the He 118 but with Japanese engines and equipment. It was one of Japan's main carrier dive bombers in World War II.
The Ju 87 had cranked wings shaped like a V — these gave the plane very strong dive recovery. The He 118 had simpler straight wings that did not handle steep dives as well. During tests, one He 118 broke up during a steep dive while a Ju 87 came through fine. The Luftwaffe chose the safer plane.
The Junkers Ju 87 Stuka offered better dive-bombing accuracy, more-rugged construction for pulling out of dives, and Ernst Udet's political support. The He 118 was significantly faster (415 km/h vs. 380 km/h) but the Luftwaffe competition emphasised dive-bombing precision over speed. Ernst Udet's 4 August 1936 test flight that ended in structural failure (Udet ejected by parachute) demonstrated the He 118's inadequate airframe strength for high-G dive-bomber pullouts — a fatal flaw the Ju 87 lacked.
Japan acquired the licence in 1937. Yokosuka used the He 118 design as basis for the Yokosuka D4Y Suisei naval dive bomber (NATO reporting name "Judy"). The D4Y entered Imperial Japanese Navy service in 1942 + about 2,000 D4Ys were built 1942-1945. The Japanese refined the He 118 airframe (longer fuselage, refined wings, internal bomb bay) — the result was a more-successful Japanese aircraft than the original He 118 had been in Germany.
Only 4 prototypes 1936-1937. The Luftwaffe selected the Ju 87 instead + the He 118 programme was cancelled. Japan acquired the design for licensed Japanese production (as Yokosuka D4Y Suisei) but did not import any He 118 airframes from Germany.