The Japanese were not impressed with the Heinkel HD 23 shipborne biplane fighter of Germany - leading to just four examples being built in total.
Authored By: Staff Writer | Last Edited:
Credit: Image from the Public Domain.
Ernst Heinkel Flugzeugwerke (Heinkel) of Germany began operations in the aviation business during December of 1922. From a Japanese Empire government request, their first single-seat, single-engine fighter became the "HD 23", a traditionally-arranged biplane intended for shipborne (catapult-launched, crane-recovered) operations. Following a first-flight in 1925-1926 and delivery of two prototypes from Germany in 1927, Aichi of Japan made some local modifications to the aircraft and built a further two more examples. Beyond these offerings, the GD 23 - known to the Japanese as the "Type H Carrier Fighter" - was not adopted for service after being evaluated at length by Imperial Japanese Navy (IJN) authorities.
As built, the HD 23 seated one pilot in an open-air cockpit positioned high over the nose section. The wing mainplanes were of equal span and included an upper and lower wing section joined by a network of support struts (N-style) and cabling. The lower fuselage incorporated a boat-like hull and held flotation bags for on-water landings in case of emergency. The undercarriage was wheeled at the two main leg members and fixed during flight. Dimensions included a length of 24.8 feet, a wingspan of 35.4 feet and a height of 12.4 feet. Empty weight was 3,240lb against an MTOW of 4,560lb.
The original German prototype (HD 23a) was powered by the BMW VIa 12-cylinder, water-cooled engine delivering 600 horsepower and the second followed with a Hispano-Suiza 12Ha engine of 450 horsepower. In-service aircraft were to carry 2 x 7.92mm machine guns synchronized to fire through the spinning propeller blades.
Once available to Aichi engineers in Japan, workers installed a jettisonable undercarriage for on-water operations (landing and take-off) as well as wing-based slats for better control. In testing the aircraft was found to possess poor qualities for a shipborne fighter - it was underpowered and heavy and exhibited inadequate control. In testing the HD 23a reached a speed of 160mph and a service ceiling of 26,000 feet.
[ 4 Units ] : Ernst Heinkel Flugzeugwerke (Heinkel) - Germany / Aichi - Imperial Japan
Imperial Japan (cancelled)
- Navy / Maritime
- X-Plane / Developmental
24.77 ft (7.55 m)
35.43 ft (10.8 m)
12.47 ft (3.8 m)
(Showcased structural dimension values pertain to the Heinkel HD 23a production model)
3,241 lb (1,470 kg)
4,564 lb (2,070 kg)
(Showcased weight values pertain to the Heinkel HD 23a production model)
1 x BMW VIa 12-cylinder water-cooled inline piston engine developing 660 horsepower and driving a two-bladed propeller at the nose.
(Showcased powerplant information pertains to the Heinkel HD 23a production model)
155 mph (250 kph; 135 kts)
25,919 feet (7,900 m; 4.91 miles)
(Showcased performance values pertain to the Heinkel HD 23a production model; Compare this aircraft entry against any other in our database)
2 x 7.92mm machine guns mounted over the nose, synchronized to fire through the spinning propeller blades.
(Showcased armament details pertain to the Heinkel HD 23a production model)
HD 23 - Base Series Designation
HD 23a - Initial prototype form; two completed in Germany, two completed in Japan.
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