Hanriot HD20

The Hanriot HD.20 was a French single-seat shipboard fighter prototype completed in 1923, with only one example built. It was an all-metal two-bay biplane, featuring outward-leaning parallel interplane struts and wire bracing. The wings displayed significant stagger, with the lower plane having a greater span and straight-edged, unswept, constant-chord design. Ailerons were mounted on the upper plane, overhung with horn balances extending beyond the wingtips.

The aircraft had a rectangular tailplane atop the fuselage, a curved fin, and balanced elevators. The rudder was broad-chorded, meeting the fin's flat top vertically and reaching down to the keel. Powered by a Hispano-Suiza 8Fb water-cooled V-8 engine, the HD.20 featured an open cockpit over the lower wing's trailing edge, with central cut-outs in both wings for improved visibility. It included a fixed tailskid undercarriage and mainwheels on a single axle, supported by V-struts.

The HD.20 was equipped with a large inflatable buoyancy airbag between its undercarriage legs for emergency sea landings. First flown in 1923, the prototype tested higher altitude performance before development ceased. Its specifications included a length of 8.10 meters (26 ft 7 in), wingspan of 12.50 meters (41 ft 0 in), and gross weight of 1,360 kg (2,998 lb). The Hispano-Suiza engine provided 220 kW (300 hp), enabling a maximum speed of 205 km/h (127 mph) and a service ceiling of 9,800 meters (32,200 ft). Flight time to 5,000 meters was 12 minutes. Armament consisted of two fixed forward-firing 7.7 mm machine guns.