Design development of a compact, well-proportioned two-seat fighter was initiated as the HD.3 in the autumn of 1917, and a prototype flew before the end of the year. Powered by the excellent new 260hp Salmson (Canton-Unne) 9Za radial, the HD.3 had an armament of two fixed synchronised 7.7mm Vickers guns and two 7.7mm Lewis guns on a flexible mounting for the aftfacing gunner. A preliminary order was placed on behalf of the Aviation miiitaire for 120 HD.3s in April 1918, the total subsequently being raised to 300 when it was also ordered for the Aviation maritime. Few HD.3s had been delivered, in fact, by the time of the Armistice, but at least 75 were completed for the Aviation miiitaire and a rather smaller quantity for the naval service. One example of the HD.3 was fitted with twin floats as the prototype of the HD.4, series production of which was frustrated by the Armistice, and a night fighter version was tested as the HD.3bis. This latter had mainplanes of thicker section, enlarged ailerons and a revised rudder.

3-View

A three-view drawing (800 x 554)