Hanriot Two Seat Fighter Planes
The idea of two seat fighters was first validated by the British Bristol F.2 "Bristfit" Fighter during 1917. The French began moving to a two seat fighter model at about the same time. This trend continued till the end of the war.
From Wikipedia Hanriot HD.3
The Hanriot HD.3 was a two-seat fighter aircraft produced in France during World War One. Similar in appearance to a scaled-up HD.1, it was a conventional, single-bay biplane with staggered wings of equal span. The pilot and gunner sat in tandem, open cockpits and the main units of the fixed tail skid undercarriage were linked by a cross-axle. Short struts braced the fuselage sides to the lower wing.
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 synchronized 7.7mm Vickers guns and two 7.7mm Lewis guns on a flexible mounting for the aft facing 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 main-planes of thicker section, enlarged ailerons and a revised rudder.
Flight testing revealed excellent performance, and the French government ordered 300 of the type in 1918, in preparation for a major offensive the following year. When the war ended, the contract was cancelled with around 75 aircraft having been delivered to the Aéronautique Militaire and at least 15 to the Aéronautique Maritime. One example was delivered to the Aéronautique Maritime in summer 1918 equipped with twin float undercarriage and a larger tail fin; it was intended that this would be the prototype of a dedicated float plane fighter designated HD.4, but the war ended before any further development took place. The Armistice also led to the abandonment of a dedicated night fighter variant, the HD.3bis, with enlarged and balanced ailerons and rudder and with a wing of increased section.
- From Wikipedia Hanriot HD.3, "http://en.wikipedia.org/wiki/Hanriot_HD.3"
- Bruce, J.M. (1972). War Planes of the First World War: Volume Five Fighters. London: Macdonald, p.19, p.21, pp.24-27, pp.32-35. ISBN 356 03779 7.
- Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. London: Studio Editions. pp. 469. ISBN 0-51710-316-8.
- World Aircraft Information Files. London: Bright Star Publishing. pp. File 896 Sheet 11.