J.Davilla, A.Soltan French Aircraft of the First World War (Flying Machines)

Hanriot-Dupont HD.3 C2 and Cn2

  On 24 May 1917 General Duval decided to obtain a two-seat fighter to supplement the single-seat fighters then in service. To meet this specification the C2 category was formulated by the STAe. The specification called for an aircraft with forward-firing machine guns and two flexible machine guns. An option was also requested for the aircraft to be capable for use in the photo-reconnaissance role by fitting a camera in place of the rear machine guns. The aircraft designed for the C2 classification were to have a speed of 220 km/h at 5,000 meters, a minimum speed of 110 km/h, a service ceiling of 8,000 meters, and a payload of 375 kg. The aircraft designed to meet this category were the Borel HS 300, Hanriot-Dupont 5 C2, Vickers Lorraine 370, Farman F.31, Morane Saulnier 16, Morane Saulnier 31, Morane Saulnier 32, Hanriot Dupont C1, Breguet 17, SPAD 20, SEA 4, and the Hanriot-Dupont 3 C2. Only the Breguet 17, SPAD 20, SEA 4, and the Hanriot Dupont 3 were selected for production.
  The Hanriot firm had built Salmson 2s under license. Apparently Rene Hanriot and Dupont were impressed with the 260-hp Salmson 9Za engine used in the Salmson 2, and they utilized that engine lor the HD.3 C2.
  The HD.3 was a single-bay biplane with ailerons on both the upper and lower wings. Each wing had two spars of spruce covered with plywood. The upper wing spar had sections reinforced in duralumin. The ribs were of plywood reinforced by spruce or poplar strips and attached to the spar by wood screws. The upper wing was attached to the fuselage by central cabane struts made of duralumin. The lower wing was attached directly to the fuselage by metal fasteners.
  The fixed portion of the rudder had a crescent shape and was constructed of four tubular supports; the rudder also had a metal framework.
  The forward portion of the fuselage was made of metal up to the cockpit. The rear portion had four ash longerons with spruce formers reinforced by a network of piano wire. The motor mount consisted of two metal plates connected by a U-shaped former. The fuel tank held 114 liters and the oil tank had a capacity of 24 liters. The fuel tank was within the fuselage, while the oil tank was located on the right side of the fuselage.
  The landing gear consisted of three struts on either side which were bolted to the metal portion of the lower fuselage. The metal axle was articulated and encased in a wooden fairing. Bungee chord served as shock absorbers. The tail skid was made from ash and articulated at its attachment point to the lower fuselage.
  Armament was two synchronized 7.7-mm Vickers machine guns and two turret-mounted 7.7-mm Lewis machine guns.
  The prototype, which carried the military serial 1001, was tested al Villacoublay by a Lieutenant Bourgeois of the STAe on 10 March 1918 and had an impressive performance. The maximum speed was found to be 210 km/h, while the speed at 2.000 m was 207 km/h. The aircraft could climb to 1.000 meters in 3 minutes and 23 seconds.
  The satisfactory performance of the HD. 3, SEA 4, SPAD 20, and Breguet 17 led to all four aircraft being ordered. By 18 April 120 HD.3s were ordered, but later this number was increased to 300. Changes to the production aircraft included a reduction of the upper wing span, which resulted in top and bottom wings of being equal span, and the addition of horn-balanced ailerons.
  The first production example left the factory in the fall of 1918. Apparently the performance of the first production examples was inferior to the prototype, but it appears that replacing the Chauviere airscrew by one designed by Ratmanoff resulted in considerable improvement.
  The HD.3 entered service very late in the war and, in fact, only 18 were in service at the time of the Armistice. Fifteen were in service with HD 174 which was formed in October 1918. Serials were 1010, 1012, 1013, 1015, 1016, 1020, 1021, 1025, 1026, 1027, 1029, 1035, 1052, 1063, and 1066. The unit was assigned to GC 17. In 1920 HD 174 became the 109th Escadrille of the 3rd Group de Chasse assigned to the 2nd Regiment de Chasse based at Strasbourg. After 1920 the HD.3s were assigned to training units. It has been estimated that about 75 aircraft were built; it is certain that many more would have been obtained had the war continued.
  While it appears that only one escadrille was completely equipped with HD.3s, it is likely that the remaining HD.3s were assigned to other units. In a communique from the Conferences du Centre d'Etudes Aeronautiques it was stated that HD.3s were to be used in multiple roles including day bombardment and long-range escort for Breguet 14s. Postwar, the type was to be assigned to the aviation units attached to the Corps d'Armee. While serving with these units it was intended that the HD.3s would provide protection for the reconnaissance units and engage in ground attack.
  The French were impressed with the German night fighters which had caused not inconsiderable losses to French bombers. A night fighter version of the Hanriot HD.3 was developed and designated HD.3 Cn2 (two-seat night fighter). A single prototype was constructed by September 1918. Changes from the standard HD.3 included a lower wing of thicker cross-section with heavy under-camber, enlarged ailerons, and an enlarged rudder. The aircraft was not selected for series production.
  A single HD.3 was flown by Puget in the 7 September 1920 Michelin Coupe Militaire. It flew from Strasbourg to Angers in 18 hours and 40 minutes, but the race was won by a Breguet (probably a Breguet 17).
  Several HD.3s obtained by the Aviation Maritime in 1921 were used to practice arrested carrier landings on the Bearn.


HD.3 Two-Seat Fighter with 260-hp Salmson 9Za
   Span 9.170 m; length 6.95 m; height 3.00 m; wing area 25.5 sq. m.
   Empty weight 723 kg; loaded weight 1,150 kg
   Maximum speed:
ground level 210 km/h
2,000 m 207 km/h
3,000 m 203 km/h
4,000 m 196 km/h
5,000 m 187 km/h
   Climb:
1,000 m 3 minutes 23 seconds
2,000 m 6 minutes 39 seconds
3,000 m 11 minutes 4 seconds
4,000 m 17 minutes 9 seconds
5,000 m 34 minutes 34 seconds
6,000 m 71 minutes 45 seconds
   Service ceiling 5,700 m; range 400 m; endurance 2 hours
   Armament: two synchronized 7.7-mm Vickers machine guns and two flexible 7.7-mm Lewis machine guns
   Approximately 75 built

HD.3 Cn2 Night Fighter with 260-hp Salmson 9Za
   Span 9.42 m; length 6,92 tn; height 3.20 m
   Maximum speed: 200 km/h at 2,000 m; ceiling 6,200 m; range 400 km
   One built


HD.4 and Navalized HD.3

  The development of single-engined landplanes for use in the maritime patrol role was inhibited by the fact that the engines of the period were unreliable. An engine failure while over the sea would mean the definite loss of the plane and the probable death of its crew. On the other hand, fitting the aircraft with floats would seriously degrade performance. A novel solution was tried at the Saint-Raphael naval air station. Although the aircraft was not flown until after the war, it merits inclusion in this volume as it was a conversion of the HD.3 two-seat reconnaissance/fighter. The wheels were removed from the axle and replaced by twin skis. An inflatable float made of thin rubber was fitted at the base of each wing. Normally, these floats would remain deflated and thus produce minimal drag. In an emergency, however, they could be inflated by compressed air within 30 seconds. The floats were designed by Harry Busteed and weighed 30 kg; the compressed air bottle weighed 7 kg.
  The navalized version of the HD.3 had a shorter wing span than the standard HD.3 but otherwise was quite similar. This HD.3 successfully proved the validity of the inflatable float concept. Although it was considered to be a successful design, the war's end as well as the development of naval aircraft with watertight fuselages and more reliable engines led to the abandonment of the plan to use the Busteed floats on naval aircraft. Thus, further development was unnecessary and only the single example was built.
  HD.3 No.2003 was sent to the RAF Naval Air Station at Grain in September 1918. Here it was fitted with jettisonable wheels, a hydrovane, and flotation gear to permit operation from naval vessels. A test conducted on 23 October resulted in the aircraft nosing over when ditching in the water. It was subsequently fitted with a revised hydrovane for the main gear and a smaller hydroplane was added to the tail skid. A successful water landing was made on 4 December 1918.
  The HD.4 was an HD.3 (serial 2000) fitted with floats, a Chauviere propeller, and an enlarged fin and rudder. While it had been the intention of the French Aeronavale to operate these aircraft, it seems that the HD.2 was preferred over the HD.4 and only the single example was built and tested on the Seine in 1918.
  Some sources mention a Hanriot-designed floatplane intended to carry a torpedo. No such aircraft is mentioned in the May 1918 Ministry of Munitions report; it is possible that the floatplane version of the HD.3 was the aircraft referred to. However, it is not possible to confirm that the HD.3 floatplane was ever modified to carry a torpedo


HD.4 Navalized Two-Seat Floatplane Fighter with 260-hp Salmson 9Za
   Wing span 9.10 m
   Maximum speed: 168 km/h
   One built

W.Green, G.Swanborough The Complete Book of Fighters

HANRIOT HD.3 France

   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 260 hp Salmson (Canton-Unne) 9Za radial, the HD.3 had an armament of two fixed synchronised 7,7-mm Vickers guns and two 7,7-mm Lewis guns on a flexible mounting for the aft-facing gunner. A preliminary order was placed on behalf of the Aviation militaire 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 militaire 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.

Max speed, 119 mph (192 km/h) at 6,560 ft (2 000 m), 116 mph (187 km/h) at 9,840 ft (3 000 m).
Time to 3,280 ft (1 000 m), 3.35 min.
Service ceiling, 18,700 ft (5 700 m).
Endurance, 2.0 hrs.
Empty weight, 1,675 lb (760 kg).
Loaded weight, 2,601 lb (1180 kg).
Span, 29 ft 6 1/4 in (9,00 m).
Length, 22 ft 9 1/2 in (6,95 m).
Height, 9 ft 10 in (3,00 m).
Wing area, 274.49 sq ft (25,50 m2).