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

Societe des Etablissements Donnet-Denhaut

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  Denham joined the army as a pilot in 1914. The authorities eventually realized that he could make a more valuable contribution to the French war effort by designing aircraft rather than simply flying them, and he was quickly released from military service.
  After leaving Donnet-Leveque, Donnet went to work for the Goupy firm for which he designed an all-metal glider and a seaplane with a 100-hp Omega engine. However, at the outbreak of the First World War the Goupy factory was destroyed by a fire and Donnet lost his job. Donnet and Denhaut opened their aviation factory, the Societe des Etablissements Donnet-Denhaut, in May 1915. Their workshop was located on the Isle de la Jatte.



D.D.1

  The first aircraft to be built by the Donnet-Denhaut seaplane firm was a two-seater powered by an 80-hp RH 9C Le Rhone engine. It flew in late 1915 and was intended to meet the navy's requirement for a short-range coastal patrol aircraft. It was not selected for production.


Donnet-Denhaut D.D.1 Single-Seat Flying Boat with 80-hp Le Rhone RH 9C
   Wing span 10.48 m, wing area 22 sq. m
   One built



D.D.2

  The D.D.2 was the follow-on to the D.D.1 design and reflected the new naval requirement for an anti-submarine aircraft. Flying boats then in service were incapable of dealing with the submarine threat. If an aircraft found a submarine it carried insufficient armament to sink or even damage it. Furthermore, aircraft were unable to summon ships quickly to deal with U-boats because the flying boats did not carry radios, the crews having to rely on carrier pigeons to communicate with their base. Finally, the flying boats were underpowered and easy prey for German fighters; seaplanes often had to be accompanied by landplanes to provide some measure of protection. Realizing that the flying boats of 1914/15 were unable to deal with the growing undersea menace, the navy issued a requirement for a two-seat aircraft capable of carrying a machine gun, two 35-kg bombs, and a radio. It was expected to have an endurance of 4 hours and 30 minutes.
  The Donnet-Denhaut firm responded by producing the D.D.2. The first 35 aircraft were powered by 160-hp Canton Unne R9 engines; later production aircraft received the more reliable 150-hp Hispano Suiza 8Aa. One source refers to a version with a 160-hp Lorraine engine, but it is not known how many D.D.2s used it. Aircraft fitted with the Hispano-Suiza engine had four additional struts to support it. The crew of two consisted of a pilot and a machine gunner/bombardier. The aircraft had an unequal span wing, the upper wing being larger than the lower. There were two bays of struts; earlier aircraft had only a single bay. The engine was mounted at the base of the upper wing. The slim fuselage had a single step and the fin was mounted integrally with the fuselage. The gunner was seated in the nose; the pilot sat ahead of the wings.The tailplane was mounted midway up the fin and the rudder was bisected by the tailplane. Protection was provided by a single 7.7-mm machine gun in the nose. A radio could also be carried.
  The D.D.2 was quite successful and about 400 were built. They were assigned to naval aviation bases in the Atlantic, Mediterranean, and North Sea. A total of 211 D.D.2s were delivered from January to October 1917.


Donnet-Denhaut D.D.2 Two-Seat Flying Boat with 160-hp Canton Unne R9
   Span 14.20 m; length 10.80 m; height 3.50 in; wing area 36 sq. m
   Empty weight 800 kg; loaded weight 1,380 kg
   Maximum speed: 150 km/h, climb to 3,000 m in 11 minutes; range 450 km
   Armament was a single 7.7-mm machine gun
   A total of 36 built

Donnet-Denhaut D.D.2 Two-Seat Flying Boat with 150-hp Hispano-Suiza 8Aa
   Span 14.20 m; length 10.80 m; height 3.50 m; wing area 36 sq. m
   Empty weight 850 kg; loaded weight 1,450 kg
   Maximum speed: 160 km/h (at sea level); range 450 km
   Armament: one 7.7-mm machine gun; initially two 35-kg bombs, later two 50-kg bombs
   A total of 365 built

G.Swanborough, P.Bowers United States Navy Aircraft Since 1911 (Putnam)

DONNET-DENHAUT FLYING-BOAT

US Navy patrol operations along the coast of France in World War I initiated with Tellier flying-boats, were supplemented by larger quantities of French Donnet-Denhaut flying-boats, which were directly comparable designs with 200 hp Hispano-Suiza pusher engines, wooden hulls, and accommodation for two or three crew members. Out of a total of 58 Donnets procured by 1918, two were sent to the US, where they acquired Navy serial numbers A5652 and A5653. Span, 53 ft 7 in; length, 35 ft 5 in; gross weight, 3,860 lb; max speed, 72 mph.

Jane's All The World Aircraft 1919

DONNET FLYING BOAT.
  
  
   Three-ply wood central float or boat, so constructed that fixed tail fin forms part and whole with it. Two small three-ply floats at wing ends. Sent for pilot and observer side by side. Third sent for gunner in front. Several watertight compartments.
  
  
  
Type of machine Donnet Flying Boat.
Name or type No. of machine Type D.D., 200 h.p.
Purpose for which Intended Bombardment.
Span 16.80 m.
Gap 1.83 m.
Overall length 9 m. 50.
Maximum height 3 m.
Chord Top plane, 2 m.;
   Lower plane, 1 m. 45.
Total surface of wings 53 sq. m.
Span of tail 3 m. 20.
Total area of tail 7 sq. m.
Area of rudder 1.20 sq. m.
Area of each aileron 2 sq. m.
Maximum cross section of body 1 m. 20.
Engine type and h.p. 200 h.p. Hispano-Suiza.
Weight of machine empty 950 kgs.
Tank capacity in hours 4 hours.
Tank capacity in litres 140 each (two tanks).
Performance.
   Speed 130 km.p.h.
   Landing speed 80 km.p.h.
   Climb.
   To 1.000 metres 6-30 mins.
   To 2.000 metres 15 mins.
Disposable load apart from fuel 650 kgs.
Total weight of machine loaded 1,800 kgs.