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

D.D.8

  The D.D.3, 4, 5, 6, and 7 have not been identified and possibly were unbuilt projects.
  When the 240-hp Hispano Suiza 8B engine became available in 1917 the French navy ordered the seaplane manufacturers to submit new designs using this power plant. The F.B.A. firm designed the type S, Levy-Besson submitted a triplane flying boat, and Tellier built a twin-engined flying boat. The Donnet-Denhaut firm redesigned the D.D.2 to take advantage of the more powerful engine. The new design, designated the D.D.8, flew in May 1917 and carried a crew of three (a pilot and two gunners), two 50-kg bombs, and two 7.7-mm machine guns on ring mounts in the nose and behind the wings. A radio was carried, powered by a wind-driven generator mounted on the center section of the upper wing. To support the weight of the crew and engine, the airframe was strengthened and diagonal bracing struts added to the outer wings. The wing was enlarged and now had three bays of struts; the upper wing was still longer than the lower. A version of the D.D.8 with jettisonable wheels to enable it to take off from land and alight at sea was tested at St. Raphael during the war. Unfortunately, one of the wheels fell off in flight and the plane was destroyed when the pilot attempted to alight on the water.
  More than 500 examples of the D.D.8 were ordered in June 1917. They served at naval air stations in the Mediterranean and along the channel coast. A total of 34 D.D.8s were delivered from January to October 1917.
  Some served in the patrol and light bombing role along with the contemporary FBA Type S, Levy-Besson 200-hp Triplane, and Tellier T.3.


Foreign Service

Portugal
  Portugal purchased 18 D.D.8s in 1918. They initially had 160-hp Lorraine-Dietrich engines; later, some were fitted with 200-hp Hispano Suiza 8 Ac engines. The aircraft remained in service until 1923. The D.D.8s were initially assigned to the Servico de Aviacao de Armada and were used for coastal patrol work.

United States
  The U.S. Navy operated D.D.2s, D.D.8s, and D.D.9s. The antiquated D.D.2s were used as trainers because of their limited bomb load. D.D.8s were larger and, since they could carry a useful bomb load, were used in the patrol/bombing role. Some were converted to amphibians by fitting wheels to the hull. Some D.D.9s were also obtained to provide protection for the lightly-armed D.D.8s. The aircraft were based at Ile Tudy and Dunkerque, where they were used for patrols; at Moutchic they were used for training.
  The main duty of the aircraft based at Ile Tudy was to escort convoys passing in the vicinity of the base. A pair were assigned to escort each convoy; to escort each the full distance at least eight planes a day were needed. One aircraft would circle over the convoy while the other flew ahead of it.
  The first attack on a submarine by Ile Tudy's aircraft was made on 23 April 1918 when two of them detected what was later discovered to have been the German U-108. Their bombs missed, but they directed the U.S. destroyer Stewart to the scene. Her depth charges were believed at the time to have destroyed the enemy submarine, but in fact it escaped.
  Other aerial attacks on submarines or what were believed to be submarines during 1918 were made on 5 July, 3 August, 10 August, 27 August, 27 September, 22 October, and 25 October. In no case was a U-boat sunk or damaged, but the Ile Tudy aircraft successfully escorted 6,900 ships during the time the station was operational.
  Serial numbers for the Donnet-Denhaut flying boats were 1219, 1440, 1451,1 150, 1151, 1193, 1217, 1218, 1220, 1240, 1241, 1253, 1441, 1442, 1443, 1450, 1454, 1455, 1452, 1453, 1473, 1474, 1475, 1208, 1209, 1110, 1211, 507, 447, 1179, 1 180, 1 181, 1 182, 809, 810, 81 1, 813, 814, 815, 816, 817, 823, 815, 829, 831, 833, 835, 840, 841, 842, 843, 844, 845, 846, 847, 848, and 849.

Donnet-Denhaut D.D.8 Three-Seat Flying Boat with 200-hp Hispano-Suiza 8B
   Wing span 16.28 m; length 9.50 m; height 3.00 m; wing area 45.77 sq. m
   Empty weight 950 kg; loaded weight 1550 kg; payload 600 kq,
   Max speed at sea level 140 km/h; climb to 2,000 m in 15 minutes; range 500 km
   Armament: two 7.7-tnm Lewis guns and two 35-kg (Dunkerque flying boat) or two 50-kg, bombs (patrol class flying boat).



D.D.9

  The French naval aviation squadrons had suffered heavily al the hands of German fighters. These losses were nowhere more apparent than at the Dunkerque station. In May 1917 alone four flying boats were brought down by enemy aircraft. The navy responded to the increased threat by issuing a specification for a flying boat capable of defending itself and other seaplanes. Donnet-Denhaut responded by producing the D.D.9, a dedicated hydravion de combat.
  The D.D.9 was based on the earlier D.D.8 but featured an increased armament and crew complement. It had four machine guns on ring mounts, a pair in the nose and another pair behind the wing. The crew consisted of a pilot, a mechanic, and two gunners. To give the aircraft an adequate performance despite the additional crew and guns, the airframe was enlarged and eventually fitted with a more powerful engine. The span of the lower wing was increased and four bays of struts were used. The rudder was larger and more rounded than that of the D.D.8. Initially the D.D.9s had the same 200-hp Hispano-Suiza 8Ba engines as the D.D.8. However, in the spring of 1918 the 260-hp Hispano-Suiza 8 Fb had become available and was used in the D.9. Some were fitted with a 300-hp Canton-Unne Z9 in late 1918. These were designated "Donnet-Denhaut 300-hp." About 100 D.D.9s were built in 1918. The degree of their success is not known but, given that their performance was no better than the D.8s they were designed to protect it seems unlikely they were able to provide much defense against German fighters.
  They served at four air stations in late 1918, including the aeronautical school and bases in North Africa. Postwar, they were used to make long-distance flights, some D.D.9s were used by the United States Navy (see entry under D.D.8).


Donnet-Denhaut Three-Seat or Four-Seat Flying Boat Fighter with 200-hp Hispano-Suiza 8Ba
   Span 16.28 m (some sources state 16.00 m); length 10.75 m (11.00 m); height 3.50 m; wing area 61 sq. m
   Empty weight 1,075 kg; loaded weight 1,975 kg (1,800 kg); payload 900 kg
   Maximum speed 140 km/h (130 km/h) at sea level; climb to 1,000 m in 6 minutes 30 seconds; climb to 2,000 m in 18 minutes (15 minutes); climb to 3,000 m in 27 minutes; range 200 km
   Armament: two to four 7.7-mm guns and two 35-kg "F" bombs
   Approximately 100 built (including versions with the 260-hp Hispano-Suiza 8 Fb and 300-hp Canton-Unne Z9)