U.S. Air Service




Donnet-Denhaut Flying Boat

Development and Operation

The first Donnet-Denhaut seaplane was a 2-seater powered by an 80 hp Le Rhône RH9c engine. It first flew in 1915. It was not selected for production. The DD 2 reflected a new naval requirement for an anti-submarine aircraft. It was initially powered by a 160 hp Canton Unné R9 engine, but later production aircraft used the more reliable 150 hp Hispano-Suiza 8a engine.

When the 240 hp Hispano-Suiza 8b engine became available in 1917 the French navy ordered the seaplane manufacturers to design an airframe to take the new engine. The Donnet-Denhaut firm redesigned the DD-2 and desginated it the DD-8. The new machine carried a crew of three {pilot and two gunners}, two 50 kg bombs, and two 7.7 mm machine guns {one mounted on a mount in the nose and one behind the wings}. A radio was also carried. The machine first flew in May 1917.

To support the weight of the crew and engine the airframe was strengthened and diagonal struts added to the outer wing tips. The wing was enlarged to have three-bay struts. In response to a Navy Specification for a large, more powerful, flying boat, Donnet-Denhaut responded with its DD 9 design--a dedicated Hyravion de Combat. It had four machine guns on ring mounts, a pair in the nose, and another pair behind the wings.

The crew consisted of a pilot, a mechanic, and 2 gunners. To achieve adequate performance the air frame was enlarged and fitted with Canton-Unné Z9 engine. The span of the lower wing was increased and four bay struts were used. Also, the rudder was enlarged and made more rounded.

The U.S. Navy purchased DD-2's, DD-8's and DD-9's. TheDD-2's were used as trainers. The DD-8's were used in anti-submarine roles while the DD-9's were used to protect the more lightly armed DD-8's. The Navy based the aircraft in NAS Ile Tudy and NAS Dunkirk. At Ile Tudy pairs of aircraft were assigned to each convoy entering the patrol area of the station. At least 8 aircraft a day were used in this mode. The first attack on a submarine by the Ile Tudy aircraft occurred on 23 April 1918, when the U-108 was detected. The attack was unsuccessful. Other aerial attacks took place on 5 July, 3 August, 10 August, 27 August, 27 September, 22 October, and 25 October.

Serial numbers of the DD aircraft purchased by the U.S. Navy were: 447, 507, 809, 810, 811, 813-817, 823, 829, 831, 835, 840-843, 845-849, 1110, 1112, 1151, 1179-1181, 1193, 1208, 1209, 1211, 1217, 1218-1220, 1240, 1241, 1253, 1440, 1441-1443, 1450-1453, 1455, 1473, and 1474.


Aircraft and Flight Characteristics

French Aircraft of the First World War, Davilla, Jim and Art Soltan


16.28 m


10.75 m


3.5 m




1075 kg


1975 kg

Maximum Speed

140 km/hr. at sea level



   To 1000 m

6 minutes 30 seconds

   To 2000 m

18 minutes 15 seconds

   To 3000 m

27 minutes


2 or 4 7.7 mm machine guns and two 35 kg `F' bombs


  1. Davilla, Jim and Art Soltan, French Aircraft of the First World War
  2. Photo courtesy of the author.

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