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

SEA 4

  The SEA 2 and SEA 3 were projects only and were never built, but the SEA 4 was to prove more successful. Despite the unfortunate experience with the Clerget engine, the team decided to gamble on another new engine - the 370-hp Lorraine-Dietrich 12Da. The prototype was completed in 1918, intended to meet the C2 classification for a two-seat fighter. The aircraft featured a streamlined fuselage and even used piano wire for bracing because it was hoped that its thin cross-section would reduce drag. The two-bay wing had no sweepback. The ribs were closely spaced to maintain the airfoil shape.
  The fuselage had a rectangular cross section with rounded angles. There were four longerons made of spruce, and the cowling was made of aluminum. The vertical fin was triangular in shape and made of wood. The landing gear consisted of V-shaped struts made of ash. These struts were fixed to the fuselage and carried a heavy steel axle. Bungee chords served as shock absorbers. The landing gear was reinforced by steel cables. The armament was a synchronized 7.7-mm Vickers machine gun and two T.O.3 ring-mounted 7.7-mm Lewis guns. A Winchester rifle could be fired from a trapdoor beneath the aircraft. There were special supports within the fuselage on which a camera or T.S.F. unit could be mounted.
  The aircraft was tested in April 1918 at Villacoublay, Plessis-Belleville (where the machine was tested in combat conditions), and the training field at Fertile. One thousand were ordered by the STAe. To meet that demands a new firm, called the Anjou Aeronautique Company, was formed. However, it was far from Paris, resulting in production delays. This angered the Minister of Munitions, who demanded an increased production rate from both the SEA firm and its subcontractors. Potez was sent to Angers to supervise assembly and the first production aircraft was finally ready on November 11 1918 - Armistice Day. The SEA 4 was also to be built at the Societe SCAF (Ste de Construction Aeronautiques Francaise) at Lavallois-Perret, Janoir, and SAIB.
  A version of the SEA 4 was produced which was intended for long-range flights. This version, designated the P.M., had additional fuel tanks fitted and had an endurance of 6 hours.
  With the end of the war the order for 1,000 aircraft was canceled, but the government accepted the first series of 115. Those built for the Aviation Militaire were used to meet the type Ap2 classification for a long-range reconnaissance aircraft. Many of these were assigned to the 34th RAO at Bourget.
  To make use of surplus airframes, a number of planes were converted to airliners by the addition of an enclosed cabin for two passengers in the position previously occupied by the gunner. About 25 of these were used by the Franco-Roumaine de Navigation and operated as far as Warsaw and Constantinople. At least two passed to the French airline CIDNA in 1925.


SEA 4 Two-Seat Fighter with 370-hp Lorraine-Dietrich 12Da
   Span 12.00 m; length 8.50 m; height 3.0 m; wing area 36.80 sq. m
   Empty weight 1,040 kg; loaded weight 1,620 kg
   Maximum speed:
ground level 218 km/h
1,000 m 215 km/h
2,000 m 210 km/h
3,000 m 206 km/h
4,000 m 203 km/h
5,000 m 197 km/h
   Climb:
1,000 m 3 minutes 1 seconds
2,000 m 6 minutes 18 seconds
3,000 m 10 minutes 45 seconds
4,000 m 16 minutes
5,000 m 23 minutes 29 seconds
   Endurance: 2.25 hours
   Armament: synchronized 7.7-mm Vickers machine gun and two T.O.3 ring-mounted 7.7-mm Lewis guns. A Winchester rifle could be fired through a trapdoor beneath the aircraft.
   115 aircraft built



SEA Floatplane

  SEA had a floatplane under construction in mid-1918. It had twin floats and carried a crew of two. The engine was a 400-hp Lorraine. It is not known if construction was ever completed.


SEA Two-Seat Floatplane with 400-hp Lorraine
   Wing area 35 sq. m
   Payload 120 kg
   Estimated Maximum speed: 200 km/h at 2,000 m; climb to 2,000 tn in 10 minutes