Flight, January 1935

THIRTY-SEVEN TONS in the AIR
First Tests of the French Latecoere Transatlantic Flying Boat: Six 860 h.p. Hispano Engines: Seventy-two Passengers to be Carried on Short-range Journeys: De Luxe Cabins - with Furniture!

   THE new Latecoere 37-ton flying-boat, the Lieutenant Paris, which is equipped with six Hispano-Suiza 860 h.p. liquid-cooled engines, began its trials at the Biscarosse seaplane base last week. With a six-ton load this machine made its initial flight around the lake on January 16, flying at a height of about 600 ft. These tests will be continued with gradually increasing loads until a loaded weight of 37 tons is reached.
   One of the largest boats yet constructed, the Lieutenant Paris has been designed as a passenger transport and postal machine which can be adapted for several different services. For operation on the Air France Marseilles - Algiers line, the machine can be equipped to transport seventy-two passengers with a crew of four. Its total weight for this service will be 69,519 lb. (approximately 31 tons) divided as follows:-
   Weight empty, including equipment 43-454 lb. (19 730 kg)
   Fuel 9,394 lb. (4 270 kg)
   Crew (four men) 880 lb. (400 kg)
   Seventy-two passengers 15,791 lb. (7 170 kg)
   Total 69,519 lb. (31 500 kg)
   For the South Atlantic crossing, Dakar (French West Africa) to Natal (Brazil), some 2,000 miles, the Lieutenant Paris will carry its full load of fuel, 5,333 Imperial gallons, and thirty passengers, in addition to the mail and freight. In making the trip from France to the United States, it is designed to make the crossing with a stop at the Azores and transport twenty-four passengers. In both these crossings the machine, when fully loaded, will weigh thirty-seven tons. The following are the estimated performance figures in fully loaded condition:-
   Speed at ground level, 150 m.p.h. (250 km/h); speed at cruising height, 125 m.p.h. {201 km/h); ceiling, 16,400 ft. (5000 mi; range with no wind, 2,812 miles (4300 km).
   The Lieutenant Paris is constructed of duralumin and stainless steel throughout with the exception of the fabric covering of the outer wing panels and the tail. The hull consists of two sections: the main hull and the superstructure which covers almost its entire deck.
   The main hull is constructed with a heavy keel and equipped with two steps. It is divided into seven watertight compartments, in which all the longerons, stiffeners and cross struts are of open section and easily inspected, the forward part of the hull contains a hold for storing mooring tackle, anchors, and so on. Three compartments directly aft of this hold are fitted with armchairs and folding tables to accommodate ten first-class passengers, six de luxe cabins each containing two beds, a wardrobe and a private bathroom. A bar and a kitchen, together with the second-class cabin, are arranged in the after hull.
   The captain's and navigator's cabin is located in the nose of the upper section of the hull. The pilots' compartment, fitted with dual controls, is installed directly aft of the captain's room and the radio compartment and mechanics' quarters behind it. A gangway, giving access to the engine nacelles, is located in the centre of the upper structure, and the rest of the space toward the stern is devoted to a cabin fitted with accommodation for the forty-two second-class passengers. A flight of stairs connects the cabins situated in the main hull and superstructure.
   The framework of the wings, of which the centre section is anchored to the top of the upper hull structure, is composed of two box spars which, together with the ribs and the interior bracing, are of duralumin. The surface of the centre section is covered with duralumin sheet metal, while the outboard wing panels are fabric covered. The wing profile is of medium thickness with a chord of approximately twenty-five feet. This wing unit is braced by four streamline struts, mounted in Vee form, to the two stub wings which serve as planing fins. The ailerons are aerodynamically compensated.

Large Sponsons

   A large sponson is attached to each side of the lower portion of the hull. These sponsons are made with numerous stiffeners which transmit the stresses to the frames and the longerons of the hull. Each is also braced by two pairs of streamlined struts mounted in Vee form to the wing above it. In order to augment lateral stability on the water and to damp out shocks, the ends of the sponsons are built so as to bulge underneath, thus forming wing tip floats. The petrol tanks, containing 528 gall. (2 400 l) are located in the sponsons, each containing three separate compartments, so that the engines can be fuelled separately. Two intermediate fuel tanks of 111 gall. (500 l) each are located in the wings.
   The framework of the tail is constructed of duralumin and fabric covered. The tail plane is braced by struts to the lower part of the hull. The elevators and rudder are aerodynamically balanced.
   Each of the six twelve-cylinder Hispano-Suiza liquid-cooled and geared engines is rated at 860 h.p. and supercharged to establish this power at 13,123 ft. (4 000 m). These engines are mounted in four groups: two engines at the leading edge and one at the trailing edge of the centre section of the wings on either side of the superstructure. The engine mountings are accessible through a gangway in the wing. Radiators are mounted in the rear of the engine nacelles under the lower side of the wing.
   The following are the general characteristics:-
   Wing span, 160 ft. (49.30 m); length, 103 ft. (31.62 m); height, 29.5 ft. (9,07 m); wing surface, 3,554 sq. ft. (330 sq m) Total horse-power, 5,160.