http://members.aol.com/kamyansoft/home.htm British RAF Se5a The SE5a airframe may appear fragile to modern eyes but they were surprisingly sturdy and very successful. They were extremely fast and, although not as manoeuvrable as the Nieuport, could be thrown about and dived hard without fear of their folding in the air. Disliked by many pilots at first, Albert Ball remarked that it was a "...rotten machine", the SE5a had a dramatic effect on the course of the war. Faster and more stable than the Nieuport, its initial unpopularity was certainly down to its bulk and relative lack of responsiveness, a failing more than made up for in the long term by its speed and stable gun platform. The RAF SE-5a was a single-seat fighter and entered service in April 1917. It proved to be one of the best fighters of WW I. It stayed in service till the end of the war. Its one weakness was the machine gun arrangement which tended to decrease the effective forward firepower. This was due to the wing-mounted Vickers machine gun, since the pilot had difficulties to aim properly with it. Unless this disadvantage, the SE-5a was welcome among the pilots, since the decreased firepower was offset by the airplane's good structural strength and its ability to absorb a large amount of punishment. Engine : 200-, 220-, or 240 hp Hispano-Suiza 200 hp Wolsey Viper Performance: Maximum Speed 132 mph (212 km/h) Service Ceiling 20,000 ft Endurance: 2 h 30 m Aramament: 1 forward-firing Vickers (mounted on hull, 400r) 1 forward-firing Lewis (mounted on upper wing, 4x97r) Following is a translation of the description of the British S.E.v.A. (scouting, experimental) fighting single-seater, published in the March issue of the German Airmen's Journal, "Luftwaffe," reading thus :- The aeroplane in question was built by Vickers, Ltd., and numbered B.507, wearing further as recognition initial or that of a squadron, an A as well as a white circle. The propellor is marked: S.E.v.A., which leads to the idea that the older model of this same aeroplane type with the 150 h.p. Hispano motor not geared down is called S.E.v. The biplane has a surface of 22.8 square metres, and both planes, connected with but one pair of struts to each side, have a span of 8.15 metres, and a chord of 1.52 metres, the gap from the top of the fuselage amounting to 0.45 metre. No arrow-shape prevails. The V-shape of the equal-sized ends of the upper and lower planes mounted on the centre section and respective body rudiments amounts to 1.71 degrees. The sight field of range is improved by cutting the centre section in the middle and the lower planes near the body. Above the angle of incidence is 5 deg. mean, below by the body 6 deg., by the struts 5 deg. Both plane spars show sections of I shape, whereas the longerons of the rudiment pieces, running through the body are steel tubes 1.75 millimetre thicknes, and 45 mm. outer diameter. The plane ribs show the usual construction of most British air craft. There are no compression struts between teh spars, some of the ribs being solid struts instead. The interior wiring of the planes between the body and the struts is carried out in simple profile wire, that of the overhanging ends of thick-end wire. A wood strip forms the back edge of the planes. Further, two auxiliary ribs ranging from the leading nose edge to the main spare are arranged between each two ribs. The fabric is sewed together with the ribs, and is painted yellow below, browned above, as is the fabric of the body. Shoe-eyes are arranged on the underside of the trailing edge of the plane to assess the pressure. The centre section struts are covered steel tubes. The plane spruce struts rest in long stampings, serving as fixing points of the vertical wiring. Profile wire is employed for the plane cross wiring with twin wires for those carrying load and single for counter ones. The two spars of the upper planes are strengthened further between the centre section and the struts with two wires each. Unbalanced ailerons are hinged to the back crossbar of the upper and lower planes. The body shows the usual strut-cum-wire combination, being rounded above with half-circle frames and fairings, and having three-ply wood planking of 4 millimetre thickness to the pilot's seat. Fuselage longitudinals and struts have sections of I-shape, except the vertical struts behind the pilot's seat, which are worked out round. The tail-plane is curved to both sides and fixed to the body, so that the angleof incidence can be varied during the flight within the limits +4.5 deg. and -3 deg. To this end the front spar is turnable, while the rear spar, with its wiring, is fixed to a tube, arranged shiftable to the body stern post. This tube rests with a piece of thread in a gear nut, again resting in the stern post fixed, yet turnable. When the nut is turned from the pilot's seat by means of wheel and cable, the tube is displaced upwards or downwards, transferring thereby the same manoeuvre on the rear spar of the tail plane, and thus its angle of incidence changes. The elevator hooked to the fixed tail-plane partakes in this movement. The wires for operating the elevator are led through the body and tail-plane, which certainly saves air resistance, yet makes twice a 20 deg. direction change of each wire necessary. Main and tail planes are equipped with cellon windows, rendering a control of the rollers possible. The under-carriage shows the normal form. The through-running axle rests between two auxiliary ones. There is no limit of the springing range. The tail skid shows an unusual construction, being arranged turnable behind the stern-post and connected with the rudder cable by intermediance of springs. A brass skid bow is sprung by means of two spiral pressure springs which are prevented from sideway turning by inserted telescope tubes. According to the firm's sign board the Wolseley-Hispano-Suiza engine gave the 30th August, 1917, on brake 206 h.p. - 203 P.S. at 2005 revolutions. The r.p.m. of the four-bladed airscrew is geared down in the ratio of 4 to 3. The exhaust gas is led behind the pilot's seat in two tubes to each side of the body. The motor sits so that there is free accessibility after removing the bonnet. The radiator forms the bow of the body. A cover arrangement makes it possible to uncover the body about half-way from the pilot's seat. The main petrol tank of 120 litres' capacity is placed behind the motor on the upper fuselage longitudinals. A gravity tank of 17 litres capacity is arranged in the centre section between the leading edge and the main spar. The oil tank of a capacity of 14 litres lies across in the engine frame below the rear edge of the motor. The fuel suffices for a flight of about two hours duration. Following instruments are arranged in the pilot's seat :- To right: A box for the light pistols; a contact breaker for the self-starter; a contact breaker for the two magnetos; a triple led cock for the gravity and pressure petrol; a triple led cock for the hand and motor air pump; a thermometer for the water of the radiator; the petrol gauge placed on the back side of the main tank, and a manometer for air-pressure. To left: Gas lever; lever for regulation of the gas in altitude flights; lever for operating the radiator blinds, clip for three light cartridges. On the bottom is further arranged a hand-pump for the hydraulic machine gun gear; two boxes for drums for the moveable machine guns and self-starter. A square windshield of Triplex glass is placed in front of the pilot's seat. Behind it a box is arranged in a queer position to the body with access from outside. The fixed Vickers' machine gun lies to the left of the pilot inside the body fabric. The cartridge girdle is of metal. The firing of the machine-gun takes place hydraulically by means of a control arrangement, placed in front of the motor and connected with the machine gun through a copper main, as well as driven from the air screw by a gear set. The firing lever sits on the stick. On the bow-shaped iron band lying on the centre section rests a Lewis gun, which can be pulled down during the flight to permit vertical firing. The empty weight of the aeroplane was worked out at 706 kilos, distributed as follows :- Engine . . . . . . 225.0 Exhaust collection . . . . 12.0 Self-starter . . . . . 3.6 Radiator . . . . . 23.8 Radiator water . . . . . 31.0 Air screw . . . . . 26.6 Main petrol tank . . . . 17.8 Gravity petrol tank . . . . 6.5 Oil tank . . . . . 3.9 Motor equipment . . . . . 6.4 Body with seat and plate covers . . . 151.0 Tail plane angle of incidence change arrangements 1.9 Under carraige . . . . . 40.8 Tail skid . . . . . 3.7 Pilotage arrangement . . . . 5.4 Planes with wiring . . . . 112.2 Vertical and horizontal wiring . . . 21.0 Body equipment . . . . . 14.0 ----- Total . . . . . . 706.0 kg The fuel weight amounts with fully loaded tanks to 111 kilos., so that the total useful load can be calculated at 250., the total weight working out at 956 kilos. The load of the planes is thus: 956/22.8 = 42 kg per square metre. The performance load: 956/200 = 4.78 kg per horse power. HISPANO-SUIZA (Spanish, French, British and American). Head Office :-LA SOCIEDAD HISPANO-SUIZA, Barcelona, Spain. U.S.A. :- THE WRIGHT-MARTIN AIRCRAFT CORPORATION Simplex Works, New Brunswick, New Jersey, U.S.A. Also manufactured in France and in England. One of the most successful engines in the world, being light for its weight, reliable, and designed so as to fit neatly into an aeroplane. The distinguishing feature of the engine is the use of aluminum Monobloc cylinder castings into which steel liners are screwed. Made in three sizes :- 180 h.p. 8-cylinder. V-type, direct drive. 220 h.p. 8-cylinder. V-type, geared drive. 300 h.p. 8-cylinder. V-type, geared drive. Model A. 180 h.p. Bore: 4.7245" \ 4 cylinders in each block of the "V." Stroke: 5.1182" / Piston Displacement: 718 cubic inches. H.P.: 180, at 1750 r.p.m. Weight, without radiator, water, oil or exhaust pipes: 445 lbs. Fuel consumption: .5 lbs. per h.p. per hour. Oil consumption: 3 quarts per hour. The 220 h.p. type is the same as the 180 h.p., but running at 2,200 r.p.m. The 300 h.p. type is as the 220 h.p., but with bigger bore and longer stroke. THE WRIGHT-MARTIN HISPANO-SUIZA AERO ENGINE. Specification: Type Model 1. No. of cylinders 8 (Vee type) Bore 120 m/m. (4.724 in.) Stroke 130 m/m. (5.118 in.) Normal b.h.p. 150 Normal r.p.m. 1,500 Maximum b.h.p. 170 Maximum r.p.m. 1,700 Weight (with airscrew) 455 lbs. Fuel Consumption .51 lbs. per h.p. per hour Oil Consumption .03 lbs. per h.p. per hour