Blackburn Type E The Blackburn Type E was a development of the earlier Blackburn Mercury single - engined monoplanes , but innovative it its use of steel tubing to construct the fuselage . It was built during 1912 to compete in the Military Aeroplane Trials . A single - seat version flew , but the military two - seater did not . Design and development . The Type E was a natural development of the line that led from the Blackburn Second Monoplane through the Mercury series . The main difference was in the construction of the fuselage , designed for military and overseas use and built with an aluminium covered steel frame . It was the first British aircraft to have an all - metal fuselage , and with steel used in both wings and tail structures was referred to as an all - steel aircraft . The wings of the Type E , like those of the earlier Mercurys , were thin in cross section and rectangular in plan . The span was the same as that of the Mercury I , but they used the construction methods of the Mercury III , with twin tubular steel spars and wooden ribs , the whole fabric covered . Lateral control was by wing warping . The wing , mounted in mid position was wire braced from above via a kingpost and below from the undercarriage . The fuselage used three steel longerons , arranged so the cross section was a downward pointing triangle . The Type E used the same long triagular fixed tail surfaces as the Mercury . The fixed surfaces fabric covered over a steel frame with ash trailing edges . The tailplane carried a single wide elevator of almost semicircular shape , and the fin carried two small triangular rudders , one above and one below the fuselage . Both were wide chord and triangular in shape . The Type E sat high off the ground to accommodate a large propeller and almost horizontally because of a long tail skid from the fuselage to the end of the rudder post . The main undercarriage had a pair of forward - projecting skids which reached from forward of the propeller almost to the trailing edge of the wing . Each skid carried a pair of wheels on a short axle . The skids were attached to the upper fuselage longerons with a pair of near vertical struts on each side and by further bracing to the lower fuselage longeron . Two rather different versions of the " all - metal " Type E were built . The first was a single - seater made for a private buyer ( Lt . W . Lawrence ) for use in India . It was powered by a 60 hp ( 45 kW ) four - cylinder water - cooled inline Green engine . It first flew in April 1912 . Painted grey , it acquired the name " L ' Oiseau Gris " and was entered for the round - London Aerial Derby of June 1912 , but scratched as unready . It seems that engine cooling problems caused Lawrence to abandon the aircraft . Perhaps because of these engine problems , the second Type E , intended for the Larkhill military trials taking place later in the year used a 70 hp ( 52 kW ) aircooled V - 8 Renault engine . As required by the War Office , it was a tandem two - seater ; the pilot ' s seat , with its Blackburn - style triple control wheel was at the trailing edge and there was a second cockpit at mid - chord , immediately behind the kingpost . On the " military machine " , as it was sometimes known , there was a curved fuselage decking that extended back to the fin root as well as an additional streamlined fuel tank mounted under the fuselage at about mid - chord . This was intended to increase endurance from four to five hours ; the specification called for 4 . 5 hours . Apart from these changes the military machine was very like the first Type E , but when tested in June 1912 it was overweight , failed to fly and was withdrawn from the Larkhill trials . Despite this failure , it attracted crowds when displayed on a Leeds school playing field late in 1912 .