Vickers F . B . 16 The Vickers F . B . 16 was a British single - seat fighter aircraft of the First World War . It was originally designed to be powered by an experimental radial engine , development of which was abandoned . When re - engined with more powerful and reliable water - cooled V - 8 engines , the F . B . 16 demonstrated good performance , but only a few prototypes were built , the type not entering service . Design and development . In 1914 , following the outbreak of the First World War , the British engineering company , Vickers Limited , entered into an agreement with the Hart Engine Company of Leeds to fund development of an air - cooled radial engine , planned to generate 150 hp ( 112 kW ) . Vickers planned several aircraft around the promising new engine , including a tractor configuration single - seat fighter designed by Rex Pierson , the F . B . 16 . Pierson ' s new fighter , also known as the Hart Scout was a single - bay biplane with heavily staggered wings of unequal span . It had a tubby , ellipical section fuselage , with the pilot sitting in an open cockpit above the lower wing and the Hart engine enclosed in a neat cowling . Armament was a single synchronised Vickers machine gun . The prototype FB . 16 made its maiden flight sometime during 1916 , but testing showed that the pilot had a poor view , and the engine was prone to overheating . The aircraft was modified by removing the cowling to improve cooling and cutting down the fuselage behind the cockpit to improve the rearwards view . The problems with the Hart engine continued , however , and development of the radial was soon stopped . The F . B . 16 was redesigned to use the water - cooled Hispano - Suiza 8 V - 8 engine , rated at the same power as the Hart , with the new fuselage allowing a narrower fuselage . The revised aircraft ( which may have been a rebuilt of the Hart powered prototype ) , designated F . B . 16A emerged late in 1916 but was destroyed in a crash on 20 December that year . A second prototype , serial number " A8963 " was completed in January 1917 , being tested at Martlesham Heath in April . Although a maximum speed of 120 mph ( 193 km / h ) was demonstrated , no orders followed , the Royal Aircraft Factory S . E . 5 , easier to maintain and already in production , being preferred . " A8963 " was rebuilt with a 200 hp ( 149 kW ) Hispano - Suiza engine , and modified wings as the F . B . 16D , emerging in this form in June 1917 . It was armed with a single Lewis gun mounted between the cylinder banks of the engine and firing through a hollow propeller shaft , while a second Lewis gun was mounted on a sliding mount above the upper wing . Performance was once again good , impressing the fighter pilot and air ace James McCudden , who recorded reaching a speed of 136 mph ( 219 km / h ) and said " Whilst flying this machine I got some idea of the speed of future machines , for at 10 , 000 ft it was 30 mph faster than anything I had yet flown . " Officials were less impressed with the FB . 16D , however , it being criticised for structural problems and maintenance access , being described as " not considered suitable in its present form for active service " . Vickers again redesigned the F . B . 16 , fitting it with two - bay wings of longer ( 31 foot ( 9 . 45 m ) ) span and a 275 hp ( 205 kW ) Lorraine - Dietrich 8 Bd engine as the FB . 16E . Armament was a more conventional two Vickers machine guns . It was hoped to sell the revised fighter to the French " Aéronautique Militaire " , it being allocated the French official designation Vic . 16 . C1 , but no orders followed , the FB . 16E being destroyed in a crash on 29 July 1918 . A final version was the F . B . 16H , which replaced the Lorrane - Dietrich with a 300 hp ( 224 kW ) Hispano - Suiza , a speed of 147 mph ( 237 km / h ) being claimed , but yet again , no production followed .