During early 1918 the second prototype was completed. Unlike the first, it had plain elevators and ailerons which had an inverse taper; the tops of the wings and tailplanes also differed. The defensive armament was increased, giving the rear gunner two separate guns; these changes would be standardised on production aircraft. The second prototype was powered by a pair of Sunbeam Maori engines, which were found to have an unreliable cooling system during initial testing at Joyce Green. On 26 April 1918 the aircraft was dispatched to RAF Martlesham Heath for official tests; however, testing was interrupted by its loss in a crash following an engine failure.