single 18-inch torpedo. A pair of prototypes were built. On 17 April 1926, the first prototype made its maiden flight in a landplane configuration, flown by P. W. S. Bulman. On 26 August of that year, the second prototype made its first flight as a seaplane, piloted by J. D. Rennie. During December 1926, the Marine Aircraft Experimental Establishment at Felixstowe commenced a formal evaluation of the aircraft. Initial trials against its competitors, the Handley Page Harrow and the Avro Buffalo, showed that none of the competitors were adequate, so the Ripon was redesigned with an improved engine installation, an enlarged rudder and increased sweepback on the wings. The revised aircraft was evaluated and declared to be the winner, after which Blackburn was awarded a production contract for the type. Into production The first production aircraft made its first flight in late 1927. Referred to as the Ripon II, design changes from the prototypes gave it a distinctly different appearance, such as its more pointy nose as a consequence of the new cowling and retractable radiators for engine cooling. The undercarriage had been drastically redesigned as well, featuring telescopic oleo struts fitted to the outboard ends of the bottoms centre front spar. Structurally the aircraft was largely unchanged and continued to conform with established Blackburn practices of the era, The gun ring was redesigned for a lower positioning, along with a slot in the rear decking for it to be locked into when not in use; the cockpit was also extended rearwards to house more apparatus. On 15 May 1928, the first production aircraft made its public debut, performing a flying demonstration that included a practice torpedo deployment over the Humber along with some aerobatic manoeuvres in front of the assembled press. During 1928 and 1929, Blackburn received contracts for a combined 20 Ripon IIs. In early 1930, more substantial orders for 40 of the improved Ripon IIA were placed; this variant made greater use of duralumin in its wings and provided a mildly raised all-up weight. The production rate reached two aircraft per week around this time, which was facilitated by the subcontracting of some component manufacturing to the competing British aviation manufacturer Boulton Paul Aircraft. Between 1931 and 1932, 31 Ripon IICs were constructed, which had greater sweepback and eliminated all use of wood present in the structure of the mainplane. Many of the earlier production aircraft were