Blackburn Ripon

The origins of the Ripon can be traced back to the mid-1920s and the issuing of Air Ministry Specification 21/23, which sought a replacement for the Fleet Air Arm's (FAA) single-seat Dart that could operate both as a torpedo bomber and an reconnaissance aircraft.[2] It was stipulated that it should have a two-man crew, comprising a pilot and navigator/gunner to facilitate long-range reconnaissance missions;[3] for the same reason, the aircraft was to have a maximum endurance of at least 12 hours. A further requirement was that it should have an interchangeable undercarriage between wheeled and float-equipped configurations, facilitating its operation from both land and sea.[2]

Blackburn begin work on its response to the specification during 1925, directed by F. A. Bumpus.[2] The resulting aircraft, which was designed around the Napier Lion V engine, drew heavily on the preceding Blackburn Velos coastal defence seaplane, having a broadly similar structure with the exception of its use of single-bay wings and the anhedral on the bottom central section. The lower mainplane was of a slightly larger span than the lower, while an atypical feature in the form of a lower wing root fairing.[2] A single Lewis gun fitted on a rotating mounting around the rear cockpit formed the defensive armament. Offensive armaments consisted of six 230lb bombs, or three 520lb bombs, or a single 18-inch torpedo.[2]

A pair of prototypes were built.[2] 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.[3] During December 1926, the Marine Aircraft Experimental Establishment at Felixstowe commenced a formal evaluation of the aircraft.[2] 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.[3][4]

The first production aircraft made its first flight in late 1927.[4] 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.[4] 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.[5]

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.[6] 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.[7] 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.[8]

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.[9] Many of the earlier production aircraft were rebuilt to the Ripon IIC standard during the early 1930s. It was the final production standard of the Ripon to be procured by a domestic air service.[10] Instead, the Ripon served as the basis for the Baffin, which was effectively more advanced version of the type. Starting in January 1934, the Baffin begun to replace its predecessor in FAA service. Many of the Ripons were returned to Blackburn and remanufactured into Baffins.[11]

In addition to the British armed forces, Blackburn had extensive efforts to promote the Ripon to potential overseas customers.[11] These efforts involved explorations of its reengining with BMW and Hispano-Suiza powerplants, largely due to the later models of the Napier Lion engine being still on the official secrets list at that time. The Spanish Navy was one of the company's acknowledged targets.[11] During August 1928, an order for a single pattern aircraft was issued by Finland; this aircraft, designated T.5D, was outfitted with a Bristol Jupiter radial engine and an interchangeable undercarriage and delivered to the Finnish Air Force on 29 September 1929. Finland also purchased a license to produce the Ripon from Blackburn.[12]

• Jackson, A. J. Blackburn Aircraft since 1919. Putnam, 1968.