The Blackburn B-54 and B-88 were shipborne, anti-submarine aircraft designed against Specification GR.27/45. As such they were required to carry a pilot and observer, depth charges and a search radar.
The first design in this series was the B54 or YA5. This type was designed around the proposed Napier Double Naiad turbo-prop engine, driving co-axial contra-rotating propellers. A deep fuselage contained a weapons bay and a radar system with a retractable radome under the rear fuselage.
The monoplane design featured a tricycle undercarriage and an inverted gull-wing, fitted with an effective high-lift flap system drawing upon experience with the B-48 Firecrest. The crew sat in tandem under a long cockpit enclosure. Not wanting to depend on a different, untried powerplant, the design was similar in its general concept to the Fairey Gannet.
When development of the Double Naiad was cancelled, the first prototype (WB781) was completed with a 2,000 hp Rolls-Royce Griffon 56 engine, driving two, three-blade contra-rotating propellers.
At the same time, the type designation was updated from YA5 to YA7.
The YA7 was flown for the first time from Brough on 20th September 1949 before carrying out deck landing trials on HMS Illustrious, starting from 8th February 1950.
The Blackburn B-54 (YA7) WB781 flying with the revised fin and rudder, as fitted to the YA8 WB788.
At this stage, the requirement was changed to seek accomodation for three crew thus introducing a second observer.
The second Griffon-powered prototype (WB788) provided the required increased capacity and was designated the YA8. It featured a taller fin and a narrower rudder (which was mass-balanced) rather than the aerodynamically-balanced previously utilised.
The YA8 was first flown on 3rd May 1950 and introduced changes in the wing planform, presumably associated with changes in the aircraft centre of gravity. The revised fin and rudder geometry of the YA8 was also retrospectively fitted to the first (YA7) aircraft.
In parallel with these developments, a third prototype (WB797) was built, using the Armstrong Siddeley Double Mamba turboprop engine, driving two four-bladed propellers. In this form, the Blackburn Type number was changed to the Blackburn B-88, with the alternative designation YB1.
The Blackburn YB1 was flown for the first time from Brough on 19th July 1950.
The turboprop Blackburn B-88 (YB1) WB797 photographed on 20th July 1950, the day after its first flight.
After initial flight trials, the span of the YB1 was slightly increased, requiring their own outward-folding hinge to ensure that they did not foul each other as the main outer panels were folded inwards.
Following competitive trials, the Fairey Gannet was eventually selected in March 1951 and it was this type that entered large-scale production. The B-88 YB1 was passed to Armstrong Siddeley Motors who used it to support the development of the Double Mamba until it was scrapped in July 1955.
Early however, the YA7 and YA8 had been transferred to RAE Farnborough during 1954 although both aircraft were withdrawn from use and scrapped by the end of 1957.
The Blackburn B-88 (YB1) WB797 displays its manoeuvrability and its large weapons bay at the 1950 SBAC Show.