|Andres Erdös, e-mail, 06.09.2012 05:15|
The Blackburn B-20 was an experimental aircraft, first flying in 1940, that attempted to drastically increase the performance of flying boat designs. Blackburn Aircraft undertook an independent design study based on a patent filed by their chief designer, J. D. Rennie.
The B-20 was an attempt to combine the best features of both the flying boat and the floatplane. While on the water, the B-20 was essentially a floatplane, using a large float under the fuselage for buoyancy, and two smaller floats near the wing tips for stability. In flight, the main float retracted towards the fuselage, fitting into a "notch" to become streamlined as a part of the fuselage. The wing floats folded outward to become the wing tips.
Blackburn along with Supermarine and Saunders-Roe tendered designs against Air Ministry Specification R1 /36. What would enter service as the Saunders Roe Lerwick was the chosen aircraft but the Ministry was interested enough to authorise prototype of the B-20, serial number V8914. The prototype would fly for the first time on March 26, 1940. On 7 April, during a test run, the aircraft experienced extreme vibration due to aileron flutter and the crew bailed out, three were lost the other two were picked up by HMS Transylvania, a converted merchantman. Development ceased when the first prototype crashed, as Blackburn's resources were dedicated to the war effort.
The aircraft's wreck still exists, but remains undisturbed as it is designated a War grave. In 1998, one of the engines was raised as it had been caught in a fishing boat's nets and dragged away from the wreck, into shallower water. It is currently an exhibit in the Dumfries and Galloway Aviation Museum.
Length: 69 ft 8 in (21.2 m)
Wingspan: 82 ft (25 m tip-floats retracted)
Height: 25 ft 2 in (7.65 m)
Wing area: 1,066 ft² (99 m²)
Max. takeoff weight: 35,000 lb (16,000 kg)
Powerplant: 2 × Rolls-Royce Vulture 24-cylinder X-type engines, 1,720 hp (1,280 kW) each
Maximum speed: 306 mph (266 kn, 490 km /h) at 15,000 ft (4,600 m)
Range: 1,500 mi (810 nmi, 2,400 km)
Guns: provision for two turrets and other defensive positions
Bombs: bomb-cells in centre section