Short locker
| Short SA.4 Sperrin | |
|---|---|
 Short Barrier at the Farnborough SBAC Show |
|
| Type: | four-engine test aircraft |
| Design country: | |
| Manufacturer: |
Short Brothers and Harland , Belfast |
| First flight: |
August 10, 1951 |
| Commissioning: |
Flight tests canceled |
| Number of pieces: |
2 |
The Short SA.4 Sperrin was a design for a British strategic bomber from the early 1950s. It was built by the Short Brothers and Harland in Belfast , often abbreviated as "Shorts". The Sperrin is named after the Sperrin Mountains , a range of hills in Northern Ireland .
history
In the period after the Second World War, the British government considered it necessary to have its own strategic bomber weapon, independent of the US Strategic Air Command . At the end of 1948, the British Ministry of Aviation therefore published Specification B.14 / 46 for a jet bomber . This should have at least equivalent performance in comparison with American and Soviet projects. The exact requirements required a maximum weight of 63.5 tons and the ability to engage a target at a distance of 1500 nm (2700 km).
The machine should fly between 45,000 ft (14,000 m) and 50,000 ft (15,000 m) altitude and be so easy to maintain that it could be deployed on bases outside the country. In addition, a 10,000 pound (about 4500 kg) atomic bomb with a length of 30 ft (9.1 m) and a diameter of 10 ft (3.0 m) should be able to be accommodated in the fuselage.
A year earlier there was a tender specification B.35 / 46 for a medium-range bomber that should be able to carry a 10,000 lb bomb from any base in the world into a target 1500 nm away. This 1947 requirement required that the fully laden weight be less than 100,000 lb (45 t) and that the bomber should still have a cruising speed of 926 km / h (500 kn ) and a service ceiling of about 50,000 ft (approx. 15,000 m) . These requirements then formed the basis for the later V-bombers . However , it was also clear to the British Aviation Ministry that these requirements were still beyond the capabilities of the British aircraft manufacturers. It was therefore on a withdrawal position in the form of the earlier tender specification B.14 / 46 . This was far more conservative in its requirements and according to this tender a contract for two prototypes and a static cell with short was concluded.
construction
The design, first known as SA.4 and later as Sperrin , had more in common with the designs of the Second World War than with those of the dawning jet age. With the exception of the leading edge - which had a slight arrow angle - the wings were not swept. The engines were housed in nacelles in the center of the wing, but the arrangement of two engines on top of each other in each wing was unusual. The construction consisted mainly of aluminum alloys.
The crew consisted of five men: pilot, copilot, bombardier, navigator and radio operator; only the pilot had an ejector seat .
testing
The first prototype ( VX158 ) had its maiden flight with test pilot Tom Brooke-Smith on August 10, 1951. The propulsion system consisted of four Rolls-Royce Avon RA.2 engines, each with a thrust of 6,000 pounds (26.7 kN) . At this point, however, the decision about an order in favor of Vickers Valiant had already been made , so that the Sperrin project should actually have been canceled. The British Ministry of Procurement , however, spoke out in favor of continuing to operate the Sperrin as a research aircraft.
Work continued on the second prototype XV161 , which was able to complete its maiden flight on August 12, 1952 under the control of Squadron Leader "Wally" Runciman. This machine was already equipped with the more powerful Avon RA.3 engines, each generating 6,500 pounds (28.9 kN) of thrust. The two machines were used in a variety of test flights in the 1950s, including engine tests in which the VX158 was equipped with the De Havilland Gyron jet engine. At the time, this was one of the most powerful engines ever with a thrust of 15,500 pounds (28.19 kN). The Gyron Gy 1 replaced the lower Avon engine on the left wing. During the first flight in this configuration on July 7, 1955, the aircraft was piloted by Jock Eassie and Chris Beaumont.
The test flights with this asymmetrical engine arrangement lasted until March 1956, after which the single Gy 1 was replaced by two Gyron Gy 2. The two new engines were each installed below the remaining original Avon RA.2. The Gy 2 even delivered 20,000 pounds (89.1 kN) of thrust. The first flight of the VX158 with these engines took place on June 26, 1956. During the flight, the landing gear cover on the left wing partially came off, for the repair the corresponding part of the VX161 was used, which then no longer began flight operations and was scrapped in Sydenham in 1957. The VX158 still flew at the Farnborough Airshow in 1956 in the engine configuration last tested, six months later the gyron program was canceled and the VX158 scrapped in Hatfield.
The VX161 was involved , among other things, in the experiments in which the external shape of the Blue Danube atom bomb was to be determined. The machine was also involved in experiments with the Blue Boar rocket. The tests took place with concrete replicas of the devices, but none of the projects was pursued further.
Technical specifications
| Parameter | Data |
|---|---|
| crew | five (pilot, copilot, bombardier, navigator and radio operator) |
| length | 31.14 m |
| span | 33.2 m |
| height | 8.69 m |
| Wing area | 176.2 m² |
| Empty mass | 33,000 kg |
| Takeoff mass | 52,200 kg |
| Top speed | 912 km / h |
| Service ceiling | 13,700 m |
| Range | 5,150 km |
| Engines | 4 × Rolls-Royce Avon with 26.7 kN each |
See also
literature
- Bill Gunston: Short's Stop Gap Bomber. Airplane Monthly, July 1980, pp. 340-346.
- Clive Richards: Short SA.4 Blocker: Britain's' Insurance Bomber. WINGS OF FAME, Volume 19/2000, pp. 112-119.
Web links
- Short Sperrin at wingweb.co.uk (English) ( page no longer available , search in web archives )
- Short Sperrin at Aviastar.org (engl.)
- Short blocked at fliegerweb.com