Short SC.1
SC.1 | |
---|---|
Short SC.1 XG900 at Farnborough SBAC Show September 1958 | |
Role | Experimental aircraft |
National origin | United Kingdom |
Manufacturer | Short Brothers |
First flight | 2 April 1957 (CTOL)[1] 26 May 1958 (VTOL)[1] |
Retired | 1971 |
Status | Retired and preserved |
Primary user | Royal Aircraft Establishment |
Number built | 2 |
The Short SC.1 was the first British fixed-wing vertical take-off and landing (
The SC.1 was designed and produced in response to a Ministry of Supply (MoS) requirement for a suitable aircraft for conducting flight studies into VTOL flight, as well as specifically into the transition between vertical and horizontal flight. Two prototypes were used for flight testing between 1957 and 1971. Research data from the SC.1 test programme contributed to the development of the Hawker Siddeley P.1127 and the subsequent Hawker Siddeley Harrier, the first operational VTOL aircraft.
In October 2012, the Short SC.1 received Northern Ireland's first Engineering Heritage Award as a recognition of its significant achievement in the engineering field.[2]
Development
During the 1940s, various nations became interested in developing viable aircraft capable of
The SC.1 has its origins in a submission by Short Brothers to meet a Ministry of Supply (MoS) request for tender (ER.143T) for a vertical take-off research aircraft, which had been issued in September 1953. On 15 October 1954, the proposed design was accepted by the Ministry and a contract was promptly placed for two aircraft to meet Specification ER.143D. As envisioned, the aircraft was to be used for a series of flight tests to investigate its behaviour during the transition between vertical and horizontal flight modes, to determine the optimum and minimum level of assistance required from the auto-stabiliser during the transition process, to uncover likely operational issues, and to develop related support aids and equipment for the pilot to develop an all-weather approach and landing system.[1]
Short constructed two prototypes, designated XG900 and XG905.[1]
Design
The Short SC.1 was a single-seat low wing tailless delta wing aircraft of approximately 8,000 lb all-up weight (max. 7,700 lb for vertical flight).[3] It was powered by four vertically-mounted, lightweight Rolls-Royce RB.108 lift engines that provided a total vertical thrust of 8,600 lb, along with a single RB.108 cruise engine in the rear of the aircraft to provide thrust for forward flight. The lift engines were mounted vertically in side-by-side pairs in a central bay so that their resultant thrust line passed close to the centre of gravity of the aircraft. These pairs of engines could be swivelled fore-and-aft to produce vectored thrust for acceleration/deceleration along the aircraft's longitudinal axis.[3]
During conventional flight, the lift engines would be shut down; before beginning the transition from horizontal to vertical flight, they would be started using compressed air from the single cruise engine. The compressed air provided the initial rotation of the engine but a pressure drop from intake to exhaust had to be present also as the compressed air alone was not adequate for reaching idle speed.[3] Considerable wind-tunnel and flight development of the air intake was required because at the start of transition from horizontal flight vertically-mounted engines have to tolerate a crosswind equal to the forward flight speed without surging or excessive vibrations. The required uniformity of flow was achieved with the help of a set of 7 hinged gills which opened to a forward-facing position to direct air into a plenum which supplied the engines. The behaviour of a vertically-mounted RB.108 in terms of re-ingestion and ground erosion had been investigated with an installation representative of that intended for the SC.1 during ground operation in a Meteor at Hucknall Aerodrome.[4] Initially, a series of scuttles were fitted to the exit nozzles of the lift engines to maintain a low-pressure environment beneath the engines to ensure that the engine rotor would be "windmilling" in the correct direction prior to supplying the compressed air for starting; due to the effectiveness of intake and engine design changes, the scuttles became unnecessary.[5]
The cockpit layout was mainly conventional, but complicated by the large number of systems the pilot had to monitor.[3] For its role as a research aircraft it had comprehensive recording equipment.[6]
The common throttle lever for the four vertical lift engines was the only additional primary control in the cockpit; it was operated in a similar manner to that of the
The SC.1 was also equipped with the first "fly-by-wire" control system to be fitted to a VTOL aircraft.[8] This electrically-signalled control system, which also comprised the auto-stabiliser, not only transferred signals from cockpit controls such as the position of the stick, but also monitored feedback signals from the servos to provide stability of the systems itself. A total of three modes of control for the aerodynamic surfaces and/or the nozzle controls were permitted by the system:
- Aerodynamic surfaces and air-jet nozzles controlled electrically via three independent servo-motors (with "three-way parallel" or "triplex" fail-safe operation) in conjunction with three autostabilizer control systems ("full fly-by-wire")
- Hybrid-mode, in which the nozzles were controlled by servo/autostabilizer and the aerodynamic surfaces were linked directly to the manual controls
- Direct mode, in which all controls were linked to the control stick
Modes 1 and 2 were selected on the ground; whenever the autostabilizer was in use, the pilot had an emergency override lever available with which to revert to direct control mode in flight.[9] The outputs from the three control systems were compared and a "majority rule" enforced, ensuring that a failure in a single system was overridden by the other two (presumably correct) systems. Any failure in a "fly-by-wire" pathway was indicated to the pilot as a warning, which he could either choose to ignore or respond to by switching to direct (manual) control.[10]
In common with other VTOL aircraft, the Short SC.1 suffered from vertical thrust loss due to the
Testing
Constructed at Short's
Just over a year later, on 26 May 1958, the second prototype made the first tethered vertical flight.[1] Initial flights of the type were performed while attached to a specially-devised gantry, which accommodated only a limited amount of freedom, up to 15 ft vertically and 10 ft off-centre in any direction, vertical velocity was also restricted to less than 10 ft/second; progressive arresting of the aircraft occurred beyond these limitation.[13] It would take off from a grid platform positioned 6 ft above the ground itself in order to circumvent the ground effect phenomenon; considerable effort on the part of Shorts had been made during development of a suitable platform to eliminate the negative impact of ground effect and was redesigned several times. The gantry facility was used for ab initio training and familiarisation purposes for the first 8 pilots to fly the SC.1.[14]
On 25 October of that year, the type performed the first 'free' vertical flight. On 6 April 1960, the first in-flight transition between vertical and horizontal flight was successfully conducted.[15][16] While successful at transitioning between the two modes, the Short SC.1 had a reputation as being somewhat ungainly as an aircraft.[15]
The SC.1 was publicly displayed at the Farnborough Airshow in 1958 and 1960; it also appeared at the Paris Air Show in 1961, at which it performed a demonstration flight.[1] On 2 October 1963, the second test aircraft crashed in Belfast, killing the pilot, J.R. Green; the cause was later determined to have been a control malfunction.[17] Following the accident, the aircraft was rebuilt and returned to flight for further testing, both continued flying until 1967.[15] By 1965, a total of 14 different pilots had flown the type.[1]
As a result of ground suitability tests, it was determined that conventional runway concrete, pavement, and even grass strips would be adequate for vertical takeoff and landing of the SC.1; however, debris that may be forced out from imperfect surfaces would pose a risk to personnel but not to the aircraft itself.[18] The test programme also allowed experience upon the maintenance and serviceability of a VTOL aircraft to be acquired, even though these were not primary objectives of the design nor the research effort; throughout the programme, an overall average of 2.6 flights were performed per week. While numerous errors with the auto-stabiliser were reported during flights, no fault ever occurred that endangered the aircraft or had any effect upon its control.[19]
Testing found significant difficulty in measuring actual engine thrust, leading to further tests using improved intakes and instrumentation.[20] Ultimately, the engines proved to be far less problematic than might have been expected considering the experimental nature of the aircraft and its power-plants; and when faults occurred in the triplex auto-stabiliser they were easy to locate, in part due to the system's self-checking nature. According to a Ministry of Aviation report, the SC.1 was determined to have been an effective research vehicle when operated within the limits imposed by its small size and restricted capacity; however it was found that a larger aircraft would be necessary for more extensive tests of the instruments and guidance equipment.[20]
The SC.1 flew for over ten years, during which it provided a great deal of data that served to influence later design concepts such as the "puffer jet" controls on the Hawker Siddeley P.1127, the precursor of the Hawker Siddeley Harrier. The flight testing work relating to vertical takeoff and landing techniques and technologies also proved to be invaluable, and helped further Britain's lead in the field.[16] The Short SC.1 was ultimately rendered obsolete by the emerging Harrier which, amongst other things, proved that it was unnecessary to carry an additional four engines solely for the purposes of lift-off and landing.[15]
Aircraft on display
The first SC-1 (
The second SC-1 (XG905) was also preserved and is on static display at the Flight Experience exhibit at the
Operators
Specifications
Data from Shorts Aircraft since 1900,[23] Ministry of Aviation[24]
General characteristics
- Crew: 1
- Length: 25 ft 6 in (7.77 m)
- Wingspan: 23 ft 6 in (7.16 m)
- Height: 10 ft 8 in (3.25 m) [25]
- Wing area: 211.5 sq ft (19.65 m2)
- Aspect ratio: 2.61:1[25]
- Airfoil: NACA 0010[25]
- Empty weight: 6,260 lb (2,839 kg)
- Gross weight: 7,700 lb (3,493 kg) (VTOL operations)
- Max takeoff weight: 8,050 lb (3,651 kg) (CTOL operations)
- Powerplant: 1 × Rolls-Royce RB.108 turbojet, 2,130 lbf (9.5 kN) thrust (forward flight)
- Powerplant: 4 × Rolls-Royce RB.108 turbojets, 2,130 lbf (9.5 kN) thrust each (lift engines)
Performance
- Maximum speed: 246 mph (396 km/h, 214 kn)
- Range: 150 mi (240 km, 130 nmi)
- Service ceiling: 8,000 ft (2,400 m) [25]
- Rate of climb: 700 ft/min (3.6 m/s) [25]
- Wing loading: 38.1 lb/sq ft (186 kg/m2)
- Thrust/weight:
- (CTOL): 0.265
- (VTOL): 1.11
See also
Aircraft of comparable role, configuration, and era
Related lists
References
Notes
- ^ a b c d e f g h i j Lean and Chinn 1965, p. 4.
- ^ "SC1 gets NI's first Engineering Heritage Award." BBC News, 4 October 2012.
- ^ a b c d e f Lean and Chinn 1965, p. 5.
- ISBN 1-85260-037-3, p.157
- ^ a b Lean and Chinn 1965, pp. 5–6.
- ^ Lean and Chinn 1965, p. 10.
- ^ a b c Winchester 2005, p. 223.
- ^ Lean and Chinn 1965, pp. 6–7.
- ^ Lean and Chinn 1965, p. 7.
- ^ Lean and Chinn 1965, pp. 7–8.
- HMSO. Retrieved: 12 December 2007.
- ^ Winchester 2005, p. 222.
- ^ Lean and Chinn 1965, p. 8.
- ^ Lean and Chinn 1965, pp. 8–9.
- ^ a b c d "Short SC1 experimental vertical take-off aircraft, 1956." Science Museum, Retrieved: 15 January 2017.
- ^ a b c "Short SC1 vertical take-off aircraft receives Northern Ireland’s first Engineering Heritage Award." Institute of Mechanical Engineers, 5 October 2012.
- ^ "Test Flying Memorial". Archived from the original on 18 June 2009. Retrieved 5 October 2009. Test Flying Memorial site of British test pilots and engineers who died while test-flying (1946–1970 page).
- ^ Lean and Chinn 1965, pp. 13–14.
- ^ Lean and Chinn 1965, pp. 14–17.
- ^ a b Lean and Chinn 1965, p. 17.
- ^ "Short SC 1 aircraft, 1957." makingthemodernworld.org.uk, Retrieved: 15 January 2017.
- ^ "Air." Ulster Folk and Transport Museum, Retrieved: 15 January 2017.
- ^ Barnes and James 1989, p. 465.
- ^ Lean and Chinn 1965, pp. 4–8.
- ^ a b c d e Taylor 1966, pp. 168–169.
Bibliography
- Barnes, C. H. with revisions by Derek N. James. Shorts Aircraft since 1900. London: Putnam, 1989 (revised). ISBN 0-85177-819-4.
- Buttler, Tony and Jean-Louis Delezenne. X-Planes of Europe: Secret Research Aircraft from the Golden Age 1946-1974. Manchester, UK: Hikoki Publications, 2012. ISBN 978-1-902-10921-3
- Carbonel, Jean-Christophe (October 2022). "Aventures françaises en VTOL: French Testing of the Shorts SC.1, 1962". The Aviation Historian (41): 48–56. ISSN 2051-1930.
- Illingworth J. K. B. and Chinn H.W. Variable Stability and Control Tests on the S.C.1 Aircraft in Jet-Borne Flight, with Particular Reference to Desirable VTOL Flying Qualities (R & M No, 3584). London: HMSO, 1969. Retrieved: 11 December 2007.
- Jones, Barry. "Shorts' Early Risers". Aeroplane Monthly, May 1994, Vol 22 No 5, Issue No 253. London:IPC Magazines. pp. 12–19.
- Lean D. and Chinn H.W. Review of General Operating Experience with a Jet-Lift VTOL Research Aircraft (Short S.C.l.) (Aeronautical Research Council Current Papers CP No. 832). London: HMSO, 1965. Retrieved: 2 December 2008.
- Taylor, John W. R. Jane's All The World's Aircraft 1966–67. London:Sampson Low, Marston & Company, 1966.
- Vickery, Adrian. British Jet Aircraft. Cambridge, UK: Patrick Stevens Limited,1982. ISBN 0-85059-589-4.
- Warner, Guy (July–August 2002). "From Bombay to Bombardier: Aircraft Production at Sydenham, Part One". ISSN 0143-5450.
- Winchester, Jim. Concept Aircraft: Prototypes, X-Planes and Experimental Aircraft. Rochester, UK: Grange Books, 2005. ISBN 1-84013-809-2.
External links
- "Jet hovering under automatic control" a 1959 advertisement in Flight
- "Test-Bed for the SC.1" a 1961 Flight article