Thursday, November 5, 2009

The Short SC.1

The Short SC.1 was the first British fixed-wing vertical take-off and landing (VTOL) aircraft. The SC.1 was designed to study the problems with VTOL flight and the transition to and from forward flight.
The SC.1 was designed to meet a Ministry of Supply (MoS) request for tender (ER.143T) for a vertical take-off research aircraft issued in September 1953. The design was accepted by the ministry and a contract was placed for two aircraft (XG900 and XG905) to meet Specification ER.143D dated 15 October 1954.

The 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). It was powered by four vertically-mounted, lightweight Rolls-Royce RB108 lift engines providing a total vertical thrust of 8,600 lb and one RB.108 cruise engine in the rear 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 about transverse axes; they were therefore able to produce vectored thrust for acceleration/deceleration along the aircraft's longitudinal axis.

Bleeds from the four lift engines (using approximately 10% of the intake air mass/thrust) powered variable nose, tail and wing tip jets providing pitch, roll and yaw control at low speeds, when there was insufficient airflow over the control surfaces for conventional control. Fuel tanks were located along the wing leading edges and in "bag" tanks fitted between the main wing spars.

The SC.1 was also equipped with the first "fly-by-wire" control system for a VTOL aircraft. This permitted three modes of control of the aerodynamic surfaces and/or the nozzle controls:
  1. 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")
  2. Hybrid-mode, in which the nozzles were controlled by servo/autostabilizer and the aerodynamic surfaces were linked directly to the manual controls
  3. 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. 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.

In common with other VTOL aircraft, the Short SC.1 suffered from vertical thrust loss due to the ground effect. Research into this on scale models suggested that for the SC.1 these losses would be between 15% and 20% at undercarriage height.. Fixed undercarriage legs were designed specifically for vertical flight with each leg carrying a pair of castoring wheels (the rear undercarriage was also fitted with disc brakes). Long-stroke oleos were used to cushion vertical landings.[The robust gear was able to withstand a descent rate of 18 ft (5.5m) per second.

Constructed at Short's Belfast factory in Northern Ireland, the SC.1 first undertook initial engine runs at this facility. After being transported by sea to Britain, the prototype (fitted only with the propulsion engine) was delivered to the Royal Aircraft Establishment at Boscombe Down. The first conventional takeoff and landing (CTOL) flight was made on 2 April 1957. Just over a year later the second prototype made the first tethered vertical flight was made on 26 May 1958, followed on 25 October of that year by the first free vertical flight. The first in-flight transition was made on 6 April 1960.

The SC.1 was shown at the Farnborough Airshow in 1960 and the Paris Air Show in 1961. Due to a malfunction of the controls, the second test aircraft crashed in Belfast on 2 October 1963, killing the pilot, J.R. Green. The aircraft itself was rebuilt for further testing.

The SC.1 flew for over ten years, providing a great deal of data that influenced later design concepts such as the "puffer jet" controls on the Hawker Siddeley P.1127, the precursor of the Hawker Siddeley Harrier. The work relating to vertical takeoff and landing techniques was also invaluable.

The first SC-1 (XG900) was used until 1971 for VTOL research and is now part of the Science Museum's aircraft collection at South Kensington, London. The second SC-1 (XG905) can be seen at the Flight Experience exhibit at the Ulster Folk and Transport Museum, Cultra, Northern Ireland
General characteristics
  • Crew: 1
  • Length: 25 ft 6 in (7.77 m)
  • Wingspan: 23 ft 6 in (7.16 m)
  • Height: ft in (m)
  • Wing area: 211.5 ft² (19.65 m²)
  • Empty weight: 6,260 lb (32,839 kg)
  • Loaded weight (CTOL): 8,050 lb (3,650 kg)
  • Loaded weight (VTOL): 7,700 lb (3,490 kg))
  • Powerplant: ×
  • * Powerplant:
    • Lift: 4× Rolls-Royce RB108 turbojets, 2,130 lbf (9.47 kN) each
    • Forward flight: 1× Rolls-Royce RB108 turbojets, 2,130 lbf each
  • Maximum speed: 246 mph (214 knots, 396 km/h)
  • Range: 150 mi (130 NM, 240 km)
  • Service ceiling: ft (m)
  • Wing loading: 38.1 lb/ft² (186.0 kg/m²)
  • Thrust/weight (CTOL): 0.265
  • Thrust/weight (VTOL): 1.11

    The Ryan X-13A-RY Vertijet

    The Ryan X-13A-RY Vertijet, Ryan Model 69, was an experimental Vertical Take-Off and Landing aircraft flown in the United States in the 1950s. The main objective of the project was to demonstrate the ability of a pure jet to vertically takeoff, hover, transition to horizontal forward flight, and vertically land.
    Just after World War II, Ryan engineers wondered whether the Ryan/U.S. Navy FR-1 Fireball, which had a thrust-to-weight ratio of 1 at low fuel quantities, would take off vertically. The Navy's Bureau of Aeronautics in 1947 awarded Ryan a contract to investigate the development of a vertically launched jet fighter. This was part of a program to evaluate the feasibility of submarine-based aircraft. Ryan conducted remote controlled VTOL tethered rig tests from 1947 to 1950 and a flying rig in 1951. Ryan was awarded an Air Force contract in 1953 to develop an actual flying jet-powered VTOL aircraft, which was given the designation X-13. Two prototypes were built.

    The Ryan X-13 Vertijet was 23 ft 5 in (7.14 m) long. It was just large enough to accommodate the single place cockpit (with a tilted seat) and the 10,000 lbf (45 kN) thrust Rolls-Royce Avon turbojet. The high mounted delta wing of the aircraft had a wingspan of only 21 ft (6.4 m) and was capped with flat endplates. The nose of the aircraft had a hook on the underside and a short pole for gauging distance from the trailer. The hook was used to hang the Vertijet from the vertical trailer bed landing platform. After the aircraft was secured vertically, the trailer was lowered to horizontal and then used to transport the aircraft on the ground. Pitch and yaw control in hover were provided by vectored engine thrust. Roll control was provided by "puffer" jets (also known as 'jet reaction control') mounted outboard of the wingtip endplates. The first prototype (#54-1619) was fitted with temporary landing gear and made its first horizontal flight on December 10, 1955. Later, it made full horizontal to vertical attitude conversions and back again at altitude. The first prototype then had the landing gear replaced with a tail mounted framework that held it in a vertical attitude on the ground. Using this rig, hooking practice was conducted. The second prototype (#54-1620), on April 11, 1957, made a vertical take-off from the vertically raised trailer, transitioned to horizontal flight and back again. It then returned to the vertical trailer and landed by hooking the landing wire. Flight tests were performed by Ryan's Chief Test Pilot Peter F. 'Pete' Girard.

    On July 28-July 29, 1957, the X-13 was demonstrated in Washington, D.C. It crossed the Potomac River and landed at the Pentagon.

    The Air Force chose not to continue development of the Ryan X-13 Vertijet because of the lack of an operational requirement.

    The X-13 was designed to investigate vertical takeoff, horizontal flight transition, and return to vertical flight for landing. The first prototype of the X-13 was equipped with temporary tricycle landing gear. The X-13 was flown conventionally on December 10, 1955 to test its aerodynamic characteristics. The Vertijet was then fitted with a temporary "tail sitting" rig. On May 28, 1956, it was flown from the ground in a vertical position to test its hovering qualities. The X-13 VertiJet completed its first full-cycle flight at Edwards AFB, California on April 11, 1957, when it took off vertically from its mobile trailer, angled over into a horizontal attitude, and flew for several minutes. The X-13 then transitioned to vertical flight and slowly descended back onto its trailer and landed.

    The two X-13 aircraft are now on display at aviation museums.
    • The Vertijet which made the full-cycle flight on April 11, 1957 (#54-1620), was transferred to the National Museum of the United States Air Force, Dayton, Ohio in May 1959.[1] It is on display in the Museum's Research and Development Hanger.
    • Prototype #54-1619 is on display at the San Diego Air & Space Museum.

    Aircraft serial numbers

    • X-13 #1 - USAF 54-1619
    • X-13 #2 - USAF 54-1620
    General characteristics
    • Crew: one pilot
    • Length: 23 ft 5 in (7.14 m)
    • Wingspan: 21 ft 0 in (6.40 m)
    • Height: 15 ft 2 in (4.62 m)
    • Wing area: 191 ft² (17.8 m²)
    • Empty weight: 5,334 lb (2,424 kg)
    • Loaded weight: 6,730 lb (3,059 kg)
    • Max takeoff weight: 7,200 lb (3,272 kg)
    • Powerplant: 1× Rolls-Royce Avon turbojet, 10,000 lbf (44.6 kN)
    • Maximum speed: 350 mph (560 km/h)
    • Range: 192 miles (307 km)
    • Service ceiling: 20,000 ft (6,100 m)
    • Rate of climb: ft/min (m/min)
    • Wing loading: 35.2 lb/ft² (172 kg/m²)
    • Thrust/weight: 1.48

    The Bell X-2 "Starbuster

    The Bell X-2 "Starbuster was a research aircraft built to investigate flight characteristics in the Mach 2-3 range.
    Providing adequate stability and control for aircraft flying at high supersonic speeds was only one of the major difficulties facing flight researchers as they approached Mach 3. For, at speeds in that region, they knew they would also begin to encounter a "thermal barrier", severe heating effects caused by aerodynamic friction. Constructed of stainless steel and a copper-nickel alloy, and powered by a two-chamber XLR25 2,500 to 15,000 lbf (11 to 67 kN) sea level thrust throttleable rocket engine, the swept-wing Bell X-2 was designed to probe this region.
    Following launch from a modified B-50 bomber, Bell test pilot Jean "Skip" Ziegler completed the first unpowered glide flight of an X-2 at Edwards Air Force Base on 27 June 1952. Ziegler and aircraft #2 were subsequently lost on 12 May 1953, in an inflight explosion during a captive flight intended to check the aircraft's liquid oxygen system.[1][2]

    Lt. Col. Frank K. "Pete" Everest (1920-2004) completed the first powered flight in the #1 airplane on 18 November 1955 and, by the time of his ninth and final flight in late July the following year, he had established a new speed record of Mach 2.87 (1,900 mph, 3050 km/h). The X-2 was living up to its promise, but not without difficulties. At high speeds, Everest reported that its flight controls were only marginally effective. High speed center of pressure shifts along with fin aeroelasticity were major factors. Moreover, simulation and wind tunnel studies, combined with data from his flights, suggested that the airplane would encounter very severe stability problems as it approached Mach 3.

    A pair of young test pilots, Captains Iven C. Kincheloe and Milburn G. "Mel" Apt, were assigned the job of further expanding the envelope and, on 7 September 1956, Kincheloe became the first pilot ever to climb above 100,000 ft (30,500 m) as he flew the X-2 to a peak altitude of 126,200 ft (38,466 m). Just 20 days later, on the morning of 27 September, Mel Apt was launched from the B-50 for his first flight in a rocket airplane. He had been instructed to follow the "optimum maximum energy flight path" and to avoid any rapid control movements beyond Mach 2.7. Flying an extraordinarily precise profile, he became the first man to exceed Mach 3 that day, as he accelerated to a speed of Mach 3.2 (2,094 mph, 3,370 km/h) at 65,500 ft (19,960 m). The flight had been flawless to this point, but, for some reason, shortly after attaining top speed, Apt attempted a banking turn while the airplane was still well above Mach 3 (lagging instrumentation may have indicated that he was flying at a slower speed or perhaps he feared he was straying too far from the safety of his landing site on Rogers Dry Lake). The X-2 tumbled violently out of control and he found himself struggling with the same problem of "inertia coupling" which had overtaken Chuck Yeager in the X-1A nearly three years before. Yeager, although exposed to much higher vehicle inertial forces, as a result of extensive experience flying the X-1 was very familiar with its character, was able to recover. Unlike Yeager, Apt was unable to recover and both he and the aircraft were lost.

    While the X-2 had delivered valuable research data on high-speed aerodynamic heat build-up and extreme high-altitude flight conditions, this tragic event terminated the program before the National Advisory Committee for Aeronautics could commence detailed flight research with the airplane, and the search for answers to many of the riddles of high-Mach flight had to be postponed until the arrival, three years later, of the most advanced of all the experimental rocket planes, the North American X-15.

    Flight test program

    Two aircraft completed a total of 20 flights (27 June 1952 - 27 September 1956).
    • 46-674: seven glide flights, 10 powered flights, crashed 27 September 1956[2]
    • 46-675: three glide flights, destroyed 12 May 1953
    General characteristics
    • Crew: one, pilot
    • Length: 37 ft 10 in (11.5 m)
    • Wingspan: 32 ft 3 in (9.8 m)
    • Height: 11 ft 10 in (3.6 m)
    • Wing area: 260 ft² (24.2 m²)
    • Airfoil: 2S-50 bicon
    • Empty weight: 12,375 lb (5,600 kg)
    • Loaded weight: 24,910 lb (11,300 kg)
    • Max takeoff weight: 24,910 lb (11,300 kg)
    • Powerplant: 1× Curtiss-Wright XLR25 rocket engine, 15,000 lbf (67 kN)at sea level
    • Maximum speed: Mach 3.196 (2,094 mph, 3,370 km/h)
    • Service ceiling: 126,200 ft (38,466 m)

    The Fairey Delta 2 or FD2

    The Fairey Delta 2 or FD2 (internal designation Type V within Fairey) was a British supersonic research aircraft produced by the Fairey Aviation Company in response to a specification from the Ministry of Supply for investigation into flight and control at transonic and supersonic speeds.
    The design was a mid-wing tailless delta monoplane, with a circular cross-section fuselage and engine air-inlets blended into the wing roots. The engine was a Rolls-Royce Avon RA.14R with an afterburner. The Delta 2 had a very long tapering nose which obscured forward vision during landing, take-off and movement on the ground. To compensate, the nose section and cockpit drooped 10°, in a similar way to that used later on Concorde. Two aircraft were built: Serial numbers WG774 and WG777.

    The FD2 was used as the basis for Fairey's submissions to the Ministry for advanced all weather interceptor designs leading to the Fairey Delta 3 for the F.155 specification, but it never got past the drawing board stage.


    The first FD2 was aircraft WG774 which made its maiden flight on 6 October 1954, flown by Fairey test pilot Peter Twiss. On 17 November 1954, WG774 suffered engine failure on its 14th flight when internal pressure build-up collapsed the fuselage collector tank at 30,000 ft (9,100 m), 30 mi (50 km) from Boscombe Down. Fairey pilot Peter Twiss, ex-Fleet Air Arm, managed to glide to a dead-stick landing at the airfield. Only the nose gear had deployed, and the aircraft sustained damage that sidelined it for eight months. Twiss, who was shaken up by the experience but otherwise uninjured, received the Queen's Commendation for Valuable Service in the Air.

    The FD2 test programmme did not resume until August 1955.  On 10 March 1956 the aircraft broke the World Air Speed Record, raising it to 1,132 mph (1,811 km/h), an increase of some 300 mph (480 km/h) over the record set in August 1955 by an North American F-100 Super Sabre. It thus became the first aircraft to exceed 1,000 mph (1,600 km/h) in level flight. This record stood until December 1957 when it was surpassed by a McDonnell JF-101A Voodoo of the USAF.

    BAC 221

    The first Delta 2, WG774, was later rebuilt by British Aircraft Corporation (BAC), who had absorbed Fairey, in 1960 as the ogee-ogive wing form aircraft BAC 221. This was for aerodynamic research as part of the Concorde development programme. It featured a new wing, engine inlet configuration, a Rolls-Royce Avon RA.28, modified vertical stabiliser and a lengthened undercarriage to mimic Concorde's attitude on the ground. It flew from 1964 until 1973.


    WG774, in BAC 221 form, is now on display alongside the British Concorde prototype at the Fleet Air Arm Museum at Yeovilton. The second FD2, WG777, is preserved at the Royal Air Force Museum at RAF Cosford, alongside many other supersonic research aircraft.

    Fairey Delta 2

    World speed record holder WG774
    high-speed research aircraft
    National origin
    United Kingdom
    Fairey Aviation Company
    First flight
    6 October 1954
    1966 (WG777), 1973 (WG774)
    On Public Display
    Primary user
    Royal Aircraft Establishment
    Number built