Short S.C.1 by Pro Resin

1/72 scale
Kit No. R72-046
Cost: $28.00
Decals: One version – XG900 experimental aircraft
Comments: All resin kit; photo-etch details; vacuform canopy

History

The Short S.C. 1 was an experimental research aircraft developed in the 1950’s to explore the feasiblity of VTOL (vertical take-off and landing) technology. The success of the program led to the development of the Hawker Siddeley Kestrel, evolving into the revolutionary Hawker Siddeley Harrier, which drew worldwide attention during the 1982 Falklands War as the Harrier “jump jet,” a rather crude term that simultaneously summarized and somehow vaguely belittled an impressive technological achievement.

While it took flight for the first time on April 2, 1957, the prototype S.C. 1 was three years in development. In 1954 Dr. A.A. Griffith, Chief Scientist at Rolls Royce Limited, began development of a lightweight lift turbojet intended to make a then undesignated aircraft achieve vertical takeoff — the Rolls Royce RB 108. As Dr. Griffith put the boffins to work in the Rolls Royce lab, the Ministry of Supply was issuing Specification ER. 143, calling for a small vertical take-off aircraft capable of lifting off with vertically mounted engines, but also capable of accelerating forward into normal cruising flight once airborne with an independent, rearward-directed turbojet.

Griffith set the goal for the RB 108 to have a thrust-to-weight ratio of 8:1 (compared to the Rolls Royce Avon turbojet’s ratio of 3:1). Short Brothers & Harland submitted a small, delta-winged aircraft design featuring four vertically mounted RB 108’s grouped around the airplane’s center of gravity, with a fifth RB 108 pointing aft out of the tail. The fifth turbojet was not fitted on a true horizontal plane, however — due to the RB 108’s lubrication system, which required vertical positioning to function properly, the rear engine was inclined sharply within the airframe, but still provided sufficient thrust for conventional forward flight. Short’s submission was accepted and two protoypes (XG900 and XG905) were ordered in August 1954.

Although small (measuring 30 feet, 10 inches long, or 9.1 meters, with a wingspan of just 24 feet, 6 inches or 7.16 meters), the S.C. 1 was an exceptionally complex aeroplane, involving considerable development effort to perfect a three-axis autostabilizer (for vertical, horizontal, and lateral axes), powered controls, integrated reaction controls and specialized fixed landing gear. An analog computer was used in the design of the hydraulic and electronic control systems, which employed magnetic amplifiers in place of thermal electron emission valves. The fixed tricycle undercarriage could be raked forward to put the plane at the proper gound angle for conventional take-off, or moved to the classic vertical position for VTOL (vertical take-off and landing). It was decided to withstand a vertical velocity of 18 feet per second.

Flight Testing

First came a series of tethered hovering tests. These occurred while the S.C. 1 was attached via cable to a raised platform gantry with open-grid decking, to ensure proper circulation of gases and allow the vertical lift engines to operate at maximum efficiency. The flight testing then moved on to untethered tests with landings on unprepared ground, and eventually taking off from unprepared ground. One such test in November 1959 might have ended badly when there was an abundance of freshly mowed grass in the operating area at Farnborough. While hovering over the freshly cut grass, the S.C. 1’s downward jet wash caused the bits of grass to rise in clouds around it, and the debris guards over the lift engines, situated on the aircraft’s dorsal surface and just forward of the intake fan near the tail, quickly became clogged. Test pilot Tom Brooke-Smith noticed a loss of power and was forced to land rather quickly. That aborted test, which had been planned to run the S.C. 1 through accelerating and decelerating transition, was rescheduled and came off successfully on April 6, 1960.

The autostabilizer was a critical component of the aircraft, for it was designed to maintain stability in the form of a relatively level attitude in flight in the event one of the four main vertical lifting turbojets failed. It permitted instant reversion from automatic to manual control, and had a fail-safe design featuring three parallel-circuited channels so that a faulty signal by one channel would be overwhelmed by the other two until the pilot could assume manual control. Nonetheless, a fatal accident occurred on October 2, 1963 when a fault developed in the autostablizer’s gyro input of XG905, the second prototype. Test pilot J.R. Green, who had joined Short just four months earlier from the Royal Aircraft Establishment, immediately assumed manual control — but all three gyros failed to lock in position, diverging to their default positions. This gave a false vertical reference, causing the autostabilizer to somersault the aircraft and fly it into the ground, killing Green.

XG905 required extensive repairs, but returned in 1966 with a modified autostabilizer in which the gyros would always cage, or lock, under all combinations of attitude or acceleration. It also featured a pilot’s head-up display and a ground-air data link for all-weather and night trials with a Blind Landing Experimental Unit (BLEU).

The S.C. 1 was the first reliable VTOL aircraft to be produced anywhere in the world, despite its tragic 1963 accident. It left a legacy of research and experimental test flights allowing further progress to be made by other designers in the field of multiple-engine take-off and landing. While part of the motivation for this research was to make the technology available to commercial airliners, when this idea proved economically unfeasible, the potential for military applications remained. It was due largely to Rolls Royce’s decision to doggedly pursue VTOL research, often without governmental support, and to lobby the military, industrial and political interests which decided priorities and controlled purse strings, that the ultimate legacy of the S.C. 1 was the appearance of the Hawker Harrier.

The Kit

The first impression I had of this kit upon opening the box was pleasant surprise at the realization that it was nowhere near as complex as I had envisioned it to be. I was also relieved to see that there was relatively little flash, and that the instruction sheet is clear with easily understood illustrations, and a paint guide referencing Humbrol, Model Master, and Revell colors.

Pro Resin’s Short S.C. 1 consists of just 34 parts crisply cast in pale yellow resin, and a photo-etch fret containing an additional 20 metal detail parts. Most notable of these is the instrument panel for the cockpit and the large mesh part forming the debri guard on the aircraft’s dorsal surface. In addition there are two clear vacuform parts (one part and one spare) for the S.C. 1’s large, bulbous canopy situated in the nose of the aircraft.

The exterior surfaces feature a high degree of engraved detail along both wings and fuselage, and there is ribbed detail for the internal fuselage surfaces of the engine compartment. The cockpit consists of a highly detailed two-sided resin insert which forms the floor and rear bulkhead. An equally detailed resin seat and control column are to be cemented onto this, along with photo-etch parts for the main instrument panel and a large side panel to the pilot’s right. There is a resin part for the main panel, onto which both a film insert and the photo-etched part forming the face of the panel are cemented. Lastly in the cockpit are PE parts for rudder pedals, and for two smaller instrument panels on the pilot’s left.

The landing gear are highly detailed, as are the four vertical turbojets which form a total of eight resin parts, four for the main engines, and four for the detailed exhaust nozzles. There is a fifth, rearward-directed exhaust nozzle that has been cast along with the part fitting onto the aft end of the fuselage. The wings and tail all feature crisp engraved detail, but as this is a resin kit, there are no locator pins to assist in their placement. However, the surfaces onto which they must be cemented all feature smooth contact points — which some modelers may want to roughen a bit with some sanding to assist adhesion when the time comes. The decals are Pro Resin’s own brand and thin with rich, realistic color and are perfectly in register.

Conclusion

This is a great looking kit of an important VTOL aircraft that led to the development of the Hawker Harrier. Every kit has some surprises in store once you begin the build, but this one appears to be so well engineered that they will be minimal.
Highly recommended.

References

  • Harrier by Francis K. Mason (2nd Edition); Naval Institute Press, Annapolis; Copyright 1983
  • Virtual Aircraft Museum – www.aviastar.org

 

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