The Short SB.1 was a British tailless glider designed by

David Keith-Lucas David Keith-Lucas (25 March 1911 – 6 April 1997) was a British aeronautical engineer. Early life David Keith-Lucas was one of the sons of Alys Hubbard Lucas and Keith Lucas, who invented the first aeronautical compass. After the death of K ...

and Professor

Geoffrey T.R. Hill Geoffrey Terence Roland Hill, (1895 – 26 December 1955) was a British aviator and aeronautical engineer. Early life Geoffrey Terence Roland Hill was born in 1895, the son of Michael J. M. Hill, Professor of Mathematics at the University Colle ...

. Built by Shorts as a private research venture to test the concept of the aero-isoclinic wing, it was the first aircraft to incorporate this feature. It was in effect a one-third scale glider version of Keith-Lucas' ambitious preliminary design P.D.1, intended to meet the Air Ministry's (

V bomber The "V bombers" were the Royal Air Force (RAF) aircraft during the 1950s and 1960s that comprised the United Kingdom's strategic nuclear strike force known officially as the V force or Bomber Command Main Force. The three models of strategic ...

) specification B.35/46, which was the basis for the Avro Vulcan, the Handley-Page Victor and the

Vickers Valiant The Vickers Valiant was a British high-altitude jet bomber designed to carry nuclear weapons, and in the 1950s and 1960s was part of the Royal Air Force's "V bomber" strategic deterrent force. It was developed by Vickers-Armstrongs in response ...

Design and development

After extensive testing with wind-tunnel and flutter models, the design team proposed that a manned glider be built.Gunston 1977, p.512. Shorts (Belfast) undertook construction on a single-seat glider incorporating the "aero-isoclinic" wing originated by Professor Hill. This radical wing configuration was designed to maintain a constant

angle of incidence Angle of incidence is a measure of deviation of something from "straight on" and may refer to: * Angle of incidence (aerodynamics), angle between a wing chord and the longitudinal axis, as distinct from angle of attack In fluid dynamics, ang ...

regardless of flexing, by placing the torsion box well back in the wing so that the air loads, acting in the region of the quarter-

chord Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...

line, have a considerable moment arm about it. The torsional instability and tip stalling characteristics of conventional

swept wing A swept wing is a wing that angles either backward or occasionally forward from its root rather than in a straight sideways direction. Swept wings have been flown since the pioneer days of aviation. Wing sweep at high speeds was first investigate ...

s were recognised at the time, together with their tendency to aileron-reversal and

flutter Flutter may refer to: Technology * Aeroelastic flutter, a rapid self-feeding motion, potentially destructive, that is excited by aerodynamic forces in aircraft and bridges * Flutter (American company), a gesture recognition technology company acqu ...

at high speed. It was to prevent these effects that the aero-isoclinic wing was designed. The SB.1 glider was designed to be an inexpensive, simple machine, constructed primarily of spruce with reinforced sections using light alloy steel. The all-important wing controls had "elevons" pivoted on long, tapered light-alloy tubes extending from the leading edge of the tip, just inside the fixed part of the wing (illustrated by photographs in the

Short SB.4 Sherpa The Short SB.4 Sherpa was an experimental aircraft designed and produced by the British aircraft manufacturer Short Brothers. Only a single example was ever produced. The Sherpa was developed during the 1950s for the purpose of testing a nove ...

article). The pivoting mechanism had a double-ball bearing unit on the inboard end with main loads transferred to a needle roller bearing at the outboard end of the fixed wing. Anti-balance tabs were fitted along trailing edges along with small pneumatically actuated flaps under the inboard sections. When the elevons were rotated in the same direction they functioned as elevators; when rotated in opposite directions they functioned as ailerons.

Testing

After final construction at Aldersgrove, the Shorts SB.1 bearing Class B registration G-14-5 was readied for flight testing early July 1951. For the first flight on 14 July 1951, the SB1 was winch-launched and the gliding characteristics were found by Shorts' Chief Test Pilot

Tom Brooke-Smith Tom or TOM may refer to: * Tom (given name), a diminutive of Thomas or Tomás or an independent Aramaic given name (and a list of people with the name) Characters * Tom Anderson, a character in ''Beavis and Butt-Head'' * Tom Beck, a character ...

("Brookie") to be satisfactory. A further successful test flight on 15 July 1951 was followed by the first towed launch from RAF Aldergrove on 30 July 1951. The SB.1 was towed behind a Short Sturgeon TT2 (VR363) piloted by "Jock" Eassie to a height of 10,000 ft, the height of the release. Although Brooke-Smith experienced turbulence inherent in flying a light aircraft in the wake of the towing aircraft, the subsequent test flight was completed successfully. During the second flight of the day (using a longer towline intended to alleviate the turbulence), the test pilot encountered severe buffeting problems and he had to cast off at low altitude. The flight ended catastrophically when Brooke-Smith attempted to side-slip out of the wake and struck the ground "nose-down" at 90 mph, injuring himself seriously and heavily damaging the aircraft. During his recovery, Brooke-Smith expressed concerns about the towed launches and was adamant that testing the SB.1 required a new approach. The Shorts company persevered with the project, redesigning the aircraft six months later. The new design retained the wings and tail of the SB.1 but (at Tom Brooke-Smith's insistence) featured two small turbojet engines housed in a new, light-alloy fuselage. The result was the

Specifications (SB.1)

Short SB-1 tail-less aero-isoclinic wing

Notes

Bibliography

* *Buttler, Tony and Jean-Louis Delezenne. ''X-Planes of Europe: Secret Research Aircraft from the Golden Age 1946-1974''. Manchester, UK: Hikoki Publications, 2012. * Barnes, C.H. with revisions by James, Derek N. ''Shorts Aircraft since 1900''. London: Putnam, 1989 (revised). . * Gunston, Bill. "Short's Experimental Sherpa." ''Aeroplane Monthly Vol. 5, no. 10, October 1977.'' p. 508–515. * ''Short SB4 Sherpa RAF (EJA18c philatelic cover)''. Croydon, Surrey, UK: Aviation Collectibles

Access date: 1 February 2007. *

External links