Engineering:Slingsby Kirby Tutor

Short description: British single-seat glider, 1937

T.8 Kirby Tutor (Cadet TX.2)
Role	Sport Glider
National origin	United Kingdom
Manufacturer	Slingsby Sailplanes
Designer	John Sproule
First flight	1937
Number built	T.8 Kirby Tutor - ca 44 (+kits and wing sets) T.8 Cadet TX Mk.2 - 62
Developed from	Slingsby T.7 Kirby Kadet and BAC VII
Variants	Slingsby T.29 Motor Tutor

The Slingsby T.8 Kirby Tutor was a single-seat sport glider produced from 1937, by Fred Slingsby in Kirbymoorside, Yorkshire.

Design and development

The T.8 Kirby Tutor (a.k.a. Taper-wing Kadet) came about at the request of the Midland Gliding Club which wanted a higher performance aircraft to progress to after the T.7 Kirby Kadet. John Sproule adapted the wings from a BAC VII to fit onto the T.7 Kirby Kadet fuselage. The higher-aspect ratio wings gave a measurable increase in performance for minimum cost. Gliding clubs could also elect to buy the wings alone and fit them to Kirby Kadet fuselages as required. Post-war the absence of spoilers was rectified by a modification which was applied to most surviving aircraft.

History

The T.8 Kirby Tutor was immediately popular but only seven complete aircraft were sold before the outbreak of World War II, as well as kits of parts, spares and sets of wings (for retrofit to T.7 Kirby Kadets). The T.8 Tutor was also produced for use by the Air Training Corps, being renamed Slingsby T.8 Cadet TX Mk.2. Sixty-two Cadet TX Mk.2s were ordered from 1944 with simple windscreens and landing wheels.

Postwar Slingsby sub-contracted Martin Hearn Ltd. to build 25 new T.7 Kirby Kadets and 25 new T.8 Kirby Tutors as well as about a dozen more at Kirbymoorside. The interchangeability of the components led to many hybrid aircraft having wings and fuselages of all types mixed together. During the 1960s the numbers dwindled, especially when an urgent inspection of the main-spars was called for. The cost of the inspection and resultant rectification work often exceeded the value of the aircraft, with many being withdrawn from use. An example is on display at the Gliding Heritage Centre.

Operators

United Kingdom

Air Training Corps

Specifications

Data from British Gliders and Sailplanes 1922-1970, and The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde

General characteristics

• Crew: 1
• Length: 20 ft 11 in (6.37 m)
• Wingspan: 43 ft 5 in (13.24 m)
• Wing area: 170.0 sq ft (15.79 m²)
• Aspect ratio: 11
• Airfoil: Göttingen 426
• Empty weight: 353 lb (160 kg) equipped
• Max takeoff weight: 570 lb (258.5 kg)

Performance

• Stall speed: 30 mph (49 km/h, 26 kn)
• Never exceed speed: 90 mph (145 km/h, 78 kn)
  
• Aerotow speed: 70 mph (110 km/h; 61 kn)
• Winch launch speed: 66 mph (106 km/h; 57 kn)
• g limits: +6
• Rate of sink: 175 ft/min (0.89 m/s) at 34 mph (55 km/h; 30 kn)
• Lift-to-drag: 18 at 39 mph (63 km/h; 34 kn)
• Wing loading: 3.4 lb/sq ft (16.4 kg/m²)

See also

• Slingsby Kirby Cadet

Aircraft of comparable role, configuration and era

• BAC VII

Related lists

• List of gliders

References

Bibliography

• Shenstone, B.S.; K.G. Wilkinson; Peter Brooks (1958) (in en, fr, de). The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs dans Le Monde (1st ed.). Zurich: Organisation Scientifique et Technique Internationale du Vol a Voile (OSTIV) and Schweizer Aero-Revue. pp. 120–125. 
• Bridgman, Leonard (1956). Jane's All the World's Aircraft 1956-57. London: Jane's All the World's Aircraft Publishing Co. Ltd. 

Further reading

• Ellison, Norman (1971). British Gliders and Sailplanes. London: A & C Black Ltd. ISBN 0-7136-1189-8. 
• Simons, Martin (1996). Slingsby Sailplanes (1st ed.). Shrewsbury: Airlife. pp. 162–167. ISBN 1-85310-732-8.