M.Hardy. Gliders & Sailplanes of the world

Slingsby T 21 Sedbergh

  Well known to several generations of ATC and gliding club members as the type on which they received their ab initio training, this big side-by-side two-seater was designed to meet the ATC's requirements for a simple ДальшеMore>>> dual control sailplane of medium performance and low price. The prototype, designated T21P, first flew in 1944 and had a wing span of 50ft 0in, and the first production version was the T21A for clubs and other civil customers, with the span increased to 54ft 0in, which first flew in April 1947. The T21B (originally designated T28) was the version of the T21A ordered for the ATC and known as the Sedbergh TX Mk 1 in Service use, being named after the famous Yorkshire public school; this first flew in December 1947. Altogether 121 civil T21As were built and 73 T21B Sedberghs for the ATC, plus 19 more T21Bs built under sub-contract by Martin Hearn Ltd, who had also built Cadets for Slingsby. Three more T21s were built outside - by the Midland Gliding Club, by Leighton Park School and by Mr J. Hulme, making a total, including prototypes, of 218 T21s; the 1948 price was £780. The Slingsby T33 was a projected version of the T21 of 1950 with cantilever instead of braced wings and an enclosed canopy, and this led a few years later to the rather similar T46 with the span increased to 56ft 6in, a braced wing with air brakes but no flaps, an enclosed cockpit and a revised tail unit similar to the T45 Swallow's. The prototype T46 first flew in October 1957 but the type did not go into production. One example of the T21C, a slightly modified T21A with enclosed cockpit was however, built for use by Slingsby.
  Of conventional wood and fabric construction, the T21 has a single-spar pylon-mounted braced wing with a leading edge torsion box and a light secondary spar to carry the ailerons; there is fabric covering aft of the main spar, and spoilers are fitted in the wing upper surfaces. The forward portion of the fuselage back to the two main wing attachment frames is a wooden stressed skin structure, and the centre and rear portions are of fabric-covered girder construction. The tailplane is braced and the rudder and elevators fabric-covered. Landing gear consists of a large non-retractable monowheel with a nose skid in front of it, and a sprung tailskid. The two pilots sit side-by-side in an open cockpit with dual controls, and with two small windscreens ahead of them; the spoiler lever, cable quick-release and trimming controls are positioned on a console between the two pilots.


Data: T21B
Span: 54 ft 0 in
Length: 26 ft 8 in
Wing area: 260.5 sq ft
Aspect ratio: 11.2
Empty weight: 589 lb
Max weight: 1,047 lb
Max speed: 105 mph
Min sinking speed: 2.79 ft/sec at 38.5 mph
Best glide ratio: 21:1 at 43 mph



Slingsby T 30 Prefect

  This single-seat intermediate trainer is basically an updated and improved version of the Grunau Baby, of which Slingsby had built a small number under licence before the war as the T5 Baby. The Prefect, which first flew in prototype form in June 1948, is semi-aerobatic and suitable for cloud flying and cross-country flights. Of conventional wood and fabric construction, it has a braced wing with air brakes but no flaps, and a nose skid under the forward fuselage just ahead of the non-retractable monowheel; there is also a tailskid, and the tailplane is braced. The pilot sits in an open cockpit and has a small windscreen. Altogether 30 Prefects were built for clubs and other civil users, and 16 for the ATC as the T30A Prefect TX Mk 1 (WE979 to WE993 and WG783). Prefect WG783 was initially delivered with camera mounting fittings and flaps fixed in the down position for the second stage of carrier wake trails, which involved flying a glider from the deck of an aircraft carrier to investigate characteristics of the wake over the flight deck.


Span: 45 ft 0 in
Length: 21 ft 3 1/2 in
Height: 4 ft 2 in
Wing area: 154 sqft
Aspect ratio: 13.2
Empty weight: 390 lb
Max weight: 587 lb
Max speed: 100 mph
Min sinking speed: 2.75 ft/sec
Best glide ratio: 21:1