The de Havilland DH.52 was a single seat, high-winged glider produced as an entrant to a 1922 prize competition. Two were built but insufficient torsional stiffness in the wings lead to control problems and the DH.52 was rapidly abandoned.

Development

The DH.52 was de Havilland's only glider, built to compete for the £1000 prize in the Daily Mail Gliding Competition, held at Itford, Sussex

Sussex

Sussex , from the Old English Sūþsēaxe , is an historic county in South East England corresponding roughly in area to the ancient Kingdom of Sussex. It is bounded on the north by Surrey, east by Kent, south by the English Channel, and west by Hampshire, and is divided for local government into West...

 in 1922. It
was a high-wing monoplane with an aspect ratio

Aspect ratio

The aspect ratio of a shape is the ratio of its longer dimension to its shorter dimension. It may be applied to two characteristic dimensions of a three-dimensional shape, such as the ratio of the longest and shortest axis, or for symmetrical objects that are described by just two measurements,...

 of 11.4; the wing was wire braced, with pairs of wires from the keel to the front and rear wing spars at about ⅓ and ¾ span. Similar pairs of wires to a central
kingpost supported the weight of the wings and kept the bracing in tension. The kingpost consisted of two members, one from each wing spar at the centre line, meeting about 2 ft 9 in (840mm) above the wing. The resulting triangular structure appears to have been covered with cambric

Cambric

Cambric, pronounced , "one of the finest and most dense species of the cloth manufacture", is a lightweight plain weave cloth, originally from Cambrai, woven in greige, then bleached and piece-dyed, often glazed or calendered. Initially made from flax, then cotton in the 19th century, it is also...

. Unbalanced ailerons with an unusually large angular travel were fitted, in order to maintain control at low speeds.

The square section fuselage was built from cross braced spruce longerons and covered with 0.04 in (1 mm) plywood. At the nose these longerons curved together, giving the glider a slight boat-like look. The single seat cockpit was just in front and below the wing. There was a cambric fairing round the cockpit and also behind the wing to the tail, the latter made by stretching the material over a wire that ran from the wing mounting to the rear fuselage. The fin and generous rudder were a slightly pointed version of the characteristic de Havilland shape; the elevator area was also large compared with that of the fixed tailplane.

Two DH.52s were built. The first machine (competition no.4) had a single cross axle, strutted undercarriage for its first flight on 5 October 1922, but this was replaced by a pair of smaller wheels mounted close to the fuselage sides on an axle fixed to the lower longerons. The second (no. 33) had this undercarriage from the start.

Both aircraft flew in the competition on 16 October with rubber rope launches. They each flew for about 2½ mins, but both were damaged on landing. Both showed problems with lateral control, the wings twisting under the aileron loads, cancelling their effects. No. 33 was flying again three days later, now with wing warping to try to beat the control problems, but the wing twisted so much after tow release that the centre section failed and the aircraft was lostFlight, November 1922 The pilot was not seriously hurt, but it was clear the torsional stiffness of the wing was insufficient and nothing could be done about within the competition time limits, so no more flights were made and the two DH.52s were scrapped.

Specifications