M.Simons The World's Vintage Sailplanes 1908-45

THE AIRSPEED TERN

  A. Hessell Tiltman and Nevil Shute Norway, who had worked together on the design of the Vickers airship, R 100, under Barnes Wallis, decided in 1930 to set up a new company to build aircraft. They established the firm, Airspeed Ltd, with a workshop in an empty bus depot in York. Their first project was a high performance sailplane.
  The Airspeed Tern was far in advance of any other British sailplane design of that time. It had a 15.24 metre (50 ft) span cantilever wing, but instead of the usual German single-spar construction, it was built along orthodox powered aircraft lines with two spars, cross-braced. The thin plywood covering ahead of the front spar was intended only to give a smooth entry to the aerofoil, and took no torsional loads. The rest of the surface was fabric. The profile was Goettingen 549, as on Kronfeld’s Wien. There were no spoilers or airbrakes. Only the outer panels of the wing were detachable, the 1.5 metre wide centre section being built integrally with the fuselage. Rigging was quick and easy, the ailerons connecting automatically as the wings were put on. The tailplane and rudder were fabric covered and had the distinctive outlines that were to become characteristic of Airspeed designs.
  The fuselage was large, with plywood covered belly and sides, the upper decking ahead of and behind the wing being fabric covered over light stringers, very much like the construction of contemporary biplanes.
  Only two Terns were ever built and only one seems to have done much flying. A third was started but never completed by Airspeed, who later sold the parts to the Dart Aircraft Co at Dunstable. Soon after completion the prototype was soared by Carli Magersuppe, a German pilot then touring the country with Kronfeld at the invitation of the newly formed British Gliding Association. He flew 13.4 km, soaring along the cliffs from Ravenscar to Scarborough, and set a height record, for an English sailplane, of 250 metres. In spite of the attendant publicity, buyers did not come forward quickly. The only aircraft sold went to a group from the Southdown Club and it participated in the Balsdean gliding meeting held by the BGA east of Brighton on October 1931. In the following year, E. H. Mole borrowed the other Tern from Airspeed and with it tried to break the British duration record. He succeeded in setting a height record of 440 m.
  The Southdown Tern attended most of the British National Competitions from 1932 onward, but never distinguished itself. Potentially, the Tern was a fine sailplane and it must be concluded that it was ahead of its time in England. It was the glider pilots themselves who were not yet capable of using such an aircraft fully.
  Post war, the remains of the two Terns, the Southdown example and the one completed by Dart Aircraft, were purchased by Andy Coulson and one serviceable aircraft was made from the two, with some modifications, but after resale to a group of RAF pilots, nothing more was ever heard of it.

  Technical data:
  Tern: Span, 15.24 m. Wing area, 18.7 sq m. Aspect ratio. 12.44. Empty weight. 101 kg. Flying weight, 181 kg. Wing loading, 9.8 kg/sq m.