Slingsby Gull

T.12 Gull
The sixth Gull I at Great Hucklow in 1949 when operated by the Derbyshire & Lancashire Gliding Club
Role	Glider
National origin	United Kingdom
Manufacturer	Slingsby Sailplanes
Designer	Fred Slingsby
First flight	March 1938
Number built	11

The Slingsby T.12 Gull was a British single-seat glider designed and built by Slingsby Sailplanes and first flown in 1938.

In the late 1930s the gliding movement in the UK did not receive the support from the government that was forthcoming in other European states. Fred Slingsby designed the Type 12 Gull to be relatively inexpensive and easy to fly in the hands of the inexperienced pilots in the UK. Slingsby had had a bad experience with the Type 9 King Kite entering incipient spins at low airspeed which was ascribed to the use of a NACA 4312 aerofoil section at the wing-tips, so he designed the Gull with a modified RAF 34 profile at the tips. The cause of the wing drop problem on the King Kite was later found to be inaccurate manufacture, but the Gull retained the modified RAF 34 section.

Construction of the Gull aircraft was of semi-monocoque wood and plywood throughout, with a mixture of plywood and fabric skinning and covering. The wings were skinned with plywood forward of the main spar to form torsion boxes which increased their rigidity. They had a distinctive gull wing form, as the inner 2 metres carried marked dihedral out to the attachment points of the lift struts to the wing spars. Beyond, the wings lacked dihedral. The rectangular planform of the inner wings included the gulled portion and 2 metres beyond, with spoilers in the upper surface outboard of the gull joint in some later aircraft. Ailerons filled the trailing edge of the tapered outer wings.

The cockpit was enclosed with a neatly faired multi-panel canopy which was removed for entry and egress. Ten Gulls were built, nine by Slingsby at Kirbymoorside and one by Herman Kursawe in the United States, from plans supplied by Slingsby.

The design was developed in 1939 to include what Slingsby called the cantilever Gull, designated as the T15. More commonly known as the Gull III, it had a slightly higher performance, and was fitted with spoilers on the upper surfaces of the wing. Built in 1939, it was not until January 1940 that the type first flew, and was such a success that Slingsby intended to put the type into production once the War was over.

With the tight post-war economy within Britain, gliders of simplified production quickly became a factor in being able to produce cost-effective sailplanes. This led to the Gull 4, which had a more conventional, less complicated straight wing.

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