The Slingsby Type 34 Sky is a high performance single seat competition sailplane

Glider (sailplane)

A glider or sailplane is a type of glider aircraft used in the sport of gliding. Some gliders, known as motor gliders are used for gliding and soaring as well, but have engines which can, in some cases, be used for take-off or for extending a flight...

 built in the United Kingdom. It was successful in major events, particularly in the World Gliding Championships

World Gliding Championships

The World Gliding Championships is a gliding competition held every two years or so by the FAI Gliding Commission. The dates are not always exactly two years apart, often because the contests are sometimes held in the summer in the Southern Hemisphere....

 of 1952.

Design and development

The single seat Slingsby Sky resulted from Slingsby's experience at the 1948 International Gliding Contests, where they flew their 15 m span Gull IV. This convinced them that to be competitive against aircraft like the German Weihe, the Gull's successor would have to have a span of 18 m or more. Consequently, the Sky was aerodynamically identical to the Gull IV apart from span (and hence aspect ratio) and length, though it differed in construction. It dominated the 1952 Contests and was well placed in both 1954 and 1956.

The Sky is a wooden aircraft, using the traditional spruce for stressed members and birch ply elsewhere. Its wing has a constant chord inner section over the first 30% of span, then tapers on both edges to a rounded tip. The 20% increase in span over the Gull IV was achieved with two extra rib bays in the inner part and a 2 in (51 mm) increase in rib separation outboard. The Sky was designed to meet semi-aerobatic requirements which together with an aspect ratio of 18.7, which was high for the time, required the single box spars, 6 in (152 mm) wide at their greatest, to be massive. Their weight is 25% of that of the whole aircraft. The wing ahead of this spar, positioned at 30% chord, forms a plywood covered torsion box. Behind it, the wing is fabric covered. Ailerons, divided to allow for wing flexure, fill the tapered trailing edges. Air brakes are mounted on the spars as aerodynamically balanced pairs above and below wing; the lower panel open into the airstream and lever the upper ones against it. There were no flaps.

The cockpit of the Sky is of standard Slingsby design and built on the same jigs as those used on the Gull IV and Kite II

Slingsby Kite

-See also:-References:* Ellison, N.H. British Gliders and Sailplanes 1922-1970. A & C Black, 1971* Simons, M. Slingsby Sailplanes. Airlife Publishing, 1996 - ISBN 1-85310-732-8...

, with a single piece perspex canopy hinged on the starboard side. It is placed immediately in front of the leading edge of the wing and the fuselage neck on which the wing is mounted. Behind the cockpit the fuselage is a semi-monocoque structure, with a stress bearing 1/16 in (1.6 mm) plywood skin formed over light frames positioned by three longitudinal stringers. There is additional strengthening around the wheel bay, where the single wheel has its axle held clear of the fuselage by small triangular pieces. An ash skid is mounted away from the fuselage, running forward to the nose. The wheel brake is applied at the greatest air brake extension. As a weight saving alternative to the mono-wheel, a jettisonable two wheel dolly can be used for take-off. Another ash skid at the rear forms a bumper. The tail unit was initially identical to that of the Gull IV: the tailplane has a ply covered leading edge and fabric behind, mounted forward of the ply covered fin so that the rudder hinge is in line with the trailing edge of the single piece, fabric covered elevator. The latter caries trim tabs.

The Sky first flew in September 1950. Trials led to readjustment of the centre of gravity and the replacement of the Gull IV rudder with an aerodynamically balanced one of greater chord. The airbrakes were also increased in area and their linkage revised to ensure the Sky did not exceed its design terminal speed in dives, and to make the brakes easier to close at higher speeds.

Slingsby designed an improved version of the Sky, designated Type 34B Sky 2 for the 1954 World Competition, but did not build it. It would have had laminar flow wings with square tips and a revised, squared off tail.

Operational history

The prototype Sky was one of the exhibits at the Festival of Britain

Festival of Britain

The Festival of Britain was a national exhibition in Britain in the summer of 1951. It was organised by the government to give Britons a feeling of recovery in the aftermath of war and to promote good quality design in the rebuilding of British towns and cities. The Festival's centrepiece was in...

 held in May 1951.

The first two Skys had immediate success in 1951 in the English championships held at Camphill, Derbyshire, coming in first and second. More significant was their dominance of the World Gliding Championships

World Gliding Championships

The World Gliding Championships is a gliding competition held every two years or so by the FAI Gliding Commission. The dates are not always exactly two years apart, often because the contests are sometimes held in the summer in the Southern Hemisphere....

 held the following year at Madrid

Madrid

Madrid is the capital and largest city of Spain. The population of the city is roughly 3.3 million and the entire population of the Madrid metropolitan area is calculated to be 6.271 million. It is the third largest city in the European Union, after London and Berlin, and its metropolitan...

 in Spain. Eight Skys were entered, five by the British team, two by Argentina and one by the Netherlands. One British Sky was forced to retire after the first day, but Final placings put all seven remaining Skys in the top fourteen out of thirty-nine, and they claimed first, third and fourth places. Skys continued to do well in later Championships, with second place in both 1954 and 1956.

A Swiss Sky was flown across the Alps from Bern to Béziers

Béziers

Béziers is a town in Languedoc in southern France. It is a sub-prefecture of the Hérault department. Béziers hosts the famous Feria de Béziers, centred around bullfighting, every August. A million visitors are attracted to the five-day event...

 in France in 1955 by Hans Nietlispach, a distance of 536.2 km (333.2 mi) which still stands as the Swiss straight line record.

Sixteen Skys were built. Of these, five still fly in the UK and one in the Netherland

Netherland

Netherland is a critically acclaimed novel by Joseph O'Neill. It concerns the life of a Dutchman living in New York in the wake of the September 11 attacks who takes up cricket and starts playing at the Staten Island Cricket Club.-Plot summary:...

s. Three others are under restoration and one of these (HB-561) the Swiss record holder, is expected to fly in 2011 in its original colour scheme from 1955. One Sky (EC-RAT) is a non-flying exhibit in the Museo del Aire (Spain).

Specifications