The Slingsby Type 34 Sky is a high performance single seat competition
sailplane
A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding (also called soaring). This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplan ...
built in the United Kingdom. It was successful in major events, particularly in the
World Gliding Championships
The World Gliding Championships (WGC) 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 ...
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
DFS Weihe
The DFS Weihe (English: ''Harrier'') is a German single-seat, high-wing, 18 metre wingspan, high-performance glider that was designed by Hans Jacobs in 1937-38.
Design and development
Jacobs designed the Weihe to be the pre-eminent performance ...
, the Gull's successor would need 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.
[''Flight'' 14 September 1951 p.356](_blank)
/ref> 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, 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 carries 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
The Festival of Britain was a national exhibition and fair that reached millions of visitors throughout the United Kingdom in the summer of 1951. Historian Kenneth O. Morgan says the Festival was a "triumphant success" during which people:
...
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.[''Flight'' 3 August 1951 p.156](_blank)
/ref> More significant was their dominance of the World Gliding Championships
The World Gliding Championships (WGC) 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 ...
held the following year at Madrid
Madrid ( , ) is the capital and most populous city of Spain. The city has almost 3.4 million inhabitants and a metropolitan area population of approximately 6.7 million. It is the second-largest city in the European Union (EU), and ...
in Spain. Eight Skys were entered, five by the British team, two by Argentina and one by the Netherlands.[''Flight'' 11 July 1952 p.31](_blank)
/ref> 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.
/ref> Skys continued to do well in later Championships, with second place in both 1954
/ref> and 1956.
/ref>
A Swiss Sky was flown across the Alps from Bern
german: Berner(in)french: Bernois(e) it, bernese
, neighboring_municipalities = Bremgarten bei Bern, Frauenkappelen, Ittigen, Kirchlindach, Köniz, Mühleberg, Muri bei Bern, Neuenegg, Ostermundigen, Wohlen bei Bern, Zollikofen
, website ...
to Béziers
Béziers (; oc, Besièrs) is a Subprefectures in France, subprefecture of the Hérault Departments of France, department in the Occitania (administrative region), Occitanie Regions of France, region of Southern France. Every August Béziers hos ...
in France in 1955 by Hans Nietlispach, a distance of which still stands as the Swiss straight line record.
Survivors
Sixteen Skys were built; of these, six still fly in the UK, including the Swiss record holder, and one in the Netherlands
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, anthem = ( en, "William of Nassau")
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, subdivision_type = Sovereign state
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, established_title = Before independence
, established_date = Spanish Netherl ...
;[Sky list](_blank)
/ref> two others are under restoration. One Sky (EC-RAT) is a non-flying exhibit in the Museo del Aire (Spain)
Museum of Aeronautics and Astronautics ( es, Museo de Aeronáutica y Astronáutica), also known as Air Museum (), is an aviation museum located near of Madrid, is situated at Cuatro Vientos Air Base, Spain. The objective of the museum is to acqu ...
.Museo del Aire
/ref>
Variants
;T.34A Sky 1
:Sixteen aircraft built ostensibly to compete in World Gliding championships of the late 1940s and early 1950s.
;T.34B Sky 2
:Designed for the 1954 World Championships, the Sky 2 featured NACA 5-figure aerofoil sections, with square cut wing-tips and tail unit, but was not built.
Specifications
See also
References
Notes
Bibliography
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Further reading
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{{Slingsby aircraft
1950s British sailplanes
Sky
The sky is an unobstructed view upward from the surface of the Earth. It includes the atmosphere and outer space. It may also be considered a place between the ground and outer space, thus distinct from outer space.
In the field of astronomy, ...
Aircraft first flown in 1950
High-wing aircraft