The Scheibe SF-27 Zugvogel V () is a single-seat Standard Class

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 ...

, designed and built in Germany in the 1960s. A motorised version was also produced. Significant numbers remain active.

Design and development

The SF-27 is a shoulder-wing, single-seat Standard Class

, succeeding the Scheibe Zugvogel IIIB in production. It was designed to 1960s Standard Class competition rules requiring a span of no more than 15 m and a fixed undercarriage. Built of wood and steel, its structure was conservative; at a time when many manufacturers were using

glassfibre Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...

structurally in wings and fuselages, the SF-27 only used it to cover the forward

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

. The wing of the SF-27 is built around a single

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boxspar, with

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ribs and a leading edge

torsion box A torsion box consists of two thin layers of material (skins) on either side of a lightweight core, usually a grid of beams. It is designed to resist torsion under an applied load. A hollow core door is probably the most common example of a torsio ...

. The wing covering is largely ply, entirely so over the outer section. The inner section is covered with ply from the leading-edge to behind the spar, the rest with a mixture of ply and fabric. Ailerons and Schempp-Hirth airbrakes are likewise ply covered. The cantilever horizontal tail is an all-moving ply and fabric-covered surface, set at the top of the fuselage; the fin is covered with ply and the rudder with fabric. The fuselage is a welded steel structure covered, from nose to wing trailing edge, with a glassfibre shell. The wing root fairing is also glassfibre. Further aft the fuselage is fabric covered over wooden stringers. The cockpit, within the glassfibre shell, has a single piece

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, the pilot sitting in a semi-reclined position. The SF-27 has a fixed monowheel undercarriage, fitted with brakes, plus a small tailwheel. The SF-27 first flew on 12 May 1964. 30 had been built by February 1966, the final total being about 120. Scheibe also produced a motorised version, the SF-27M, with a 26 hp (19 kW) 4-cylinder Hirth F-102 A2 two stroke engine on a retractable mast above the wing behind the cockpit. Its gross weight is increased to 386 kg (850 lb) and it is longer, with a best glide ratio 32:1.

Operational history

Around 58 of the original 120 Sf-27s are still active in 2010, including several SF-27Ms.

Variants

;SF-27A :Standard class sailplane. ;SF-27B :One-off 17 m span version. ;SF-27M :Motorised version. ;SLCA-10 Topaze :Licence built variant built in France by Société Lorraine de Constructions Aéronautiques (SLCA)

Specifications (SF-27A)

References

;Notes ;Bibliography * {{Scheibe aircraft 1960s German sailplanes SF-27 Shoulder-wing aircraft Aircraft first flown in 1964 Single-engined piston aircraft