Scheibe SF-27

The Scheibe SF-27 Zugvogel V (Migratory Bird) is a single-seat Standard Class sailplane, 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 sailplane, 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 structurally in wings and fuselages, the SF-27 only used it to cover the forward fuselage.

The wing of the SF-27 is built around a single beechwood boxspar, with plywood ribs and a leading edge torsion box. 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 Plexiglas canopy, 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 115 mm 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)