Scheibe SF-27

SF-27 Zugvogel V
Role	Single seat Standard Class Sailplane
National origin	Germany
Manufacturer	Scheibe-Flugzeugbau-gmbh, Dachau
First flight	12 May 1964
Number built	about 120
Developed from	Scheibe Zugvogel

The Scheibe SF-27 Zugvogel V (English: 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.^[1]

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.^[1]

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.^[1]

The SF-27 first flew on 12 May 1964. 30 had been built by February 1966,^[1] 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 millimetres (4.5 in) longer, with a best glide ratio 32:1.^[2]

Operational history

Around 58 of the original 120 Sf-27s are still active in 2010, including several SF-27Ms.^[3]

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)^[4]

Specifications (SF-27A)

Data from Jane's All the World's Aircraft 1966/7^[1]

General characteristics

Crew: 1
Length: 7.05 m (23 ft 2 in)
Wingspan: 15.0 m (49 ft 3 in)
Wing area: 12.99 m² (139.8 sq ft)
Aspect ratio: 18.6
Airfoil: Wortmann FX 61-184 at root, FX 60-126 at tip
Empty weight: 215 kg (474 lb) equipped
Max takeoff weight: 330 kg (728 lb)

Performance

Stall speed: 55 km/h (34 mph, 30 kn)
Maximum glide ratio: 34:1 at 88 km/h (55 mph)
Rate of sink: 0.64 m/s (126 ft/min) best, at 74 km/h (46 mph)

References

Notes

^ ^a ^b ^c ^d ^e Taylor, John W R (1966). Jane's All the World's Aircraft 1966-67. London: Sampson Low, Marston & Co. Ltd. p. 392.
^ "Private Aviation". Flight Magazine: 495. 1972-04-03.
^ "List of SF-27s". Retrieved 2011-01-13.
^ Taylor 1973, p. 543

Bibliography

Taylor, John W.R., ed. (1973). Jane's All the World's Aircraft 1973-74. London, United Kingdom: Jane's Yearbooks. ISBN 0-354-00117-5.

[JAWA66-1] Taylor, John W R (1966). Jane's All the World's Aircraft 1966-67. London: Sampson Low, Marston & Co. Ltd. p. 392.

[Flight-2] "Private Aviation". Flight Magazine: 495. 1972-04-03.

[active-3] "List of SF-27s". Retrieved 2011-01-13.

[Janes73-4] Taylor 1973, p. 543

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