Engineering: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
- ↑ 1.0 1.1 1.2 1.3 1.4 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. http://www.flightglobal.com/pdfarchive/view/1972/1972%20-%200811.html.
- ↑ "List of SF-27s". http://www.sf27.de/.
- ↑ 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.
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