Akaflieg Braunschweig SB-5 Danzig

The Akaflieg Braunschweig SB-5 is a German single-seat Standard Class sailplane designed and prototyped by students of Brunswick University.[1] More than 100 were built to their design, in several different variants.[2]

SB-5
SB-5b
Role Single seat Standard Class glider
National origin West Germany
Manufacturer Fa Eichelsdörfer, Bamberg
First flight 3 June 1959
Number built 100+

Design

The Akaflieg Braunschweig or Akademische Fliegergruppe Braunschweig (English: The Brunswick Academic Flying Group) is one of some fourteen German undergraduate student flying groups attached to and supported by their home Technical University. Several have designed and built aircraft, often technically advanced and leading the development of gliders in particular.[3]

The SB-5 is a cantilever shoulder-wing monoplane with a plywood monocoque fuselage which has an outer fibre glass skin, a single spar wooden wing with plywood skinning, and a V-tail. Its wing, with a constant chord centre section and tapered outer panels,[4] has 2.50° of dihedral and Schempp-Hirth airbrakes at 50% chord. The pilot has an enclosed cockpit with a Plexiglass canopy and the landing gear is a non-retractable, unsprung monowheel with a tailskid.[1][2][5]

The SB-5 prototype first flew on 3 June 1959. A licence to build it went to Firma Eichelsdörfer at Bamberg, who produced more than 100 including all variants.[2] The first three variants, SB-5a-c detailed below, differed chiefly in their forward fuselages and canopy shapes and the last (SB-5e) by having an extended span[4]

Airworthiness directives

Luftfahrt-Bundesamt, the national civil aviation authority of Germany, has issued two airworthiness directives concerning the structure of the tail section of this glider. Both related to issues with frame components towards the rear of the fuselage: the first, dated 30 January 1986, required an immediate inspection of frame 25 for cracking; the second, issued on 11 July 1991, required the gluing of frame 26 to be reinforced. The UK Air Accidents Investigation Branch cited these directives in its investigation of an accident in Cumbria, England, on 7 August 2019, when the tail section of a model SB-5e broke away in turbulent air conditions, causing the loss of the aircraft.[6][7][8]

Operational history

In 2010, there were thirty seven SB-5s on the German civil register and one each on the Belgian and UK registers. Of these, eighteen were SB-5bs, twenty SB-5es and one a SB-5c.[9][10]

Variants
SB-5a
Original version, with a short, tear drop style canopy proud of upper fuselage line. Braking parachute, no air brakes. Only one, crashed June 1961.[4]
SB-5b
First production model. Lengthened forward fuselage with pilot in reclined seat under long canopy reaching forward almost to the nose and blended into fuselage line over wings. Airbrakes. Around 50 built.[4]
SB-5c
Second production model. Shorter canopy not reaching nose, ground clearance raised by placing monowheel in short fairing rather than directly within fuselage. Some GRP in fuselage. About 10 built.[4] First flown 1965.[2]
SB-5d
SB-5e
16 m (52 ft 6 in) span to meet Club Class rules. Entered production 1974,[2] with at least 20 built.
IPE SB-2
Between 1970 and 1980 two were built under license using local wood by IPE Aeronaves.[11]

Aircraft on display

Specifications (SB-5c)

Data from Jane's All the World's Aircraft 1966/7[5]

General characteristics

  • Crew: One
  • Length: 6.6 m (21 ft 8 in)
  • Wingspan: 15.00 m (49 ft 3 in)
  • Wing area: 13.00 m2 (139.9 sq ft)
  • Aspect ratio: 17.3
  • Airfoil: NACA 633618
  • Empty weight: 220 kg (485 lb) equipped
  • Max takeoff weight: 325 kg (717 lb)

Performance

  • Maximum speed: 200 km/h (120 mph, 110 kn) smooth air
  • Stall speed: 60 km/h (37 mph, 32 kn)
  • Maximum glide ratio: best 32.5:1 at 77 km/h; 42 kn (48 mph)
  • Rate of sink: 0.63 m/s (124 ft/min) minimum at 66 km/h; 37 kn (41 mph)
  • Wing loading: 23.1 kg/m2 (4.7 lb/sq ft) maximum

See also

Related lists

References

Notes
  1. Taylor 1973, p. 545
  2. Hardy 1982 pp.4-5
  3. Simons 2005 p.41
  4. Akademische Fliegergruppe Braunschweig e.V. "Akademische Fliegergruppe Braunschweig e.V". Akaflieg-braunschweig.de. Retrieved 19 July 2012.
  5. Taylor 1966 pp.389-90
  6. "AAIB Bulletin G-DEJH". Air Accidents Investigation Branch. Retrieved 25 March 2021.
  7. "Mögliche Risse im Rumpfspant Nr25" (PDF) (in German). Luftfahrt-Bundesamt. Retrieved 26 March 2021.
  8. "Rumpfspant Nr 26 Losleimungen" (PDF) (in German). Luftfahrt-Bundesamt. Retrieved 26 March 2021.
  9. Partington 2010
  10. GINFO Search Results, Access date 2012-07-19
  11. Andrade 1997, pp. 206–224
  12. Ogden 2009 p.198

Bibliography
  • Andrade, Roberto Pereira de (1997). Construção Aeronautica no Brasil 1910–1976. p. 206. ISBN 85-250-2137-7.
  • Hardy, Michael (1982). Gliders & Sailplanes of the World. London: Ian Allan Ltd. ISBN 0 7110 1152 4.
  • Ogden, Bob (2009). Aviation Museums and Collections of Mainland Europe. Air Britain (Historians) Ltd. ISBN 978 0 85130 418 2.
  • Partington, Dave (2010). European registers handbook 2010. Air Britain (Historians) Ltd. ISBN 978-0-85130-425-0.
  • Simons, Martin (2005). Sailplanes 1965-2000 (2nd revised ed.). Königswinter: EQIP Werbung & Verlag GmbH. ISBN 3-9808838-1-7.
  • Taylor, John W R (1966). Jane's All the World's Aircraft 1966-67. London: Sampson Low, Marston & Co. Ltd.
  • 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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