Akaflieg Braunschweig SB-14

The Akaflieg Braunschweig SB 14 is an 18 m (59 ft) Open-class sailplane designed and built in Germany in the early 2000s.

SB 14
The SB-14 at ILA Berlin 2008
Role single seat sailplane
National origin Germany
Manufacturer Akaflieg Braunschweig
First flight 17 January 2003
Number built 1

Design and development

The SB 14 was designed to minimalist principles, reducing wetted area and use of high speed aerofil sections in a high aspect-ratio wing. As an economy measure, the tail unit of the Schleicher ASH 26 was utilised. To improve performance of the wing in a wide range of conditions, the wing-tips have swept wing-lets, as well as turbulators forward of the flaps on the undersurface of the wings.[1]

The SB 14 is a shoulder-wing sailplane constructed from carbon-fibre composite materials. The wings are of very high aspect-ratio and incorporate full span flaperons with slots for when the flaps are extended. The fuselage follows contemporary design practice with a cockpit pod and slender rear fuselage terminating in a T-tail. The cross section of the fuselage has been minimised throughout, reducing wetted area and therefore minimising drag.[1]

Control is through conventional elevator and rudder with full span slotted flaperons on the wings and Schempp-Hirth airbrakes on the upper surfaces at about 1/3 span. The undercarriage is a conventional retractable mono-wheel main undercarriage with a steel tipped rubber block tail-skid under the fin.[1]

Flight testing, from 17 January 2003, revealed very promising performance, optimised with various aero-dynamic refinements.[1]

Specifications (SB-14 prelim flight testing performance figures)

Data from [1]

General characteristics

  • Crew: 1
  • Capacity: payload (pilot + equipmqnt) 96 kg (212 lb) ; Water ballast 160 kg (350 lb)
  • Length: 6.95 m (22 ft 10 in)
  • Wingspan: 18.00 m (59 ft 1 in)
  • Height: 1.23 m (4 ft 0 in)
  • Wing area: 10.84 m2 (116.7 sq ft)
  • Aspect ratio: 29.89
  • Airfoil: root: CA2-134 / 15V2 ; tip: CAJ1-134 / 18
  • Empty weight: 285 kg (628 lb)
  • Max takeoff weight: 541 kg (1,193 lb)

Performance

  • Never exceed speed: 272 km/h (169 mph, 147 kn)
  • Minimum speed: 70 km/h (43 mph; 38 kn)
  • Maximum glide ratio: 50:1 (approx)
  • Rate of sink: 0.5 m/s (98 ft/min)
  • Wing loading: 33.9 kg/m2 (6.9 lb/sq ft) to 50 kg/m2 (10 lb/sq ft)

References
  1. "SB 14 – Akaflieg Braunschweig e.V." Akaflieg Braunschweig (in German). Retrieved 12 March 2019.
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