Akaflieg Braunschweig SB-10 Schirokko
The SB-10 Schirokko is an attempt to create a tandem two-seater sailplane of exceptional performance and aerodynamic refinement, and the choice of a high aspect ratio (36.6) wing of 29m (95ft 1.75in) span has enabled a best glide ratio of 53:1 and a minimum sinking speed of only 1.3ft/sec to be achieved.
Design of the SB-10 began in 1969 and it first flew in prototype form on 22 July 1972; it can also be flown with a wing of 26m (85ft 3.25 in) span instead of the 29m one. The wing structure is in five parts: the centre section is of plywood, balsa wood and carbon-fibre, while the outer wing panels and air brakes, as well as the wing tips, are the same as those of the SB-9 Nimbus, but of balsa wood and glassfibre construction with foam filling. Foam-filled carbon-fibre is used for the camber-changing flaps, which can be drooped in conjunction with ailerons; there are three of the latter each side on the 29m wing. The pod-and-boom type fuselage has a finely streamlined forward part, housing the pilots, tapering to a thin boom carrying the tail, and is a steel tube frame covered with a balsa/glassfibre sandwich shell and with light alloy at the rear. The tail unit is also of balsa/glassfibre sandwich construction and has a fixed incidence tailplane mounted low. The landing gear consists of an airassisted retractable monowheel with a hydraulic brake, and a tailskid. The landing gear, air brakes and rudder controls were later modified, and several other changes made, and in this form the SB-10 set up a German distance record of 577 miles on 16 April 1974.
The SB-10 was still used by the group for performance flights.
Wing span: 29m / 95 ft 1.75 in
Wing area: 22.95 sq.m / 247.1 sq.ft
Length: 33 ft 11.75 in
Empty Weight: 608kg / 1,272 lb
Gross Weight: 889kg / 1,978 lb
Wing Load: 40.8kg/sq.m
Aspect ratio: 36.64
Airfoil: FX 62-K-153
Max speed: 124mph
L/DMax: 48.5 @ 101 kph
Best glide ratio: 53:1 at 56mph
MinSink: 0.53 m/s / 1.3 ft/sec at 85 kph / 47mph
No. of Seats: 2
No. Built: 1