Scheibe SF-28 Tandem Falke
The Tandem-Falke is a development of the SF-25C Falke wth the two seats in tandem positioned over the wings under a lengthened one-piece perspex canopy, instead of the side-by-side layout of the earlier Falke series. The Tandem-Falke can be flown solo from the front seat, with space for up to 198lb of baggage on the rear seat.
Design work on the SF-28 began in 1970 and the prototype, registered D-KAFJ, made its first flight in May 1971, powered by a 45hp Stamo MS 1500 modified Volkeswagen engine. The production SF-28A has a 65hp Limbach SI 1900EA1 engine, the same as fitted to the SF-25C Falke but fitted to drive a Hoffman two-blade variable-pitch feathering propeller; a fixed-pitch prop was available as an option and the fuel capacity totals 8.8 Imp gallons. Full electric system and starter were standard equipment.
Scheibe SF-28A Tandem-Falke
The type has the same basic wooden construction with fabric covered welded steel tube fuselage as the SF-25 Falke series; both wing span and length are slightly greater than the SF-25C's, the fin and rudder are now unswept. The single-spar wooden wings have spoilers in the upper surfaces and no flaps; there is an outrigger stabilising wheel on a nylon leg under each wing, as well as a faired non-retractable monowheel with internal brake and a steerable tailwheel. There is a trim tab in the elevator.
Altogether 112 Tandem-Falkes had been built by January 1980 and the Tandem-Falke has competed in the German Motor Glider Competition. In 1973, SF-28A’s took the first four places in the two-place class of the international motorglider contest at Burg Feuerstein in Germany. One flown by Peter Ross set up two United Kingdom records for motor gliders in 1976.
SF-28A Tandem Falke
Tandem Falke SF-28A
Engine: 48 kW/ 65 bhp Limbach SL 1700 EA
Wing span: 16.28m / 53.4ft
Wing area: 18.49 sq.m / 199 sq.ft
Length: 27 ft 3 in
Height: 5 ft 1 in
Empty Weight: 410kg / 903lb
Payload: 200kg / 441lb
Gross Weight: 610kg / 1344lb
Wing Load: 32.99kg/sq.m / 6.75lb/sq.ft
Aspect ratio: 14.5
Max speed: 118 mph (in smooth air, power off)
Max cruising speed: 87 mph
MinSink: 0.90 m/s / 2.95 fps / 1.75 kt at 43.5 mph
L/DMax: 26 @ 85 kph / 46 kt / 53 mph
Take-off run: 575 ft
Climb rate: 450 fpm
Range with max fuel: 261 miles
Structure: steel-tube/ fabric fuselage, wood/ fabric wings and tail.