Rolladen-Schneider LS 4
Design work on this Standard Class sailplane began by Wolf Lemke in the winter of 1978 as the successor to the LS-1. The LS4 has a modified LS3-a GFRP/foam sandwich fuselage married to a new thin-section Wortmann mod. wing mounted in the mid position, and with a double taper planform, and a variety of rigging improvements. It has larger upper-surface double segment Schempp-Hirth type air brakes in the upper surfaces, but flaps are not fitted. The cantilever T-tail has separate elevators rather than an all-moving tailplane,and the retractable monowheel has rubber suspension and a cable-operated brake. There is a rubber bumper type tailskid with a semi-recessed tailwheel offered as an alternative. The pilot sits under a canopy that hinges upward and forward to open, and up to 140 litres of water ballast can be carried. The same glassfibre/foam sandwich construction as the LS3's is employed.
The prototype LS- 4, registered D-6680, first flew 28 March 1980. Production began in the autumn of that year and by the spring of 1981 50 LS4s had been built out of 160 on order.
The type took the first seven places in the Standard Class at the 1981 World (Gliding Championships at Paderborn, West Germany.
The improved LS-4a has an increased gross weight and ballast capacity and strengtened landing gear. LS-4s took the first 6 places (and 21 out of the first 25) in the Standard Class at the 1983 World Championships at Hobbs, NM.
Over 600 were built.
Span: 49 ft 2.5 in
Length: 22 ft 1 in
Area: 10.5 sq.m / 113 sq.ft
Aspect ratio: 21.4
Airfoil: Wortmann mod
Empty Weight: 238 kg / 525 lb
Payload: 234 kg / 515 lb
Gross Weight: 472 kg / 1040 lb
Wing Load: 44.9 kg/sq.m / 9.21 lb/sq.ft
Water Ballast: 140 kg / 308 lb
L/DMax: 40.2 102 kph / 55 kt / 63 mph
MinSink: 0.60 m/s / 1.97 fps / 1.17 kt at 51.5 mph