LS-8t - High Performance Standard Class Sailplane

To be back again on the contest scene and to win over more top pilots, we had to think about our range of standard class sailplane.


What could we do to improve them?

Twist the performance screw again sounds very good. Viewing the scene revealed no guarantee for success by using new wing sections, derived by ingenious computer calculations and theoretical improvements of performance. Handling in turbulent air, manoeuvrability, sensitivity to rain and insects and last but not least gain in performance cannot be predicted.

So, where should we twist?

Wolf Lemke had the stirring idea. He remembered earlier flight tests with the LS6 and recommended further comparison flights with the LS6 and LS7 models, but under different conditions. We increased the wing angle of incidence compared to the fuselage to yield the correct in-flight wing position for thermalling and good take-off handling. We used the unmodified LS-6c flapped wing plus winglets for this optimum positioning. This comparison met our expectation completely. Differences in straight flight were promising. This modified LS6 could fly slower at a lower rate of sink and was advantageous in the range of best glide angle. To make sure that this modification was good enough to justify the otlay for the new model range, we decided to test this LS6 in a standard class contest with flaps fixed in one position. This plane caused a stir. It was superior compared to other standard class sailplanes and even the weight penalty of the flapped wing, resulting in about by 3-4 kg /m² increased wing loading, yielded no disadvantage even in weak conditions. The same impression resulted during the German Championships at Neustadt-Glewe. New for LS-sailplanes are the integral wing ballast tanks. Automatic coupling of all control systems is state of the art.

Construction


Much more Carbon is being used than in the past. The wings are fabricated of Carbon-sandwich-construction, as are the ailerons, winglets and horizontal stabilizer. The elevator utilizes both Carbon and Kevlar. Both Carbon and Kevlar allow manufacturing of lighter weight components. The strength to weight ratio of materials used in composite construction techniques is very important. This gives the designers of a component to make a part with equal strength and lighter weight, or a part that has the same weight and is therefore stronger, and any combination there-of. The sailplanes are still being constructed with the use of gel-coat as an exterior coating.
The manufacturing process, when observed from a distance, is quite simple. The fuselage is made in two halves, a left and right halve, then joined at a later time when interior components have been installed into one of the halves. The wings, ailerons, horizontal stabilizer and elevator follow a similar procedure, but they are fabricated with an upper and lower halve. After the parts are removed from the moulds they are finished by sanding, polishing etc. as required. The sailplane is then assembled to the specified work-order.


Standard Equipment for LS8t


o automatic control system connections
o retractable and sprung undercarriage
o C.G. hook, retractable with landing gear
o Nose hook
o adjustable rudder pedals, with feet operated wheel brake
o hinged forward canopy and instrument panel
o infinitely adjustable trim system
o oxygen flask receptacle
o radio antenna in vertical fin
o standard instrument panel
o double tapered wing
o 15 m winglets
o ready to use water ballast system, integral tanks
o upper surface, double height air brakes
o all control surface gaps sealed
o backrest including headrest
o pivot point at canopy rear for clean separation during canopy jettison
o total energy connection in vertical fin
o safety harness ( multiple point buckle type)
o registration, call sign, markings

***For a list detailing the options please go to the list contained in this web-page***






Tech Specs

Span

Wing Area

Aspect Ratio

Length

Width

Height

Empty Weight

Max. wing loading

Max. all up weight

Max. speed (Vne)

Min. speed (stall)

Glide ratio

15m

10.5 m²

21.43

6.72m

.64m

.80m

255 Kg

50.0 Kg/m²

525 Kg

280 Km/h

about 66 Km/h

about 43
49.2 ft

113.02ft²

21.43

22.05 ft

25 in

31.5 in

562 lbs

10.24 lbs/ft²

1157 lbs

151 kts

37 kts

18m

11.4 m²

29.13

6.72

.64m

.80m

265 Kg

46.05 kg/m²

525 Kg

280 Km/h

about 66 Km/h

about 49

59.05 ft

122.7 ft²

29.13

22.05 ft

25 in

31.5 in

584 lbs

9.43 lbs/ft²

1157 lbs

151 kts

37 kts