Rolladen-Schneider LS1
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| Type designation | LS1 |
| Competition class | Club (formerly Standard) |
| Number built | 23 (LS1-0/LS1-a/LS1-b) 198 (LS1-c/LS1-d) 3 (LS1-e) 240 (LS1-f) |
| Crew | 1 |
| Length | 6.80 m 7.20 m (LS1-f) |
| Height | 1.37 m 1.23 m (LS1-f) |
| Cockpit width | 0.60 m |
| Cockpit height | 0.80 m |
| Wingspan | 15 m |
| Wing area | 9.74 m² |
| Aspect ratio | 23.1 |
| Wing profile | FX 66-S-196 mod FX 66-S-196 V1 (LS1-f) |
| Empty mass | ca. 200 kg 210 kg (LS1-f) |
| Water ballast | 60 kg (LS1-d) 90 kg (LS1-f) |
| Maximum mass | 321 kg 341 kg (LS1-d) 391 kg (LS1-f) |
| Wing loading | ca. 33 kg/m² ca. 33 - 35 kg/m² (LS1-d) ca. 33 - 40 kg/m² (LS1-f) |
| Maximum speed | 220 km/h 240 km/h (LS1-d) 250 km/h (LS1-f) |
| Speed in turbulence | 220 km/h 240 km/h (LS1-d) 250 km/h (LS1-f) |
| Maneuver speed | 160 km/h 170 km/h (LS1-d) 190 km/h (LS1-f) |
| Minimum sink rate | ca. 0.63 m/s at 80 km/h ca. 0.62 m/s (LS1-f) |
| Best glide ratio | ca. 36 at 100 km/h ca. 37 (LS1-f) |
The Rolladen-Schneider LS1 is a Standard Class single seater glider manufactured by Rolladen-Schneider from 1968 to 1977.
History
The LS-1 Standard Class design was the first aircraft type arising from the partnership between Wolf Lemke and Walter Schneider, who had already worked together as students on the ground breaking Akaflieg Darmstadt D-36. Here, and in subsequent Lemke-Schneider (LS) designs, Wolf Lemke concentrated on the aerodynamics while Walter Schneider contributed mostly to the structural and production issues.The LS1 made its debut at the 1968 German National Championships, taking first and second place with the designers themselves at the controls. The success of this design increased in the subsequent years until, in 1975, it was the most flow glider in the German Nationals. The LS1 took first place in the 1970 World Championships at Marfa, Texas.
The manufacture of the LS1 was discontinued after the IGC introduced the new unrestricted 15 meter Class in the spring 1977, as the manufacturer needed all its resources to increase production of the LS3.
A total of 464 LS1 were built. It was succeeded by the LS2 and LS4.
Design
Aerodynamics
- The designers desired to demonstrate that high performance and pleasant flight characteristics could coexist in a standard class sailplane built with the then still unexplored GRP technology.
- The performance came from the high wing aspect ratio, the double tapered wing and the new FX 66-S-196 profile. This profile possesses a relatively shallow but very wide laminar bucket, and is also found in the ASK 21.
- The natural qualities of the profile combined with careful wing design yielded gentle low speed behaviour.
- Variants up to the LS1-d had an all-flying tail with oversensitive handling characteristics at high speeds. A conventional stabiliser and elevator were adopted for later variants. Although fractionally less efficient, this is much safer and pleasant to fly.
- The front of the original two-piece canopy was blended with the fuselage for best aerodynamics.
Construction
- The materials used were glass fibre, Conticell foam, polystyrene, plywood for the spar webs and hardwood in reinforcements. Wood was phased out in the LS1-f version.
- The FX 66-S-196 profile, with a thickness to chord ratio of almost 20%, made it possible to build a light and economical spar. This was important because in the late sixties glass fibre was the only affordable reinforcement material - carbon was still too expensive.
- The GRP fuselage shell was produced in female moulds, in an innovative method developed by Wolf Lemke. The LS1 V-1 prototype was the pattern or ‘plug’ for the serial production moulds.
- The undercarriage was initially fixed, as required by the standard class rules of the time. The wheel was sprung and had its own wheel housing, separate from the internal fuselage space. The wheel brake was coupled to the air brake system.
- The new one-piece canopy of the LS1-f required an innovative hinge with complex kinetics to deliver the forward opening movement.
Variants
The LS-1 was produced in several sub-models:
- The LS1-0 V-1 prototype had an internal load bearing tubular steel scaffold (as in present-day Schempp-Hirth sailplanes). This structure was substituted by full GRP construction in production versions.
- The angle of incidence was increased for the LS1-0, that also saw improvements to the control system.
- The trailing edge air brakes of the prototype were dropped in favour of conventional Schempp-Hirth air brakes starting with the LS1-a.
- the LS1-d was the first to have water ballast, following a class rule change.
- The LS1-e version was built privately by a Rolladen-Schneider employee under the direction of Wolf Lemke. Differs from the LS1-c only in the use of an LS1-f type tailplane. Only three were built.
- The LS1-f introduced the one-piece canopy, conventional tailplane, redesigned rudder and structural changes that allowed more water ballast and higher flight mass. It also has a reduced wing incidence relative to the fuselage, resulting in noticeably better high speed performance than the earlier LS1 variants.
Sources
- [LS-Flugzeugbau website]
- Thomas F, Fundamentals of Sailplane Design, College Park Press, 1999
- Simons M, Segelflugzeuge 1965-2000, Equip, 2004
- Selinger P, Segelflugzeug-Geschichten, Deutsches Segelflugmuseum
- [German-language Wikipedia]
- [Sailplane Directory]
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