DG Flugzeugbau LS10

DG Flugzeugbau LS10

File:DG-808B und LS10 Niederöblarn.JPG The LS10-a and a DG-808B at Niederöblarn, Austria.
Type designation	LS10-s
Competition class	18 metre
Number built	2 (prototypes)
Crew	1
Length	6.72 m
Height	1.33 m
Cockpit width	0.61 m
Cockpit height	0.80 m
Wingspan	18 m
Wing area	11.4 m²
Aspect ratio	28.4
Empty mass	ca. 305 kg
Water ballast	190 kg
Tail water ballast	7.5 kg
Maximum mass	600 kg
Wing loading	30 - 53 kg/m²
Maximum speed	280 km/h
Maneuver speed	190 km/h
Stall speed	66 km/h
Minimum sink	0.51 m/s unballasted
Glide ratio	> 48

File:Rolladen-Schneider LS10-a in flight.JPG

LS10-a in flight.

The Rolladen-Schneider LS10-a is a prototype 18 metre sailplane that first flew in 2003 and currently is in pre-production development at DG Flugzeugbau.

History

By the mid-nineties Rolladen-Schneider, prompted by customers, began designing a successor to the LS6. Development was protracted, as the LS8 and LS9 projects had higher priority and the company's owner, Walter Schneider, felt the LS6 was still competitive.

The initial design was made under the direction of Wolf Lemke. Werner Scholz then developed the prototype, the LS10-a. Although early 3-view drawings of the LS10 showed a curved canopy rail similar to that of the ASW24, when the prototype was revealed it had the same straight canopy rail as the LS6 and LS8.

The first flight took place at Egelsbach on 6 June 2003. This was followed by extensive flight-testing and then evaluation in competitions. The prototype won the Hockenheim and Bayreuth contests in 2004 and the German Nationals in Lüsse in 2005. It took second place in the 2005 European Championships in Nitra, Slovakia. The flying qualities were reported in the German aviation magazine, Aerokurier, to be excellent.

DG Flugzeugbau expects to start serial production of the LS10 at the beginning of 2007. The company is engaged in an extensive redesign to reduce production costs, and is completing the usual lengthy certification process.

A 15 metre version is likely to be developed in the future. A ‘turbo’ version LS10-st is also planned, using the same engine installation as the LS8-st.

Design of the wing

The LS10 differs from the LS6 mainly in its wing; its other features are similar. The aerofoil was derived from the FX 81-K-130 profile used in the LS6, having as improvements: higher performance at the low and high ends of the speed range, and very low sensitivity to turbulence, rain and bugs. The wings have turbulator tape on the underside to prevent laminar separation bubbles. This suggests the profile lacks the clean natural transition of the Wortmann profile of 1981 and is probably more extensively laminar.

The initial design had an elliptical leading edge similar to the SZD-55-1. However the prototype adopted a triple-tapered shape that is easier to build and - most importantly - to repair. The production version will have a thicker profile at the wing root, especially modified for the turbulent flow in the vicinity of the fuselage (as with other recent gliders including the LAK-17a, ASW 28, DG-1000, Discus-2 and the eta).

The wing is built in four parts. By changing wing tips, 15 and 18 metre spans will be possible. The partition line for the wing extensions was located considerably inboard in the prototype, a feature that first appeared in the Schempp-Hirth Ventus 2c and which allows optimal planforms for both spans and easier rigging. The series production, however, will have the partition farther out, at seven metres from the fuselage axis, as DG-Flugzeugbau decided to give priority to structural and constructional considerations that favour a location farther towards the wingtip.

Other design features

• The ballast system has four integral tanks in the wings. The outboard tanks are filled first and dumped last for better spanwise load distribution. The tail ballast system is identical to that of the LS8-b.

• Although a mock-up for a new fuselage with a larger cockpit had been prepared at Rolladen-Schneider, the prototype LS10-a uses an LS6-c fuselage with minor changes including some details carried over from the LS8-b and so has the same ergonomics and crashworthiness.

• A taller undercarriage increases ground clearance and gives a higher angle of attack than an LS6, allowing a lower speed for take-off and landing. This increases safety when aerotowing from short runways and when landing out.

• The LS10 has the typical LS full-span flaperons and large, double-blade air brakes, and Hänle-type automatic control connections.

Sources

• LS-Flugzeugbau website
• Aerokurier Aviation Magazine
• Marzinzik G, LS10: Meistermacher?, Aerokurier, Aug 2004