 | This article includes a list of general references, but it lacks sufficient corresponding inline citations .(December 2012) |
| LS3 | |
|---|---|
 | |
| General information | |
| Type | 15 metre-class sailplane |
| National origin | Germany |
| Manufacturer | Rolladen-Schneider |
| Number built | 429 |
| History | |
| First flight | 4 February 1976 |
The Rolladen-Schneider LS3 is a 15 metre single-seat glider produced by Rolladen-Schneider from 1976 to 1983.
The LS3 was developed as Rolladen-Schneider's first entry to the new 15-metre competition class created in 1974 by the International Gliding Commission of the Fédération Aéronautique Internationale. Building upon previous experience with the LS1 and LS2, chief designer Wolf Lemke developed a new fuselage with a larger cockpit and more generous horizontal and vertical stabilisers.
Lemke selected a relatively thick airfoil profile developed in 1967 by University of Stuttgart Professor Franz Wortmann, the FX 67-K-170, which offered the structural economy made possible by a tall spar - an important consideration as glass fibre was still the only affordable reinforcement material - as well as good performance for the time.
This profile and its sister profile FX 67-K-150 are among the most prolific in the history of gliding, as they were employed also in the Nimbus-2, Mini-Nimbus, DG-200 and DG-400, PIK-20 and PIK-30, Kestrel, Mosquito, Vega, Jantar and LAK-12 among other types.
Unusually for Rolladen-Schneider, the LS3 wings are single-tapered, entailing a slight aerodynamic loss. On the other hand, this geometry went along well with a straight axis for the full-span flaperons which gave the LS3 good handling and roll rate characteristics. The control system was rigged to reduce the available control stick throw with negative flap settings, therefore giving a measure of in-built protection against overstressing at high speeds. One feature not shared with some competing designs was fully automatic control hookups.
The flaperon drives are located at the wing roots, an elegant solution that required a large amount of lead for mass balancing the control surfaces to preclude any risk of flutter. Due to this the LS3 wings are heavy, about 85 kg each semi-span (thus the nickname LS-Blei, a pun exploiting the phonetic similarity in the German language between 'drei' (three) and 'Blei' (lead)).
In spite of its weight the LS3 is a nimble climber. It is also less sensitive to rain or dirt than other types with the same profile. Its thicker wing takes its toll at higher speeds, where it could not keep up with the contemporary ASW 20, the best 15-metre glider of its generation. One puzzle is how Dick Johnson's flight tests showed essentially identical glide performance for the LS3 and ASW 20 when new, which was not borne out over time. This was attributed to shrinkage over the LS3 spar caps, which resulted in flat spots in the airfoil after a few years. Owners who corrected this flaw (through profiling) found their LS3s once again equal to the best 15-metre gliders of the day, but by then ASW 20 had become almost ubiquitous in contest entry lists.
A variant with separate flaps and ailerons and a slightly taller tail, the LS3a, was introduced in 1978. This version did away with the flaperon mass balancing, making each wing about 10 kg lighter. A span extension to 17-metres was later developed for this version. Although not very successful due to speed and ballasting limitations, these extensions pioneered a trend that has become extremely popular. Today most new standard and 15-metre class gliders offer tip extensions as an option.
The LS3 was superseded in 1983 by the LS6. Its production run reached 429 exemplars of which two-thirds are of the -a version. It remains a popular glider in the second-hand market although it is seldom found in club fleets, possibly due to the added complexity of flaps and undercarriage.
General characteristics
Performance
Related lists
The Glaser-Dirks DG-200 is a 15 metre class glider built by Glaser-Dirks, now DG Aviation GmbH
The Rolladen-Schneider LS6 is a 15 metre and 18 metre single-seat flapped glider manufactured by Rolladen-Schneider Flugzeugbau GmbH between 1984 and 2003.
The Rolladen-Schneider LS7 is a high-performance Standard Class single-seat sailplane produced by Rolladen-Schneider Flugzeugbau GmbH from 1988 to 1993.
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The Rolladen-Schneider LS2 is a 15-metre span single seat glider prototype with trailing-edge flaps, designed and built by Rolladen-Schneider Flugzeugbau GmbH c. 1973.
The Schempp-Hirth Mini Nimbus is a 15 Metre-class glider designed and built by Schempp-Hirth GmbH in the late 1970s.
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The Rolladen-Schneider LS1 is a Standard Class single-seat glider manufactured in Germany by Rolladen-Schneider from 1968 to 1977.
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The Rolladen-Schneider LS8 is a Standard and 18 metre class single-seat glider developed by Rolladen-Schneider and in series production since 1995. Currently it is manufactured by DG Flugzeugbau.
The ASW 28 is a Standard Class glider with a fifteen-metre span built of modern fibre reinforced composites. The manufacturer of the ASW-28 is Alexander Schleicher GmbH & Co. The 'W' indicates this is a design of the influential and prolific German designer Gerhard Waibel. Serial production started in 2000.
The Glaser-Dirks DG-300 is a Standard Class single-seat high-performance glider built from glass-reinforced plastic. The DG-300 was designed by Wilhelm Dirks and manufactured by Glaser-Dirks Flugzeugbau's Slovenian partner company Elan (company). A total of 511 of all versions were built since production started in 1983. Representative contemporary types from competing manufacturers are the Rolladen-Schneider LS4 and the Schempp-Hirth Discus.
The Rolladen-Schneider LS10 is an 18 metre sailplane designed in Germany by Rolladen-Schneider. A prototype flew in 2003.
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The Glasflügel 201 Standard Libelle is an early composite Standard Class single-seat sailplane produced by Glasflügel from 1967.
The PIK-20 sailplane was designed at the Helsinki University of Technology by Pekka Tammi, with advice from Ilkka Rantasalo and Raimo Nurminen. The prototype first flew on 10 October 1973. It was produced initially by Molino Oy who were taken over by Eiri-Avion Oy between 1974 and 1980. Later, production was taken over by the French company, Siren SA, under the name Siren PIK-20.
The Glasflügel 303 Mosquito is a composite 15 metre Class single-seat sailplane manufactured by Glasflügel between 1976 and 1980.
The Grob G104 Speed Astir was a competition sailplane produced in Germany in the late 1970s as Grob's first design in the 15 metre class.
The Akaflieg Darmstadt D-40 is an experimental variable geometry single seat sailplane, fitted with almost full span, camber changing flaps for optimum aerodynamics in weak thermals and integrated into the wing so as to minimise flap tip drag. One flew successfully but the D-40, like other variable geometry sailplanes, was not commercialised.
