| 词条 | Schleicher ASW 20 | ||||||||||||||||
| 释义 |
The ASW 20 is an FAI 15 metre Class glider designed by Gerhard Waibel and built by Alexander Schleicher GmbH & Co. Its fuselage is nearly identical to the ASW19's, mated to newly designed wings for the 15 metre Class. The prototype first flew in 1977. It proved to be a highly successful glider, winning several World Championships, and was still being flown at this level up to 1995. Developments along its production life included winglets, pneumatic turbulators, and wingtip extensions. It remained in production until 1990, when it was superseded by the ASW27. 765 were built by Schleicher and a further 140 were made under license by Centrair in France. The ASW20 first flew in 1977 and was an instant success, winning numerous world and national championships. Dick Johnson reported that the ASW20 was the first 15 m glider to demonstrate a measured L/D in excess of 40/1. Roy McMaster, Karl Striedieck and John Seymour won jointly, with others, the world triangle distance record of {{convert|1,435|km|mi|abbr=on}} in 1994 in an ASW20B. ASW20s won 2nd and 3rd places in the FAI 15 metre Class at the 1983 World Championships at Hobbs, NM. ASW20s are still flown in FAI 15 metre Class at Regional and National levels, and are also flown in Sports Class in the United States. ConstructionThe ASW20 is constructed from glass-reinforced plastic. It features trailing edge flaps which interconnect with the ailerons and allow the entire trailing edge to operate as a flap between -9 and +5 degrees. The flaps also act as ailerons, but deflect only half of the aileron amount. Schempp-Hirth type airbrakes are provided on the upper wing surface. The B model (introduced in 1983) differs from the A and C model in that it uses a reinforced wing spar, which provides an increased water ballast capacity at the expense of the flexible wing. The B and C model include several enhancements over the original A model, including a lifting panel, hydraulic disc brake, and automatic elevator hookup. The B and C wings also incorporate a pneumatic turbulator system, which draws high pressure air from pitot inlets on the wing and injects it through approximately 860 pinholes into the boundary layer to control underwing airflow separation. ASW20s that include a L designation may be fitted with a 1.59 m wingtip extension. The F designation was assigned to A variants produced in France by Centrair. Centrair also produced an FL variant equivalent to the German ASW20L, most of these are only permitted to fly without the wingtip extensions due to a deficiency in the wing spar construction. At least three different winglet designs have been produced for the ASW-20, including a NASA winglet fitted to the Centrair gliders (FP), a design by Peter Masak, and a second generation winglet designed by Prof. Mark D. Maughmer of Penn State University(USA). Flight characteristicsThe ASW-20 is known as a very pleasant handling glider in most respects. The wing structure composite layup was designed to twist slightly as the wings flexed upward, resulting in the ability to "store" some of the energy from atmospheric gusts, and then release that energy with a very slight forwrd thrust force as the wings flexed back downward to their normal position. This concept is known as the Katzmayr Effect, and somewhat mimics a bird's ability to use a flapping motion to propel itself forward in flight. This unique wing twisting movement gave the AS-W20 an ability to make very small but consistent performance gains (or reduced losses) in turbulent and gusty thermal conditions compared to other competition level sailplanes. The landing flaps (55° in early models, 38° in later models), in conjunction with very effective airbrakes, allow the pilot to make exceptionally steep approaches at slow speeds, permitting very short landings when required. Second generation winglets further improved the handling and reduced drag at low to mid speeds. These characteristics have made the AS-W20 a much beloved and desirable aircraft, even after it was no longer competitive in racing. One very common modification was the addition of another intermediate flap setting detent (between Zero and +1 position) which mitigated or softened any "tip- stall" and incipient spin risk while thermaling in tight, gusty thermals. The flexible wing of the A and C models is particularly favored for ridge running, where it absorbs some of the tremendous turbulence found at ridgetop. Variants
Specifications (ASW 20B){{Aircraft specs|ref=Jane's All the World's Aircraft 1988-89[1] |prime units?=met
ASW20BL / ASW20CL {{convert|16.59|m|abbr=on}} |height m=1.45 |wing area sqm=10.5 |wing area note= ASW20BL / ASW20CL {{convert|11.05|m2|abbr=on}} |aspect ratio=21.4 ASW20BL / ASW20CL 24.9 |airfoil=root:Wortmann FX-63-131-K; tip:Wortmann FX-60-126 |empty weight kg=260 |empty weight lb= |empty weight note= ASW20C {{convert|250|kg|abbr=on}} ASW20BL {{convert|265|kg|abbr=on}} ASW20CL {{convert|255|kg|abbr=on}} |max takeoff weight kg=525 |max takeoff weight note= ASW20C {{convert|454|kg|abbr=on}} ASW20BL {{convert|430|kg|abbr=on}} ASW20CL {{convert|380|kg|abbr=on}} |more general=
ASW20C {{convert|120|l|USgal impgal|abbr=on}} ASW20BL {{convert|50|l|USgal impgal|abbr=on}}
ASW20BL / ASW20CL {{convert|64|kph|kn mph|abbr=on}} (without ballast) |never exceed speed kmh=280 |never exceed speed note=in smooth air Smooth air ASW20BL / ASW20CL {{convert|250|kph|kn mph|abbr=on}} in smooth air Rough air ASW20B {{convert|191|kph|kn mph|abbr=on}} ASW20BL {{convert|180|kph|kn mph|abbr=on}} ASW20C {{convert|180|kph|kn mph|abbr=on}} ASW20CL {{convert|165|kph|kn mph|abbr=on}} Aero-tow ASW20B {{convert|191|kph|kn mph|abbr=on}} ASW20C {{convert|180|kph|kn mph|abbr=on}} ASW20BL {{convert|165|kph|kn mph|abbr=on}} ASW20CL {{convert|160|kph|kn mph|abbr=on}} Winch launch ASW20B {{convert|129|kph|kn mph|abbr=on}} ASW20C {{convert|125|kph|kn mph|abbr=on}} ASW20BL {{convert|130|kph|kn mph|abbr=on}} ASW20CL {{convert|120|kph|kn mph|abbr=on}} |g limits= +5.3 -2.65 |glide ratio= 42.5 at {{convert|100|kph|kn mph|abbr=on}} (without ballast); 43 at {{convert|120|kph|kn mph|abbr=on}} (with ballast) ASW20C 43 at {{convert|90|kph|kn mph|abbr=on}} (without ballast); 42 at {{convert|115|kph|kn mph|abbr=on}} (with ballast) ASW20BL 45 at {{convert|90|kph|kn mph|abbr=on}} (without ballast) ASW20CL 46 at {{convert|91|kph|kn mph|abbr=on}} |sink rate ms=0.59 |sink rate note= at {{convert|84|kph|kn mph|abbr=on}} (without ballast) ASW20C {{convert|0.57|m/s|ft/min|abbr=on}} at {{convert|87|kph|kn mph|abbr=on}} (without ballast); {{convert|0.68|m/s|ft/min|abbr=on}} at {{convert|96|kph|kn mph|abbr=on}} (with ballast) ASW20BL {{convert|0.56|m/s|ft/min|abbr=on}} at {{convert|80|kph|kn mph|abbr=on}} (without ballast) ASW20CL {{convert|0.53|m/s|ft/min|abbr=on}} at {{convert|84|kph|kn mph|abbr=on}} |lift to drag= |wing loading kg/m2=50 |wing loading note= ASW20C: {{convert|43.24|kg/m2|lb/sqft|abbr=on|}} ASW20BL {{convert|38.91|kg/m2|lb/sqft|abbr=on|}} ASW20CL {{convert|34.39|kg/m2|lb/sqft|abbr=on|}} |more performance= |avionics= }}{{aircontent |see also= |related= |similar aircraft= |lists= }} References1. ^{{cite book |title=Jane's All the World's Aircraft 1988-89 |year=1988 |publisher=Jane's Information Group |location=London |isbn=0-7106-0867-5 |editor=John W.R. Taylor|pages=632}} Further reading
External links{{Commons category|ASW 20}}
7 : German sailplanes 1970–1979|Schleicher aircraft|Glider aircraft|Motor gliders|T-tail aircraft|High-wing aircraft|Aircraft first flown in 1977 |
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