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DAR 21S
The DAR 21 Vector II is a Bulgarian ultralight aircraft, designed and produced by Aeroplanes DAR, first flying on 1 August 2000. When it was available the aircraft was supplied as a kit for amateur construction or as a complete ready-to-fly-aircraft.Bayerl, Robby; Martin Berkemeier; et al: ''World Directory of Leisure Aviation 2011-12'', page 20. WDLA UK, Lancaster UK, 2011. ISSN 1368-485X The aircraft was introduced in 2001 and production apparently ended in 2014, as by that year the aircraft was no longer advertised for sale by the company. Design and development The aircraft was designed to comply with the Fédération Aéronautique Internationale microlight rules. It features a strut-braced high wing, a two-seats-in- tandem enclosed cockpit, conventional landing gear and a single engine in tractor configuration. The Vector II has riveted stressed skin made with 1050 and 3105 aluminum sheet for corrosion resistance. The fuselage has a square cross-section. Its span ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WikiProject Aircraft
A WikiProject, or Wikiproject, is a Wikimedia movement affinity group for contributors with shared goals. WikiProjects are prevalent within the largest wiki, Wikipedia, and exist to varying degrees within sister projects such as Wiktionary, Wikiquote, Wikidata, and Wikisource. They also exist in different languages, and translation of articles is a form of their collaboration. During the COVID-19 pandemic, CBS News noted the role of Wikipedia's WikiProject Medicine in maintaining the accuracy of articles related to the disease. Another WikiProject that has drawn attention is WikiProject Women Scientists, which was profiled by '' Smithsonian'' for its efforts to improve coverage of women scientists which the profile noted had "helped increase the number of female scientists on Wikipedia from around 1,600 to over 5,000". On Wikipedia Some Wikipedia WikiProjects are substantial enough to engage in cooperative activities with outside organizations relevant to the field at issue. For e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuselage
The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage, which in turn is used as a floating hull. The fuselage also serves to position the control and stabilization surfaces in specific relationships to lifting surfaces, which is required for aircraft stability and maneuverability. Types of structures Truss structure This type of structure is still in use in many lightweight aircraft using welded steel tube trusses. A box truss fuselage structure can also be built out of wood—often covered with plywood. Simple box structures may be rounded by the addition of supported lightweight stringers, allowing the fabric covering to form a more aerodynamic shape, or one more pleasing to the eye. Geodesic construction Geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2000s Bulgarian Ultralight Aircraft
S, or s, is the nineteenth letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''ess'' (pronounced ), plural ''esses''. History Origin Northwest Semitic šîn represented a voiceless postalveolar fricative (as in 'ip'). It originated most likely as a pictogram of a tooth () and represented the phoneme via the acrophonic principle. Ancient Greek did not have a phoneme, so the derived Greek letter sigma () came to represent the voiceless alveolar sibilant . While the letter shape Σ continues Phoenician ''šîn'', its name ''sigma'' is taken from the letter ''samekh'', while the shape and position of ''samekh'' but name of ''šîn'' is continued in the '' xi''. Within Greek, the name of ''sigma'' was influenced by its association with the Greek word (earlier ) "to hiss". The original name of the letter "sigma" may have been ''san'', but due to the complica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archive
An archive is an accumulation of historical records or materials – in any medium – or the physical facility in which they are located. Archives contain primary source documents that have accumulated over the course of an individual or organization's lifetime, and are kept to show the function of that person or organization. Professional archivists and historians generally understand archives to be records that have been naturally and necessarily generated as a product of regular legal, commercial, administrative, or social activities. They have been metaphorically defined as "the secretions of an organism", and are distinguished from documents that have been consciously written or created to communicate a particular message to posterity. In general, archives consist of records that have been selected for permanent or long-term preservation on grounds of their enduring cultural, historical, or evidentiary value. Archival records are normally unpublished and almost alway ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Stroke
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of the crankshaft. A four-stroke engine requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust (or scavenging) functions occurring at the same time. Two-stroke engines often have a high power-to-weight ratio, power being available in a narrow range of rotational speeds called the power band. Two-stroke engines have fewer moving parts than four-stroke engines. History The first commercial two-stroke engine involving cylinder compression is attributed to Scottish engineer Dugald Clerk, who patented his design in 1881. However, unlike most later two-st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bungee Cord
Bungee cords equipped with metal hooks A bungee cord (sometimes spelled bungle; also known as a shock cord) is an elastic cord composed of one or more elastic strands forming a core, usually covered in a woven cotton or polypropylene sheath. The sheath does not materially extend elastically, but it is braided with its strands spiralling around the core so that a longitudinal pull causes it to squeeze the core, transmitting the core's elastic compression to the longitudinal extension of the sheath and cord. Specialized bungees, such as some used in bungee jumping, may be made entirely of elastic strands. Uses upA child on a bungee cord device in Moscow, Russia Bungee cords have been used to provide a lightweight suspension for aircraft undercarriages from before World War I, and are still used on many small homebuilt aircraft where weight remains critical. Bungee cords were also used in parachuting to assist in opening the old-style parachute container after the ripcord wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotax 912
The Rotax 912 is a horizontally-opposed four-cylinder, naturally aspirated, four-stroke aircraft engine with a reduction gearbox. It features liquid-cooled cylinder heads and air-cooled cylinders. Originally equipped with carburetors, later versions are fuel injected. Dominating the market for small aircraft and kitplanes, Rotax produced its 50,000th 912-series engine in 2014. Originally available only for light sport aircraft, ultralight aircraft, autogyros and drones, the 912-series engine was approved for certified aircraft in 1995. Design and development The Rotax 912 was first sold in 1989 in non- certificated form for use in ultralights and motorgliders. The original 912 UL engine has a capacity of and a compression ratio of 9.1:1. The engine differs from previous generation aircraft engines (such as the Lycoming O-235) in that it has air-cooled cylinders with liquid-cooled heads and uses a 2.43:1 PSRU reduction gearbox to reduce the engine's relatively high 5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Four-stroke
A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed: #Intake: Also known as induction or suction. This stroke of the piston begins at top dead center (T.D.C.) and ends at bottom dead center (B.D.C.). In this stroke the intake valve must be in the open position while the piston pulls an air-fuel mixture into the cylinder by producing vacuum pressure into the cylinder through its downward motion. The piston is moving down as air is being sucked in by the downward motion against the piston. #Compression: This stroke begins at B.D.C, or just at the end of the suction stroke, and ends at T.D.C. In this stroke the piston compresses the air-fuel mixture in preparation for ignition during the power stroke (below). Both the intake and exhaust valves are close ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-stroke
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a Thermodynamic power cycle, power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of the crankshaft. A four-stroke engine requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust (or Scavenging (automotive), scavenging) functions occurring at the same time. Two-stroke engines often have a high power-to-weight ratio, power being available in a narrow range of rotational speeds called the power band. Two-stroke engines have fewer moving parts than four-stroke engines. History The first commercial two-stroke engine involving cylinder compression is attributed to Scotland, Scottish engineer Dugald Clerk, who pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotax 582
The Rotax 582 is a two-stroke, two-cylinder, rotary intake valve, oil-in-fuel or oil injection pump, liquid-cooled, gear reduction-drive aircraft engine manufactured by BRP-Rotax GmbH & Co. KG. It is for use in non-certified aircraft operating in day visual flight rules. Production of the engine ended at the end of 2021. Development The Rotax 582 is based upon the earlier Rotax 532 engine design and was designed for ultralight aircraft.Raisner, William: ''LEAF catalog'', pages 6-105. Leading Edge Airfoils, 1995. The 582 increased the bore from the 532 engine's . This increased the displacement from to , an increase of 11%. The increased displacement had the effect of flattening out the 532's torque curve and allowed the 582 to produce useful power over a wider rpm range. Reliability over the 532 was also improved. The 582 features liquid-cooled cylinder heads and cylinders with a rotary intake valve. Cooling is via an externally mounted radiator. Lubrication is either by use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flap (aircraft)
A flap is a high-lift device used to reduce the stalling speed of an aircraft wing at a given weight. Flaps are usually mounted on the wing trailing edges of a fixed-wing aircraft. Flaps are used to reduce the take-off distance and the landing distance. Flaps also cause an increase in drag so they are retracted when not needed. The flaps installed on most aircraft are partial-span flaps; spanwise from near the wing root to the inboard end of the ailerons. When partial-span flaps are extended they alter the spanwise lift distribution on the wing by causing the inboard half of the wing to supply an increased proportion of the lift, and the outboard half to supply a reduced proportion of the lift. Reducing the proportion of the lift supplied by the outboard half of the wing is accompanied by a reduction in the angle of attack on the outboard half. This is beneficial because it increases the margin above the stall of the outboard half, maintaining aileron effectiveness and reduci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
