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Haase-Kensche-Schmetz HKS-1
The HKS-1 was a German 19 span high performance two seat sailplane, designed around 1950 to use recent advances in laminar flow airfoils. To avoid premature transition from laminar flow caused by surface interruptions, the HKS-1 dispensed with hinged ailerons, flaps and spoilers and replaced them with a flexible trailing edge. Two were built, setting several records. Design and development Any aerodynamic approach that decreased wing drag was welcomed by sailplane designers, who reduced lift-induced drag with high aspect ratio wings. Profile drag was reduced by maintaining laminar flow over as much of the wing as possible. The NACA 6-series profiles of the late 1930s suggested that laminar flow might be maintained as far back as 70% chord, though military experience during World War II showed that much less ambitious targets were hard to achieve with riveted surfaces on wings with gaps for control surfaces, armament, service hatches etc. After the war, sailplane des ... [...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] |
NACA Airfoil
The NACA airfoils are airfoil shapes for aircraft wings developed by the National Advisory Committee for Aeronautics (NACA). The shape of the NACA airfoils is described using a series of digits following the word "NACA". The parameters in the numerical code can be entered into equations to precisely generate the cross-section of the airfoil and calculate its properties. Origins NACA initially developed the numbered airfoil system which was further refined by the United States Air Force at Langley Research Center. According to the NASA website: Four-digit series The NACA four-digit wing sections define the profile by: # First digit describing maximum camber as percentage of the chord. # Second digit describing the distance of maximum camber from the airfoil leading edge in tenths of the chord. # Last two digits describing maximum thickness of the airfoil as percent of the chord. For example, the NACA 2412 airfoil has a maximum camber of 2% located 40% (0.4 chords) from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leading Edge
The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, 1997. Characteristics Sweep Seen in plan the leading edge may be straight, curved, kinked or a combination of these. A straight leading edge may be swept or unswept, while curves or kinks always mean that part of the leading edge is swept. On a swept wing the sweep angle may differ from that of the wing, as wing sweep is conventionally measured at the airfoil 25% chord line. However on a delta wing the leading edge sweep defines the wing sweep. Radius and stagnation point A rounded leading edge helps to maintain a smooth airflow at varying angles of incidence to the airflow. Most subsonic airfoils therefore have a rounded leading edge. The degree of rounding is characterised by the profile radius at that point. The airflow divides to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spruce
A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfamily Piceoideae. Spruces are large trees, from about 20 to 60 m (about 60–200 ft) tall when mature, and have whorled branches and conical form. They can be distinguished from other members of the pine family by their needles (leaves), which are four-sided and attached singly to small persistent peg-like structures (pulvini or sterigmata) on the branches, and by their cones (without any protruding bracts), which hang downwards after they are pollinated. The needles are shed when 4–10 years old, leaving the branches rough with the retained pegs. In other similar genera, the branches are fairly smooth. Spruce are used as food plants by the larvae of some Lepidoptera (moth and butterfly) species, such as the eastern spruce budwo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Foam
A polymeric foam is a foam, in liquid or solidified form, formed from polymers. Examples include: * Ethylene-vinyl acetate (EVA) foam, the copolymers of ethylene and vinyl acetate; also referred to as polyethylene-vinyl acetate (PEVA) * Low-density polyethylene (LDPE) foam, first grade of polyethylene (PE) * Nitrile rubber (NBR) foam, the copolymers of acrylonitrile (ACN) and butadiene * Polychloroprene foam or Neoprene * Polyimide foam * Polypropylene (PP) foam, including expanded polypropylene (EPP) and polypropylene paper (PPP) * Polystyrene (PS) foam, including expanded polystyrene (EPS), extruded polystyrene foam (XPS) and sometimes polystyrene paper (PSP) ** Styrofoam, including extruded polystyrene foam (XPS) and sometimes expanded polystyrene (EPS) * Polyurethane (PU) foam ** LRPu low-resilience polyurethane ** Memory foam ** Sorbothane *Polyethylene foam, as used in PEF rod * Polyvinyl chloride (PVC) foam ** Closed-cell PVC foamboard * Silicone foam * Microcellular foam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plywood
Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured boards which include medium-density fibreboard (MDF), oriented strand board (OSB) and particle board (chipboard). All plywoods bind resin and wood fibre sheets (cellulose cells are long, strong and thin) to form a composite material. This alternation of the grain is called ''cross-graining'' and has several important benefits: it reduces the tendency of wood to split when nailed at the edges; it reduces expansion and shrinkage, providing improved dimensional stability; and it makes the strength of the panel consistent across all directions. There is usually an odd number of plies, so that the sheet is balanced—this reduces warping. Because plywood is bonded with grains running against one another and with an odd number of composite part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing Tip
A wing tip (or wingtip) is the part of the wing that is most distant from the fuselage of a fixed-wing aircraft. Because the wing tip shape influences the size and drag of the wingtip vortices, tip design has produced a diversity of shapes, including: * Squared-off * Aluminium tube bow * Rounded * Hoerner style * Winglets * Drooped tips * Raked wingtips * Tip tanks * Sails * Fences * End plates Winglets have become popular additions to high speed aircraft to increase fuel efficiency by reducing drag from wingtip vortices. In lower speed aircraft, the effect of the wingtip shape is less apparent, with only a marginal performance difference between round, square, and Hoerner style tips The slowest speed aircraft, STOL aircraft, may use wingtips to shape airflow for controllability at low airspeeds. Wing tips are also an expression of aircraft design style, so their shape may be influenced by marketing considerations as well as by aerodynamic requirements. Wing tips are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing Root
The wing root is the part of the wing on a fixed-wing aircraft or winged-spaceship that is closest to the fuselage,Peppler, I.L.: ''From The Ground Up'', page 9. Aviation Publishers Co. Limited, Ottawa Ontario, Twenty Seventh Revised Edition, 1996. and is the junction of the wing with the fuselage (not with a nacelle or any other body). The term is also used for the junction of the wing with the opposite wing, ie on the fuselage centerline, as with the upper wing of a biplane. The opposite end of a wing from the wing root is the wing tip. The aerodynamic properties of the overall aircraft can be greatly impacted by the shaping and other design choices of the wing root. During both normal flight and landings, the wing root of an aircraft would be typically subjected to the highest bending forces through the aircraft. As a means of reducing interference drag between the wing and the fuselage, the use of fairings (often referred to as "wing fillets") became commonplace during the fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing Warping
Wing warping was an early system for lateral (roll) control of a fixed-wing aircraft. The technique, used and patented by the Wright brothers, consisted of a system of pulleys and cables to twist the trailing edges of the wings in opposite directions. In many respects, this approach is similar to that used to trim the performance of a paper airplane by curling the paper at the back of its wings. Description In 1900, Wilbur Wright wrote, "...my observations of the flight of birds convince me that birds use more positive and energetic methods of regaining equilibrium than that of shifting the center of gravity...they regain their lateral balance...by a torsion of the tips of the wings. If the rear edge of the right wing tip is twisted upward and the left downward the bird becomes an animated windmill and instantly begins to turn, a line from its head to its tail being the axis." After Wilbur demonstrated the method, Orville noted, "From this it was apparent that the wings of a mac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aileron
An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around the aircraft's longitudinal axis), which normally results in a change in flight path due to the tilting of the lift vector. Movement around this axis is called 'rolling' or 'banking'. Considerable controversy exists over credit for the invention of the aileron. The Wright brothers and Glenn Curtiss fought a years-long legal battle over the Wright patent of 1906, which described a method of wing-warping to achieve lateral control. The brothers prevailed in several court decisions which found that Curtiss's use of ailerons violated the Wright patent. Ultimately, the First World War compelled the U.S. Government to legislate a legal resolution. A much earlier aileron concept was patented in 1868 by British scientist Matthew Piers Watt Bou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ross-Johnson RJ-5
The Ross-Johnson RJ-5 is a single seat competition glider that was designed by Harland Ross and constructed partially by Ross and finished by Dick Johnson. The RJ-5 became one of the most famous gliders ever built when Johnson flew it in 1951, setting a new world distance record that endured for 13 years.Said, Bob: ''1983 Sailplane Directory, Soaring Magazine'', page 60. Soaring Society of America, November 1983. USPS 499-920 Design and development The RJ-5 was conceived by Johnson, who contracted Ross to design and built a glider with record-setting performance. The aircraft utilizes a NACA 63 (2)-615 laminar flow airfoil and was one of the first gliders to achieve a 40:1 glide ratio. Johnson asked Ross to build the RJ-5 in 1948. Ross completed the design work and much of the construction, with help from Stan Hall, but by 1950 the glider was still incomplete. Johnson took delivery of it, finishing work on it at Mississippi State University, and incorporated some design chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lift Coefficient
In fluid dynamics, the lift coefficient () is a dimensionless quantity that relates the lift generated by a lifting body to the fluid density around the body, the fluid velocity and an associated reference area. A lifting body is a foil or a complete foil-bearing body such as a fixed-wing aircraft. is a function of the angle of the body to the flow, its Reynolds number and its Mach number. The section lift coefficient refers to the dynamic lift characteristics of a two-dimensional foil section, with the reference area replaced by the foil chord. Abbott, Ira H., and Doenhoff, Albert E. von: ''Theory of Wing Sections''. Section 1.2 Definitions The lift coefficient ''C''L is defined by :C_\mathrm L \equiv \frac = = , where L\, is the lift force, S\, is the relevant surface area and q\, is the fluid dynamic pressure, in turn linked to the fluid density \rho\,, and to the flow speed u\,. The choice of the reference surface should be specified since it is arbitrary. For examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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