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55-546: Ampere, Inc., a Japanese computer systems company founded by Takashi Kusanagi in the early 1980s, first announced the WS-1 in June 1984 under the prototype name BIG.APL . The WS-1 weighs 16.5 pounds (7.5 kg) and occupies a footprint of 12 by 12 by 3 inches (30.5 by 30.5 by 7.6 cm). Technology journalists noted the laptop's striking, airfoil -esque case design, rendered by Japanese industrial designer Kumeo Tamura—better known as

110-638: A general purpose airfoil that finds wide application, and pre–dates the NACA system, is the Clark-Y . Today, airfoils can be designed for specific functions by the use of computer programs. The various terms related to airfoils are defined below: The geometry of the airfoil is described with a variety of terms : The shape of the airfoil is defined using the following geometrical parameters: Some important parameters to describe an airfoil's shape are its camber and its thickness . For example, an airfoil of

165-470: A new link. This is also called "infinite-content pages" or "endless pages". The title of one of the brands, Looper, refers to this design. Established around 2011, ZergNet's business model, being paid to place links in third-party online articles at the bottom of ZergNet pages, has been compared to the business model of Outbrain , Taboola , and others. The company's investors include Mark Cuban and Greycroft Partners . Static Media owns and promotes

220-484: A port on the back, allowing the user to connect the laptop to external devices including hard drives, floppy drives, and further RAM. Ampere themselves sold a 3.5-inch floppy disk drive exclusively for use with the WS-1. Also present on the WS-1 are two serial ports and a Centronics parallel port, a 300-baud modem , and a microcassette deck. The microcassette deck allows the user to store both programs, data, and voice recordings. Both saving programs and data to cassette

275-553: A principal behind the Datsun 240Z coupé. Powering the WS-1 is the HD68000 —a second-source version of Motorola 's 32-bit 68000 microprocessor—manufactured by Hitachi and running at a clock speed of 8 MHz. The laptop is also designed around VMEbus , an open-standard computer bus built upon the 68000. Both the 68000 and VMEbus were seldom used by laptops at the time of its release. The WS-1's VMEbus accommodates expansions via

330-437: A sharp leading edge. All have a sharp trailing edge . The air deflected by an airfoil causes it to generate a lower-pressure "shadow" above and behind itself. This pressure difference is accompanied by a velocity difference, via Bernoulli's principle , so the resulting flowfield about the airfoil has a higher average velocity on the upper surface than on the lower surface. In some situations (e.g., inviscid potential flow )

385-421: A subsonic flow about a thin airfoil can be described in terms of an outer region, around most of the airfoil chord, and an inner region, around the nose, that asymptotically match each other. As the flow in the outer region is dominated by classical thin airfoil theory, Morris's equations exhibit many components of thin airfoil theory. In thin airfoil theory, the width of the (2D) airfoil is assumed negligible, and

440-429: A suitable angle, a solid body moving through a fluid deflects the oncoming fluid (for fixed-wing aircraft, a downward force), resulting in a force on the airfoil in the direction opposite to the deflection. This force is known as aerodynamic force and can be resolved into two components: lift ( perpendicular to the remote freestream velocity ) and drag ( parallel to the freestream velocity). The lift on an airfoil

495-476: Is Big.APL, an implementation of APL 68000 (itself a derivative of IBM 's APL.SV). Big.APL runs on top of the laptop's built-in disk operating system, Big.DOS. Big.DOS also features a full-screen line editor , a word processor , a spreadsheet application, a modem utility, and a database program, all running in a windowing text-based user interface with multitasking capability. Both Big.DOS and Big.APL were designed by Philip Van Cleave . Ampere originally designed

550-511: Is Food Republic, founded in 2010 but launched in 2011. In September 2023, Static Media launched another food site, Foodie, bringing its total food brands to four. On October 3, 2023, Static Media launched its first financial journalism site, Money Digest . On October 26, 2023, the company launched its second homegrown travel and outdoors brand, titled Outdoor Guide and focused on outdoor living, including camping, gear, travel, and wildlife. The company followed this several days later with

605-491: Is a Static Media original site, and it debuted in the third quarter of 2020. Alongside general health reporting, many of the brand's early articles covered the COVID-19 pandemic . Tasting Table was launched in 2008 and was acquired by Static Media in 2021, the same year as /Film , which began in 2005. House Digest is one of the site's newer homegrown brands, launching as a Static original site in 2021. Wrestling Inc.

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660-401: Is increased before the wing achieves maximum thickness to minimize the chance of boundary layer separation. This elongates the wing and moves the point of maximum thickness back from the leading edge. Supersonic airfoils are much more angular in shape and can have a very sharp leading edge, which is very sensitive to angle of attack. A supercritical airfoil has its maximum thickness close to

715-411: Is loaded continuously as the user scrolls down. For example, scrolling down on the homepage loads more articles in perpetuity (until the user reaches the very first article written for the site). Scrolling down on individual articles also does not reach the page footer, instead loading a different, related article, so the user can continue reading content from the site indefinitely without needing to click

770-406: Is primarily the result of its angle of attack . Most foil shapes require a positive angle of attack to generate lift, but cambered airfoils can generate lift at zero angle of attack. Airfoils can be designed for use at different speeds by modifying their geometry: those for subsonic flight generally have a rounded leading edge , while those designed for supersonic flight tend to be slimmer with

825-401: Is the position at which the pitching moment M ′ does not vary with a change in lift coefficient: ∂ ( C M ′ ) ∂ ( C L ) = 0 . {\displaystyle {\frac {\partial (C_{M'})}{\partial (C_{L})}}=0{\text{.}}} Thin-airfoil theory shows that, in two-dimensional inviscid flow,

880-547: Is the second-oldest of Static Media's branded sites, founded in 1996. Wrestling Inc. and Glam, the latter of which was started in 2003, were both acquired in 2022. The Daily Meal launched in 2011 and was acquired by Static in 2022. Explore, a travel-focused brand, launched as a Static Media original site in November 2022. Women.com is the oldest brand that Static Media owns, having been founded in 1995, but it wasn't acquired by Static until early 2023. Also acquired in 2023

935-495: The Biot–Savart law , the vorticity γ( x ) produces a flow field w ( x ) = 1 2 π ∫ 0 c γ ( x ′ ) x − x ′ d x ′ , {\displaystyle w(x)={\frac {1}{2\pi }}\int _{0}^{c}{\frac {\gamma (x')}{x-x'}}\,dx'{\text{,}}} oriented normal to

990-1287: The change of variables x = c ⋅ 1 + cos ⁡ ( θ ) 2 , {\displaystyle x=c\cdot {\frac {1+\cos(\theta )}{2}},} and then expanding both dy ⁄ dx and γ( x ) as a nondimensionalized Fourier series in θ with a modified lead term: d y d x = A 0 + A 1 cos ⁡ ( θ ) + A 2 cos ⁡ ( 2 θ ) + … γ ( x ) = 2 ( α + A 0 ) ( sin ⁡ θ 1 + cos ⁡ θ ) + 2 A 1 sin ⁡ ( θ ) + 2 A 2 sin ⁡ ( 2 θ ) + … . {\displaystyle {\begin{aligned}&{\frac {dy}{dx}}=A_{0}+A_{1}\cos(\theta )+A_{2}\cos(2\theta )+\dots \\&\gamma (x)=2(\alpha +A_{0})\left({\frac {\sin \theta }{1+\cos \theta }}\right)+2A_{1}\sin(\theta )+2A_{2}\sin(2\theta )+\dots {\text{.}}\end{aligned}}} The resulting lift and moment depend on only

1045-648: The convolution equation ( α − d y d x ) V = − w ( x ) = − 1 2 π ∫ 0 c γ ( x ′ ) x − x ′ d x ′ , {\displaystyle \left(\alpha -{\frac {dy}{dx}}\right)V=-w(x)=-{\frac {1}{2\pi }}\int _{0}^{c}{\frac {\gamma (x')}{x-x'}}\,dx'{\text{,}}} which uniquely determines it in terms of known quantities. An explicit solution can be obtained through first

1100-411: The trailing edge angle . The slope is greatest if the angle is zero; and decreases as the angle increases. For a wing of finite span, the aspect ratio of the wing also significantly influences the slope of the curve. As aspect ratio decreases, the slope also decreases. Thin airfoil theory is a simple theory of airfoils that relates angle of attack to lift for incompressible, inviscid flows . It

1155-663: The 1/4 chord point will thus be C M ( 1 / 4 c ) = − π / 4 ( A 1 − A 2 ) . {\displaystyle C_{M}(1/4c)=-\pi /4(A_{1}-A_{2}){\text{.}}} From this it follows that the center of pressure is aft of the 'quarter-chord' point 0.25 c , by Δ x / c = π / 4 ( ( A 1 − A 2 ) / C L ) . {\displaystyle \Delta x/c=\pi /4((A_{1}-A_{2})/C_{L}){\text{.}}} The aerodynamic center

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1210-467: The 1980s revealed the practicality and usefulness of laminar flow wing designs and opened the way for laminar-flow applications on modern practical aircraft surfaces, from subsonic general aviation aircraft to transonic large transport aircraft, to supersonic designs. Schemes have been devised to define airfoils – an example is the NACA system . Various airfoil generation systems are also used. An example of

1265-458: The Datsun 240Z, the WS-1 is now a collector's item. Airfoil An airfoil ( American English ) or aerofoil ( British English ) is a streamlined body that is capable of generating significantly more lift than drag . Wings, sails and propeller blades are examples of airfoils. Foils of similar function designed with water as the working fluid are called hydrofoils . When oriented at

1320-409: The NACA 4-digit series such as the NACA 2415 (to be read as 2 – 4 – 15) describes an airfoil with a camber of 0.02 chord located at 0.40 chord, with 0.15 chord of maximum thickness. Finally, important concepts used to describe the airfoil's behaviour when moving through a fluid are: In two-dimensional flow around a uniform wing of infinite span, the slope of the lift curve is determined primarily by

1375-466: The United States for software development. The company aimed WS-1 at users of APL , a programming language that uses graphic symbols to represent most functions and operators. To this end, the WS-1's 70-key QWERTY keyboard includes a second layer with APL symbols , activated via a function key actuated in tandem with the desired symbol. The WS-1's included APL programming environment of choice

1430-635: The WS-1 in Japan in November 1985. Workspace Computer, Inc., of Torrance, California , secured the rights to resell the WS-1 in the United States, while Nissei, a subsidiary of Nissan, secured the rights to resell it in the United Kingdom. The WS-1 reportedly never shipped in the United States, according to Jalopnik , on account of the laptop failing to meet the FCC Class A RF emissions compliance . Due to its unique styling, use of APL, and ties to

1485-401: The WS-1 was slated to come in multiple SKUs of varying amounts of CMOS RAM on board, with a 1-MB ceiling via RAM expansion cartridges in increments of 64 KB. The laptop was later manufactured as a single configuration set at 64 KB, expandable via the aforementioned cartridges to a lower RAM ceiling of 512 KB. While Ampere designed the WS-1's hardware in Japan, they turned to

1540-466: The WS-1 with an abridged 80-column-16-line (480 × 128 pixel) LCD . They later expanded it to 25 columns (480 × 200 pixel). John J. Anderson , writing in Creative Computing , called the display an improvement over that included with the earlier Data General/One laptop: "[E]xtremely easy to read, even in less than optimal lighting conditions". Ampere delivered the first units of

1595-599: The aerodynamic center is at the quarter-chord position. Jalopnik Static Media Inc. , the business name of 7Hops.com Inc. , is an American internet company established in 2012, incorporated in Delaware, and based in Indianapolis . It operates ZergNet, a content recommendation business that promotes paid content across their network of brands. Each site the company owns uses the same website model and design, sometimes dubbed "infinite scroll", whereby content

1650-428: The airfoil at x . Since the airfoil is an impermeable surface , the flow w ( x ) {\displaystyle w(x)} must balance an inverse flow from V . By the small-angle approximation , V is inclined at angle α- dy ⁄ dx relative to the blade at position x , and the normal component is correspondingly (α- dy ⁄ dx ) V . Thus, γ( x ) must satisfy

1705-466: The airfoil generates a circulation around the blade, which can be modeled as a vortex sheet of position-varying strength γ( x ) . The Kutta condition implies that γ( c )=0 , but the strength is singular at the bladefront, with γ( x )∝ 1 ⁄ √ x for x ≈ 0 . If the main flow V has density ρ , then the Kutta–Joukowski theorem gives that

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1760-399: The airfoil itself replaced with a 1D blade along its camber line, oriented at the angle of attack α . Let the position along the blade be x , ranging from 0 at the wing's front to c at the trailing edge; the camber of the airfoil, dy ⁄ dx , is assumed sufficiently small that one need not distinguish between x and position relative to the fuselage. The flow across

1815-407: The chord line.) Also as a consequence of (3), the section lift coefficient of a cambered airfoil of infinite wingspan is: Thin airfoil theory assumes the air is an inviscid fluid so does not account for the stall of the airfoil, which usually occurs at an angle of attack between 10° and 15° for typical airfoils. In the mid-late 2000s, however, a theory predicting the onset of leading-edge stall

1870-457: The company acquired Jalopnik, an automotive blog that was a sister site to the Takeout. In October 2024, Static Media announced Hunker, a home brand it had acquired that same year, with a focus on cleaning, home improvement, garden, and lifestyle reporting. The same month, Static launched Cuteness, a website geared toward pet owners, which it had also purchased that year. On November 3, 2024,

1925-403: The design of aircraft, propellers, rotor blades, wind turbines and other applications of aeronautical engineering. A lift and drag curve obtained in wind tunnel testing is shown on the right. The curve represents an airfoil with a positive camber so some lift is produced at zero angle of attack. With increased angle of attack, lift increases in a roughly linear relation, called the slope of

1980-598: The first few terms of this series. The lift coefficient satisfies C L = 2 π ( α + A 0 + A 1 2 ) = 2 π α + 2 ∫ 0 π d y d x ⋅ ( 1 + cos ⁡ θ ) d θ {\displaystyle C_{L}=2\pi \left(\alpha +A_{0}+{\frac {A_{1}}{2}}\right)=2\pi \alpha +2\int _{0}^{\pi }{{\frac {dy}{dx}}\cdot (1+\cos \theta )\,d\theta }} and

2035-463: The following entertainment websites: Looper was the first site acquired by Static Media, in 2015. Mashed, Nicki Swift, Grunge, and the List are original Static Media brands, and all four launched in 2016. The next site Static Media added was SVG, an original brand, in 2017. SlashGear was launched in 2005 and was acquired by Static Media sometime after the company's debut, in 2015. Health Digest

2090-405: The following important properties of airfoils in two-dimensional inviscid flow: As a consequence of (3), the section lift coefficient of a thin symmetric airfoil of infinite wingspan is: (The above expression is also applicable to a cambered airfoil where α {\displaystyle \alpha \!} is the angle of attack measured relative to the zero-lift line instead of

2145-795: The laminar flow, making it turbulent. For example, with rain on the wing, the flow will be turbulent. Under certain conditions, insect debris on the wing will cause the loss of small regions of laminar flow as well. Before NASA's research in the 1970s and 1980s the aircraft design community understood from application attempts in the WW II era that laminar flow wing designs were not practical using common manufacturing tolerances and surface imperfections. That belief changed after new manufacturing methods were developed with composite materials (e.g. laminar-flow airfoils developed by Professor Franz Wortmann for use with wings made of fibre-reinforced plastic ). Machined metal methods were also introduced. NASA's research in

2200-594: The leading edge to have a lot of length to slowly shock the supersonic flow back to subsonic speeds. Generally such transonic airfoils and also the supersonic airfoils have a low camber to reduce drag divergence . Modern aircraft wings may have different airfoil sections along the wing span, each one optimized for the conditions in each section of the wing. Movable high-lift devices, flaps and sometimes slats , are fitted to airfoils on almost every aircraft. A trailing edge flap acts similarly to an aileron; however, it, as opposed to an aileron, can be retracted partially into

2255-433: The lift curve. At about 18 degrees this airfoil stalls , and lift falls off quickly beyond that. The drop in lift can be explained by the action of the upper-surface boundary layer , which separates and greatly thickens over the upper surface at and past the stall angle. The thickened boundary layer's displacement thickness changes the airfoil's effective shape, in particular it reduces its effective camber , which modifies

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2310-433: The lift force can be related directly to the average top/bottom velocity difference without computing the pressure by using the concept of circulation and the Kutta–Joukowski theorem . The wings and stabilizers of fixed-wing aircraft , as well as helicopter rotor blades, are built with airfoil-shaped cross sections. Airfoils are also found in propellers, fans , compressors and turbines . Sails are also airfoils, and

2365-747: The moment coefficient C M = − π 2 ( α + A 0 + A 1 − A 2 2 ) = − π 2 α − ∫ 0 π d y d x ⋅ cos ⁡ ( θ ) ( 1 + cos ⁡ θ ) d θ . {\displaystyle C_{M}=-{\frac {\pi }{2}}\left(\alpha +A_{0}+A_{1}-{\frac {A_{2}}{2}}\right)=-{\frac {\pi }{2}}\alpha -\int _{0}^{\pi }{{\frac {dy}{dx}}\cdot \cos(\theta )(1+\cos \theta )\,d\theta }{\text{.}}} The moment about

2420-486: The overall flow field so as to reduce the circulation and the lift. The thicker boundary layer also causes a large increase in pressure drag , so that the overall drag increases sharply near and past the stall point. Airfoil design is a major facet of aerodynamics . Various airfoils serve different flight regimes. Asymmetric airfoils can generate lift at zero angle of attack, while a symmetric airfoil may better suit frequent inverted flight as in an aerobatic airplane. In

2475-404: The region of the ailerons and near a wingtip a symmetric airfoil can be used to increase the range of angles of attack to avoid spin – stall . Thus a large range of angles can be used without boundary layer separation . Subsonic airfoils have a round leading edge, which is naturally insensitive to the angle of attack. The cross section is not strictly circular, however: the radius of curvature

2530-480: The relaunch of Chowhound, in early November 2023; the site was originally founded in 1997 and had been shut down in 2022. In early 2024, the company launched its third travel and outdoor brand, titled Islands and more focused on exotic destinations, cruises, and travel than Outdoor Guide. The print publication of Islands had been around since 1981, owned by Bonnier LLC alongside Outdoor Life , Popular Science , Marlin , and Salt Water Sportsman . The website

2585-458: The total lift force F is proportional to ρ V ∫ 0 c γ ( x ) d x {\displaystyle \rho V\int _{0}^{c}\gamma (x)\,dx} and its moment M about the leading edge proportional to ρ V ∫ 0 c x γ ( x ) d x . {\displaystyle \rho V\int _{0}^{c}x\;\gamma (x)\,dx.} From

2640-471: The underwater surfaces of sailboats, such as the centerboard , rudder , and keel , are similar in cross-section and operate on the same principles as airfoils. Swimming and flying creatures and even many plants and sessile organisms employ airfoils/hydrofoils, common examples being bird wings, the bodies of fish, and the shape of sand dollars . An airfoil-shaped wing can create downforce on an automobile or other motor vehicle, improving traction . When

2695-441: The wind is obstructed by an object such as a flat plate, a building, or the deck of a bridge, the object will experience drag and also an aerodynamic force perpendicular to the wind. This does not mean the object qualifies as an airfoil. Airfoils are highly-efficient lifting shapes, able to generate more lift than similarly sized flat plates of the same area, and able to generate lift with significantly less drag. Airfoils are used in

2750-505: The wing if not used. A laminar flow wing has a maximum thickness in the middle camber line. Analyzing the Navier–Stokes equations in the linear regime shows that a negative pressure gradient along the flow has the same effect as reducing the speed. So with the maximum camber in the middle, maintaining a laminar flow over a larger percentage of the wing at a higher cruising speed is possible. However, some surface contamination will disrupt

2805-427: Was devised by German mathematician Max Munk and further refined by British aerodynamicist Hermann Glauert and others in the 1920s. The theory idealizes the flow around an airfoil as two-dimensional flow around a thin airfoil. It can be imagined as addressing an airfoil of zero thickness and infinite wingspan . Thin airfoil theory was particularly notable in its day because it provided a sound theoretical basis for

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2860-465: Was handled and voice recording was handled by the laptop's built-in operating system, Big.DOS. The WS-1 includes a built-in speaker and microphohe, allowing the laptop to be used as a handset, an answering machine , a call recorder and transcription machine . The WS-1 sports three expansion cartridge slots, allowing the user to equip the machine with more RAM, with aftermarket software on ROMs , or with custom-burned EPROM software. On its announcement,

2915-432: Was not brought back in 2021, and it has not returned to the brand under Static Media's purview, either. Editor Allaya Cooks-Campbell, who previously worked at Health Digest, was appointed lead editor of Islands and Explore in 2023 and led Islands through its acquisition and relaunch under Static ownership. In 2024, Static Media acquired its sixth food brand, The Takeout , which originally launched in 2016. Later that year,

2970-465: Was originally launched in 2000. Though the print publication shuttered in 2014 and the publication shifted exclusively to digital, the site continued operating through the pandemic , growing to include its own Islands-brand "All-Inclusive Awards" for resorts. These annual awards ran in 2019 and 2020 and recognized resorts that had the best food, bar, rooms, pool, overwater bungalow, spa, butler service, and amenities, among other categories. The award system

3025-418: Was proposed by Wallace J. Morris II in his doctoral thesis. Morris's subsequent refinements contain the details on the current state of theoretical knowledge on the leading-edge stall phenomenon. Morris's theory predicts the critical angle of attack for leading-edge stall onset as the condition at which a global separation zone is predicted in the solution for the inner flow. Morris's theory demonstrates that

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