The Porsche 914 or VW-Porsche 914 was a mid-engined, targa-topped two-seater roadster designed sports car manufactured and marketed collaboratively by Volkswagen and Porsche from 1969 to 1976. Ferdinand Piëch, who was in charge of research and development at Porsche, was put in charge of the 914 project, on March 1,1968, the first 914 prototype was presented. However, development became complicated after the death of Volkswagens chairman, Heinz Nordhoff and his successor, Kurt Lotz, was not connected with the Porsche dynasty and the verbal agreement between Volkswagen and Porsche fell apart. In Lotzs opinion, Volkswagen had all rights to the model, with this decision, the price and marketing concept for the 914 had failed before series production had begun. As a result, the price of the chassis went up considerably, the 914/6 sold quite poorly while the much less expensive 914/4 became Porsches top seller during its model run, outselling the Porsche 911 by a wide margin with over 118,000 units sold worldwide.
Volkswagen versions originally featured an 80 PS fuel-injected 1.7 L flat-4 engine based on the Volkswagen air-cooled engine. Porsches 914/6 variant featured a carbureted 110 PS2.0 L flat-6 engine from the 1969 911T, karmann manufactured the rolling chassis at their plant, completing Volkswagen production in-house or delivering versions to Porsche for their final assembly. The 914/6 models used lower gear ratios and high brake gearing in order to try to overcome the weight of the 6 cylinder engine along with higher power output. Suspension and handling were otherwise the same, a Volkswagen-Porsche joint venture, Volkswagen of America, handled export to the U. S. where both versions were badged and sold as Porsches. The four-cylinder cars were sold as Volkswagen-Porsches at European Volkswagen dealerships, for 1974, the 1.7 L engine was replaced by a 85 PS1.8 L, and the new Bosch L-Jetronic fuel injection system was added to American units to help with emissions control. The 914s production ended in 1976, the 2.0 L flat-4 engine continued to be used in the 912E, introduced that year as an entry-level model until the front-engined I-4 cylinder 924 was introduced the following model year.
The 914 was Motor Trends Import Car of the Year for 1970, a 914/6 GT driven by Frenchmen Claude Ballot-Lena and Guy Chasseuil won the GTS class and finished sixth overall at the 197024 Hours of Le Mans. Brian Redman used a 914/6 to scout the course in practice runs for the 1970 Targa Florio, the Porsche 914 was produced from 1969 to 1976 in the following models, * Measurement of auto motor und sport Two prototype 914s, dubbed 914/8, were built during 1969. The orange 914/8 was the first constructed, at the instigation of Ferdinand Piëch, powered by the full-blown,350 hp 908 racing engine, it was based on a surplus 914 handbuilt development prototype bodyshell, hence the many differences from the standard vehicle. The second, road-registered car, powered by a carburetted and detuned 908 race engine making 300 hp was prepared as a gift to Ferry Porsche on his 60th birthday. Also based on a spare prototype shell, it was closer to the standard car in detail. By all accounts Ferry didnt like the car very much and it is now in the Porsche Museum, neither car saw a racetrack except for the purposes of testing.
The 914/8 was not considered for production as a regular model, another factory prototype, a 914/6 surfaced in the US in 2001
North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can be considered a subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16. 5% of the land area. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia and Europe. In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7. 5% of the worlds population, North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago, the Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the migrations and the arrival of European settlers during the Age of Discovery.
Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants, European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French, the Americas are usually accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass previously unknown by Europeans. In 1507, Waldseemüller produced a map, in which he placed the word America on the continent of South America. He explained the rationale for the name in the accompanying book Cosmographiae Introductio, for Waldseemüller, no one should object to the naming of the land after its discoverer.
He used the Latinized version of Vespuccis name, but in its feminine form America, following the examples of Europa and Africa. Later, other mapmakers extended the name America to the continent, In 1538. Some argue that the convention is to use the surname for naming discoveries except in the case of royalty, a minutely explored belief that has been advanced is that America was named for a Spanish sailor bearing the ancient Visigothic name of Amairick. Another is that the name is rooted in a Native American language, the term North America maintains various definitions in accordance with location and context. In Canadian English, North America may be used to refer to the United States, usage sometimes includes Greenland and Mexico, as well as offshore islands
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder, in some engines, the piston acts as a valve by covering and uncovering ports in the cylinder wall. An internal combustion engine is acted upon by the pressure of the combustion gases in the combustion chamber space at the top of the cylinder. This force acts downwards through the rod and onto the crankshaft. The connecting rod is attached to the piston by a swivelling gudgeon pin and this pin is mounted within the piston, unlike the steam engine, there is no piston rod or crosshead.
The pin itself is of hardened steel and is fixed in the piston, a few designs use a fully floating design that is loose in both components. All pins must be prevented from moving sideways and the ends of the pin digging into the cylinder wall, gas sealing is achieved by the use of piston rings. These are a number of iron rings, fitted loosely into grooves in the piston. The rings are split at a point in the rim, allowing them to press against the cylinder with a light spring pressure. Two types of ring are used, the rings have solid faces and provide gas sealing, lower rings have narrow edges. There are many proprietary and detail design features associated with piston rings, pistons are cast from aluminium alloys. For better strength and fatigue life, some racing pistons may be forged instead, early pistons were of cast iron, but there were obvious benefits for engine balancing if a lighter alloy could be used. To produce pistons that could survive engine combustion temperatures, it was necessary to develop new alloys such as Y alloy and Hiduminium, a few early gas engines had double-acting cylinders, but otherwise effectively all internal combustion engine pistons are single-acting.
During World War II, the US submarine Pompano was fitted with a prototype of the infamously unreliable H. O. R, although compact, for use in a cramped submarine, this design of engine was not repeated. Media related to Internal combustion engine pistons at Wikimedia Commons Trunk pistons are long relative to their diameter and they act both as a piston and cylindrical crosshead. As the connecting rod is angled for much of its rotation, a longer piston helps to support this
Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power.
The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations.
In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
A chassis consists of an internal vehicle frame that supports an artificial object in its construction and use, can provide protection for some internal parts. An example of a chassis is the underpart of a motor vehicle, if the running gear such as wheels and transmission, and sometimes even the drivers seat, are included, the assembly is described as a rolling chassis. In the case of vehicles, the rolling chassis means the frame plus the running gear like engine, drive shaft, differential. An under body, which is not necessary for integrity of the structure, is built on the chassis to complete the vehicle. For commercial vehicles, a rolling chassis consists of an assembly of all the parts of a truck to be ready for operation on the road. The design of a car chassis will be different than one for commercial vehicles because of the heavier loads. Commercial vehicle manufacturers sell chassis only and chassis, as well as chassis cab versions that can be outfitted with specialized bodies and these include motor homes, fire engines, box trucks, etc.
In particular applications, such as buses, a government agency like National Highway Traffic Safety Administration in the U. S. defines the design standards of chassis. An armoured fighting vehicles hull serves as the chassis and comprises the part of the AFV that includes the tracks, drivers seat. This describes the hull, although common usage might include the upper hull to mean the AFV without the turret. The hull serves as a basis for platforms on tanks, armoured carriers, combat engineering vehicles. In an electronic device, the chassis consists of a frame or other supporting structure on which the circuit boards. In the absence of a frame, the chassis refers to the circuit boards and components themselves. The combination of chassis and outer covering is called an enclosure. Vietnam Studies, Department of the Army, Washington, D. C.1978
Air-cooled engines rely on the circulation of air directly over hot parts of the engine to cool them. Thus, while they are not ultimately cooled by the liquid, in contrast, heat generated by an air-cooled engine is released directly into the air. Typically this is facilitated with metal covering the outside of the Cylinder Head. Air may be fed with the use of a fan. In all combustion engines, a percentage of the heat generated escapes through the exhaust. About 8% of the heat energy finds its way into the oil, many motorcycles use air cooling for the sake of reducing weight and complexity. Few current production automobiles have air-cooled engines, but historically it was common for many high-volume vehicles, volkswagen Type 4 Chevrolet Corvair Citroën 2CV. Citroën GS and GSA Honda 1300 NSU Prinz Royal Enfield Motorcycles, while water cooled engines were widely used from the early days of flight, air cooled engines were the dominant choice in aircraft. Following the Second World War and jet powered aircraft have come to dominate flight regimes where water cooled piston engines offered a drag advantage.
Thus today, piston engines are used in slower general aviation aircraft where low weight is an advantage. Therefore, most aero engines produced today are of the air cooled variety, most of the engines currently manufactured by Lycoming and Continental and used by major manufacturers of light aircraft Cirrus, Cessna and so on. Notable exceptions have included the Allison V-1710 and Rolls-Royce series of liquid-cooled V12 engines which powered P-51 Mustangs, Avro Lancasters, other engine manufactures using air-cooled engine technology are ULPower and Jabiru, more active in the Light-Sport Aircraft and ultralight aircraft market. Rotax uses a combination of air-cooled cylinders and liquid-cooled cylinder heads, some small diesel engines, e. g. those made by Deutz AG and Lister Petter are air-cooled. Probably the only big Euro 5 truck air-cooled engine is being produced by Tatra, stationary or portable engines were commercially introduced early in the 1900s. The first commercial production was by the New Way Motor Company of Lansing, the company produced air-cooled engines in single and twin cylinders in both horizontal and vertical cylinder format.
Subsequent to their production which was exported worldwide, other companies took up the advantages of this cooling method. Applications include mowers, outboard motors, pump sets, saw benches, Alfred P. McDonald, John, ed. My Years with General Motors, Garden City, NY, USA, Doubleday, LCCN64011306, republished in 1990 with a new introduction by Peter Drucker
A sports car is a small, usually two seater, two door automobile designed for spirited performance and nimble handling. According to the Merriam-Webster dictionary, the first known use of the term was in 1928, Sports cars may be spartan or luxurious, but high maneuverability and minimum weight are requisite. The basis for the car is traced to the early 20th century touring cars and roadsters. These raced in rallies, such as the Herkomer Cup, Prinz-Heinrich-Fahrt. These would shortly be joined by the French DFP and the Rolls-Royce Silver Ghost. In 1921, Ballot premiered its 2LS, with a remarkable 75 hp DOHC two liter, designed by Ernest Henry, capable of 150 km/h, at most, one hundred were built in four years and this was followed by the SOHC 2LT and 2LTS. The same year, Benz built a supercharged 28/95PS four for the Coppa Florio, duerkopps Zoller-blown two liter in 1924, as well. There was a clear cleavage by 1925, by the end of the 1920s, AC produced a 2-liter six, the 3. Benz introduced the powerful SS and SSK, and Alfa Romeo, hispano-Suizas Alfonso XIII is considered the first sportcar developed between 1911 and 1914.
Two companies would offer really reliable sports cars, Austin with the Seven, the drive train and engine layout significantly influences the handling characteristics of an automobile, and is crucially important in the design of a sports car. The front-engine, rear-wheel-drive layout is common to cars of any era and has survived longer in sports cars than in mainstream automobiles. Examples include the Caterham 7, Mazda MX-5, and the Chevrolet Corvette, more specifically, many such sports cars have a FMR layout, with the centre of mass of the engine between the front axle and the firewall. In search of improved handling and weight distribution, other layouts are sometimes used, the RMR layout is commonly found only in sports cars—the motor is centre-mounted in the chassis, and powers only the rear wheels. Some high-performance sports car manufacturers, such as Ferrari and Lamborghini have preferred this layout, Porsche is one of the few remaining manufacturers using the rear-engine, rear-wheel-drive layout.
The motors distributed weight across the wheels, in a Porsche 911, provides excellent traction, Porsche has continuously refined the design and in recent years added electronic driving aids to counteract these inherent design shortcomings. The front-engine, front-wheel-drive layout layout which is the most common in sport compacts and hot hatches, its conservative handling effect, particularly understeer, and the fact that many drivers believe rear wheel drive is a more desirable layout for a sports car count against it. The Fiat Barchetta, Saab Sonett, and Berkeley cars are cars with this layout. Before the 1980s few sports cars used four-wheel drive, which had added a lot of weight
Rear-engine, rear-wheel-drive layout
In automotive design, an RR, or Rear-engine, Rear-wheel-drive layout places both the engine and drive wheels at the rear of the vehicle. In contrast to the RMR layout, the center of mass of the engine is between the axle and the rear bumper. Most of the traits of the RR configuration are shared with the mid-engine rear-wheel-drive, the front-engine front-wheel-drive layout has this advantage. The farther back the engine, the greater the bias, typical weight bias for an FR, is 55/45 front/rear, for MR, 45/55, for RR, 35/65. Rear weight bias reduces forward weight transfer under braking, and increases rear weight transfer under acceleration, the former means that traction is more evenly distributed among all four wheels under braking, resulting in shorter stopping times and distances. The latter means that the wheels have increased traction when accelerating, allowing them to put more power on the ground. The disadvantage to a weight bias is that the car can become unstable. When this happens, rotational inertia dictates that the added weight away from the axis of rotation will be likely to maintain the spin.
This is an inherent instability in the design, making it easier to induce, all cars, regardless of drivetrain layout, obey the same laws of physics and can do this, but it is much easier to do and harder to correct in MR and RR vehicles. When not braking, the weight over the front wheels means less traction, resulting in the car having a tendency to understeer. To counteract this, it is necessary to induce forward weight transfer to increase front grip, but this significantly destabilizes the car and can be hard to do properly, that is, without spinning. In these respects, an RR can be considered to be an exaggeration of MR - harder braking and earlier acceleration, and increased oversteer, in off road and low-traction situations, the RR layout has some advantages compared to other 2WD layouts. The weight is biased towards the driven wheels- as with FF vehicles and this both improves drive-wheel traction and reduces the tendency for the undriven wheels to dig in. In addition, the driving and steering requirements are split between front and rear- as with FR vehicles- making it likely for either to lose traction.
Many dune buggies successfully use a Volkswagen beetle as the car for this reason. The relative simplicity and light compared to 4WD can therefore sometimes outweigh the disadvantage of only having two driven wheels. Where RR differs from MR is in that the engine is located outside the wheelbase, the major advantage of MR - low moment of inertia - is negated somewhat, and there is more room for passengers and cargo. Furthermore, because both axles are on the side of the engine, it is technically more straightforward to drive all four wheels
Volkswagen, shortened to VW, is a German automaker founded on May 28,1937 by the German Labour Front and headquartered in Wolfsburg. It is the flagship marque of the Volkswagen Group and is the largest automaker worldwide, Volkswagen is German for peoples car, and the companys current international advertising slogan is just Volkswagen. American English pronunciation is approximately volks wagon, for vehicle timeline tables, Volkswagen. Volkswagen was originally established in 1937 by the German Labour Front, in the early 1930s, the German auto industry was still largely composed of luxury models, and the average German could rarely afford anything more than a motorcycle. As a result, only one German out of 50 owned a car, seeking a potential new market, some car makers began independent peoples car projects – the Mercedes 170H, Adler AutoBahn, Steyr 55, and Hanomag 1. 3L, among others. The trend was not new, as Béla Barényi is credited with having conceived the design in the mid-1920s. Josef Ganz developed the Standard Superior, in Germany, the company Hanomag mass-produced the 2/10 PS Komissbrot, a small, cheap rear engined car, from 1925 to 1928.
Also, in Czechoslovakia, the Hans Ledwinkas penned Tatra T77, Ferdinand Porsche, a well-known designer for high-end vehicles and race cars, had been trying for years to get a manufacturer interested in a small car suitable for a family. He felt the cars at the time were just stripped down big cars. He wanted his German citizens to have the access to a car as the Americans. The Peoples Car would be available to citizens of the Third Reich through a plan at 990 Reichsmark —about the price of a small motorcycle. Despite heavy lobbying in favor of one of the existing projects, Hitler chose to sponsor an all-new, state-owned factory using Ferdinand Porsches design. The intention was that ordinary Germans would buy the car by means of a savings scheme, the entire project was financially unsound, and only the corruption and lack of accountability of the Nazi regime made it possible. Prototypes of the car called the KdF-Wagen, appeared from 1938 onwards, the car already had its distinctive round shape and air-cooled, flat-four, rear-mounted engine.
The VW car was just one of many KdF programs, which included such as tours. The prefix Volks— was not just applied to cars, but to products in Germany. On May 28,1937, Gesellschaft zur Vorbereitung des Deutschen Volkswagens mbH, more than a year later, on September 16,1938, it was renamed to Volkswagenwerk GmbH. Erwin Komenda, the longstanding Auto Union chief designer, part of Ferdinand Porsches hand-picked team, developed the car body of the prototype and it was one of the first cars designed with the aid of a wind tunnel—a method used for German aircraft design since the early 1920s
F. Porsche AG, usually shortened to Porsche AG, is a German automobile manufacturer specializing in high-performance sports cars, SUVs and sedans. Porsche AG is headquartered in Stuttgart, and is owned by Volkswagen AG, Porsches current lineup includes the 718 Boxster/Cayman,911, Panamera and Cayenne. Ferdinand Porsche founded the company called Dr. Ing. h. c, F. Porsche GmbH in 1931, with main offices at Kronenstraße 24 in the centre of Stuttgart. Initially, the company offered motor vehicle development work and consulting, One of the first assignments the new company received was from the German government to design a car for the people, that is a Volkswagen. This resulted in the Volkswagen Beetle, one of the most successful car designs of all time, the Porsche 64 was developed in 1939 using many components from the Beetle. During World War II, Volkswagen production turned to the version of the Volkswagen Beetle, the Kübelwagen,52,000 produced. Porsche produced several designs for heavy tanks during the war, losing out to Henschel & Son in both contracts that ultimately led to the Tiger I and the Tiger II.
However, not all work was wasted, as the chassis Porsche designed for the Tiger I was used as the base for the Elefant tank destroyer. Porsche developed the Maus super-heavy tank in the stages of the war. At the end of World War II in 1945, the Volkswagen factory at KdF-Stadt fell to the British, Ferdinand lost his position as Chairman of the Board of Management of Volkswagen, and Ivan Hirst, a British Army Major, was put in charge of the factory. On 15 December of that year, Ferdinand was arrested for war crimes, during his 20-month imprisonment, Ferdinand Porsches son, Ferry Porsche, decided to build his own car, because he could not find an existing one that he wanted to buy. He had to steer the company through some of its most difficult days until his fathers release in August 1947, the first models of what was to become the 356 were built in a small sawmill in Gmünd, Austria. The prototype car was shown to German auto dealers, and when pre-orders reached a set threshold, production was begun by Porsche Konstruktionen GesmbH founded by Ferry, many regard the 356 as the first Porsche simply because it was the first model sold by the fledgling company.
After the production of 356 was taken over by the fathers Dr. Ing. h. c. In 1952, Porsche constructed a plant across the street from Reutter Karosserie, the main road in front of Werk 1. The 356 was road certified in 1948, Porsches company logo was based on the coat of arms of the Free Peoples State of Württemberg of former Weimar Germany, which had Stuttgart as its capital. The arms of Stuttgart was placed in the middle as an inescutcheon, on 30 January 1951, not long before the creation of Baden-Württemberg, Ferdinand Porsche died from complications following a stroke. The 356, had several stages, A, B, and C, while in production
Aerodynamics, from Greek ἀήρ aer + δυναμική, the study of the motion of air, particularly its interaction with a solid object, such as an airplane wing. Aerodynamics is a sub-field of fluid dynamics and gas dynamics, the term aerodynamics is often used synonymously with gas dynamics, the difference being that gas dynamics applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the sense in the eighteenth century. Most of the efforts in aerodynamics were directed toward achieving heavier-than-air flight. Recent work in aerodynamics has focused on issues related to flow, turbulence. Fundamental concepts of continuum and pressure gradients appear in the work of Aristotle, in 1726, Sir Isaac Newton became the first person to develop a theory of air resistance, making him one of the first aerodynamicists. In 1757, Leonhard Euler published the more general Euler equations which could be applied to both compressible and incompressible flows, the Euler equations were extended to incorporate the effects of viscosity in the first half of the 1800s, resulting in the Navier-Stokes equations.
The Navier-Stokes equations are the most general governing equations of fluid flow, in 1871, Francis Herbert Wenham constructed the first wind tunnel, allowing precise measurements of aerodynamic forces. Drag theories were developed by Jean le Rond dAlembert, Gustav Kirchhoff, in 1889, Charles Renard, a French aeronautical engineer, became the first person to reasonably predict the power needed for sustained flight. Otto Lilienthal, the first person to become successful with glider flights, was the first to propose thin, curved airfoils that would produce high lift. Building on these developments as well as carried out in their own wind tunnel. During the time of the first flights, Frederick W. Lanchester, Martin Wilhelm Kutta and Zhukovsky went on to develop a two-dimensional wing theory. Expanding upon the work of Lanchester, Ludwig Prandtl is credited with developing the mathematics behind thin-airfoil, as aircraft speed increased, designers began to encounter challenges associated with air compressibility at speeds near or greater than the speed of sound.
The differences in air flows under such conditions leds to problems in control, increased drag due to shock waves. The ratio of the speed to the speed of sound was named the Mach number after Ernst Mach who was one of the first to investigate the properties of supersonic flow. Theodore von Kármán and Hugh Latimer Dryden introduced the term transonic to describe flow speeds around Mach 1 where drag increases rapidly, by the time the sound barrier was broken, aerodynamicists understanding of the subsonic and low supersonic flow had matured. The Cold War prompted the design of an line of high performance aircraft. Understanding the motion of air around an object enables the calculation of forces, in many aerodynamics problems, the forces of interest are the fundamental forces of flight, drag and weight