Aircraft (Aircraft, plane, aeroplane, airplane, aeronef, aeroplane, flying machine), the technical term is fixed-wing aircraft (fixed-wing aircraft), which generally refers to being heavier than air, driven by a power device, and An aircraft whose wings are fixed to the fuselage and do not move relative to the fuselage and rely on the force of air on the wings to generate lift. This definition is to distinguish it from gliders and gyroplanes. Fixed-wing aircraft are currently the most common type of aircraft. The source of power includes piston engines, turboprop engines, turbofan engines or rocket engines, etc. At the same time, airplanes are also an indispensable means of transportation in modern life. An airplane has two most basic characteristics: one is that its density is greater than that of air, and it is driven forward by power; the other is that the airplane has fixed wings, and the wings provide lift to enable the airplane to soar in the sky. Anything that does not have the above characteristics cannot be called an aircraft. Both of these two are indispensable. For example: an aircraft whose density is less than that of air is a balloon or airship; if it has no power device and can only glide in the air, it is called a glider; if the wings of the aircraft are not fixed and rely on the rotation of the wings to generate lift, it is called a glider. Helicopter or gyroplane. The shapes of the upper and lower sides of an airplane's wings are different. The upper side is more convex, while the lower side is flatter. When an airplane is taxiing, the wings move in the air. From a relative motion perspective, the air flows along the wings. Since the shapes of the upper and lower sides of the wing are different, in the same time, the air on the upper side of the wing flows longer than the air on the lower side (the curve is longer than the straight line), that is, the air flow on the upper side of the wing has to be faster than the air below. According to the principle of flow mechanics, when the aircraft slides, the air pressure on the upper side of the wing is less than the lower side, which causes the aircraft to generate an upward lift. When the aircraft taxis to a certain speed, this lift reaches enough force to make the aircraft fly. So, the plane took off. To put it more intuitively: the data on the upper surface are all assumed to be 1, and the data on the lower surface are all assumed to be 2. Then: the length of the upper surface of the wing is S1, and the length of the lower surface is S2. The time for the upper surface and the lower surface to move in the air is fixed, set to T, T1=T2, from which it can be concluded: V1=S1/fingerprint T1 V2 =S2/T2 S1>S2 T1=T2, so: V1>V2, according to Panulli's theorem - "The pressure exerted by a fluid on the surrounding material is inversely proportional to the relative velocity of the fluid.", so the air on the upper surface exerts The pressure F1 on the wing is less than F2 on the lower surface. The combined force of F1 and F2 must be upward, which creates lift. Aircraft are not only widely used in civil transportation and scientific research, but also an important weapon in modern military, so they are divided into civilian aircraft and military aircraft. In addition to passenger aircraft and transport aircraft, civil aircraft also include agricultural aircraft, forest protection aircraft, aerial survey aircraft, medical ambulance aircraft, sightseeing aircraft, business aircraft, sports aircraft, experimental research aircraft, weather aircraft, aerobatic aircraft, law enforcement aircraft, etc. Aircraft can also be classified according to the shape, number and relative position of the components. According to the number of wings, it can be divided into monoplane, biplane and multi-plane. According to the position of the wings relative to the fuselage, they can be divided into low-wing, mid-wing and high-wing aircraft. According to the wing plane shape, it can be divided into straight-wing aircraft, swept-wing aircraft, forward-swept-wing aircraft and delta-wing aircraft. According to the position of the horizontal tail and the presence or absence of the horizontal tail, it can be divided into normal layout aircraft (the horizontal tail is behind the wing), canard aircraft (the front fuselage is equipped with a small wing) and tailless aircraft (no horizontal tail); normal The layout of the aircraft includes single vertical tail, double vertical tail, multiple vertical tail and V-tail. According to their uses, they can be divided into fighters, bombers, attack aircraft, and interceptors. According to the type of propulsion device, it can be divided into propeller aircraft and jet aircraft; according to the type of engine, it can be divided into piston aircraft, turboprop aircraft and jet aircraft; according to the number of engines, it can be divided into single-engine aircraft, twin-engine aircraft engine aircraft and multi-engine aircraft. According to the type of landing gear, it can be divided into land aircraft, seaplanes and amphibious aircraft.
The aircraft can also be classified according to its flight performance: According to its flight speed, it can be divided into subsonic aircraft, supersonic aircraft and hypersonic aircraft. According to the range of the aircraft, it can be divided into short-range aircraft, medium-range aircraft and long-range aircraft. Among the U.S. Air Force aircraft types, the abbreviation of attack aircraft is A, the abbreviation of bombers is B, the abbreviation of transport aircraft is C, the abbreviation of electronic warfare aircraft is E, the abbreviation of fighter aircraft is F, and the abbreviation of helicopters is H. , the abbreviation of trainer aircraft is T, the abbreviation of piston aircraft is generally P, and the abbreviation of reconnaissance aircraft is R. Boeing's main models Boeing 707 Boeing 727 Boeing 737 series aircraft is a short- to medium-range twin-engine jetliner produced by the American Boeing Company. There are nearly 1,000 737s flying in the sky at any time in the world. The 737 includes 737-100/-200, 737-300/-400/-500, and the new generation 737 includes 737-600/-700/-800/-900. The traditional 737 has been discontinued. Boeing 747 The Boeing 747 aircraft is a four-engine (engine) long-range, wide-fuselage civilian transport aircraft developed and produced by the American Boeing Company. It is the world's first wide-body jet airliner. It is a civil aviation passenger aircraft that has been successfully developed and sold. Since the Boeing 747 aircraft was put into operation, it has been the world's largest civil aviation aircraft and has monopolized the market of large transport aircraft. This situation continued until the emergence of the competitor Airbus A380 large passenger aircraft. Boeing 757 Boeing 767 Boeing 777 Boeing 787 Dreamliner The Boeing 787 is expected to start production in 2006, conduct first flight and testing in 2007, and obtain certification in 2008. It has not yet been delivered and put into operation. Airbus main models Airbus A300 Airbus A310 Airbus A320 The 320 series aircraft include A318, A319, A320 and A321, which form a single-aisle aircraft series. Airbus A330 Airbus A340 Airbus A350 Airbus A380 is a four-engine long-range 550-seat ultra-large wide-body passenger aircraft developed and produced by European Airbus Industries. When it was put into production, it was also the passenger aircraft with the largest passenger capacity in the world. The A380 is a full-length, double-cabin, four-engine passenger aircraft that can carry 850 passengers in the highest density seating arrangement and 555 passengers in a typical three-class configuration (first class - business - economy class). After the A380 was put into service, it broke the 35-year record of the Boeing 747 in the field of long-range ultra-large wide-body passenger aircraft. The emergence of the A380 ended the 30-year monopoly of the Boeing 747 in the large transport aircraft market. The civilian aircraft with the largest payload is still the Soviet-made An-225 Dream transport aircraft. Most airplanes are made up of five main parts: wings, fuselage, tail, landing gear, and powerplant. The main function of the wing is to provide lift for the aircraft to support the aircraft's flight in the air, and also play a certain role in stability and control. Ailerons and flaps are generally installed on the wings. Operating the ailerons can make the aircraft roll; lowering the flaps can increase the lift coefficient of the wings. In addition, engines, landing gear and fuel tanks can also be installed on the wings. Wings come in various shapes and numbers. In the early days when aviation technology was underdeveloped, in order to provide greater lift, aircraft were mainly biplanes or even multi-planes, but modern aircraft are generally monoplanes. In the process of wing design, a contradiction often mentioned is the stability and maneuverability of the aircraft. The upper monoplane is like a plastic bag lifted up. It is very stable, but the maneuverability is slightly worse; the lower one is like a plastic bag lifted up. The monoplane is like a vase held up, its maneuverability is very flexible, but its stability is slightly inferior. Therefore, civil aircraft generally adopt a high-wing design, while performance purposes or other aircraft with high operational requirements adopt a low-wing design. Fuselage The main function of the fuselage is to load passengers, passengers, weapons, cargo and various equipment; it can also connect other parts of the aircraft such as tail, wings and engines into a whole. But flying wings hide the fuselage within the wings. Tail The tail includes horizontal tail (flat tail) and vertical tail (vertical tail).
The horizontal tail consists of a fixed horizontal stabilizer and a movable elevator (the entire horizontal tail of some types of civilian and military aircraft is a movable control surface and does not have a dedicated elevator). The vertical tail includes a fixed vertical stabilizer and a movable rudder. The main function of the tail is to control the pitch and deflection of the aircraft, and to ensure that the aircraft flies smoothly. Landing gear, also known as landing gear, is used to support the aircraft and enable it to take off, land and park on the ground and other horizontal surfaces. The landing gear of land aircraft generally consists of shock absorbing struts and wheels. In addition, there are also landing gear with float devices specially designed for seaplane takeoff and landing, and skid landing gear for takeoff in snow. It is used to support the aircraft during take-off and landing rolls, taxiing on the ground and parking. A general aircraft landing gear has three support points. According to the arrangement of these three support points, it is often divided into front delta landing gear and rear delta landing gear. Among them, the front triangular landing gear refers to the form of landing gear with one support point in the front and two support points in the back. Aircraft using this type of landing gear often have a small elevation angle when stationary, and can quickly reach high speeds when taking off. When the speed reaches a certain value, pull the control stick backward and lower the horizontal tail. At this time, the front landing gear will be slightly raised. In an instant, the wind speed difference on both sides of the wing reaches a critical value, and the aircraft can take off after getting enough lift; rear triangle The landing gear adopts the form of two support points in the front and one support point in the back. Aircraft using this type of landing gear often have a larger elevation angle when stationary. When the aircraft reaches a certain speed on the runway, the wind speed difference on both sides of the wing will A critical point is reached. At this time, the rear landing gear will be raised. The pilot continues to push the throttle lever and at the same time pulls the operating lever backward to control the balance of the aircraft. When the speed reaches a certain value, the aircraft can take off. Power unit The power unit is mainly used to generate pulling force or thrust to make the aircraft move forward. Secondly, it can also provide power for electrical equipment on the aircraft and provide air source for air conditioning equipment and other gas equipment. The power devices of modern aircraft mainly include turbine engines and piston engines. There are four widely used power devices: aviation piston engines plus propellers; turbojet engines; turboprop engines; and turbofan engines. With the development of aviation technology, rocket engines, ramjet engines, atomic aviation engines, etc. may also be gradually adopted. In addition to the engine, the power unit also includes a series of systems that ensure the normal operation of the engine, such as the fuel supply system. When talking about the power plant of an aircraft, we have to talk about the thrust-to-weight ratio of the aircraft. The thrust-to-weight ratio is the ratio of the thrust of the aircraft to the gravity received by the aircraft. At present, the thrust of ordinary civil aircraft is less than the gravity of the aircraft, because every additional KN of thrust increases the manufacturing cost of the aircraft. So many airplanes have certain climb speeds and climb angles. When the thrust of the aircraft is greater than the gravity of the aircraft, the aircraft can achieve high-speed climb or even vertical climb. Many aircraft that require high maneuverability, such as fighter jets, have large thrust and small gravity. In addition, under the requirement of equal gravity, the greater the thrust of the aircraft, the smaller the wing area, the smaller the cruise resistance of the aircraft, the faster the speed, and the longer the taxiing distance. vice versa. In addition to the above five main parts, the aircraft is also equipped with various instruments, communication equipment, navigation equipment, safety equipment and other equipment. Other structures, such as the canard structure, consist of a rear main wing and a canard that can be understood as a front horizontal tail. That is to say, the canard is used to control the elevation angle of the aircraft, and the position of the horizontal tail is the main wing of the canard structure to control the roll of the aircraft. Tailless structure, a tailless structure aircraft that benefits from vector thrust engines, has only one mostly triangular main wing, and no horizontal tail and canards to control the elevation angle. The aircraft's elevation angle is controlled by changing the direction of the engine thrust vector. An aircraft with a three-wing structure, including a main wing, a horizontal tail, and a canard. Higher operating performance. The dual vertical tail structure is currently used in fighter jets. When the rudder is stepped on, the aircraft can turn without having to roll further. Internet transfer