Since the Wright brothers invented the airplane in 1903, after a series of improvements, human beings have thoroughly mastered and perfectly applied the flight technology.

Takeoff and landing performance

The main indicator is the take-off and landing distance; Take-off and landing distances; Ground speed and ground speed.

Take-off distance refers to the ground distance from the take-off line on the airport take-off runway, releasing the brakes, sliding across the ground and climbing to a height of 25 meters above the ground. Landing distance refers to the ground distance that the plane passes from the landing airport to a height of 25 meters, after descending, level flight deceleration, falling to the ground, ground taxiing and other stages, until it stops. The take-off and landing distance is calculated only from the ground or from the ground. Ground speed refers to the instantaneous speed at which the pilot pulls back the joystick to make the plane head up and leave the ground when taking off. The smaller this value, the shorter the ground taxi distance of the aircraft. Landing speed refers to the instantaneous speed at which an aircraft lands during landing. The smaller this value, the shorter the landing process.

Cruise speed

The flight speed of an engine installed on an airplane with the lowest fuel consumption per kilometer is called cruising speed.

In the aviation field, the flight state suitable for continuous flight and near-stable flight is generally called cruising. The parameters in this state are called cruise parameters, such as cruise altitude and cruise thrust. Cruise speed is also one of the cruise parameters of the special plane. The cruise state is not unique. The cruise state of each flight depends on many factors, such as meteorological conditions, load, flight distance, economy and so on. Therefore, the cruise parameters (including cruise speed) selected for each flight are often different. It is also a cruise, because the mission requirements are different, and the cruise speed is different. Such as voyage cruise, voyage cruise, minimum fuel consumption cruise within a given interval, etc. Although the plane is required to cruise at a more fuel-efficient and economical speed, these indicators are different. Voyage cruising requires that the aircraft can fly at the longest cruising speed; Endurance cruise requires the aircraft to fly at the cruising speed with the longest idle time and so on. So the cruising speed can be subdivided into "long-distance speed" and "long-distance speed".

Maximum horizontal flight speed

When the plane flies in a horizontal straight line, the engine thrust increases to the maximum speed that can be achieved. (This speed should be able to maintain a distance of more than 3 kilometers.) Generally, the maximum horizontal flight speed of a jet plane is reached at an altitude of 1 1000 meters. For military aircraft, low-altitude flight capability is of great significance. The maximum horizontal flight speed at low altitude is an important performance index to measure multi-role fighters, attack aircraft and bombers.

minimum velocity

The lowest speed at which an airplane can maintain a uniform level flight at a certain altitude. The lower the value, the slower the take-off and landing speed of the aircraft and the shorter the required airport runway. At the same time, the stronger the safety and maneuverability of the aircraft. The minimum speed of an airplane is usually obtained at sea level.

stalling speed

The lift coefficient of aircraft increases with the increase of attack angle. When the angle of attack increases to a certain value, the lift coefficient does not rise but falls, resulting in the lift of the aircraft being less than the gravity of the aircraft, and the aircraft will fall quickly. This phenomenon is called stall.

keep patience

Battery life is also called "time of flight". It refers to the time that the plane can continue to fly when the available fuel is exhausted without refueling in the air. Endurance is one of the most important performance indexes of aircraft, which directly indicates the sustained combat or sustained flight ability of aircraft after refueling. The endurance time is related to many parameters such as flight speed, flight altitude and engine working state. Reasonable selection of flight parameters can make the aircraft consume the least fuel per unit time, and the aircraft can get the longest endurance time. At this time, the corresponding cruising speed is called "long speed".

Climbing rate

Climbing rate, also known as climbing speed or ascending train, is one of the important performance indexes of various aircraft, especially fighters. It is the height that the aircraft increases in unit time when it is required to climb constantly, and its unit of measurement is meter/second. At a certain height, when the aircraft climbs at different climb angles with the maximum throttle, the maximum climb rate that can be obtained is called the "maximum climb rate" of that height. The flight speed corresponding to the maximum climbing train flight is called "fast rising speed", and the climbing time required at this speed is the shortest. The climbing performance of an aircraft is related to the flying height. The lower the altitude, the greater the maximum climb rate of the aircraft. When the altitude increases, the engine thrust will generally decrease, and the maximum climb rate of the aircraft will also decrease accordingly. When the upper limit is reached, the climb rate is equal to 0. Take the F- 16 fighter as an example. Its maximum climbing rate at sea level is as high as 305m/s, and the altitude is 1000? When the altitude is10000m, it will drop to 283m/s, and when the altitude reaches17000m, its maximum climbing rate is only12m/s..

ceiling

The so-called ceiling refers to the lowest flying height that an aircraft can reach. When the flying height of an airplane increases gradually, the air density will decrease with the increase of the altitude, thus affecting the intake of the engine. When the air intake of the engine decreases, its thrust will generally decrease. At a certain height, the plane has no climbing ability because of insufficient thrust, so it can only maintain a level flight. This height is the ceiling of the plane. Ceiling can be divided into theoretical ceiling and service ceiling. The theoretical upper limit is defined as: the maximum altitude at which the aircraft can keep flying in a horizontal straight line with the engine at the maximum throttle. The upper service limit is defined as: when the engine is at the maximum throttle, the aircraft climb rate is a specified small value (such as 5? M/s), the corresponding flying altitude. In actual flight, due to the influence of fuel load and other factors, most aircraft can not reach the theoretical upper limit, because it takes a long time to climb to the theoretical upper limit, and the fuel will be exhausted if it fails to meet the standard. Therefore, people often use the service ceiling. The measures to improve the ceiling of the aircraft mainly include increasing the thrust of the engine at high altitude, improving the lift of the aircraft, reducing the flight resistance and reducing the weight of the aircraft.

Subsonic, transonic, supersonic and M number: Generally speaking, the flight speed of an aircraft is lower than the speed of sound, which is called subsonic flight; The flight speed of an aircraft is higher than the speed of sound, which is called supersonic flight; And the speed of the plane is equal to the speed of sound, which is called equisonic flight. In order to study the problem conveniently, people introduced the concept of M number: in the M: * * formula, V represents the flight speed (or air speed) of an airplane at a certain altitude, and A represents the local sound speed. M number is also called Mach number. For the above three flight situations, m

Return overload (g)

G is originally a symbol of gravity acceleration, and its value varies with latitude and height from sea level. The international standard value is 980.665 cm/s *. All objects on the earth are subjected to the gravity that causes lg acceleration, so all objects have weight. In the aviation field, G is generally used to represent the overload of aircraft or missiles. When aircraft and missiles do various movements, the airframe and various parts of the missile body bear various loads accordingly. The greater the overload, the greater the lift is, which means the greater the pressure on the aircraft or missile. In level flight, the lift is equal to the weight of the aircraft or missile, and the overload is equal to L. In maneuvering, the lift is often not equal to the weight of the aircraft or missile, and the overload is often not equal to L. For example, the overload 6 means that the lift is 6 times the weight of the aircraft or missile, which is expressed by 6g.

space travel

To make an object escape from the sun's gravity and fly to the outer space of the solar system, its speed must be equal to or greater than 16.7km/s, that is, the third cosmic velocity.

First Cosmic Velocity (V 1) The speed that a spacecraft must have when it makes a circular motion along the earth's surface, also known as the speed around the earth. According to the mechanics theory, V 1 = 7.9 km/s can be calculated. The spacecraft runs at an altitude of hundreds of kilometers above the ground, and the gravity on the ground is smaller than that on the ground, so its speed is slightly lower than V 1.

The second cosmic velocity (V2) When the spacecraft exceeds the first cosmic velocity V 1 to a certain value, it will break away from the gravitational field of the earth and become an artificial planet orbiting the sun. This velocity is called the second cosmic velocity, also known as the escape velocity. According to the mechanical theory, the second cosmic velocity V2 = 1 1.2km/s can be calculated. Because the moon does not exceed the gravity of the earth, the initial velocity of spacecraft launched from the ground to explore the moon is not less than10.848 km/s.

The minimum speed required for third cosmic velocity (V3) to launch a spacecraft from the earth's surface, fly out of the solar system and roam to the vast galaxy is called third cosmic velocity. According to the mechanical theory, third cosmic velocity V3 = 16.7km/s can be calculated. It should be noted that this is the V3 value calculated when the orbital speed of the spacecraft is consistent with the revolution speed of the Earth. If the directions are different, the required speed will be greater than 16.7 km/s, so it can be said that the speed of the spacecraft is the only factor separating from the gravity of the earth or even the sun. At present, only rockets can break the speed of the universe. Title: Flying

Author: Cai Tianxin

Press: Zhejiang University Press

Release date: 20 11July1.

ISBN:9787308087070

Format: 16

Pricing: 36.00 yuan to travel around the world for 49 days.

0. Write in front

1. Departure: Shanghai-Hangzhou Line

2. Pudong International Airport

3. Lufthansa menu

4. Think of Genghis Khan in the distance

Transsiberian

Stay in Frankfurt

7. Eiffel Tower in the moonlight

8. Visit Lachez Cemetery

9. The fragrance of wine on the Seine River

10. London as a transit point

1 1. Eliot's cat

12. Cambridge and Brighton

13. Flying over the North Atlantic

14. Martinique

15. Lake Maracaibo

16. Medellin Carnival

17. master's thesis defense meeting

18. Summer in Cali

19. Say goodbye to Colombia

20. Stop at the equator.

2 1. Fly over the Inca Empire

22. Arriving in Santiago

23. Visit Nie Luda's former residence

24. Valparaiso

25. Marianne's love

26. I flew to the Antarctic circle

27. From Argentina to New Zealand

Tasman sea and Maori

29. Sydney with seams

30. A trip to Amidel

3 1. Crossing the dry island country

32. Changi International Airport

33. From South China Sea to East China Sea

34. Iizuka Mathematics Conference

35. A trip to Mount Asu

36. Nagasaki of the atomic bomb

37. End: Go back to the beginning.

First visit to Europa

1. Fly to Barcelona

2. Arabic digital travel

3. Basque girls

4. Academic reports and cocktail parties

5. The largest port city in the Mediterranean.

6. Antoni Gaudi

7. First Street in Barcelona

8. The dream of Gibraltar

9. Hometown of Olympics and Football

10. Farewell to the banquet and tourism kingdom

1 1. From Barcelona to Nice

12. Micro-country: Monaco

13. I went to Italy before breakfast

14. From Monte Carlo to Paris

15. The Tour de France has reached the finish line.

16. Pompidou Center and North Island

Notre Dame and the Hyperbolic Spiral

Picasso and the street painter.

19. Lonely travelers in the East

20. St. Michel station exploded

2 1. Mobile banking in Paris

22. The last subway

23. Poets and diplomats

24. Louvre and Apollinaire

25. Lips are the tentacles of wisdom

26. From Descartes to Pound

27. China people are lost in Paris.

28. Youth Hostels and Shopping

29. From Paris to Moscow

30. Return: Another World

Interviewer: My life includes traveling.

Postscript Cai Tianxin, a native of Taizhou, Zhejiang Province, is a Ph.D. student of Shandong University, and is now a professor and doctoral supervisor in the Department of Mathematics of Zhejiang University. At the same time, he is also a poet, essayist and travel writer, and has created more than 65,438+00 works, such as poetry collection Roaming, Song of a Lonely Room, Prose Collection, On the Cliff of the Ear, Travel Notes, Walking with Elizabeth, Borges in the South, Childhood Memoirs, and. It has been translated into more than 20 languages and published in English, French, Spanish, Korean, Slavic and Turkish. He likes to draw travel maps since he was a child, and has held many personal photography exhibitions in recent years. He first saw the train on his way to college, and now he has traveled all over 94 countries and regions on five continents.