How many seconds are there in an ordinary 24-hour day? It turns out, only 86400 (24x60x60). So: there are more than 85,000 flights per day, on average, by civil aviation alone (and then there are military aircraft, transport aircraft, and the private airline fleet). This means that planes take off or land every second. At any time of the day or night. 365 days a year.
Heavier than air
Sometimes even brilliant minds are eclipsed, otherwise one cannot explain the remark by the prominent physicist J. Thomson, made in 1895 at a meeting of the Royal Society of Science: “Aircraft heavier than air cannot fly”? Has the eminent scientist, having lived to a respectable age, lost his sight and memory? After all, birds do fly!
However, it is possible that Thomson’s words were misinterpreted, as happened later with the statement of the reputable astronomer and mathematician Simon Newcom that “no combination of mechanisms and known forms of energy can make any machine heavier than air fly”. It turned out that Newcom was referring only to the level of modern machines and mechanisms, and not an absolute denial of the possibility of flight. The reason for such a harsh statement was the work of Professor Samuel Pierpont Langley. The famous astronomer, having gained authority by pioneering works on the physics of the Sun, suddenly with a youthful enthusiasm began to design and build flying machines, in the future – manned and equipped with an engine.
The latter fact was what confused Newcom the most. At that time (in the last quarter of the XIX century) steam engines prevailed – the devices are very bulky and heavy. Their specific weight, that is, the ratio of the total mass of the machine to the power produced, exceeded a centner per horsepower! What was suitable for ships (for which the weight of the power plant is not so critical) was of little use for aircraft. Alberto Santos-Dumont, the aviation pioneer who challenged the Wright Brothers, partly confirmed Newcom’s fears. His first flying machines, which marked an attempt to fly where one wants to fly rather than in the direction of the wind, were motor-driven airships, floating in the air ocean by Archimedes’ force.
To Professor Langley’s credit, his steam-powered airplanes flew quite successfully. The lack of engine power was compensated for by a launching catapult installed on a barge in the middle of the Potomac River. On May 5, 1896, Langley’s unguided machine flew about a mile and landed safely on the river, partially defeating the predictions of the skeptics
Wright Brothers
But why the Wright Brothers and not the same Langley, Santos-Dumont or Mozhaysky? Why not the desperate Otto Lilienthal, who devoted and gave his life to solving the phenomenon of soaring birds? The answer is simple: we are talking about controlled, manned flight in an arbitrary direction on a heavier-than-air aircraft equipped with a propulsion system that allows you to get off the ground on your own. “Flyers” (Flyer I, II, III) were built according to the “biplane” scheme with two supporting wings, partly borrowed from Lilienthal.
But the main thing was something else: the Flyer control system made it possible to control the glider movement along three spatial axes. The wing tilt created a roll (longitudinal axis), the nose rudder of altitude (this scheme the tail rudder controlled yaw (vertical axis), and the tail rudder controlled yaw (vertical axis). In the vast majority of cases, modern airplanes retained the control system invented by the Wright brothers.
Only half a century later, another method of motion control was introduced on jet machines – controlled thrust vectoring, first commercially used on deck fighters – vertical takeoff bombers “Harrier” of the British firm Hawker Siddeley.
“Pilot” cost the brothers only 1000 dollars (at today’s prices – about 27 thousand, the price of not the most “cool” “parket”). Thus, only own money earned by sale and repair of bicycles was spent on the project. Even the Wright family had to make the 16-horsepower gasoline engine themselves: the market had nothing similar to offer. The result of their efforts went down in history along with the first manned space flight: December 17, 1903, 59 seconds of flight, a distance of 260 meters.
Henceforth aviation
Henceforth aviation decided on the main direction of development, putting aside the previously promising projects of flyboys, gyroplanes, etc. Although, to be fair, it should be noted that in terms of energy efficiency, i.e. energy consumption for moving a unit of mass, airplanes are still losing to birds. Let us compare such a parameter as power load. It shows how much mass is lifted into the air by one horsepower. For example, a goose has a power load of 150 kg/hp, and a pigeon has 40-45 kg/hp. What about this value in airplanes? The most mass combat aircraft of all time Il-2 can “boast” of only… 4 kg/hp. The most popular fighter in history, the German Bf109 of the final modifications – 1.7 kg / hp And the legendary DC-3 barely exceeds 5 kg / hp!
The airplanes of the XXI century have not gone far at all. Having replaced the piston engines in the jet turbines, increasing speed, payload and range, they still “trample” near the mark of 10 kg / hp, hopelessly inferior to the most brilliant designer – nature.
Chasing the evolution of single-engine piston fighter firm Messerschmitt (Germany) has become the most mass machine of the class. It was produced in quantities of over 30 thousand in dozens of modifications. The Bf109 is one of the few aircraft that, figuratively speaking, went through the entire Second World War, including the Spanish Civil War. The bird’s wing is a model of functionality and rationality, honed by evolution over millions of years. It simultaneously serves as a source of thrust and creates lift, while allowing an almost instantaneous change of direction and speed of flight (in airplanes, these functions are divided between numerous nodes).
Formally, both the airplane and the swallow stay in the air due to the Bernoulli effect, which links the flow velocity of the medium (gas or liquid) with the dynamic pressure: the lower the one, the higher the other. Note that the effect is true only for laminar, i.e. smooth and continuous, flows. At turbulence, orderliness is replaced by chaos, leading to unpredictable local perturbations of density, velocity and pressure of the medium.
German turbojet fighter designed by Willi Messerschmitt, bomber and reconnaissance aircraft of World War II. The world’s first mass-produced turbojet and the world’s first jet fighter involved in combat operations.
Nature came up with a brilliant antidote – feathers! It turns out that they destroy the micro-rotations of air on the rear surface of the wing, restoring the laminar nature of the airflow. Notice how geese or ducks flap their wings loudly on takeoff.
Maximum lift is needed for takeoff, and this can only be achieved at a large angle of attack (the angle between the direction of airflow and the plane of the wing). But under such uncomfortable aerodynamic conditions, the air flow behind the wing turns into turbulent, increasing the drag, so the bird has to take off in the afterburner mode, spreading out and flapping its wings more vigorously.
After gaining altitude, it switches to economical cruising with a low angle of attack and low drag. It is under these conditions that the wing shows itself in all its brilliance, allowing, for example, the golden plover (Pluvialis) to cross the Pacific Ocean from Alaska to Hawaii without landing. And that’s 3,500 kilometers! The B-29 Superfortress is at the limit and behind it. This strategic bomber, which was the first and only aircraft in the world to use atomic weapons for their intended purpose, was also developed under the direction of Assen Jordanov.
What is easy and natural in aviation is achieved by mechanization, which turns the wing into a complex and expensive machine, not at all like the cloth-covered planes of the first airplanes. All these flaps, leading-edge flaps, spoilers, interceptors and flaps are the fruits of aerodynamic compromises, allowing the configuration of the single supporting plane to be changed to some extent. It works best in cruising flight mode, when the aircraft is flying at high speed at a considerable altitude.
The wings are streamlined by a laminar flow of air, creating a relatively small lifting force and not providing much resistance. One of the first jet-powered long-haul passenger airliners. Thanks largely to it, commercial passenger transportation became fast, comparatively cheap and comfortable. Produced from 1956 to 1991, the plane was built in the quantity of 1,010 copies only in civilian version.
Numerous military modifications – KS-135 (air tanker), E6 and E8 (electronic reconnaissance and target designation aircraft), E3 “AWACS” – are still used today. Takeoff and landing, the shortest and most critical phases of flight (80% of crashes occur in the first three minutes after takeoff and the final eight minutes before landing), are another matter. This is when the mechanization of the wing shows its full brilliance.
Low speeds, non-uniformity of the ground air mass, big angles of attack (remember the goose!) make the wing geometry change literally on the fly, and some machines (most often military) solve the problem even more radically – they change the wings sweep angle! Keeping time One of the most mass and widely known transport-passenger planes designed by Assen Jordanov, American engineer of Bulgarian origin.
The DC-3 made its first flight in 1935. The total production output was more than 16 thousand machines. And to this day in service are almost half a thousand planes! The plane changed the idea of travel forever, reminding man every time that the most precious and irreplaceable thing is time. It has literally raised mobility to unprecedented heights, allowing the average passenger to see more in a few minutes than his distant ancestors could see in a lifetime. It’s hard to imagine, but at any given time almost a quarter of a million people are in the air, an entire flying city, and in a year its “population” is nearly 4 billion passengers (“pax” in pilots’ slang).
At the dawn of the XX century pioneers could not have imagined that in just 2-3 generations, aviation from an amusing and often dangerous “toy” will become an extremely powerful force, changing transportation, military affairs and culture, and the fragile “etagger”, created by the work and talent of engineers and designers, will turn into silvery beauties linking the vast planet into a single whole.
Of course: aviation is the highest speed of transportation, relatively low dependence on the condition and functioning of ground technical means (mainly airfields and means of control and dispatch services). The world’s first supersonic passenger airliner designed by A.N. Tupolev. N.Tupolev design.
The plane was flown on the line “Moscow-Almaty” for only 7 months (1977-78), then its operation was considered as too difficult and expensive. Despite this, the plane became a symbol of Soviet aviation engineering and jet passenger aviation in general. However, one should not be too flattered. Aviation is still too expensive for really mass use, otherwise it is difficult to explain the boom of the so-called “discounters”-“low-cost carriers (more than 20% of the airline market), offering low prices by “cutting” part of the services and amenities.
We should not forget about the dependence of aircraft on meteorological conditions, which greatly affects the safety and efficiency of flights. It is also important that the burning of each kilogram of aviation fuel (most often kerosene) leads to the emission of more than 3 kilograms of carbon dioxide, water vapor and soot into the atmosphere. And if we take into account that the long-haul Boeing 747 has fuel reserves of up to 180 tons, we can imagine how much of the vital oxygen is lost from the atmosphere just for one flight.
The iconic plane, which became the most recognizable “movie hero” of all civil planes. Produced in 1,446 units, it is still in production today only in a cargo version. The current U.S. president’s VC-25 aircraft is a converted special-order Boeing 747-200B version from 1990.
The situation is somewhat better with the newer machines. Thus, relatively recently introduced Airbus A380, Boeing 787 Dreamliner, ATR-600 and some others use less than three liters of fuel per 100 passenger-kilometers. Not all compact cars can boast such parameters! But the most powerful and expensive Ferrari cannot do what even a decrepit airplane can do – it cannot fly…