The plane is most afraid of hitting the carrier pigeon in the air, because the carrier pigeon has aluminum rings on its feet, and the metal aluminum chips will scratch the inner wall of the engine and ignite, which will cause great damage to the engine, and the pilot will turn off the engine and return with the remaining engine. Maybe you don't know that the windshield of an airplane is stronger than the fuselage.
Figures 1 and 2 are at an air show in Australia in 2019, when a C-17A transport aircraft was taking off, the No. 4 engine sucked in a big bird, a random explosion appeared and a fire appeared, the pilot urgently interrupted the take-off procedure, and opened the engine's thrust back device, avoiding the accident. The C17 uses a fence-type reverse push, which needs to change the jet flow direction of the engine from the inside, and ejects from the side air refractor to stop the aircraft as soon as possible.
A sparrow was enough to crash the engine of a plane it landed, and a bird-caused crash has killed 219 people since 1988. The formula for calculating the impact force of a bird is: 1/20×th of the square of the bird's mass × velocity ÷ half the length of the bird's body. For example, a pigeon is 20 cm long and weighs 1 pound, and the speed of the aircraft is 60 meters per second. Then according to the formula, it can be concluded that the impact force is 900 kg.
If it is an ordinary bird, it is good, after all, it is all flesh and blood, even if the relatively hard bones are mainly composed of calcium, they will be twisted into pieces when passing through the engine. Carrier pigeons are different because they are domesticated and will have metal rings on their legs, usually aluminum and of course plastic. Although the metal aluminum is not very hard, it is metal after all, much stronger than the bone, so it will cause damage to the aircraft.
Aircraft engine blades are made of composite materials and superalloys, the blades are relatively thin, and high-speed rotation, can reach 30,000 rpm / min, although the birds will be crushed after inhalation, but will also lose most of the power, at this time can only rely on the remaining engines to return to the sea. If there is a fire, the pilot will immediately turn off the engine, so the aluminum ring on the pigeon's leg is extremely damaging.
Now the fuselage of civil aviation airliners is getting thinner and thinner, which can reduce fuel consumption, the strongest of which is the windshield of civil aviation airliners, in the bird strike crash test, the windshield can withstand the direct impact of a bird weighing 1.8 kg at the highest speed. When the same bird hits the nose of the machine, a large crater will appear directly.
The fur of the fuselage of civil airliners does not exceed 2 mm, and the wing part is stronger, but it does not exceed 10 mm. Therefore, the fuselage of a civil aviation airliner is equivalent to a piece of paper, and once it collides with other objects, it will be "punctured".
The windshield is made of inorganic silicate glass composite with organic transparent materials, usually using multi-layer structures such as 388 and 386. The so-called 388, that is, the thickness of each layer of glass is 3mm, 8mm, of which the outermost 3mm glass surface needs to be coated with a transparent conductive film, with de-icing and defrosting electric heating function. In addition, it is also required to have ballistic and bird-impact safety functions.
In order to avoid bird collision accidents at the airport, bird repellent equipment such as gas cannons, terror eyes, recorded bird repellents, hunting, and breeding birds of prey will generally be used to drive them away. It is also necessary to regularly relocate the habitat of nearby birds, or directly destroy the bird habitat to drive birds away. #Punch Card Challenge Bureau ## Topic Big Inventor ##所见所得, very scientific ##大有学问 #
