этапы отбора и ответы. Этапы отбора и ответы. REV2. Этапы отбора в Аэрофлот
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Ground effecthttps://en.wikipedia.org/wiki/Ground_effect_(aerodynamics) In fixed-wing aircraft, ground effect is the increased lift (force) and decreased aerodynamic drag that an aircraft's wings generate when they are close to a fixed surface. When landing, ground effect can give the pilot the feeling that the aircraft is "floating". When taking off, ground effect may temporarily reduce the stall speed. The pilot can then fly just above the runway while the aircraft accelerates in ground effect until a safe climb speed is reached. When an aircraft flies at a ground level approximately at or below the length of the aircraft's wingspan or helicopter's rotor diameter, there occurs, depending on airfoil and aircraft design, an often noticeable ground effect. This is caused primarily by the ground interrupting the wingtip vortices and downwash behind the wing. When a wing is flown very close to the ground, wingtip vortices are unable to form effectively due to the obstruction of the ground. The result is lower induced drag, which increases the speed and lift of the aircraft. Flying close to a surface increases air pressure on the lower wing surface, nicknamed the "ram" or "cushion" effect, and thereby improves the aircraft lift-to-drag ratio. The lower/nearer the wing is with regards to the ground, the more pronounced the ground effect becomes. While in the ground effect, the wing requires a lower angle of attack to produce the same amount of lift. If the angle of attack and velocity remain constant, an increase in the lift coefficient ensues, which accounts for the "floating" effect. Ground effect also alters thrust versus velocity, where reduced induced drag requires less thrust in order to maintain the same velocity. Speed wobble, flutter, buffetingWobble, shimmy, tank-slapper, speed wobble, and even death wobble are all words and phrases used to describe a quick (4–10 Hz) oscillation of primarily just the steerable wheel(s) of a vehicle. Initially, the rest of the vehicle remains mostly unaffected, until translated into a vehicle yaw oscillation of increasing amplitude producing loss of control. Vehicles that can experience this oscillation include motorcycles and bicycles, skateboards, and in theory any vehicle with a single steering pivot point and a sufficient amount of freedom of the steered wheel, including that which exists on some light aircraft with tricycle gear where instability can occur at speeds of less than 50 mph; this does not include most automobiles. The initial instability occurs mostly at high speed and is similar to that experienced by shopping cart wheels and aircraft landing gear. Flutter is a combination of self-exciting undamped bending and twisting auto-oscillations of the aircraft's design elements: mainly the wing of an airplane or the helicopter's main rotor. As a rule, the flutter manifests itself when a certain critical velocity is reached, depending on the characteristics of the structure of the aircraft; The resulting resonance can lead to its destruction. Buffeting - one of the types of self-oscillation, which is a forced oscillation of the entire structure or its parts, caused by the periodic disruption of turbulent vortices from located in front of the structural elements during their flowing. For aircraft, buffeting often manifests itself as a sudden unsteady tail oscillation caused by aerodynamic impulses from the vortices behind the wing. Подхват самолета (aerodynamic pick-up)https://ru.wikipedia.org/wiki/%D0%90%D1%8D%D1%80%D0%BE%D0%B4%D0%B8%D0%BD%D0%B0%D0%BC%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B9_%D0%BF%D0%BE%D0%B4%D1%85%D0%B2%D0%B0%D1%82 Aerodynamic pick-up - spontaneous (not associated with the actions of pilots) increase in the pitch (angle of attack) of the aircraft. The pickup effect is associated with the dynamic unbalance of the aircraft in relation to the environment in which it moves (air). Causes of aerodynamic pick-up: Offset of the center of gravity of the aircraft in flight Change in thrust of engines (power) Change the point of application of the lifting force Симметричный профиль vs несимметричныйAirfoil design is a major facet of aerodynamics. Various airfoils serve different flight regimes. Asymmetric airfoils can generate lift at zero angle of attack, while a symmetric airfoil may better suit frequent inverted flight as in an aerobatic airplane. In the region of the ailerons and near a wingtip a symmetric airfoil can be used to increase the range of angles of attack to avoid spin–stall. Thus a large range of angles can be used without boundary layer separation. Subsonic airfoils have a round leading edge, which is naturally insensitive to the angle of attack. The cross section is not strictly circular, however: the radius of curvature is increased before the wing achieves maximum thickness to minimize the chance of boundary layer separation. This elongates the wing and moves the point of maximum thickness back from the leading edge. Принцип работы высотомера, вариометра, указателя скорости (Рассказать про полное аэродинамическое давление и статическое давление)Static pressure is the result of the weight of the atmosphere pressing down on the air beneath. Static pressure will exert the same force per square metre on all surfaces of an airplane. The lower the altitude the greater the force per square metre. Dynamic pressure is the pressure of the air molecules impacting onto a surface caused by either the movement of a body (e.g., an aircraft) through the air or the air flowing over a stationary object. The altimeter is an instrument that measures the height of an aircraft above a given pressure level. The pressure altimeter is an aneroid barometer that measures the pressure of the atmosphere at the level where the altimeter is located, and presents an altitude indication in feet. The altimeter uses static pressure as its source of operation. A stack of sealed aneroid boxes comprise the main component of the altimeter. An aneroid box is a sealed box that is evacuated to an internal pressure of 29.92 inches of mercury (29.92 "Hg). These boxes are free to expand and contract with changes to the static pressure. A higher static pressure presses down on the boxes and causes them to collapse. A lower static pressure (less than 29.92 "Hg) allows the boxes to expand. A mechanical linkage connects the box movement to the needles on the indicator face, which translates compression of the boxes into a decrease in altitude and translates an expansion of the boxes into an increase in altitude. The VSI, which is sometimes called a vertical velocity indicator (VVI), indicates whether the aircraft is climbing, descending, or in level flight. Although the VSI operates solely from static pressure, it is a differential pressure instrument. It contains a diaphragm with connecting linkage and gearing to the indicator pointer inside an airtight case. The inside of the diaphragm is connected directly to the static line of the pitot-static system. The area outside the diaphragm, which is inside the instrument case, is also connected to the static line, but through a restricted orifice (calibrated leak). Both the diaphragm and the case receive air from the static line at existing atmospheric pressure. The diaphragm receives unrestricted air while the case receives the static pressure via the metered leak. When the aircraft is on the ground or in level flight, the pressures inside the diaphragm and the instrument case are equal and the pointer is at the zero indication. When the aircraft climbs or descends, the pressure inside the diaphragm changes immediately, but due to the metering action of the restricted passage, the case pressure remains higher or lower for a short time, causing the diaphragm to contract or expand. This causes a pressure differential that is indicated on the instrument needle as a climb or descent. The airspeed indicator shows the aircraft's speed (usually in knots) relative to the surrounding air. ASI measures pressure difference (dynamic) between impact (total) and static pressure. Capsule is fed with impact pressure, instrument case – with static. The needle tracks pressure differential but the dial is marked off as airspeed. The dynamic pressure represents the indicated airspeed (IAS) as knots per hour. The instrument is color coded to indicate important airspeeds such as the stall speed, never-exceed airspeed, or safe flap operation speeds. The attitude indicator (also known as an artificial horizon) shows the aircraft's relation to the horizon. From this the pilot can tell whether the wings are level (roll) and if the aircraft nose is pointing above or below the horizon (pitch). This is a primary instrument for instrument flight and is also useful in conditions of poor visibility. Pilots are trained to use other instruments in combination should this instrument or its power fail. AHRS Rather than using a spinning rotor for the horizon reference, modern AHRS use 3-dimension magnetometers and accelerometers to detect the airplane's pitch and roll attitude, with no moving parts. A gyroscope is a body (usually a rotor/wheel) rotating freely in one or more directions that possesses the gyroscopic properties of rigidity and precession. Temperature Errorhttps://www.skybrary.aero/index.php/Altimeter_Temperature_Error_Correction Altimeter Temperature Error Correction is applied to altimeters to compensate for error caused by deviation from ISA conditions. Pressure altimeters are calibrated to ISA conditions. Any deviation from ISA will result in error proportional to ISA deviation and to the height of the aircraft above the aerodrome pressure datum. When temperature is LESS than ISA an aircraft will be LOWER than the altimeter reading. For example, if the OAT is - 40 °C then for a 2000 ft indicated altitude the true altitude is 1520 ft thus resulting in a lower than anticipated terrain separation and a potential obstacle-clearance hazard. When the aerodrome temperature is 0°C or colder, the temperature error correction must be added to: DH/DA or MDH/MDA and step-down fixes inside the final approach fix (FAF). All low altitude approach procedure altitudes in mountainous regions (terrain of 3000 ft AMSL or higher) IAS, TAS, CAS, mach numberIndicated airspeed (IAS) is a measure of dynamic pressure translated to a speed and displayed to the pilot on the airspeed indicator (ASI) usually as knots per hour. IAS uncorrected for variations in atmospheric density, installation error, or instrument error. Manufacturers use this airspeed as the basis for determining aircraft performance. Takeoff, landing, and stall speeds listed in the AFM/ POH are IAS and do not normally vary with altitude or temperature. Calibrated airspeed (CAS) — IAS corrected for installation and instrument error. The Calibrated Air Speed (CAS) is obtained from the difference between the total pressure (Pt) and the static pressure (Ps). Equivalent airspeed (EAS) is the airspeed at sea level in the International Standard Atmosphere at which the dynamic pressure is the same as the dynamic pressure at the true airspeed (TAS) and altitude at which the aircraft is flying. EAS is Calibrated airspeed (CAS) corrected for compressibility error. True airspeed (TAS) is the speed of the airplane relative to the air mass. TAS is CAS with air density (altitude and temperature) and compressibility correction. The true airspeed is important information for accurate navigation of an aircraft. Traditionally it is measured using an analogue TAS indicator, but as the Global Positioning System has become available for civilian use, the importance of such analogue instruments has decreased. Since indicated airspeed is a better indicator of power used and lift available, True airspeed is not used for controlling the aircraft during taxiing, takeoff, climb, descent, approach or landing; for these purposes the Indicated airspeed – IAS or KIAS (knots indicated airspeed) – is used. Ground Speed is equal True Air Speed + Wind Component. The Mach Number is a ratio of the TAS to the local speed of sound and displayed to the pilot on the Mach meter instrument. For example, half the LSS would be shown as 0.5 Mach. V1, Vr, V2, Vmcg, etc.V1 (decision speed) is the maximum speed at which the crew can decide to reject the takeoff, and is ensured to stop the aircraft within the limits of the runway. VR is the speed at which the pilot initiates the rotation, at the appropriate rate of about 3° per second. VLOF is the calibrated airspeed at which the airplane first becomes airborne. V2 is the minimum climb speed that must be reached at a height of 35 feet above the runway surface, in case of an engine failure. VMCG, the minimum control speed on the ground, is the calibrated airspeed during the take-off run, at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with the use of the primary aerodynamic controls alone (without the use of nose-wheel steering) to enable the take-off to be safely continued using normal piloting skill. VMCA is the calibrated airspeed, at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine still inoperative, and maintain straight flight with an angle of bank of not more than 5 degrees. VMCL, the minimum control speed during approach and landing with all engines operating, is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine still inoperative, and maintain straight flight with an angle of bank of not more than 5º. VMU is the calibrated airspeed at and above which the airplane can safely lift off the ground, and continue the takeoff. VS1g, which corresponds to the maximum lift coefficient (i.e. just before the lift starts decreasing). At that moment, the load factor is still equal to one. VS, which corresponds to the conventional stall (i.e. when the lift suddenly collapses). At that moment, the load factor is always less than one. Vэк = Vx = Speed for Maximum Endurance = Speed for Minimum Rate of Descend Vнв = Vy = Speed for Maximum Range = Best Glide Speed (Vbg) |