The mast is a cylindrical metal shaft that extends upwards from the transmission. The rotor consists of a mast, hub and rotor blades. A rotor system may be mounted horizontally, as main rotors are, providing lift vertically, or it may be mounted vertically, such as a tail rotor, to provide horizontal thrust to counteract torque from the main rotors. The rotor system, or more simply rotor, is the rotating part of a helicopter that generates lift. The compound helicopter also has a separate thrust system, but continues to supply power to the rotor throughout normal flight. By contrast the autogyro (or gyroplane) and gyrodyne have a free-spinning rotor for all or part of the flight envelope, relying on a separate thrust system to propel the craft forwards, so that the airflow sets the rotor spinning to provide lift. In the United States military, the common slang is "helo" pronounced with a long "e".ĭesign characteristics Main and anti-torque rotorsĪ helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more horizontally-spinning rotors. English language nicknames for "helicopter" include "chopper", "copter", "heli", and "whirlybird". For various reasons, the word is often erroneously, from an etymological point of view, analysed by English speakers into heli- and copter, leading to words like helipad and quadcopter. The English word helicopter is adapted from the French word hélicoptère, coined by Gustave Ponton d'Amécourt in 1861, which originates from the Greek helix ( ἕλιξ) "helix, spiral, whirl, convolution" and pteron ( πτερόν) "wing". Quadrotor helicopters ( quadcopters) were pioneered as early as 1907 in France, and along with other types of multicopters, have been developed mainly for specialized applications such as drones. However, twin-main rotor helicopters (bicopters), in either tandem or transverse rotors configurations, are sometimes in use due to their greater payload capacity than the monorotor design, and coaxial-rotor, tiltrotor, and compound helicopters are also all flying today. unicopter, not to be confused with the single-blade monocopter) has become the most common helicopter configuration. Īlthough most earlier designs used more than one main rotor, the configuration of a single main rotor accompanied by a vertical anti-torque tail rotor (i.e. In 1942, the Sikorsky R-4 became the first helicopter to reach full-scale production. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of short take-off and landing ( STOL) or short take-off and vertical landing ( STOVL) aircraft cannot perform without a runway. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally.
#Two bladed helio copter series#
Show that the resulting series does not represent the data.For other uses, see Helicopter (disambiguation).Ī Bell 206 helicopter operated by the Los Angeles Police Department Air Support DivisionĪ helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. (e) Find the ak's and be's for several values of kmax(where N the number of data points). Recall that a function has a maximum or a minimum when its derivative equals zero. Find the peak-to-peak amplitude by finding the maximum and minimum values of p as predicted by the Fourier series solution. Would you feel comfortable using this function to interpolate the data? Why or why not? (d) The actual loudness of the helicopter depends on the maximum peak-to-peak amplitude of the signal. (c) Plot the function (inverse Fourier transform) and the original data on the same plot. k to illustrate the relative size of each term in the series. (b) Any term in the Fourier series can be written: where ck =Val-Hand ?,-tan-1-ok Find the cy's and plot their amplitude on a bar graph vs. The data points are equally spaced in time, and the period of the data collection is of a seconed. The following data show measurements of acoustic pressure (made dimensionless) for a two-bladed helicopter rotor through of a rotor revolution. The army is interested in characterizing the acoustic signature of a helicopter.
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