时间：2011-03-11 23:18来源：蓝天飞行翻译 作者：航空 点击：次
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rocker arm (reciprocating engine component). A pivoted arm on the cylinder head of a reciprocating engine. The pushrod forces one end of the rocker arm up, and as the other end moves down, it forces the intake or exhaust valve off its seat. rocker box. The enclosed part of a reciprocating engine cylinder head that houses the valve mechanism. rocket. A flight vehicle propelled by expanding gases produced when the fuel combines with oxygen carried in the vehicle. Rocket engines can use either liquid or solid fuel, and they are not dependent upon oxygen in the atmosphere. Rockets are used to launch orbiting satellites. 14 CFR Part 1: “An aircraft propelled by ejected expanding gases generated in the engine from self-contained propellants and not dependent on the intake of outside substances. It includes any part which becomes separated during the operation.” rocket engine. A form of reaction engine whose fuel and oxidizer contain all of the oxygen needed for the release of heat energy. The released heat expands the gases which are ejected at a high velocity from a nozzle at the rear of the rocket. Rocket engines can operate in outer space where there is no atmosphere. rocketsonde (meteorology). A type of radiosonde launched by a rocket which makes its measurements during a parachute descent. Rocketsondes are capable of obtaining soundings to a much greater height than is possible by balloon or aircraft. rocking shaft (aircraft instrument component). A shaft used in the mechanism of a pressure-measuring instrument to change the direction of movement by 90° and to amplify the amount of movement. Rockwell hardness tester. A precision testing machine, used to measure the hardness of a material. A diamond pyramid or hardened steel ball is pressed by an accurately calibrated force into the surface of the material being tested. The depth to which the pyramid or ball penetrates the surface is measured with a dial indicator. The greater the depth of penetration, the softer the material. rock wool. A form of insulating material made by blowing a high-velocity stream of air through molten rock. Rock wool is fireproof, and the dead air space it contains makes it a good thermal insulator. roentgenology. The branch of science dealing with the use of X-rays. roll (aircraft flight maneuver). Rotation of an aircraft about its longitudinal axis. roll cloud (meteorology). A dense and horizontal roll-shaped cloud located on the lower leading edge of a cumulonimbus, or less often on a rapidly developing cumulus. Roll clouds indicate the presence of turbulence. roller bearing. A form of antifriction bearing that supports the load on hardened steel cylinders rolling between two hardened and polished races. Roller bearings are used for radial loads, rather than thrust loads. roll pin. A press-fit pin used as a pivot in certain types of machinery. A roll pin is made of spring steel sheet rolled into a small, open-sided cylinder. When a roll pin is pressed into a hole slightly smaller than its outside diameter, it squeezes together to fit into the hole. The spring action trying to expand the pin to its normal diameter holds it tightly in the hole. |
