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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retraction test (aircraft landing gear). A part of a 100-hour or annual inspection of an aircraft. The aircraft is raised off the floor with jacks, and the retractable landing gear is operated through its retraction and extension cycle. It is checked for its operating time and for any indication of improper operation. retread (tires). To apply new tread to a tire. The tread wears off most airplane tires long before the tire carcass is damaged or worn out, so for economical operation, the tire can be retreaded. The remaining tread is ground off and the carcass inspected. If it is in good condition, a new tread can be put on and vulcanized. A properly retreaded tire is as serviceable as a new tire, and it costs much less. retreating blade (helicopter rotor blade). The blade of a helicopter rotor moving in the direction opposite to that in which the helicopter is flying. The blade on the opposite side of the helicopter is called the advancing blade. retreating blade stall. The stall of a helicopter rotor disc that occurs near the tip of the retreating blade. A retreating blade stall occurs when the helicopter airspeed is high and the retreating blade airspeed is low. This results in a high angle of attack, which causes the stall. retrofit. A part made by a manufacturer, to be installed on a device that is no longer in production. If a new engine is developed that improves the performance of an older aircraft, a retrofit can be made to install the new engine on the older aircraft. When a retrofit part is produced, it is often sold as a kit which includes the new part and all of the necessary hardware and instructions. return manifold (fluid power system). The portion of a fluid power system through which the fluid is returned to the reservoir. return to service (aircraft maintenance operation). An aircraft is returned to service when it completes a test flight by an appropriately certified pilot. A certificated mechanic or authorized inspector must approve an aircraft for return to service after it has been inspected, repaired, or altered. revalidate. To make something valid again. Certain licenses and certificates are valid for a definite length of time. After this time has lapsed, the holder of the license or certificate must take some specified action or pass some type of test to revalidate the license. reverse-biased junction (semiconductor device). A voltage placed across the PN junction in a semiconductor device, with the positive voltage connected to the N-material and the negative voltage to the P-material. When the PN junction in a diode or a transistor is reverse-biased, the depletion area is enlarged so electrons cannot cross the junction to flow in the external circuit. reverse current (semiconductor device). Current in a semiconductor device that flows across a PN junction when the junction is reverse-biased. Reverse current is the movement of minority carriers in the semiconductor material. Also called leakage current, it increases with the temperature of the device. |
