直升机教员手册 Helicopter Instructor’s Handbook
时间：2014-11-10 08:35来源：FAA 作者：直升机翻译 点击：次
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To view this page ensure that Adobe Flash Player version 9.0.124 or greater is installed. Instructor Tips . Always practice positive exchange of controls procedures and acknowledgments by using a three way positive transfer of controls. [Figure 4-7] This is particularly important in the early stages of training when either the student or the flight instructor is on the controls for a long period of time. If the instructor or the student is following along on the controls, ensure that both understand who has ultimate control over the flight controls. . Always emphasize making smooth, coordinated control inputs. . Always stay close to the controls. Be ready to take control of the aircraft and never underestimate the student’s ability to make a mistake. . Always practice initial hovering over smooth surfaces, free of any protrusions that might catch the landing gear. A lack of protrusion may allow the landing gear to slide freely in case of accidental ground contact. Chapter Summary This chapter provided the instructor with techniques of introducing flight controls and their application to a student. It also offered the instructor safety related points of emphasis regarding helicopter flight controls. In addition to introducing the student to the various helicopter components and systems, the instructor should also educate the student on the different types of materials that are used to make the components and the positive and negative factors of each. If the student understands the various factors of the components, the information can begin to form the basis of component condition knowledge. This should enable the student to better determine the flight status of the components and what failure modes can appear as well as what the record of the material is. Instructors should be creative and attempt to explore comparisons for all helicopter components and systems. There are no two helicopters alike from one manufacturer to another. Flying a helicopter new to the pilot should always include some ground school instruction on the systems and a flight checkout on the specific characteristics of that helicopter. Students should never assume that knowledge of one helicopter’s systems should transfer to another. Airframe Design Airframe design is a field of engineering that combines aerodynamics, materials technology, and manufacturing methods to achieve balances of performance, reliability and cost, which can affect both maintenance and flight. Composites, for example, are very sensitive to ultraviolet (UV) radiation from the sun and must be painted to protect them, whereas aluminum has minimum UV degradation from the sunlight but will corrode over time if flown around salt water. Aluminum is light and reasonable easy to fabricate into parts, but composites can be much stronger although more difficult to manufacture. In addition, composite materials seem to suffer from bonding failures. In some structures, this appears as a thickening or expansion, sometimes forming a bubble in an area. Rotor Blade Design Wooden rotor blades have an infinite fatigue life provided that moisture is kept out of them. The metal attachment fittings on the wooden blade do have a fatigue life; therefore, a life limit is placed on the blade. Although wooden blades are used, they do not perform as well as modern metal or composite blades. Another comparison is composite rotor blades versus metal rotor blades. Composite rotor blades are closer to an “on condition” replacement status, potentially saving thousands of dollars for operations but are softer and at least require the leading edge abrasion strip to be replaced. Metal blades are generally less expensive to manufacture; composite blades may perform better and last longer with less maintenance, but at a higher initial cost. Powerplant Design When discussing the powerplant, comparisons of reciprocating and turbine engines can be explained. A reciprocating engine uses much less fuel than a turbine engine does, but turbine engines can produce much more power from a very light powerplant for more flight hours. However, a turbine engine can easily be ten times the cost of a reciprocating powerplant. Turbine engines are usually much more reliable, but failures are often much more dramatic with high-speed shrapnel flying through other structures, causing tremendous damage throughout the powerplant. Antitorque System Design Enclosed antitorque tailrotor systems are usually more resistant to foreign object damage but can be more complicated to build and heavier, which causes them to perform less well than open antitorque systems. Open tailrotors may perform better aerodynamically with less weight and less cost but are more vulnerable to damage and tend to produce more drag when flown at higher cruise airspeeds. Landing Gear System Design Wheel type landing gear systems are easier to retract for increased cruise speeds with less fuel flow and are much easier to store and move when conducting maintenance. Wheel type landing gear systems are more expensive compared to skid type landing gear with many more parts to inspect, buy, and maintain. They usually have brakes, which also require inspection, service, repair, or replacement. Skid type landing gear is a simpler design, easier to manufacture, and reasonably light in weight. Skid landing gear is a parasitic drag source, which increases exponentially at faster airspeeds. Skid landing gear are less expensive overall but more difficult to move for maintenance or storage and always requires additional equipment on the ground. Inform the student to use care when handling the actual helicopter, training aids, and/or training devices. Moving parts, sharp edges, protruding components, and/or hydraulic pressures may cause hazardous situations. Material Safety Data Sheets (MSDS) instruction should be reviewed during preflight and postflight if the student comes in contact with any of the fluids in or on the helicopter. Airframe Airframe discussions should explain that the airframe, or structure, of a helicopter can be made of different types of material. Figure is an example of the many different materials that are used in the construction of a helicopter. |
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