旋翼机飞行手册 ROTORCRAFT FLYING HANDBOOK

时间：2011-04-05 11:32来源：蓝天飞行翻译 作者：航空 点击：次

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A helicopter flown at the “best rate-of-climb” speed will obtain the greatest gain in altitude over a given period of time. This speed is normally used during the climb after all obstacles have been cleared and is usually maintained until reaching cruise altitude. Rate of climb must not be confused with angle of climb. Angle of climb is a function of altitude gained over a given distance. The best rate-of-climb speed results in the highest climb rate, but not the steepest climb angle and may not be sufficient to clear obstructions. The “best angle-of-climb” speed depends upon the power available. If there is a surplus of power available, the helicopter can climb vertically, so the best angle-ofclimb speed is zero.
Wind direction and speed have an effect on climb performance, but it is often misunderstood. Airspeed is the speed at which the helicopter is moving through the atmosphere and is unaffected by wind. Atmospheric wind affects only the groundspeed, or speed at which the helicopter is moving over the earth’s surface. Thus, the only climb performance affected by atmospheric wind is the angle of climb and not the rate of climb.

SAMPLE PROBLEM 4
Determine the best rate of climb using figure 8-5. Use the following conditions:

Pressure Altitude................................12,000 feet
Outside Air Temperature ...........................+10°C
Gross Weight..................................3,000 pounds
Power ...........................................Takeoff Power
Anti-ice ..........................................................ON
Indicated Airspeed .................................52 knots

With this chart, first locate the temperature of +10°C (point A). Then proceed up the chart to the 12,000-foot pressure altitude line (point B). From there, move horizontally to the right until you intersect the 3,000-foot line (point C). With this performance chart, you must now determine the rate of climb with anti-ice off and then subtract the rate of climb change with it on. From point C, go to the bottom of the chart and find that the maximum rate of climb with anti-ice off is approximately 890 feet per minute. Then, go back to point C and up to the anti-ice-on line (point D). Proceed horizontally to the right and read approximately 240 feet per minute change (point E). Now subtract 240 from 890 to get a maximum rate of climb, with anti-ice on, of 650 feet per minute.
Other rate-of-climb charts use density altitude as a starting point. [Figure 8-6] While it cleans up the chart somewhat, you must first determine density altitude. Notice also that this chart requires a change in the indicated airspeed with a change in altitude.

From the previous chapters, it should be apparent that no two helicopters perform the same way. Even when flying the same model of helicopter, wind, temperature, humidity, weight, and equipment make it difficult to predict just how the helicopter will perform. Therefore, this chapter presents the basic flight maneuvers in a way that would apply to a majority of the helicopters. In most cases, the techniques described apply to small training helicopters with:

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