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the helicopter can climb vertically, so V$_{X}$ 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. 

When planning for climb performance, it is first important to plan for torque settings at level flight. Climb performance charts show the change in torque, above or below torque, required for level flight under the same gross weight and atmospheric conditions to obtain a given rate of climb or descent. 

## Sample Cruise or Level Flight Problem 

Determine torque setting for cruise or level flight using Figure 7-7.  Use the following conditions: 

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Pressure Altitude............................................... 8,000 feet 

Outside Air Temperature...................................... +15 °C 

A. Indicated Airspeed........................................80 knots 

B. Maximum Gross Weight................................5,000 lb 

With this chart, first confirm that it is for a pressure altitude of 8,000 feet with an OAT of 15°. Begin on the left side at 80 knots indicated airspeed (point A) and move right to maximum gross weight of 5,000 lb (point B). From that point, proceed down to the torque reading for level flight, which is 74 percent torque (point C). This torque setting is used in the next problem to add or subtract cruise/descent torque percentage from cruise flight. 

## Sample Climb Problem 

Determine climb/descent torque percentage using Figure 7-8 . Use the following conditions: 

A. Rate of Climb or Descent .............. 500 fpm 

B. Maximum Gross Weight ...............5,000 lb 

With this chart, first locate a 500-fpm rate of climb or descent (point A), and then move to the right to a maximum gross 

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