Helicopter Performance

The purpose of studying helicopter performance is to ensure the safe operation of helicopters. In order to maintain safe aircraft operation, regulations for helicopter operations set by the FAA in the United States and EASA in Europe are followed.

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Performance Factors

The most significant factors that determine helicopter performance are engine power and lift generated by the rotor. The factors that have the greatest impact on performance are density altitude, weight, and wind.

 

Moisture (Humidity)

First, let's examine the effects of humidity and temperature on performance. Helicopters are greatly influenced by humidity and temperature variations with altitude, and cold temperature tests are often conducted in countries like Alaska. It is generally known that with increasing humidity at the same altitude and temperature, performance can decrease by 3-4%.

rainy weather

Weight

Weight is a major factor that affects performance in all aircraft. Reducing weight not only improves fuel efficiency but also allows for safer takeoff and landing. On the other hand, increased weight requires more power for operation and may necessitate a larger rotor, resulting in larger helicopter size. If two helicopters are of the same size, the heavier one will require more power, making it more challenging to perform missions at high altitudes.

Wind

While it may be easy to assume that wind speed has a significant impact on performance, the direction of the wind is actually more critical for helicopters. The relative airflow generated by wind direction demands more rotor power to maintain helicopter stability.

windstorm weather

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Performance Charts

To ensure safe helicopter flight, there are performance charts that provide a comprehensive view of helicopter performance.

helicopter cockpit

These charts, known as H/V Curve (Height-Velocity Curve) or Height-Velocity Avoid Curve, indicate safe and hazardous areas based on speed and altitude. Pilots use these charts to plan and operate helicopter flights, avoiding entry into hazardous areas. These performance charts assume calm wind conditions and favorable pilot conditions.

 

In conclusion, to operate helicopters safely, it is important to understand the factors that influence performance. Performance charts that indicate risk areas based on altitude and speed are available, and pilots need to consider these charts when planning their flights.