Ch. 7 Helicopter Performance

Question 1

What are the 3 major factors that affect a helicopter’s performance?

Answer 1

Density altitude, weight, & wind

Question 2

There’s approximately a _____ % reduction in performance in high humid conditions compared to dry air at the same altitude & temperature.

Answer 2

3-4%

• Expect a decrease in hovering & takeoff performance
• It can be the cause of a mishap when already operating at the limits of the helicopter

Question 3

In some helicopters during high altitude operations, the maximum antitorque produced by the tail rotor during a hover may not be sufficient to overcome torque even if the _____ is within limits.

Answer 3

Gross weight

At higher gross weights, the increased power required to hover produces more torque, requiring more antitorque from the tail rotor.

Question 4

_____ occurs whether the relative airflow is caused by the helicopter movement or by the wind.

Answer 4

Translational lift

Which is the improved rotor efficiency resulting from directional flight.

Question 4

_____ occurs whether the relative airflow is caused by the helicopter movement or by the wind.

Answer 4

Translational lift

Which is the improved rotor efficiency resulting from directional flight.

Question 5

_____ are an important consideration and the most desirable as they contribute to the greatest increase in performance.

Answer 5

Headwinds

As wind speed increases, translational lift increases, resulting in less power required

Question 6

Strong crosswinds & tailwinds may require the use of more _____ to maintain directional control.

Answer 6

Tail rotor thrust

Increased tail rotor thrust absorbs power from the engine, resulting in less power available to the main rotor to produce lift.

Question 7

When taking off into a headwind, _____ is achieved earlier, resulting in more lift & a steeper climb angle.

Answer 7

Effective translational lift

Question 8

When taking off with a tailwind, more _____ is required to accelerate through translational lift.

Answer 8

Distance

Question 9

Dead man’s curve refers to what?

Answer 9

The shaded areas on the Height/Weight (H/W) diagram that don’t allow sufficient time to execute a final flare & recovery during autorotation.

Somewhat analogous to base jumping from too low a height- you need to be high enough for your parachute to deploy, fill with air, & slow your decent.

Question 10

The H/W diagram defines the height & airspeed combination that will allow a _____.

Answer 10

Safe landing if any engine fails.

Question 11

The time required, and therefore, altitude necessary to attain a steady statedautorotative state descent, is dependent on the _____ of the helicopter and the _____.

Answer 11

Weight; density altitude