StudyGuide-FlightConditions/Maneuvers

Question 1

What is effective translational lift?

Answer 1

When the lift generated by the rotor disc becomes more efficient due to increased airspeed and/or wind.

(The inflow angle is decreased as more air is received horizontally versus vertically: lower angle of attack will produce the same amount of lift, so less power is required)

Question 2

What is translating tendency?

Answer 2

The movement of the helicopter go the right due to a combination of the main rotor torque and tail rotor anti-torque (both pushing the nose and tail, respectively, to the right)

Also called: rotor drift

Question 3

What is transverse flow?

Answer 3

Decreased lift at the rear of the rotor disc due to an increase in induced flow caused by forward flight or significant wind.

More induced flow on the rear half of the rotor disc produces less lift, which is felt 90° later in the plane of rotation and is felt as a right roll

10-20 KIAS

Question 4

What is blow-back? (also called flap-back)

Answer 4

The rearward tilt of the rotor disc during the transition to forward flight.

Due to increased induced flow at the rear (TFE) as well as the flapping up of the advancing blade, felt 90° later in the plane of rotation: front of the rotor disc)

Question 5

What is reverse flow?

Answer 5

A

Question 6

What is retreating blade stall?

Answer 6

When the retreating blade reaches its critical angle of attack and stalls

Question 7

What is ground resonance?

Answer 7

A vibration that can be destructive to a fully-articulated helicopter when the aircraft makes ground contact and produces a jolt/shock wave that can resonate in the aircraft, causing the helicopter to shake itself apart.

Question 8

What is dynamic rollover?

Answer 8

A catastrophic event where the rotor thrust pulls the helicopter sideways around a pivot point (skid)

Careful of foreign objects on ground.
Careful on slopes.

Question 9

What is vortex ring state?

Answer 9

Settling in your own downwash: when the helicopter’s downwash recirculates into the induced flow and the helicopter descends while under power. Three conditions must be present in order for this to occur:

1) power applied
2) descent rate of at least 300fpm
3) speed lower than ETL

Question 10

What is loss of tail rotor effectiveness?

Answer 10

LTE: when the ability to provide anti-torque thrust from the tail rotor is ineffective or highly unreliable

Question 11

Why are left pedal turns considered safer?

Answer 11

More power is required to make left turns which makes it easier to control. Right turn inputs respond very quickly as it reduces the anti-torque force opposing the natural torque tendency of the (counter clockwise) aircraft.

Question 12

What is ground reconnaissance?

Answer 12

A

Question 13

What causes abnormal vibrations in flight?

Answer 13

A

Question 14

How does the pilot handle low rotor RPM?

Answer 14

Lower collective, increase throttle, gentle aft cyclic.

Question 15

What are the three primary regions of the disc in an autorotation

Answer 15

Stalled region: area closest to the hub
Driving region: middle section of the blade, where the thrust or lift is slightly forward in the direction of rotation.
Driven region:
Outside portion of the disc which produces a lot of drag, thus not producing lift. It is being driven by the driving region of the disc.

Question 16

What is the purpose of a flare at the end of an autorotation?

Answer 16

This stops the descent., reducing the descent rate more as you flare more. It also increases rotor RPM and reduces forward airspeed.

Question 17

Why does turning left require more power during forward flight?

Answer 17

In forward flight, the front of the disc receives airflow more horizontally, while the rear portion has more induced flow. Since a left turn requires an AOA increase at the rear of the rotor disc, in forward flight the amount of AOA increase is even greater.