Aerodynamics

Question 1

Define dynamic rollover and the three conditions that must be present?

Answer 1

The susceptibility of the helicopter to a lateral-rolling tendency.

The three conditions required are pivot point, rolling motion, and exceedance of the critical angle.

TC 3-04.4 1-219, pg1-61

Question 2

What are the physical factors of dynamic rollover?

Answer 2

Main Rotor Thrust
Center of Gravity
Tail Rotor Thrust
Crosswind
Ground Surface
Low Fuel
Slopes

TC 3-04.4 1-229 pg1-63

Question 3

What are the human factors for dynamic rollover?

Answer 3

Failure to make timely corrective action
Inattention
Inexperience
Inappropriate control input
Loss of visual reference

TC 3-04.4 1-229 pg1-63

Question 4

What are the three no lift areas along the blade in forward flight, starting at the hub and working out?

Answer 4

Reverse Flow
Negative Stall
Negative Lift

(Positive Lift)
(Positive Stall)

TC 3-04.4 1-115 pg1-37

Question 5

Define Ground Effect

Answer 5

Increased efficiency of the rotor system caused by interference of the airflow when near the ground.

TC 3-04.4 1-105 pg1-33

Question 6

Define dissymmetry of lift

Answer 6

Difference in air flow over the advancing half of the blade and the retreating half of the blade due to forward flight.

TC 3-04.4 1-120 pg1-38

Question 7

How is dissymmetry of lift compensated for?

Answer 7

Blade flapping
Cyclic feathering

TC 3-04.4 1-121 pg1-38

Question 8

Define Translational Lift

Answer 8

Improved rotor efficiency resulting from directional flight.

TC 3-04.4 1-129 pg1-40

Question 9

Define Transverse Flow Effect

Answer 9

Difference in lift between the fore and aft portions of the rotor disk between 10 and 20 knots.

TC 3-04.4 1-132 pg1-41

Question 10

Define Effective Translational Lift

Answer 10

Occurs between 16 and 24 knots, the helicopter completely outruns vortexes and begins to work in relatively undisturbed air.

TC 3-04.4 1-133 pg1-42

Question 11

Define Translating Tendency

Answer 11

A single rotor helicopter has the tendency to drift laterally in the direction of tail rotor thrust.

TC 3-04.4 1-111 pg1-35

Question 12

Define Settling with Power

Answer 12

A condition in powered flight at which the helicopter settles in its own downwash.

TC 3-04.4 1-211 pg1-59

Question 13

What three conditions must exist simultaneously for settling with power to occur?

Answer 13

Vertical or near-vertical descent of at least 300 FPM
Slow forward airspeed (less than ETL)
20-100% of available engine power

TC 3-04.4 1-215 pg1-60