Aerodynamics

Question 1

What is dynamic rollover?

Answer 1

Dynamic rollover begins when the helicopter starts to pivot laterally around its skid or wheel. For dynamic rollover to occur the following three factors must be present.
1. A rolling moment
2. A pivot point other than the helicopters normal CG
3. Thrust greater than weight.

Critical angle 5-9 degrees is exceeded.

Lower collective to recover

Question 2

What is LTE? How do we recover?

Answer 2

LTE is the uncommanded, rapid yaw towards the advancing blade which does not subside of its own accord.

4 types:

1. Weathercock Stability (Tail Winds)
2. Main Rotor Disc Interference (Left Cornering blows MR vortices into Tail rotor)
3. Tail Rotor Vortex Ring State (Direct Left Crosswind)
4. LTE at Altitude

To recover:
FWD cyclic to increase airspeed
Lower Collective if altitude permits
Full left pedal fly into the wind

Question 3

Discuss SWP. Causes and escape.

Answer 3

Vortex Ring State (settling w/ Power)

Is an aerodynamic condition when the helicopter has power applied but settling into its own downwash. When this occurs controls become sloppy and decent can increase as high as 6,000 FPM.

Criteria to get into:
1. 20% or more power applied
2. Greater than 300 FPM rate of decent
3. Airspeed below ETL

Recovery:
1. Traditional - Lower power, FWD cyclic to gain airspeed

2. Vuichard - Lateral thrust, Increase power, Lateral antitorque

Question 4

What is a hazard of landing in snow or dust?

Answer 4

Brownout/Whiteout conditions may occur.

Question 5

What do you do during a brownout or whiteout?

Answer 5

Transition to instruments and climb. Do not attempt to land