NATOPS Chapter 11 (Aero)

Question 1

Blade tips move at ________.

Answer 1

725 ft/sec

Question 2

The MH-60R is considered to be in ground effect below what altitude?

Answer 2

45 ft

Question 3

Flapping fixes _____________. By reducing lift on the _________ blade and increasing it on the ___________ blade by flapping _________.

Answer 3

Asymmetrical distribution of lift

Advancing

Retreating

Flapping down

Question 4

Phase lag is felt ______ degrees from where the inputs are put in.

Answer 4

90*

Question 5

Define blowback

Answer 5

In a hover the advancing blade sees more lift than the retreating blade. Causing the rotor to be tilted aft.

Pilot input and auto pilot will counter this

Question 6

Translational lift is at approximately what?

Answer 6

17kts

Question 7

Transitioning to forward flight with tail winds will cause you to see _________ when you have relative winds of zero.

Answer 7

More power required.

Question 8

Stab begins programming at what?

Answer 8

30 kias

Question 9

Methods to eliminate Blade Stall?

DRAAGS
SCAARG

Answer 9

Decrease Collective Pitch
Rotor Rpm increase
Airspeed reduce
Altitude reduce
Gross weight reduce
Severity of maneuver (reduce)

Question 10

Blade Stall happens when

Answer 10

The retreating blade has increased is AOA so much that it has stalled.

The blade tip is traveling at rotational speed minus forward airspeed of helicopter.

Question 11

Weather vaning is what?

And occurs when?

Answer 11

Winds push on the tail and cause the helicopter to rotate into the wind.

120* to 240*

Question 12

What is tail rotor vortex ring state?

What region does it occur in?

Answer 12

The tail rotor operates in its own airflow. Causing unpredictable yaw rates

210* to 330*

Question 13

Main rotor disc vortex interaction is what?

Occurs in What region?

Answer 13

Main rotor vortex is directed onto the rotor changing the AOA on the tail rotor.

280* to 330* and possibly 030* to 080*

Question 14

How can you recover from LTE?

Answer 14

Lowering collective

Forward cyclic

In a hover, applying full left pedal.

Question 15

Vortex ring state occurs when?

When are they worst?

Answer 15

Descent rates greater than 700 fpm and 0 - 20 kias

Descent rates of 1500 fpm and 5 - 10 kias

Question 16

How do you recover from vortex ring state?

Answer 16

Decrease collective pitch

Increase forward airspeed

Enter autorotation if altitude permits.

Question 17

Regions of prop during autorotative state?

Answer 17

Prop region- 30%
Autorotative-45%
Stall region - 25%

Question 18

Prop region creates _______.

Answer 18

Usable lift

Question 19

The autorotative region creates __________________.

Answer 19

Lift and rotational forces

Question 20

Stall region creates only ___________.

Answer 20

Drag forces

Question 21

When does static Rollover occur?

Answer 21

28*

Question 22

Critical rollover occurs at?

Answer 22

12*

Question 23

How does aircraft respond to rotor blade Stall?

Answer 23

Increased vibs

Pitch up

Roll left

Question 24

When does vortex ring state occur?

Answer 24

0-20 kias & greater than 700 fpm

Worst at 5-10 kias & 1500 fpm

Question 25

Why does a heavier helo auto slower than a lighter helo?

Answer 25

Higher collective pitch is required to control Nr of heavy aircraft. This results in more lift from the rotors and a slower rate of descent.

Question 26

Order of preference with abnormal vibrations?

Answer 26

Runway

Large deck

Small deck

Running landing not recommended. Land on a spot.

Question 27

Tail Rotor Spar Loading

Answer 27

Left roll rate increases retreating blade AOE and increases torque. Left roll (aprox 30 degrees per second above 75 kts) combined with tail rotor flapping can lead to increased loads on the tail rotor.