NATOPS Chapter 11 Flashcards
Blade tips move at ________.
725 ft/sec
The MH-60R is considered to be in ground effect below what altitude?
45 ft
Flapping fixes _____________. By reducing lift on the _________ blade and increasing it on the ___________ blade by flapping _________.
Asymmetrical distribution of lift
Advancing
Retreating
Flapping down
Phase lag is felt ______ degrees from where the inputs are put in.
90*
Define blowback?
What counters this long term?
What AFCS function counter this?
What is required due to blowback?
In a hover the advancing blade sees more lift than the retreating blade. Causing the rotor to be tilted aft.
Pilot input will counter this in the long term
SAS 2 hover augmentation and gust alleviation will counter this in the short term.
When transitioning to forward flight, blowback results in more forward cyclic being required to continue acceleration.
Translational lift is at approximately what?
17kts
Transitioning to forward flight with tail winds will cause you to see _________ when you have relative winds of zero.
More power required.
Stab begins programming at what?
30 kias
Methods to eliminate Blade Stall?
SCAAAR
Severity of maneuver (reduce)
Collective pitch reduce
Altitude decrease
Aircraft weight decrease
Airspeed decrease
Rotor RPM increase
Blade Stall happens when
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.
Weather vaning is what?
And occurs when?
Winds push on the tail and cause the helicopter to rotate into the wind.
120* to 240*
What is tail rotor vortex ring state?
What region does it occur in?
The tail rotor operates in its own airflow. Causing unpredictable yaw rates
210* to 330*
Main rotor disc vortex interaction is what?
Occurs in What region?
Main rotor vortex is directed onto the rotor changing the AOA on the tail rotor.
280* to 330* and possibly 030* to 080*
How can you recover from LTE?
Lowering collective
Forward cyclic
In a hover, applying full left pedal.
Vortex ring state occurs when?
When are they worst?
Descent rates greater than 700 fpm and 0 - 20 kias
Descent rates of 1500 fpm and 5 - 10 kias
How do you recover from vortex ring state?
Decrease collective pitch
Increase forward airspeed
Enter autorotation if altitude permits.
Regions of prop during autorotative state?
Prop region- 30%
Autorotative-45%
Stall region - 25%
Prop region creates _______.
Usable lift
The autorotative region creates __________________.
Lift and rotational forces
Stall region creates only ___________.
Drag forces
When does static Rollover occur?
28*
Critical rollover occurs at?
12*
How does aircraft respond to rotor blade Stall?
Increased vibs
Pitch up
Roll left
When does vortex ring state occur?
0-20 kias & greater than 700 fpm
Worst at 5-10 kias & 1500 fpm
Why does a heavier helo auto slower than a lighter helo?
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.
Order of preference with abnormal vibrations?
Runway
Large deck
Small deck
Running landing not recommended. Land on a spot, no hover landing if possible
What are the LTE sectors and names
060 to 120 AOA reduction
120 to 240 Weather vaning
210 to 330 Vortex ring
280 to 330 Main rotor disc vortex
