Flight Characteristics 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
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
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?
DRAAGS
SCAARG
Decrease Collective Pitch Rotor Rpm increase Airspeed reduce Altitude reduce Gross weight reduce Severity of maneuver (reduce)
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.
What type of drag is dominant at slow speeds and in a hover?
Induced
Securing one engine allows a/c to operate at ___ speeds, where drag is ___, while operating a single engine at a more efficient power setting
Slower, reduced
__ roll rates of __ deg/second in forward flight above __ KIAS, can combine with induced tail rotor gyroscopic and flapping loads to cause excessive tail rotor spar loading
Left, 30 deg, 75 KIAS
Airspeed for moderate turbulence
blade stall - 15 knots
Airspeed for light turbulence
blade stall - 10 knots
Tail Rotor Spar Loading
Left roll rate increases blade AOA, driving torque up and main rotor precession loads can contribute further
Left roll rates (above 30 deg/sec in forward flight above 75 KIAS) can combine with induced tail rotor gyroscopic and flapping loads to cause excessive spar loading
When executing high roll rate maneuvers to the left, you should
Lower collective concurrently with maneuver initiation to control transient torque increases and reduce high TR spar loads
Speed for translational lift
17 KIAS
