Block 2 Tilt Rotor Aerodynamics Flashcards
What are the three modes of flight?
VTOL, Vertical Takeoff and Landing; CONV, Conversion; APLN, Airplane
Applying longitudinal stick causes pitch characteristics and airspeed changes similar to those in conventional helicopters.
Pitch
What are Nacelles used for?
- Accelerate or decelerate aircraft
- Select a desired pitch attitude while in a steady hover
- Adjust stick control margin
- Correct for extreme CG
- Recover from adverse flight conditions
What do forward nacelles produce?
Nose up attitude
What do Aft nacelles produce?
Nose down attitude
Location of the engines, prop rotors and gearboxes in the wingtip nacelles results in high inertia.
Roll
Axis inertia is high like the roll axis, but the yaw control power is less. Control is provided through the differential longitudinal cyclic.
Yaw
The ________ ___________ ________ (____) controls the overall thrust of the rotor system in a tiltrotor aircraft
Thrust Control Lever (TCL)
The Thrust Control Lever (TCL) in a tiltrotor aircraft ______ _____ operate in the same fashion as a typical helicopter collective controller
does not
Several design features have been incorporated in the software in tiltrotor aircraft to improve __________ ___________
vertical damping
For a tiltrotor aircraft, approximately _____ degree nacelles will generally give a level deck attitude on takeoff
90
During vertical takeoff to hover in a tiltrotor aircraft, _________ _________ is a decrease in power required at liftoff
ground effect
During vertical takeoff to hover in a tiltrotor aircraft, the power required ____________ with increasing altitude
increases
Aggressive pedal turns in tiltrotor aircraft should be ________ due to the high flapping associated with hovering turns
avoided
A ________ ________ _______ in a tiltrotor aircraft will require a roll angle into the wind
sideward hover taxi
________ ______ __________ refers to the pitch-up tendency of the aircraft when the empennage and horizontal tail are directly downwind of a prop rotor
Pitch-up with sideslip
Stick control margins in rearward flight can be increased with aft nacelles. In tiltrotor aircraft this is:
rearward hovering flight
During take off of a tiltrotor aircraft, ________ can be made from a hover if power available _______ power required for hover
departure
exceeds
During transition to forward flight as the aircraft builds airspeed and the nacelles continue their forward movement the control surface become _______ _______.
increasingly effective
_________ _________ is when power required decreases as forward airspeed increases wings provide lift.
Transitional lift
Approach to landing an increase in ________ will be required to maintain or arrest the decent.
Thrust Control Lever (TCL)
Vertical Landing is preferred to land with a _______ or ________ attitude.
Level or slightly nose-up pitch
Why is full aft nacelle vertical landing can be accomplished but is not recommended due to the ______ ______ _______ _______ attitude to touchdown .
Large nose down pitch
During take off of a tiltrotor aircraft, ________ can be made from a hover if power available exceeds power required for hover
departure
A vertical landing with a nose gear first-contact can be safely accomplished by ____________ _______ prior to touchdown.
Minimizing drift
In CONV mode, the use and effect of flight controls will vary with _________ ________
nacelle angle
As the nacelles rotate into CONV mode, the corresponding increase in airspeed allows the FCS to respond to pilot inputs using the ________, ________ and _________ to a greater degree than in VTOL
elevator
flappers
rudders
______ ________ (___) is used in high altitude, high density, heavy weight where a VTOL can’t be done
Short Takeoff (STO)
The Nacelle angle chosen for a short takeoff (STO) is:
nominally 60-75 degrees
Under most conditions, there is no requirement to _______ _______ ______ for short takeoff, although this will generally reduce the ground roll distance
rotate the nose
As the nacelles are rotated toward the downstops in CONV mode the aircraft transitions to wing-borne flight and the ________ ________ becomes more consistent
pitching effect
During transition, maintaining a level _________ ________ and letting the ________ accelerate the aircraft gives the best results
pitch attitude
nacelles
During transition use _____ ________ ___________ to maintain pitch attitude due to thrust and CG effects
aft stick movement
_____________ ____________ (____) may be necessary at decreased power margins or preferred in the presence of certain aircraft malfunctions
Run-on landing (ROL)
In APLN, CV-22 has flight characteristics similar to __________ ___________ ________
multi-engine turboprop aircraft
In APLN mode, power setting and aircraft attitude determine __________
performance
________ (________, ________, _________) principle is used for basic air work
P.A.T. (power, attitude, trim)
The effect of pitch-power coupling increases with ____ ____________ and _______ ____________
low airspeed
high GW
Adjust the ______ to negate any pitch coupling effects
stick
In pitch coupling with rolling maneuvers, commands are phased out as bank angle increases beyond ____,. This is due to the ________ and ________ of the engines
30 degrees
weight
placement
The FCS limits the aircrafts ability to reach the angles of attack at which ________ _______ could be encountered while maneuvering at high speed and altitude
empennage buffet
