Lecture notes Flashcards
Transition point
The point at which the laminar boundary layers changes to trubulent boundary layer (NOT SPERATING FROM SURFACE)
IAS
CAS
EAS
TAS
EAS = CAS corrected for compressibility error
Drag foruma
Cd * 1/2 * p * V^2 * S
Doubling the speed will:
1. double
2. quadruple
the lift and drag
Quadruple. Because it is v^2
What is D0
Zero lift drag
What is Di
Induced drag
Trim drag
Drag coming from other control surfaces such the elevators
More lift = ____ Drag
More induced
The airflow above the wing (low pressure) will move towards
1. Wing root
2. Wing tip
Wing root
THe airflow below the wing will move towards
1. Wing root
2. Wing tip
Wing tip
As angle of attack increases, the induced drag
Increases.
Because angle of attack increase = lift increase.
Lift icnrease = Di increase
Low airspeed = ____ induced drag
High.
Low airspeed = high angle of attack
High angle of attack = high induced drag
Induced drag is _____ porportional to V^2
1. Directly
2. Inversly
Inversly
Washout
The wing is twisted. AoA at the wing tip is lower than root.
Washout has: _______ vortices, _____ induced drag
Less, lower
Total drag = ____ + ____
Zero lift drag (parasite) + induced drag
More weight means _____ total drag
More.
More weight = More lift
More lfit = More induced drag
Vmd
Minimum drag speed (Di = D0)
When on ground effect, the upwash ___ and downwash _____
increases, descreases.
When on ground effect, the upwash ___ and downwash _____ creating ___ lift and ____ drag
More lift, more drag
Since on ground effect more lift is created, we can lift at ______ AoA
lower
Remember
graph
More weight / more load factor, ____ wing tip vortices
More
As flaps lowered, CP moves
aft
As flaps lowered ,the stalling AoA
decreases
Taper wing _____ vortices, with _____ induced drag
reduce, less
More weight & load factor, ______ vortex
More
More weight will require _____ lift,
So that means vortex is _____ with _____ AoA
More, increased, more
Vortex intensity _______ with higher TAS
Reduces
Buffet
The disturbed wake flow from the wing hits the tailplane and causes it to shake
As flaps lowered, the stalling angle of attack
Decreases
3 Modifications to avoid wing tip stall (wing root stall is preferable)
- Washout (lower angle of attack at the tip)
- Vortex generators
- Stalling strip (Forces stall to begin at root)
More weight will ______ stall speed
Increase
Stall speed foruma by changing wieghts:
(Old V) * SQAUREROOT(New weight / old weight)
remember for test in cats
Lower weight / lower load factor will _______ stall speed
decrease
Manouevres will ______ load factor
increase
When weight increases, wing loading ____
increases
Slipping turn is the nose turns _____ of the turn,
Skidding turn is the nose turns _____ of the turn
outside,
inside
On climb, the _____ wing stalls first
Outer
On descent, the _____ wing stalls first
Inner
Swept wing
A swept wing is a wing that angles either backward or occasionally forward from its root rather than in a straight sideways direction.
Autorotation
autorotation is the tendency of an aircraft in or near a stall to roll spontaneously to the right or left, leading to a spin
Spin recovery
Reduce power
Ailerons neutral
Full opoosite rudder
Slots and slats task
Allowing air from under the wing to flow over upper surface and delay separation
Using flaps on take off ______ ground roll and lift-off speed,
also _______ climb gradient
Reduces reduces
More moment arm, ______ actual force in _____ applied force
more, less
Since longer moment arm is more effective, the controls are _____
hinged
With a fwd CG, stick force is _____
high
When stick force is _____ the aircraft is _____ to manoeuvre
High, harder
If flight control is hinged at its leading edge, ____ stick force required
more
Horn balance
Portion of the control surface acts ahead of the hinge line
Inset hinge
Hinge is a bit more into the control surface, reducing the moment
Balance tab
Deflects in the direciton opposite to the eleavtor deflection
Anti-balance taab
Can be found on all-flying tailplane, since the tail is more sensistive
Control flutter
A vibraiton caused by pressure distribution over a control surface
To prevent control flutter, the CG of the control surface should be
On and or ahead the hingle line
Adverse yaw
Tendenacy of the aircraft to yaw to the opposite direction because of differential aileron drag
Differantial ailerons and frise ailerons cause _____ drag on the ______ wing to reduce adverse yaw
increased, desceding
Rudder coupled ailerons
When the aircraft is banked, the rudder automatically deflects the yaw into the turn
Static stability
The capability of the body to return to its original position
Dynamic stability
Describes the subsequent reaction
Positive dynamic stability
When a body returns to its original position through oscillations of decreasing amplitude
Neutral dyamic stability
When oscillations continue without a change in amplitude
Negative dynamic stability
When oscillations increase in amplitude
Positive static stability
A body returns to its previous condition after disturbance
Neutral static stability
A body maintains its new positions after a disturbance
Negative static stability
A body continues to move aay from its previous condition after a disturbance
Keel surface behind the CG have a stable/unstable influence
stable
Swept wings _____ direcitonal stability as the wing with more of its span exposed to the airflow has _______ drag
Increase, more
Dihedral helps ______ stability
Lateral
A high wing ____ lateral stability
increases
Propeller slipstream will have a ______ effect during a sideslip
Destabilising
Flaps will have _____ lateral stability
Less
Spiral instability occurs when the _____ stability is greater than _____ stability
Directional stability, lateral stability
Vertical component of gust hits the airplane, causing ____ AoA, and in other words:
More AoA, more lift, more load factor
Torque
Resistance to rotation
Angle of advance (helix)
The angle between the relative airflow and rotational velocity, relates to TAS
Blade angle is changed throughout the blade to
Have an equal amount of “lift” generated at each blade section
