PPL-Aerodynamics Flashcards
Coefficient of lift is generally determined by
Camber & AoA
What are coupled moments
Interaction of two forces separated by a horizontal distance
Where does the Centre of Pressure reach its forward limit on the wing
At the stalling angle
The tendency in a climb while turning is to
overbank (because outside wing is faster and has > AoA)
Why is there a tendency to underbank in a descent
Increase in AoA on inner wing outweighs effect of outer wing’s greater velocity
What is adverse aileron yaw
tendency for the aircraft to yaw out of the turn as a result of the downward aileron having more induced drag
Describe Frise type Ailerons
Uses offset hinges to deflect part of the upgoing aileron into the air on the underside of the wing (creating more drag)
Describe differential ailerons
The up-going aileron travels further than the down-going aileron
Describe what coupling the ailerons and rudder does
As the aileron moves, the rudder automatically moves to counteract the adverse yaw
What is the equation for load factor
Lift/weight
Define a spin
An aggravated stall with a wing-drop that results in autorotation (corkscrewing around a vertical axis)
What defines a fully developed spin as opposed to an incipient spin
aircraft’s angular rotation rate, airspeed and vertical speed are stabilised
When does a flat spin occur
When the mass of the aircraft is further away from the spin axis
CAS=
IAS+IEC+PEC
EAS=
CAS+CEC
TAS=
EAS corrected for density error
What effect does a higher airspeed have in a turn
Increase radius, decrease rate
At a constant airspeed, the greater the bank angle, the …… the turn
tighter
rate 1 turn=
180 degrees/min (3 dg/s)
bank angle req for rate 1=
10% IAS + 7
How does an increase in altitude affect turn performance
reduced density=increased TAS, therefore worse performance
Max range is achieved at a speed which produces….
minimum drag
range=
TAS/power or TAS/fuel flow
Does weight have an effect on RoD
Yes
Maximum endurance is achieved at
minimum power or fuel flow
What is the region of reverse command
speeds lower than that of the max endurance speed which require greater amounts of power just to maintain the airspeed
What axis does longitudinal stability occur
lateral
What axis does lateral stability occur
Longitudinal
What axis does directional stability occur
normal
In terms of longitudinal stability, what does moving the CoG forward do?
Increases it
What does a sweptback wing do to lateral stability
increases it (because one wing has more of an effective span than the other)
Which is stronger, lateral or directional stability
Directional
What is a fixed balance tab
balance tab that is bent to a set position
What is a horn balance
balance that protrudes into the airflow on the opposite side
What is an anti-balance tab
Tab that moves in the same direction as the control surface, thus resisting control surface movements
What is the purpose of an anti-balance tab
prevent stress of the aircraft through excessive handling of the controls
What does a mass balance do
reduces flutter by moving CoG closer to the hinge line
When taxiing in wind, the controls should be positioned in such a way that
they will not cause the aircraft to lift as a result of the wind (remember horizontal stabiliser is inverse to wings)
An aircraft will tend to weathercock….
into wind
Refer slide 97 of ADY lesson 1
.
The slipstream effect (for clockwise viewed from the cockpit) tends to yaw the nose to the….
left
The propellor torque effect acts to make the aircraft yaw to the…
left
The greatest influence of wake turbulence is
the weight of the aircraft
Aircraft with larger aspect ratios (long, skinny wings) tend to produce stronger/weaker wingtip vortices?
Weaker
In terms of wake turbulence, decrease in IAS=
increase in wake turbulence
In terms of wake turbulence, increase in AoA=
Increase in wake turbulence
AVOID TOUCHDOWN AND ROTATION AREAS OF HEAVY AIRCRAFT AS A RESULT OF THE WAKE TURBULENCE PRODUCED
AVOID TOUCHDOWN AND ROTATION AREAS OF HEAVY AIRCRAFT AS A RESULT OF THE WAKE TURBULENCE PRODUCED
When avoiding wake turbulence enroute, you should maintain what distance from the flight path
200’ above and 1000’ below
What distances can thrust stream turbulence be felt
200m behind a medium jet
600m behind a large jet
To what range does ground effect occur
up to one wingspan
The 2 core results of ground effect are
reduction in drag
increase in the lifting ability of the wing
