RPL Aerodynamics 1 Flashcards
Name the parts of an aircraft
Fuselage, Wings, Engine, Tail Plane, Undercarriage
What are the types of wings and which light aircraft use which?
High Wing - Cesssna 172
Low Wing - Piper Archer
What are the factors affecting total reaction?
Airspeed
Size
Angle
Density
Which axis does each primary control move?
Elevator - Lateral
Aileron - Longitudinal
Rudder - Normal
What are the primary effects of each primary control?
Elevator - Pitch
Aileron - Roll
Rudder - Yaw
What are the effects of airspeed to the primary controls?
Increased airspeed allows for movement inputs to become more sensitive
Decreased airspeed decreases the effectiveness of a primary control input
What are the secondary effects of each primary control?
Elevator - Increased/Decreased Airspeed
Aileron - Slip and Yaw
Rudder - Roll
What is the purpose of trim and where is it located?
To relieve back/forward pressure on the control column
Attached as small surfaces on the elevator
What happens if an aircraft is trimmed?
No pilot force application required on the control column in order to maintain levelled attitude
What is the purpose of flaps?
To slow down the aircraft and create better forward visibility
What are the effects of flaps when activated and retracted?
Activate - Increased lift and drag resulting in ballooning
Retract - Reverts lift and drag resulting in aircraft to sink
What does the throttle do?
Manipulating throttle lever controls amount of fuel and air entering engine and thus controls RPM (engine power)
What are the effects of slipstream?
Increased power - Nose pitches up and aircraft yaws left
Decreased power - Nose pitches down and aircraft pitches right
How does higher power affect slipstream?
Higher power will result in the rudder and elevator to become more responsive whilst ailerons will have little effect
How does the mixture lever work?
It controls the fuel to air ratio that enters the engine
What should be done to the mixture lever if air density decreases?
Decrease mixture via leaning mixture (pull back mixture level) in order to prevent a rich mixture
What does the carburetor heat do?
Enables heated air into the engine in order to prevent/remove ice build up
Why shouldn’t the carburettor heat be activated for a long period on the ground?
Enabling carburettor heat on the ground will intake unfiltered air containing air/dirt in which can damage the engine
What is carburetor ice and why is it dangerous?
Temperature decrease due to vaporisation freezes moisture in the air and forms ice, this is dangerous as it can restrict fuel/air mixture resulting into fuel starvation
What are the 4 forces that act upon a plane?
Lift/Weight Drag/Thrust
What is equilibrium?
All forces are equal
What is mass?
A measure of the amount of atoms present within an object
What is weight?
The gravitational force acting upon a body mass?
What is the weight formula?
Weight = Mass x Weight
Where is weight acted upon within the aircraft?
The centre of gravity
What is a centre of gravity?
The point where all weights are evenly distributed and where all weight apparently acts
What is span?
Span is the distance from a wingtip to the other
What are the 2 section of aerofoil?
The leading edge and the trailing edge
What is the chordline?
A straight line that joins the leading and trailing edge
What is the mean camber line?
A curved line that dissects through the middle of the wing in which connects the leading and trailing edge
What is the thickness of a wing and why does it varies?
The distance between the upper and lower surface and varies due to curvature of wing
What are the 2 theories of how lift is created?
Newtons third law of motion and Bernoulli’s theorem
What is Newton’s third law of motion?
For every action there is an equal and opposite reaction
What is Bernoulli’s theorum in the application to an aircraft’s lift?
Bernoulli’s theorem relies on the principles of static pressure’s characteristics of pushing in all directions to push the aircraft vertically from the lower wing and for the curvature of the leading edge to produce dynamic pressure and less static pressure from the upper wing to prevent a counteracting push of static pressure to prevent lift.
What is the Total Pressure formula and how is total pressure remained a constant?
Total Pressure = Static Pressure + Dynamic Pressure
Total pressure is a constant as if static pressure increases, dynamic pressure decreases and vice versa. This allows the numerical value of Static Pressure to remain the same
What is an area of low static pressure
A theory in which it is believed that air particles have to travel further distances due to the wing curvature and thus speed up in which produces greater dynamic pressure and finally creates an area of low static pressure
How is dynamic pressure made?
Dynamic pressure is produced through external motion thad directs the air in a direction
What is the Lift Formula?
L=CL x 1/2pv^2 x S
What is the angle of attack?
The angle made from the chord line and the direction of relative airflow
What are the effects of increasing angle of attack?
Increase in angle of attack will generate greater lift however, lift increases with angle of attack
What is the critical angle?
The critical angle is the absolute angle of attack before aerofoil stalls due to excessive drag over thrust
What does each pronumeral of the lift formula represent?
CL - Curvature of aerofoil + AoA
p - Rho (density of air)
v - Velocity (true airspeed)
S - Surface area of wing
What is lift proportional to?
Lift is proportional to angle of attack and velocity
What is stalling speed?
Minimum speed possible in level flight
What is thrust on an aircraft?
Result of the force produced by the propellor
What is drag?
Drag opposes the direction of motion of the aircraft in which is parallel to the relative airflow
What i total drag made of?
Parasite drag + Induced drag
What is parasite drag?
Result of moving a solid object through a fluid medium in which is more prominent in greater airspeeds
What are the 3 types of induced drag and how do they work?
Skin Friction - the unevenness and non-smooth areas of the aerofoil produce greater drag
Form Drag - The drag produced by an object of bluntness and lack of smoothening
Interference Drag - Drag produced by vital connection points from the fuselage to the wings in order to remain structurally sound
What is induced drag?
The consequence of increased drag due to increasing lift in which is created by pressure differentials above and below the wing
What is induced drag: wingtip vortices?
The wingtips of an aircraft creating a spiralling vortex of air that trails the wingtip
How can induced drag be reduced?
Keep wingtip as small as possible
What happens to total drag as angle of attack is increased?
Total drag will initially be at its peak due to great parasite drag yet parasite drag and total drag will begin to decrease with a greater angle of attack. Total drag will begin to pick up again consequentially due to induced drag from increasing angle of attack
