Aero 1: Basic Theory & Lift Flashcards
Vector
A quantity that expresses both magnitude and direction
Air Density
The total mass of air particles per unit volume
Moment
A rotational force around a point or axis
Steady Airflow
Airflow in which at every point in the moving air mass has constant pressure, density, temperature and velocity
Remember:
Train (temperature)
Passengers (pressure)
Don’t (density)
Vocalize (velocity)
Mean Camber Line
A line halfway between the upper and lower surface of an airfoil from leading edge to trailing edge
Chord
A measure of the chord line from the leading edge to the trailing edge of an airfoil
Camber
Max distance between the mean camber line and the chordline
Wingspan (b)
The length of a wing, measured from wingtip to wingtip
Wing Area (S)
The surface area of a wing from wingtip to wingtip
Chordwise Flow
Airflow perpendicular to the leading edge of an airfoil (along the chord of an airfoil)
Spanwise Flow
Airflow that travels the span of the wing, parallel to the leading edge, normally from root to tip
Pitch Attitude (θ)
The angle between the longitudinal axis of the airplane and the horizon
Flight Path
The path described by an airplane’s center of gravity as it moves through an air mass
Relative Wind
The airflow experienced by the aircraft as it flies through the air
(Always opposite direction of flight path which is dependent on center of gravity)
Angle of Attack (AOA)
The angle between the relative wind and the chord line of the airfoil
Angle of Incidence
The angle between the airplane’s longitudinal axis and the chord line of its wing
Center of Gravity
The point at which the weight of an object is considered to be concentrated
Aerodynamic Center
The point along the chord line of an airfoil where all changes in aerodynamic force effectively take place
Max Coefficient of Lift (Cʟmᴀx)
The max value for the coefficient of lift as the AOA increases
What are the different types of airspeeds?
Indicated Airspeed
Calibrated Airspeed
Equivalent Airspeed
True Airspeed
Groundspeed
Indicated Airspeed
The instrument indication for the amount of dynamic pressure that the aircraft is creating during some given flight condition
Calibrated Airspeed
IAS corrected for instrument/position error
Equivalent Airspeed
The true airspeed at sea level on a standard day that produces the same dynamic pressure as the actual aircraft condition
(CAS corrected for compressibility)
True Airspeed
The velocity of an aircraft with respect to the air mass in which it is traveling in
(EAS corrected for density)
Groundspeed
An aircraft’s actual speed over ground
What are the requirements for an aircraft to be in equilibrium flight?
The sum of all forces (drag, thrust, lift, and weight) and moments acting around the center of gravity equal zero
What is the relationship between temperature and altitude?
As altitude increases, temperature decreases.
What is the standard lapse rate?
A decrease in 2°C for every 1000ft in altitude up to 36,000 ft
What is the relationship between humidity and air density?
As humidity increases, air density decreases.
More humidity means more water molecules that take up space in the air.
What is the longitudinal axis? What is movement around this axis called?
The longitudinal axis passes from the nose to the tail of the aircraft.
Roll
What is the lateral axis? What is movement around this axis called?
The lateral axis passes from wingtip to wingtip.
Pitch
What is the vertical axis? What is movement around this axis called?
The vertical axis passes vertically through the center of gravity of the airplane.
Yaw
What are the two forces that are considered aerodynamic forces?
Lift and drag
What affecting factors of coefficient of lift can the pilot control?
Angle of attack
Camber
What does Bernoulli’s Equation say?
P(total) = P(dynamic) + P(static)
What is the relationship between area and velocity in the context of the Continuity Equation?
Area and velocity are inversely proportional.
This means that if area decreases, then velocity must increase on that same side to remain equivalent to the other side of the equation.
A1V1=A2V2
General Gas Law (formula)
P=ρRT
What are the requirements for an aircraft to be in trimmed flight?
The sum of the moments acting around the center of gravity equal zero
Where is the aerodynamic center usually located?
25% aft of the leading edge
Where the max thickness of an airfoil is
Lift Equation
L = 1/2pV²SCₗ
What factors of lift can the pilot control?
Velocity
Angle of attack
Camber
What happens when flaps are lowered?
- Cʟmᴀx increase
- Cʟmᴀx AOA decreases
