Aerofoil Terminology Flashcards
What is the purpose of the fuselage?
Purpose is to carry:
- Passengers and freight (load).
- Crew in the cockpit/flight deck.
- Flight controls and instruments.
- System equipment, avionics etc
What type of construction is the CT4B’s fuselage?
a) monocoque
b) semi-monocoque
c) cantilever
d) Breaden
b)
What is the basic purpose and other purposes of the wing?
Basic purpose: to produce lift. Also: 1. Fuel in integral tanks; 2. Lateral controls (ailerons); 3. Lift augmentation devices (flaps); 4. Under wing external stores; 5. Wing mounted engines
What type of stability does the tail plane provide?
Longitudinal Stability
What type of stability does the fin provide?
Directional Stability
What are the primary flight controls?
Elevator; Ailerons; Rudder
What are the secondary flight controls?
Trim tabs:
Elevator trim tab; rudder trim tab; aileron trim tab
Define the term aerofoil.
- Aerofoil is the cross-sectional shape of the wing;
2. It is specifically designed to produce the lifting forces necessary for flight;
Define the chord line.
Chord line - the imaginary straight line joining the leading and trailing edges of an aerofoil.
Define the chord of a wing.
Chord - Is the distance between the LE and TE of an aerofoil. It is given in feet or metres and can vary from root to tip in a tapered wing.
Define the mean Camber Line.
Mean camber line - the imaginary line from LE to TE remaining equidistant between the upper and lower surfaces of the aerofoil.
Define the Camber of an aerofoil.
Camber of an aerofoil is a measure of its curvature. It is measured as the maximum distance between the mean camber line and the chord line.
Define the Thickness of an aerofoil.
Thickness is the maximum distance (measured perpendicular to the chord line) between the upper surface and lower surface of the aerofoil.
Define the Thickness:Chord ratio.
The ratio of the thickness of an aerofoil to the chord of an aerofoil.
- Expressed as a % of Chord; and
- Position of maximum thickness expressed as a % of chord from the leading edge.
Define the Leading Edge Radius.
The radius of curvature of a given leading edge shape.
- Sharp (small radius) for thin high speed aerofoils
- Blunt (large radius) for thick low speed aerofoils.
*Normally expressed as a % of chord.
The line equidistant from upper and lower surface is termed as:
a) Camber
b) Chord Line
c) Chord
d) Mean Camber Line
d) *Mean camber line - the imaginary line from LE to TE remaining equidistant between the upper and lower surfaces of the aerofoil.
Define the wing span.
The distance between the wingtips, measured in feet or metres.
Define Wing Area. What is the equation for a rectangular wing?
The area of the wing projected on a plane perpendicular to the aircraft’s normal axis (plan view area).
S = b x c
What is the equation for Aspect Ratio? What does this tell us?
AR = Span^2 / Area = (b^2)/ S
This ratio tells us how thin (chord) and long (span) the wings are or how thick (chord) and short (span) they are.
What is the equation for Aspect Ratio of a RECTANGULAR wing?
AR = b/c = span/chord
Do gliders have:
a) Low aspect ratio wings;
b) Medium aspect ratio wings; or
c) High aspect ratio wings.
c) Gliders have high aspect ratio wings (long and thin).
Assuming a rectangular wing, find:
a) Wing Area, given span = 20 and chord = 4;
b) Aspect Ratio, given span = 20 and chord = 4;
c) Span and Wing Area, given AR = 10 and chord = 2;
d) Chord and AR, given wing area = 80 and span 20
a) 80
b) 5
c) 20 & 40
d) 4 & 5
*Just an example from Raj’s notes
Define Wing Loading. What is the equation for it?
A measure of the gross weight supported by each unit area of the wings during straight and level flight.
Wing Loading (w) = Aircraft Weight (W) / Area of the wings (S)
Define Load Factor. What is the equation for Load Factor (n)?
The ratio of lift generated by the wing over the aircraft’s weight (W) is termed the Load Factor (n)
n = Lift Produced (L) / Aircraft Weight (W)
What is a typical load factor (n) during:
a) Straight and Level flight;
b) In a turn;
c) In a steep (60 AoB) turn;
d) Aerobatics (CT4 Loop);
e) Inverted flight.
a) n = 1 (1G)
b) n = >1 (>1G)
c) n = 2 (2G)
d) n = ~ 4 (approx 4G)
e) n = -1 (-1G)
Define Relative Airflow.
The relative motion between an aircraft and the remote airflow (airflow far enough away from the aircraft and not disturbed by its presence).
Define Angle of Attack (AoA).
Angle between the chord line and the relative airflow.
What is the Total Reaction (TR) for an aerofoil and what are its two components?
TR is the resultant aerodynamic force acting on an aerofoil.
It is composed of the two ‘non-existant’ forces Lift & Drag
Define Centre of Pressure (CP)
CP is the point on the chord line where the TR is considered to act.
Lift is:
a) Perpendicular to the Relative Air Flow; or
b) Parallel.
a)
Drag is:
a) Perpendicular to the Relative Air Flow; or
b) Parallel.
b)
The Lift/Drag ratio is also known as?
The efficiency factor of an aerofoil.
Define the Angle of Incidence (WING).
The angle between the Longitudinal axis and chord line. It is a fixed angle that does not change once the aircraft has been constructed.
What is ‘Wash out’?
It is a decrease in incidence from root to tip.
What is ‘Wash in’?
It is a increase in incidence from root to tip?
Why is Wash Out good?
It increases LATERAL stability and allows greater aileron control during the stall (as the inboard part of the wing will stall first).
Define Pitch Angle (Attitude).
The angle between the longitudinal axis and the horizontal plane.
What is Dihedral and what is its purpose?
Dihedral is the upward inclination of the wing in relation to the lateral axis. It increases lateral stability.
What is Anhedral and what is its purpose?
Anhedral is the downward inclination of the wing in relation to the lateral axis, generally used as a design feature to reduce excessive lateral stability caused by swept wing, high wing designs (i.e C-17)
