Lesson 1 Flashcards
The SI Unit System stands for
System International en Francais
SI unit for velocity
meters per second
m/s
SI unit for volume
meters cubed
m3
SI unit for speed
meters per second
m/s
SI unit for acceleration
meters per second per second
m/s2
SI unit for force
Newtons
N
SI unit for pressure
Newton per meter square
N/m2
=
Pascal
SI unit for weight
KILOGRAM
Kg
SI unit for MOMENTUM
Kg.m/s
SI unit for energy
Joules
SI unit for temperature
kelvin
SI unit for power
watts
What is acceleration and what symbol and what unit
Rate of change in velocity
symbol: a
Unit: meters per second squared
m/s2
What is 1Kg in pounds Lb?
2.205
Weight is a force so expressed in what?
Newtons
What is the value for Earth’s gravitational field?
9.81 meters squared (g)
What is the equation for weight given mass and gravity?
weight = mass x gravity
w=mg
What is the name of the point that weight acts about in flight?
Centre of gravity
Newtons first law is:
A body will remain at rest or in uniform motion unless acted upon by an external force
Newton’s second law is:
The acceleration of a body in a straight line is proportional to the applied force and inversely proportional to the mass of the body
Newton’s third law is:
To each and every action there is an equal and opposite reaction
What is the equation for force given mass and acceleration?
force = mass x acceleration
f=ma
F: in Newtons
m: Mass in Kg
a: Acceleration in m/s2
What is the scientific definition of force?
(not the equation)
In scientific use, (a measure of) the influence that changes movement
F=MA
What is the equation for speed given distance and time?
speed = distance⁄time
speed: meters per second
distance: meters
time: seconds
What is 1 knot in meters per second
0.5144 meters per second
What is velocity?
vector quality that indicates distance per time (speed) and direction.
Acceleration is a measure of change of what?
Velocity
What letter represents momentum?
p
What is the formula for momentum?
momentum
mass x velocity
p = mv
In physics, WORK is a “measure “ of transfer of energy that causes a ____________ of an object
displacement
What is the equation for work?
work = force x distance
What is the unit for work?
Joules
Define power
Rate of doing work.
What is the equation for power given work and time
power=work⁄time
power: watt
work: joules
time: seconds
What is the equation for power given force and speed?
power = force x speed
power watt
force newton
speed meters per second
What are the two types of energy?
kinetic
potential
Force x distance from pivot =
Moment
Centre of pressure
The point that the lift works from. It’s usually aft of CG
What is ISA density?
1.225 Kg/m3
What is ISA pressure?
1013.25hpa
What is ISA temperature?
15°c
Volume flow = ?
frontal area x speed
Mass flow = ?
volume flow x density
What 3 factors change air density?
Air pressure
Air temperature
Humidity
What is a measure of how much water vapour (and not water?) is contained within the atmosphere?
Humidity
What does increased humidity do to air density?
reduces it.
The atmosphere contains what percentage of Oxygen?
21%
The atmosphere contains what percentage of Nitrogen?
78%
The atmosphere has 1% of trace gasses including:
Argon
CO2
Water vapour
What is an aerodynamic force?
a force exerted on a body by the air in which the body is immersed, and is due to the relative motion between the body and the fluid
As altitude increases, static pressure:
decreases
Dynamic pressure defines as:
the pressure of a fluid (the Air) exerted on a body due to motion or the motion of an object moving through it
Total pressure is the sum of
Total pressure = static pressure + dynamic pressure
1nm = ???? meters
1852 meters
How many seconds are there in an hour?
3600
1nm = ???? feet
6076 feet
IAS measures what pressure
Dynamic
Dynamic pressure is represented by which letter?
q
Dynamic pressure can be measured in ??? or ???
Pascal’s (Pa)
or
Netwon meters2
The equation for dynamic pressure is?
Dynamic pressure = 1⁄2 density x velocity squared
q = 1⁄2 ρ V2
In the equation for dynamic pressure, what does the “V2” represent?
V is TAS
When density is 1.225 kg/m3, what is the relationship between TAS and IAS?
TAS = IAS
When density is greater than 1.225 kg/m3, what is the relationship between TAS and IAS?
TAS < IAS
When density is less than 1.225 kg/m3, what is the relationship between TAS and IAS?
TAS > IAS
What is the relationship between speed and dynamic pressure?
Dynamic pressure proportionate with speed squared
Q ∝ V2
What are the 4 types of airspeed?
IAS indicated
CAS calibrated
EAS effective
TAS true
What does CAS stand for and how does it improve on IAS?
Calibrated airspeed
Corrected for Instrument and position (pressure) errors
What does EAS stand for and how does it improve on CAS?
Equivalent airspeed
Corrected for compressibility (mach numbers over 0.3)
What does TAS stand for and how does it improve on EAS?
True airspeed
Corrected for density
Coanda effect describes?
Flow moving towards low pressure
Stagnation point occurs?
Leading and trailing edge of an aerofoil when dynamic pressure is zero and static pressure is high
The narrow part of a venturi is called the:
Throat
The Total pressure through a venturi remains?
Constant?
In a venturi, if the dynamic pressure increases then the static pressure…
decreases
Describe Bernoulli’s Theorem
Bernoulli’s principle: in a flow of an ideal fluid, the sum of (static) pressure and kinetic energy per unit volume (dynamic pressure) remains constant
Leading edge of an aerofoil has a name…
Leading edge radius.
What is the line that runs from the leading to trailing edge in an aerofoil?
The Chord line
Alpha describes the angle between…..
Chord line and relative air flow
Describe The mean camber line
an imaginary line half way between the upper and lower surfaces
Describe:
The maximum camber (or camber)
describes the distance between the mean camber line and the chord line
Explain positive and negative cambers
positive will produce lift upwards
negative will produce a force downwards
How much lift will a Symmetrical aerofoil produce at 0°α (zero alpha)
zero
Describe a biconvex aerofoil.
symmetrical x and y
As AoA increases, where would you expect the centre of pressure to move to on a CAMBERED aerofoil?
Forward
As AoA increases, where would you expect the centre of pressure to move to on a symmetrical aerofoil?
Nowhere
Mass flow is a fundamental component for the production of aerodynamic force. Greater mass flow = ??
greater aerodynamic force