Principles Of Flight Flashcards
What is Speed?
The rate of change of distance
What is mass
The quantity of matter
1kg = … lbs
2.2lbs
What is acceleration?
Rate of change of velocity (m/s^2)
What is a force?
A push/pull reaction
mass x acceleration
What is weight?
Force exerted on a body by gravity
mass x gravity (g=9.81m/s^2)
What is Density?
Mass per unit volume
mass/volume
What is pressure?
Force per unit area
Force/Area
What is Energy?
Capacity for doing work
force x distance
What is Power?
(force x distance) / time
Newtons 1st law
Body remain at rest unless acted upon by external force
Newtons 2nd law
Acceleration experienced by a body is proportional to force applied and inversely proportional to mass
Newtons 3rd law
equal/opposite recation
Air properties
Incompressible fluid
little/no cohesion between air molecules (friction)
What is air density effected by?
Humidity
Temperature
Pressure
good performance occurs when density is … We get tihis with…
High
Low humidity
Cold temperature
High pressure (low pressure altitude)
What is static pressure?
Pressure felt by an object due to mass of column of air its in
What direction is static pressure felt in?
All directions
At right angles to object surface
How do you measure static pressure?
Static port
What happens when the air is fed into the static port chamber?
Changes in static pressure causes aneroid capsule to compress/expand
Compress - high sp
expand - low sp
What is Dynamic Pressure?
Pressure felt due to motion through an airmass
What direction is Dynamic pressure felt in?
Acts from one particular angle
Total Pressure equation
Static pressure + Dynamic Pressure
Ptot = Pstat + q (Dynamic)
Dynamic pressure equation
How to measure Dynamic Pressure?
Pitot Probe
How does the Pitot Tube work?
- aligned with airflow (pressure datum) and collects Ptot pressure
Pitot Tube explanation (~)
Static pressure in capsule/chmabere cancel out
Ptot fed into capsule and tries to inflate
What does IAS stand for?
Indicated Air Speed
What is IAS a measure of?
Dynamic Pressure
Why do we use IAS?
Determines how effective wing is and if can produce enough lift to fly
IAS gives us our speed relative to stall
What are the IAS errors?
Instrument
Postion
Manoeuvre
Instrument error
Instrument imperfections > wear/tear
Position Error
Due to misalignment of pitot probe (can be tested/corrected) - pressure error
Manoeuvre error
Change in pressure datum whilst manoeuvring - not correctable
CAS stands for?
Calibrated Air Speed
What is CAS
IAS corrected for instrument/position error
If a/c has air data computer - will display CAS
What is a compressibility error?
Air molecules compress in pitot probe > artificial rise in pressure
Causes overhead a/c speed
Insignificant below 300kts
What is EAS?
Equivalent Airspeed
CAS corrects for compressibility
Not used by pilots - only used for a/c designers
What is TAS?
How many air molecules are entering the pitot probe each second
What are the 3 types of airflow?
Streamline
Turbulent
Vortex - 3D Airflow
What is Bernoullis Theorem?
Sum of pressure energies of an incompressible fluid within a sreamtube
What is the camber line?
A line equidistant apart between the upper and lower edges of the aerofoil
