POF - Air, Atmosphere and Airspeed Flashcards
What is humidity?
Humidity is a measure of how much water vapour is in the atmosphere.
If the air temperature increases, what happens to the density?
The air density will decrease, due to it being inversely proportionate to temperate.
How do we convert 1 knot into m/s?
We would multiple knots by 0.5144 to convert it to m/s.
What errors must be fixed to go from IAS to CAS?
- Instrument Errors: this is due to the IAS being mechanical so there will be inaccuracies.
- Position Errors: the pitot tube may not always be aligned to the air flow, which will provide inaccurate readings.
What gases (including percentages) is the dry air within our atmosphere made up of?
- Nitrogen (78%)
- Oxygen (21%)
- Other gases (1%)
What is the formula for dynamic pressure?
Dynamic Pressure (Q) = 1/2•rho•V^2
As altitude increases, what happens to static pressure?
Static pressure will decrease as the altitude increases.
When the density level is in ISA conditions, what is the relationship between TAS & IAS?
TAS = IAS, when the density level is in ISA conditions.
What is the definition of mass flow?
The amount of mass of air that flows through a given volume of space.
If humidity of the air increases, what happens to the air density?
Air density will decrease due to vapour particles mixing with air particles.
When the density level is below ISA conditions, what is the relationship between TAS and IAS?
TAS would be more than IAS.
TAS > IAS
What is Air?
Mixture of different gases.
What is the CAS?
It is is the Indicated Air Speed (IAS) corrected for instrument and position errors.
What does mass flow depend on?
- Speed (the greater the speed, the greater the mass flow) - this is provided by a plane.
- Air density (the denser the air, the greater the mass flow) - this is provided by the location/altitude.
How would we convert 567m/s into knots?
To convert m/s into knots, you would divide the m/s by 0.5144.
So: 567 / 0.5144 = 1,102.26 knots.
What is dynamic pressure?
Dynamic pressure is a pressure that’s exerted onto a body due to it being in motion.
What is the temperature at mean sea level (MSL) in ISA conditions?
15 degrees Celsius
Air density is proportionate to _____________ and inversely proportionate to ______________
- Pressure
2. Temperature
If the air pressure increases, what happens to the air density?
The density of the air will also increase.
What is fluidity?
The ability for a liquid/gas to flow.
What is the density at mean sea level (MSL) in ISA conditions?
1.225kg/m^3
When the density level is above ISA conditions, what is the relationship between TAS and IAS?
TAS would be less than IAS.
TAS < IAS
What is the TAS?
The True Air Speed (TAS) is the Equivalent Air Speed (EAS) that’s corrected for density.
What are the four types of Airspeeds?
IAS: Indicated Air Speed
CAS: Calibrated Air Speed
EAS: Equivalent Air Speed
TAS: True Air Speed
Calculate the dynamic pressure:
TAS = 135 kts rho = 1 kg/m^3
Dynamic pressure = 2,411 Pa
What is the definition of static pressure?
Static pressure is pressure that’s exerted on an object from all given directions
What is the EAS?
The Equivalent Air Speed (EAS) is the Calibrated Air Speed (CAS) that’s corrected for compressibility issues.
How do we calculate airspeed?
We calculate airspeed by measuring the amount of dynamic pressure being exerted into the pitot tube.
