Temperature and Pressure Measurement Flashcards
How to calculate degrees Fahrenheit from degrees celsius?
Degrees celsius x 9/5 + 32
How to calculate degrees celsius from degrees Fahrenheit?
Degrees Fahrenheit x -32 x 5/9
How to calculate degrees absolute/Kelvin from degrees celsius?
Degrees celsius +273
Define “Static Air Temperature”
SAT, or OAT, or ambient air temperature, is the free air static temperature obtained either from ground met sources or from in-flight temperature readings corrected for instrument error and compressibility(No ram rise)
Define “Ram Rise”
The increase in temperature sensed due to compressibility
Define “Ram Air Temperature”
SAT/OAT plus a percentage of the rise in temperature due to ram compression. If a particular temp sensor have a recovery factor of 0.80, the sensor will measure the ambient outside air temperature plus 80% of the RAM rise.
Define “Total Air Temperature”
Outside air temperature plus 100% of the rise in temperature due to ram compression
Is SAT and OAT the same?
Yes
Under what mach speed is ram rise ignored for practical purposes?
Ram rise under mach 0.30 is negligible
The other name for TAT?
IOAT
What is the RAM RISE equation?
Ram Rise = (V/100) squared
For what type of temperature reading is a Rosemount Probe used?
For reading TAT, or true RAT.
For what type of temperature reading is a Lewis Flush Bulb used?
RAT
The thermometer that use differential expansion of two different metals as a method for reading temperature, this thermometer is called?
A direct reading low speed Bi-Metallic thermometer
The thermometer that use contraction and expansion of a liquid or gas, due to temperature change, as a method of reading is called?
The Bourdon Tube Thermometer
Explain how the aneroid capsule works, and is used for what spectrum of pressures?
The sealed capsule contains a partial vacuum, any reduction in external pressure would cause the capsule to expand and any increase in pressure will cause the capsule to contract, used mainly for low pressures.
Explain how the pressure capsule works
In this case the capsule is not completely sealed, but has an opening which may be connected to a pressure source which causes the capsule to expand or contract
The type of system used for measuring the difference between two pressure readings?
The bellows system
The system used for relatively high pressures associated with oxygen, hydraulic or engine oil pressure systems?
The bourdon tube.
A pressure capsule is one that receives?
Dynamic Pressure
Is an aneroid capsule and a pressure capsule the same?
No
Which type of measurement instrument is used for both pressure and temperature?
The bourdon tube
Mach number is the ratio between?
TAS and the local speed of sound
If Mach number = 1.00 TAS equals?
The speed of sound
If Mach number = 0.70 TAS equals?
70% of the speed of sound
As altitude increases speed of sound?
Decreases
How to calculate the mach number ratio?
TAS / speed of sound = Mach number
At a constant mach number, if altitude is increased TAS will?
Decrease
RAT will equal SAT when?
The aircraft is stationary, SAT/OAT is the undisturbed free air temperature unaffected by RAM rise. IOAT is the same as TAT. TAT is the SAT/OAT + 100% of the RAM rise.
RAT = SAT when:
TAT = RAT when:
There is no ram rise
The recovery factor is 100%
