Temperature Measuring Equipments 2

Question 1

Monitor engine parameters, outside air temperatures, liquid temperatures

Monitor health of avionics systems

Answer 1

Purpose of Temperature Measuring equipments

Question 2

Thrust is both affected by both _____ and _____

Answer 2

temperature and Altitude

Question 3

temperature can be measured _______ and _______.

Answer 3

electrically and expansion of different materials

Question 4

It is produced between junctions of dissimilar metals

Answer 4

Electromotive force (thermo-emf)

Question 5

Temperature sensing that contains a liquid in a bulb

Higher temp increases vapour pressure

High pressure straightens Bourdon Tube and increases temp indicaton

Answer 5

Gas Expansion Temperature Sensing

Question 6

Most commonly used metals for electrical type sensing

Answer 6

Nickel and platinum

Question 7

Two methods for electrical type temp sensing:

Answer 7

Variable Resistance
-Wheatstone Bridge or Ratiometer type circuit

Thermoelectric

Question 8

Powered electrically and consist of 3 fixed resistors and one variable resistor

As temperature increases, resistance increases

Answer 8

Variable Resistance Temperature Sensing (Wheatstone)

Question 9

Powered electrically and consists of variable resistor (temp sensing probe) + a fixed set of resistors and a moving coil indicator

Answer 9

Variable Resistance Temperature Sensing (Ratiometer)

Question 10

Temperature sensing used for engine temperatures (uses THERMOCOUPLE)

Independent of aircraft power

Answer 10

Thermoelectric Temperature Sensing

Question 11

What is the voltage measured in thermoelectric

Answer 11

millivolts

Question 12

What are the material used for CHT probes?

Answer 12

Iron and Constantan

Question 13

What are the material used for EGT probes?

Answer 13

Chromel and Alumel

Question 14

Two types hot junctions that are commonly used?

Answer 14

GASKET TYPE

• 2 rings of dissimilar metals pressed together
• typically installed in sparkplugs

BAYONET TYPE

• dissimilar metals inside a perforated protective sheath
• can be used for CHT (by installing a hole in cylinder head) and EGT

Question 15

Bayonet type is sometimes called?

Answer 15

Immersion type

Question 16

On ____ aircraft, the SAT sensor is typically a direct-reading thermometer that uses a bi-metallic or resistance type probe. Works by the expansion of a bimetallic element.

Answer 16

M1

Question 17

On M2 aircraft, the SAT is typically derived electronically from ___ by the CADC.

Answer 17

TAT

Question 18

TAT is static air temperature (SAT) plus any rise in temperature caused by the ______ movement of the aircraft through the air.

Answer 18

high speed

Question 19

This increase in temperature is known as

_______.

Answer 19

ram rise

Question 20

TAT systems have a probe which allows air to flow through, passing over a ______ element. The probe is designed such that the anti-icing heating element does not heat up the air the probe is measuring

Answer 20

sensing

Question 21

Air temperature is an important parameter used to monitor the aircraft’s performance relating to:

Answer 21

• True airspeed
• Temperature control
• Thrust setting
• Fuel/air ratio settings