Chap 7: engine instruments

Question 1

purpose of manifold pressure gauge

Answer 1

indicate the absolute pressure of the fuel-air mixture inside the intake manifold

Question 2

purpose of tachometer

Answer 2

indicate speed of crankshaft of reciprocating engine in rpm & speed of compressor shaft in % rpm

Question 3

types of tachometer

Answer 3

mechanical:
centrifugal-type
magnetic drag-cup type

electrical type:
DC
AC

Question 4

tachometer DC vs AC

Answer 4

DC: inaccurate reading from the uses brushes and commutators

AC: no brushes and commutator so minimum error margin
AC type is better

Question 5

types of temperature indicators

Answer 5

oil temp gauge
air temp gauge
cylinder head temp gauge
exhaust gas temp gauge

Question 6

how does thermocouple work?

Answer 6

has 2 wires of different metals, joined at 1 end creating a hot junction where temp is measured

when there is a change in temp, voltage is created on the other end to indicate the temp

Question 7

what effect does thermocouple work on

Answer 7

seebeck effect

Question 8

types of thermocouples

Answer 8

surface contact

immersion types:
stagnation
rapid response

Question 9

how does immersion stagnation thermocouple work

Answer 9

gas entry and exit holes are staggered and different sized to slow the gas down for enough time to respond

Question 10

how does immersion rapid response type thermocouple work

Answer 10

holes are opposite and equal size of each other, respond more rapidly

Question 11

thermocouple cold junction temperature compensation methods

Answer 11

thermoresistor, thermomagnetic shunt

bridge circuit

external electronic circuit

Question 12

methods of fuel quantity measurements

Answer 12

float type

capacitance type

Question 13

what is angle of attack

Answer 13

angle between the chord line of wing and the direction of the relative airflow
determines magnitude of lift generated by the wing

critical angle (stalling angle): 12 to 18 deg