14. Propulsion
A compressor shaft rotates on
- sintered bearings
- ball and roller bearings
- plain bearings
S
Spaceresearcher asked · 11 Feb 2026
What about Needle Roller bearings, those are not balls?
14. Propulsion - Q&A
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14. Propulsion
When using a test set to test an EGT thermocouple circuit
- no compensation for ambient temperature is required
- only consider ambient temperature compensation if the ambient temperature is over 20oC
- always compensate for ambient temperature
S
sauravkatwal asked · 16 Feb 2013
WRONG AGAIN!!!!
Jordi: which is the correct answer?
14. Propulsion
EPR is a ratio of
- P1 to P4
- P1 to Pfan
- P1 to P6
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sauravkatwal asked · 16 Feb 2013
WRONG ANSWER!!!!!!
Jordi: Assuming of course from the image that the right hand sector is the exhaust and the left is the intake.
14. Propulsion
Manifold pressure is measured
- at inlet port above and below ambient conditions
- at inlet port above and below standard atmosphere at sea level
- at inlet port indicating boost pressure
I
Indrajith asked · 5 Dec 2012
at inlet port above and below standard atmosphere at sea level.... If a manifold pressure gauge is measuring in a supercharged engine it will measure above 29.92 in Hg.If the supercharge is not use it will measure below that figure. EHJ Pallett Integrated Instruments Page-355
Sokeros: Correct. The second answer is the correct answer.
14. Propulsion
The inlet of a turbo fan is
- divergent
- convergent
- convergent-divergent
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rajib asked · 22 Jan 2013
How come?
ademceven: aim there is to slow air and increase pressure, making it easy to process and also if air gets faster, fan blades can achieve supersonic speed which doesnt wanted.
14. Propulsion
How are the combustion chambers cooled?
- By l.p compressor air
- By h.p compressor air
- By fan pressure air
R
rajib asked · 3 Feb 2013
how??
ademceven: fan air pressure is too low to send there but the hp comressor air is relevantly cooler than the combustion chamber also has enough pressure to work there, since the target is not making combustion chamber to zero degree hp air far better suited for the job
14. Propulsion
The variable bleed valves on a engine at start up is
- open
- closed
- modulating
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sasna asked · 16 Aug 2013
bleed valve of the engine remain open during the starting of the engine???????????????????
ademceven: yes its open in order to enable more easy startup, if you close vbvs it would be far too hard to crank the engine since pressure feedback would force compressors to slow
14. Propulsion
A thermocouple indication is taken from the
- hot junction
- cold junction
- difference between the hot junction and the cold junction
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serzeb asked · 23 Sep 2013
Cant understand this answer, it is suppose to be difference b/w hot and cold.please explain why only cold junction.
ademceven: its sayin the indication taken from it doesnt say where the current occurs
14. Propulsion
An aircraft flying at 800mph would typically use
- turbojet
- turbofan
- turboprop
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serzeb asked · 23 Sep 2013
it could be turbofan too
ademceven: turbofans cannot maintain supersonic flight by means of civil aviation aircraft that have bir engines, since its civil aviation mented, the turbojet is true, bur for military fighter jets yep since they are small in diameter they built in turbofans too
14. Propulsion
A fuel flow transmitter requires a motor or a synchronous motor to have a
- constant voltage within small tolerances
- constant frequency within small tolerances
- low EMF as it is immersed in fuel
M
Mihir Somaia asked · 28 Jun 2014
Can someone please explain.
ademceven: most basically motor or syncro motor rotates on a fixed speed (mean fixed frequency) to give the fuel to non changing flow on a pipe,after that the fuel with constant flow hits a turbine which spring loaded, turbine rotates slghtly from original position by that fuel force and that change measured as fuel flow,
14. Propulsion
What is the pressure increase over one stage of a centrifugal compressor?
- 5:1
- 1.2:1
- 8:1
C
Crystal asked · 3 May 2016
I think the answer is 8:1 because Jeppesen Gas Turbine Powerplant quotes the latest modern centrifugal compressor as having a pressure ratio of 10:1
ademceven: i dont know about your claim but its an unique situation and doesnt bind the common knowledge, most centrifugal compressors on the last decade was built around 5 to 1 ratio for single stage and around 8 to 1 ratio for dual stage centrfugal comps. for example axial compressors described as 1,2 or 1,3 but in some extraordinary examples there are some 1,5to1 ratios they built
14. Propulsion
In a FADEC system, active control switchover occurs
- on shutdown.
- when channels A and B are healthy.
- on engine startup only.
C
Crystal asked · 7 May 2016
I think the correct answer is ON SHUTDOWN. I found the below explanation from a different site. On the CF6 FADEC, each startup uses an alternative channel.But the switch-over occurs on shutdown of the previous run.The reason for this is that the switch-over at start up might interrupt the start-up sequence.
ademceven: yep you are correct, in documents this subject poorly mentioned, usually documents says that "Active/Standby transfer will occur after the engine has been run above 76% N2 and subsequentl yshutdown (N2 less than 35%)" this is confusing people. an engine has to pass 76 percent n2 speed, in order to register that attempt as an "engine cycle" means engine started normally. upon shutdown of engine the fadec changes channels will change from a to b for next cycle (assuming both channels have equal health regarding control)
14. Propulsion
Ratiometer pointer movement is achieved by
- one coil providing a torque against a permanent magnet
- two opposing coils providing a torque in a varying magnetic field
- two opposing coils providing a torque in a permanent magnetic field
W
wongyk asked · 4 Apr 2017
Do this means ratiometer in permanent magnetic field as in DC? If AC ratiometer will be in a varying magnetic field?
14. Propulsion
The fuel metering unit has direct inputs via
- only the EEC
- the EEC and the fire control handle
- the EEC, fire control handle and the engine master switch
S
sasna asked · 12 Aug 2013
EEC directly controls FMV, fire handle and master s/w is directly connected to SOV.
rwm1273: This question is specific to a particular style of engine. Not all systems work this way. Many aircraft have a separate valve connected to the fire control handle, and not connected in any way to the EEC, fuel metering device (HMU,FCU), or master switch. P&W engines (both turboprop and turbofan) are often this way.
14. Propulsion
What is the pressure increase over one stage of a centrifugal compressor?
- 5:1
- 1.2:1
- 8:1
D
descipline2 asked · 2 Jun 2016
i think the answer should be 8:1
14. Propulsion
An increase in fuel flow through the impeller type fuel flow transmitter is measured by
- drum lags impeller
- impeller lags turbine
- decreasing angle between the two
M
Mihir Somaia asked · 28 Jun 2014
Can someone please explain.
14. Propulsion
An EPR system reads slightly over 1, this would mean
- the transmitter datum point has moved and needs replacing
- no action required this is normal
- the indicator needs re-calibrating back to 1
S
sasna asked · 2 Sep 2013
EPR should read 1, is there any tolerance in EPR ????????
denbailey85: Affected by external influences such as OAT, QFE
14. Propulsion
Propeller speed is measured from
- a slip ring pulse probe
- a tachometer on the LP turbine shaft
- a pulse probe at the engine side of the reduction gear
R
rajib asked · 3 Feb 2013
can somebody give me a reference with explanation plz.
PART66Online: Here is some information flysafe.raa.asn.au/groundschool/prope...
14. Propulsion
Propeller torque is analogous to
- engine RPM
- shaft horsepower
- propeller RPM
S
sasna asked · 28 Aug 2013
not much collection of questions in this module....???/
PART66Online: Hello. Yes, this module does not contain much questions, only 160.
14. Propulsion
How is fuel flow varied in a variable displacement pressure type pump?
- Alter the camplate angle
- Remote servo pressure
- Direct cable to camplate
R
rajib asked · 5 Feb 2013
how many types of pumps are there? and what about camplate angle?
zbd: There are two basic types of fuel pump, Plunger type pump (variable displacement) and Gear type fuel pump. For Variable displacement type, the inclination of the camplate or swashplate and the movement of the rotor imparts a reciprocating motion to the plungers thus producing a pumping action. The stroke of the plungers is determined by the angle of inclination of the camplate.
14. Propulsion
in a flow type fuel system, fuel shutoff is done by
- mechanical ball valve
- fcu torque motor
- l.p fuel cock
S
sauravkatwal asked · 8 Feb 2013
Help..need some reference!!
trap2307: Hello! As I understand it.... Flow type fuel system is the simplest fuel system without any additions, and therefore fuel shutoff is done by simplest way - mechanical ball valve( en.wikipedia.org/wiki/Ball_valve ). Correct me if I'm wrong...
14. Propulsion
A short circuit in a d.c ratiometer will give
- max scale reading
- zero scale reading
- min scale reading
R
rajib asked · 5 Feb 2013
how??
14. Propulsion
Oil systems consists of
- 2 systems
- 3 systems
- 4 systems
R
rajib asked · 28 Jan 2013
Dose 3 system mean to be 'wet sump','dry sump' & 'full flow', then what about, 'pressure relief valve' & ' total loss system' please give some reference authentic enough to justify your answer. :)
PART66Online: part66-engineers.eu/index-eng-empl-me... Chapter 79
14. Propulsion
When using a test set to test an EGT thermocouple circuit
- no compensation for ambient temperature is required
- only consider ambient temperature compensation if the ambient temperature is over 20oC
- always compensate for ambient temperature
I
Indrajith asked · 5 Dec 2012
Always compensate for ambient temperature.... To test the system the test set has to be trimmed for ambient temperature,as the system when in operation is adjusted for ambient temperature by the compensating resistor.This is stated in B 737 AMM.
14. Propulsion
The inlet of a turbo fan is
- divergent
- convergent
- convergent-divergent
E
eldhosekottalil asked · 20 Apr 2012
the area of turbofan engine is like a convergent type na? more area in intake and decreasing the area while going inside na?? please clarify me
PART66Online: Indeed. Inlet is divergent but compressor itself is convergent. Thanks Chris!