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Reciprocating Engines Oral

1. How are conventional reciprocating engines classified?
They are classified according to cylinder arrangement with respect to the crankshaft, (in-line, V-type, Radial, and Opposed). Or according to cooling method, IE ( air cooled, or liquid cooled.)
reciprocating engines oral.

2. what are the different types of piston rings?
compression rings, oil control rings, and scraper rings.
reciprocating engines oral.

3. What is the purpose of the oil control rings?
they are used to control the thickness of the oil film on the cylinder walls.
reciprocating engines oral.

4. What may be the result of installing piston rings incorrectly?
excessive oil consumption.
reciprocating engines oral.

5. What type of piston rods are commonly found in radial engines?
a master and articulating rod assembly.
reciprocating engine oral.

6. What type of the bearings are in general use in reciprocating engines?
plain bearings which are generally used for crankshaft, cam rings, camshaft, connecting rods, and accessory drive shaft bearings.

roller bearings which are used primarily as crankshaft main bearings but have other applications as well.

ball bearings which are used for supercharger and impeller shaft bearings, rocker arm bearings in some engines, and as propeller thrust bearings.
reciprocating engines oral.

7. why are thrust bearings generally of the ball bearing type?
because a ball bearing can take the load on all sides.
reciprocating engines oral.

8. what is an indication of valve blow by?
valve blow by is indicated by a hissing or whistle sound on pulling the propeller through prior to starting the engine. A cylinder compression check should be made to identify the faulty cylinder.
reciprocating engines oral.

9. what is the purpose of valve overlap?
valve overlap permits better volumetric efficiency and lowers the cylinder operating temperature.
reciprocating engines oral.

10. what causes engine sudden stoppage?
striking an object or engine seizure due to internal damage.
Reciprocating engines oral.

11. what type of inspection must be made after sudden stoppage of an engine do to striking an object?
the propeller drive shaft must be checked for misalignment, and the propeller checked for track.
Reciprocating Engines Oral.

12. What is the purpose of cranckshaft dynamic dampers used in aircraft engines?
Dampers are used to overcome forces which cause deflection of the cranckshaft and torsionalvibration.  These forces are generated by the power impulses of the pistons. Crankshaft vibrations are reduced by placing floating dampers (weights) in teh counterweight assembly, particularly in a single row type cranckshaft.
Reciprocating Engines Oral.

13. How would you make a "runout" check in a crankshaft that is still installed in the engine?
Remove the propeller from the shaft and attach a dial indicator guage to teh front of the crankcase. Adjust the position of the guage needle so that it is touching the shaft. Turn the engine through with the starter and note any changes in teh guage reading.
Reciprocating Engines Oral.

14. What is detonation?
Normal combustion is when the fuel-air mixture burns at a uniform rate across the combustion chamber. The temperature and pressure within the cylinder rises at at a normal rate as teh mixture burns. All fuels have critical limits of temperature and compression and beyond this limit they will ignite spontaneously and burn with explosive violence.  This instantaneous explosive burning of the last portion of the charge is called detonation. 
Reciprocation Engines Oral.

15. What can be learned about teh condition of an engine by studying the results of a compression check?
From the cylinder compression check, you can determine if the valves, piston rings, and pistons are adequatley sealing the combustion chamber.
Turbine Engines Oral.

1. What are the major components of a typical gas turbine engine?
A typical gas turbine engine consists of an air inlet, a compression section, a combustion section, a turbine section, an exhaust section, and the accessory section.
Turbine Engines Oral.

2. What are the two principal types of compressors used in turbojet aircraft
centrifugal flow and axial flow types.
Turbine Engines Oral.

3. What are the three types of combustion chamber systems?
can, annular, and can-annular.
Turbine Engines Oral.

4. What is the purpose of the interconnector tubes between can type combustion chambers.
To spread the flameto the combustion chambers that are not equipped with igniter plugs during engine starting.
Turbine Engines Oral.

5. What prevents burning of the liner walls in can type combustion chambers?
Louvers are provided along the axial length of the liners to direct a cooling layer of air along the inside wall of the liner.
Turbine Engines Oral.

6. What types of damage may be found when inspecting compressor blades?
Dents, Gouges, Scratches, Galling, Burns, Burrs, Pitting, and Cracks.
Turbine Engine Oral.

7. What is the location and function of the diffuser section in a turbine engine?
The diffuser is the divergent section of the engine located between the compressor section and the burner cans. Its function is to change the high velocity compressor discharge air to static pressure. It location is behind the compressor and fwd of the combustion section.
Turbine Engine Oral.

8. Where is the highest pressure point in a turbine engine?
The Diffuser.
Turbine Engine Oral.

9. How are compressor blades attached to a disk-type rotor?
The compressor blades are fitted into the disk by either bulb type or fir-tree type roots. The blades are then locked by means of screws, peening, locking wires, pins, or keys.
Turbine Engines Oral.

10. What is the purpose of the nozzle diaphragm or turbine nozzle?
First, the turbine nozzle must prepare the mass airflow for driving the turbine rotor. The stationary vanes are shaped and set at such an angle that they form a number of small nozzles that discharge the gasses a extremely high speed. That is, they convert a portion of the heat and pressure energy to velocity energy to drive the turbine. 

The second purpose of the turbine nozzle is to deflect the gases to a specific angle in teh direction of turbine rotation.
turbine engines oral.

11. what is a turbofan engine?
a turbofan engine is in principle, the same as a turboprop, except that the propeller is replaced by a duct-enclosed axial flow fan.
turbine engines oral.

12. what are the two most common types of thrust reversers?
the mechanical blockage type in the aerodynamic blockage type.
turbine engines oral.

13 what is a split compressor system in a turbine engine?
the split compressor system requires two concentric shaft joining the turbine stages to their respective compressors.

Different compressors are driven by different turbines.

N1=direct air, prevent stall
N2= high speed.
turbine engines oral.

14. what is one method of relieving thermal stress on a turbine disc?
one means is to bleed cooling air on to the face of the disk
turbine engine oral.

15. what maybe the indications if a turbojet engine is out of trim?
the engine has high exhaust gas temperature (EGT) at target engine pressure ratio (EPR) for takeoff.
engine inspection oral.

1. what steps must be taken in order to prepare an aircraft for 100 hour or annual inspection?
remove or open all necessary inspection plates, access doors, fairings and cowlings, then thoroughly clean aircraft and the engine
engine inspection oral

2. what may be used as a guide for 100 hour inspection on an aircraft engine?
FAR Part 43, Appendix D.
engine inspection oral.

3. what additional inspection must be performed if the cylinder compression is weak.
you must make an internal cylinder inspection for improper internal tolerances
engine inspection oral.

4. where are the engine operating limitations found?
in the aircraft specifications or type certificate data sheet.
engine inspection oral.

5. where can a mechanic look to identify an aircraft engine?
on the engine identification plate that is affixed to the engine at an accessible location.
engine inspection oral.

6. what publication is needed to inspect an engine for conformity with specifications?
the engine specifications for engine type: certificate data sheet.
engine inspection oral.

7. what type of FAA approval is required when a change to an engine type design is not enough to require a new type certificate?
a supplemental type certificate is required.
engine inspection oral.

8. What type of FAA approval is required when a change is made to the engine principle of operation?
A new type certificate must be obtained.
engine instrument systems oral.

1. what are the units in an engine fuel flow system?
the system consists of a transmitter and an indicator for each engine.
engine instrument systems oral.

2. where is the fuel flow transmitter located?
it is mounted in the fuel line between the engine driven pump and the carburetor.
engine instrument systems oral.

3. what type of readout is indicated on the fuel flow system.
The indicator is calibrated to record the fuel flow in pounds of fuel per hour.
engine instrument systems oral.

4. what is the reason for monitoring fuel flow?
in addition to fuel consumption, the operator can determine from the fuel flow indication whether the engine is operating at the correct fuel-air mixture for a given power setting.
engine instrument systems oral.

5. what does the engine tachometer indicate?
it indicates crankshaft speeds (RPM)
engine instrument systems oral.

6. What are turbine engine tachometers designed to indicate?
they are designed to indicate percent of rotor RPM
engine instrument systems oral.

7. what is turbow jet EPR? (engine pressure ratio)
it is the ratio between total turbine discharge pressure to total inlent pressure and is an indication of thrust being developed by the engine.
engine instrument systems oral.

8. what is the electrical source for a cylinder head temperature guage?
the guage is connected to a thermocouple attached to the cylinder which tests show to be the hottest part of the engine.
engine instrument systems oral.

9. where is a carburetor air temperature bulb located?
it is located in the air intake passage to the engine.
engine instrument systems oral.

10. how can turbine EGT be checked without operating the engine?
by checking resistance to thermocouples and circuits.
engine fire protection systems oral.

1. what types of fire detectors are used for engine fire protection systems?
they are overheat detectors, rate of temperature-rise detectors, and flame detectors.
engine fire protection systems oral.

2. when using a thermocouple type fire detection system, what happens if the engine overheats slowly?
a thermocouple depends on the rate of temperature rise and will not give a warning if the engine slowly overheats or a short circuit develops.
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