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AMT 1216
Reciprocating Engines
Question | Answer |
---|---|
Reciprocating engines are classified by their: | Cylinder arrangement |
What is the most common way to cool an opposed type engine? | Air cooled |
What type engine can be mounted vertically or horizontally? | Opposed-type |
What is known as the foundation of the engine? | Crankcase |
What is commonly referred to as the backbone of the engine? | Crankshaft |
What are three shapes of the top face of a piston? | Flat, convex, and concave |
The piston face shape prevents what? | Interference with the valves |
What connects the piston to the connecting rod? | Connecting rod |
What prevents gases from leaking out of the combustion chamber? | Piston rings |
Detonation, misfiring, and excessive oil consumption can result from what? | Too much oil film of the cylinder walls |
Strong and lightweight, inexpensive to manufacture, inspect and maintain are factors of what? | Design factors for cylinders |
What two parts make up the cylinder construction? | Head and barrel |
What material is used to forge or die cast cylinder heads? | Aluminum alloy |
The first type of inspection of an engine should be what? | Visual inspection |
What is the stronger and most satisfactory shaped cylinder head? | Semispherical |
How are chrome cylinders identified? | Visually by orange on the flange barrel |
What does TBO stand for? | Time Before (or Between) Overhaul |
What is peening? | A series of blunt depressions |
What are the 3 inspection categories? | Visual, structural NDT, and dimensional |
What tool is used to inspect cylinder barrels for wear? | Cylinder bore gauge |
If a cylinder is found to be warped beyond limits, what must be done? | Cylinder must be rejected |
Who determines the actual overhaul period for a specific engine? | The manufacturer |
What is determined during the receiving inspection? | The general condition and inventory of the engine's components |
What is the first step after disassembling? | Visual inspection |
What do movable counterweights reduce? | Torsional vibrations |
During which two engine strokes does valve overlap occur? | Exhaust and intake |
What is the actual power delivered to the propeller of an engine known as? | Brake horsepower |
During normal operation, how much clearance would hydraulic valve lifters have? | Zero |
Crankshaft rotation is measured by what tool? | Timing disk |
What would happen if the intake valve opens too early on a 4 stroke engine? | Backfiring into the induction system |
What process hardens cylinders to a depth of several thousandths of an inch? | Nitriding |
Just before what stroke of the engine's 4 stroke cycle does the intake valve close? | Compression |
If you subtract friction horsepower from indicated horsepower, what is the result? | Brake horsepower |
What occurs shortly before the piston reaches the top of the compression stroke? | Ignition of the fuel and air mixture |
How could you detect exhaust valve blow-by? | A hissing sound from the exhaust stack during a compression test |
How do you determine the total piston displacement of an engine without measuring anything? | By reading the engine designation number (O-360 = 360 cubic inches of displacement) |
What would happen if a reciprocating engine is operated at high power settings before it is properly warmed up? | Bearings would not be properly oiled |
What could result from grinding the valves in a reciprocating engine? | Pre-ignition and burned valves |
What would be the cause of the oil pressure gauge fluctuating over a wide range from zero to normal operating pressure? | Low oil supply |
What occurs at the end of the exhaust stroke and the beginning of the intake stroke? | Valve overlap |
What would a lean mixture at low RPM settings cause? | Backfiring through the induction system |
What is the purpose of the camshaft lobes? | Open valves at specific time |
43. Why does the smoothness of operation of an engine increase with a greater number of cylinders? | The power impulses are spaced closer together |
How would the valve opening duration be effected if there is excessive valve clearance? | Both intake and exhaust would decrease |
At what position should the piston be when removing a cylinder? | Top Dead Center |
Why is the firing order for an opposed engine important? | balance and eliminate vibrations |
If the volume of a cylinder at BDC is 70 cubic inches and 10 cubic inches at TDC, what is the compression ratio? | 7:1 |
On an engine with hydraulic lifters, how would the valve clearance be changed? | Push rod replacement |
What type of piston pin allows movement between the pin, the piston and the small end of the connecting rod? | Full-floating |
What are the 5 events of a 4-stroke cycle engine (in order)? | Intake, compression, ignition, power, exhaust |
What enables the engine RPM to be increased with an accompanying increase in power and allow the propeller to remain at a lower, more efficient, RPM? | Propeller reduction gears |
53. When will small induction system air leaks have the most noticeable effect on engine operation? | At low RPM |
When does valve overlap occur? | Exhaust and intake |
What is valve overlap? | When both valves are off their seats (open) |
What would likely happen if too low of octane fuel were used? | Detonation |
The intake valve just closed and the exhaust valve is closed, what stroke is the engine on? | Compression |
How is liquid lock prevented in radial engines? | Turn the propeller by hand 3-4 revolutions if the engine has been shut down for more than 30 minutes |
When would an engine require pre-oiling prior to starting the engine? | Engine installation |
Why are ball bearings used instead of roller bearings in high-powered horizontally opposed engines? | There is less rolling friction |
What could a plugged crankcase breather cause? | Excessive pressure buildup in the case |
Where will the greatest amount of wear occur on the cylinder walls? | Near the top of the cylinder |
Intake vales will have larger heads than? | Exhaust valves |
63. Master rod bearings are generally what type? | Plain |
64. What does valve overlap promote? | Better scavenging and cooling characteristics |
What is the purpose of having 2 or more valve springs? | Eliminate valve spring surge |
What causes excessive valve clearance of a cylinder on a reciprocating aircraft engine? | Reduced valve overlap period |
A condition that can occur in radial engines but is unlikely to occur in horizontally opposed engines is: | Hydraulic lock |
During what stroke does the intake valve close? | Compression |
During a compression check, the propeller moves in the direction of normal rotation as the pressure is applied. What does this indicate? | The piston was positioned past top dead center |
The breaking loose of small pieces of metal from coated surfaces, usually caused by defective plating or excessive loads, is called what? | Flaking |
The actual power delivered to the propeller of an aircraft engine is called what? | Brake horsepower |
What is the best indication of worn valve guides? | High oil consumption |
What could result from high manifold pressure, high intake air temperature, and overheated engine ? | Detonation |
What would decrease valve overlap? | Excessive valve clearance |
What inspection must be completed during a 100-hour inspection? | Compression check |
What is the formula for finding total piston displacement? | 3.14 x radius squared x height of cylinder x number of cylinders |
What is an advantage of using metallic – sodium filled exhaust valves in aircraft reciprocating engines? | Reduced valve operating temperatures |