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Final review 2201
Question | Answer |
---|---|
What are factors that decrease VE? | Improper valve timing, sharp bends in the induction system, and high carburetor air temperatures |
Which strokes are both valves open? | Intake and exhaust |
Three types of bearings used | Plain, roller, and ball bearings |
Which one has the least rolling friction? | Ball bearing |
Which would make a good thrust bearing? | Deep grooved ball bearing |
How many springs are required for valves? | 2- Redundancy and reduction of vibration, valve flutter dampening |
When is the air fuel mixture ignited? | compression stroke |
Operating valve clearance | will be greater when hot |
Cam ground piston | Oval shaped that turns round when heated |
Primary concern when establishing a firing order? | – provide for balance and eliminate vibration to the greatest extent possible |
Grinding the valves of a reciprocating engine to a feather edge is likely to result in – | preignition and burned valves |
Master rod bearing for a radial engine are generally what type? | Plain |
Which bearing is least likely to be a rolling or ball bearing in a radial engine? | Master rod bearing |
. What is the HP delivered to the propeller called? | brake horsepower |
When is the combustion process completed? | Shortly after TDC on the power stroke |
A condition that occurs in radial engines but not horizontally opposed engines is | hydraulic lock |
Five events of an engine | Intake, compression, ignition, power, exhaust |
Which statement is correct in regard to engine crankshafts? | Moveable counterweights reduce dynamic vibrations |
What is the principle advantage of propeller reduction gear? | increase engine RPM without breaking sound barrier |
What is a choke or tapered ground cylinder | – slightly smaller at the top of the cylinder and expands when it heats up. Provides a straight cylinder bore at operating temperatures |
What can happen if the intake valve opens too early? | Backfiring into the induction system |
What is valve overlap? | When both valves are off their seat |
Where do most cylinders wear-out the most? | at the top because the heat and least amount of oil |
What is the operating valve clearance for an engine with hydraulic lifters? | 0 |
Method of hardening cylinder walls? | nitriding or chrome plating |
Which of the following is caused by excessive valve clearance? | Intake and exhaust valves will open late and close early |
Which statement is correct regarding 4-stroke engines? | Intake valve closes on the compression stroke |
What is compression ratio? | the ratio between cylinder volume with piston at bottom dead center and top dead center |
Which of the following will be caused by excessive valve clearance? | opening late and closing early |
Why does the smoothness of operation of an engine increase with a greater number of cylinders? | The power impulses are closer together |
What does valve overlap promote? | Better scavenging and cooling characteristics |
Excessive valve clearance causes the duration | to increase |
Excessive valve clearance causes | Reduced valve overlap period |
If the hot clearance is used to set the valves when the engine is cold, what will occur during operation of the engine? | The valves will open late and close early |
Which of the following is most likely to occur if an overhead valve engine is operated with inadequate valve clearances? | The valves will not seat positively during start and engine warmup |
Primary purpose of proper valve timing and overlap | obtain the best volumetric efficiency and lower cylinder operating temperatures |
What do full floating piston heads allow motion between? | the piston and the connecting rod |
If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is | low oil pressure |
Cast iron piston rings may be used in | chrome plated cylinders. |
Chrome plated rings may be used in | plain steel cylinders. |
If the exhaust valve closed, and the intake valve just closed, what stroke is the engine on? | Compression |
A hissing sound from the exhaust when turning the prop manually | exhaust valve isn’t seated |
What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines? | Reduced valve operating temperatures |
What is oil viscosity? | Resistance to flow |
Which of the following has the greatest effect on the viscosity of lubricating oil? | Temperature |
What component controls the oil pressure | Maybe oil pressure regulator |
Horsepower in the cylinders | indicated |
Before starting a radial engine, what should be attempted? | Rotate the prop in the same direction |
If the oil pressure of a cold engine is higher than at operating temperature | normal operation |
When does valve overlap occur? | At the end of the exhaust stroke and the beginning of the intake stroke |
Which fuel/air mixture will burn all of the fuel and air? | Stoichiometric |
Backfiring from the carburetor is caused by using | running excessively lean |
Which of the following conditions will lead to bleeding detonation? | Low octane fuel |
Which of the following is true? | preignition is caused by an area that is incandescent |
When would small induction system air leaks have the most noticeable effects | At low RPM |
What can cause excessive build-up in the crankcase of a recip engine? | Plugged crankcase breather |
An unsupercharged aircraft reciprocating engine, operated at full throttle from sea level to 10,000 feet, provided the RPM is unchanged, will | lose power due to the reduced density of the air drawn into the cylinders |
What does a TSIO engine designation stand for? | Turbocharged, supercharged, fuel injected, opposed |
What is the advantage of an inline engine? | aerodynamic |
how many cylinders does a radial engine have in the first row | An odd number of cylinders |
What does the clearance between the rocker arm and the valve tip affect? | Height of the valve opening, point at which the valve opens, duration of valve opening |
What variable can the pilot control to increase VE | RPM and Throttle |
Back suction mixture control operates by | varying the pressure acting on the fuel in the float chamber |
Purpose of the economizer | provide a richer mixture and cooling at maximum power output |
What stroke does the fuel injection system inject fuel? | all of them |
Where is the carb heat in a fuel injection system? | Doesn't have one |
What are pole shoes made of? | laminated soft iron to dissipate magnetism readily |
E-gap angle is defined as | several degrees of magnet rotation beyond the magnet's neutral position |
Spark is produced when breaker points are | Open |
What is grounded when the ignition switch it turned off? | P-leads |
What is the purpose of using an impulse coupling with a magneto? | To produce a momentary high rotational speed of the magneto |
What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines? | Reduced valve operating temperatures |