The conditions most likely to produce the highest engine power are ?
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Source: Telepilote theorique examen 28
The kind of compressor normally used as a supercharger is ?
An EGT Exhaust Gas Temperature indicator for a piston engine is used to ?
The conditions which can cause detonation are High manifold pressure low revolutions per minute. High pressure temperature in cylinder cause detonation (this when fuel/air mixture explodes rather than burns) high manifold pressure low revolutions would cause this condition the grade of fuel used in an engine must ensure that detonation doesn't occur during engine's normal operating range (for temperature pressure) a lower octane fuel allows detonation to occur at lower temperatures pressures but it doesn't actually cause detonation. 
If manifold pressure increased blade angle of a constant speed propeller High manifold pressure low revolutions per minute. Manifold pressure controls blade angle of a constant speed propeller (also know as a variable pitch propeller) a constant speed performs pretty much same function as a gearbox does in a car in that it 'maintains engine rpm over a varying conditions of roa the gearbox (or constant speed prop) there because engine work best within a certain range of rpm going too fast or too slow not good them the manifold absolute pressure (map) indicates power output of a piston engine if it increased blade angle will increase (as if you climb in mountain a car a lower gear will give more torque) fine pitch will give more thurst. 
The 'slipstream effect' of a propeller most prominent at Low airspeeds with high power setting. The high speed rotation of an airplane propeller gives a corkscrew or spiraling rotation to slipstream at high propeller speeds low forward speed (as in takeoffs approaches to power on stalls) this spiraling rotation very compact exerts a strong sideward force on airplane's vertical tail surface when this spiraling slipstream strikes vertical fin on left it causes a left turning moment about airplane's vertical axis the more compact spiral more prominent this force is as forward speed increases however spiral elongates becomes less effective the corkscrew flow of slipstream also causes a rolling moment around longitudinal axis note that this rolling moment caused the corkscrew flow of slipstream to right while rolling moment caused torque reaction to left in effect one may be counteracting other however these forces vary greatly it up to pilot to apply proper correction action use of flight controls at all times these forces must be counteracted regardless of which the most prominent at time. 
The operating principle of float type carburettors based on Difference in air pressure at venturi throat the air inlet. The carburattor uses venturi principle as speed of air increases through choke pressure reduces enough to pull fuel into it via main nozzle which connected directly to fuel system through a series of pumps jets. Question 28-8
The crank assembly of a piston engine comprises Crankshaft connecting rods pistons. The carburattor uses venturi principle as speed of air increases through choke pressure reduces enough to pull fuel into it via main nozzle which connected directly to fuel system through a series of pumps jets. Question 28-9
The purpose of blow in doors at air inlets to Provide engine with additional air at high power settings low air speeds. Spring loaded doors located in inlet duct of some gas turbine or turbofan engines these doors are normally closed but they open under conditions of low speed high engine power to permit additional air into compressor blow in doors help prevent compressor stall here are some examples . Question 28-10
On four stroke piston engines theoretical valve and ignition settings are readjusted in order to increase Provide engine with additional air at high power settings low air speeds. Spring loaded doors located in inlet duct of some gas turbine or turbofan engines these doors are normally closed but they open under conditions of low speed high engine power to permit additional air into compressor blow in doors help prevent compressor stall here are some examples . Question 28-11
For internal cooling reciprocating engines are especially dependent on The circulation of lubricating oil. Spring loaded doors located in inlet duct of some gas turbine or turbofan engines these doors are normally closed but they open under conditions of low speed high engine power to permit additional air into compressor blow in doors help prevent compressor stall here are some examples . Question 28-12
The main purpose of mixture control to Adjust fuel flow to obtain correct fuel/air ratio. Spring loaded doors located in inlet duct of some gas turbine or turbofan engines these doors are normally closed but they open under conditions of low speed high engine power to permit additional air into compressor blow in doors help prevent compressor stall here are some examples . Question 28-13
In which sections of carburettor would icing most likely occur Venturi the throttle valve. Spring loaded doors located in inlet duct of some gas turbine or turbofan engines these doors are normally closed but they open under conditions of low speed high engine power to permit additional air into compressor blow in doors help prevent compressor stall here are some examples . Question 28-14
For a reciprocating engine fuel/air ratio or mixture the ratio between Mass of fuel mass of air entering cylinder. The most accurate measure that you can get the mass of air fuel because it compensating the density volume changes with temperature the 15 1 therefore 15 parts of air weight to 1 part of fuel weight. Question 28-15
Which statement correct concerning effect of application of carburettor heat The density of air entering carburettor reduced thus enriching fuel/air mixture. When you apply carburettor heat to melt ice that has formed in throat (or venturi) air entering to mix with fuel passes around exhaust pipe to be heated this heated air has its density reduces the volume of air does not change when you apply carburettor heat. Question 28-16
Vapour lock Vaporizing of fuel prior to reaching carburettor. When you apply carburettor heat to melt ice that has formed in throat (or venturi) air entering to mix with fuel passes around exhaust pipe to be heated this heated air has its density reduces the volume of air does not change when you apply carburettor heat. Question 28-17
The reading on oil pressure gauge the Pressure of oil on outlet side of pressure pump. When you apply carburettor heat to melt ice that has formed in throat (or venturi) air entering to mix with fuel passes around exhaust pipe to be heated this heated air has its density reduces the volume of air does not change when you apply carburettor heat. Question 28-18
The main purpose of a turbocharger to Maintain power with increasing altitude. When you apply carburettor heat to melt ice that has formed in throat (or venturi) air entering to mix with fuel passes around exhaust pipe to be heated this heated air has its density reduces the volume of air does not change when you apply carburettor heat. Question 28-19
An excessively rich mixture can be detected Black smoke from exhaust. When you apply carburettor heat to melt ice that has formed in throat (or venturi) air entering to mix with fuel passes around exhaust pipe to be heated this heated air has its density reduces the volume of air does not change when you apply carburettor heat. Question 28-20
The compression ratio of a piston engine the ratio of Volume of cylinder with piston at bottom dead centre to that with piston at top dead centre. compression ratio = volume at bottom dead / volume at top dead . Question 28-21
The purpose of venturi in a carburettor to Create suction necessary to cause fuel to flow through carburettor main jets. compression ratio = volume at bottom dead / volume at top dead . Question 28-22
The mixture controller of a carburettor Varies fuel supply to main discharge nozzle. compression ratio = volume at bottom dead / volume at top dead . Question 28-23
A turbocharger system in a reciprocating engine normally driven Varies fuel supply to main discharge nozzle. this short illustration explains clearly principle. Question 28-24
An aircraft magneto switched off 1 grounding primary circuit 2 opening primary circuit 3 opening secondary circuit 4 grounding secondary circuit the combination that regroups all of correct statements Varies fuel supply to main discharge nozzle. a magneto essentially a self contained generator which gear driven the engine the ignition switch in cockpit when selected off ground magnetos to earth through primary circuit it works also the secondary circuit but usually this the primary circuit which grounded. Question 28-25
Spark timing related to engine speed in way that Faster engine functions more spark advanced. The ignition timing of a piston engine needs to be advanced at 'high rpm' because flame rate time complete combustion remain constant. Question 28-26
An impulse magneto coupling Gives a retarded spark at starting. The impulse coupling a spring loaded mechanical coupling which delays rotation of magneto during an engine start after a short period of rotation device allows magneto to catch up in effect spinning mag shaft faster than engine turning it the faster it turns hotter spark the bigger voltage impulse making easier starting after engine running rotational forces move spring loaded arms which make impulse coupling work at low speeds out of way the impulse coupling only works at very low engine speeds. Question 28-27
If an engine fails to stop with magneto switch in off position cause may be Excessive carbon formation in cylinder head. The magneto switch controls primary magneto circuit grounding it this done to isolate individual magnetos during rpm drop check if this wire broken therefore cannot be earthed then magneto will continue to supply current to engine it will continue to run the correct answer as stated excessive carbon formation this forms hot spots which remain heated continue to ignite mixture even though plugs are not sparking!. Question 28-28
An impulse coupling installed on a magneto of a piston engine to Provide a stronger spark on top dead centre engine starting. The impulse coupling a spring loaded mechanical coupling which delays rotation of magneto during an engine start after a short period of rotation device allows magneto to catch up in effect spinning mag shaft faster than engine turning it the faster it turns hotter spark the bigger voltage impulse making easier starting after engine running rotational forces move spring loaded arms which make impulse coupling work at low speeds out of way the impulse coupling only works at very low engine speeds. Question 28-29
The part of a piston engine that transforms reciprocating movement into rotary motion termed Provide a stronger spark on top dead centre engine starting. The impulse coupling a spring loaded mechanical coupling which delays rotation of magneto during an engine start after a short period of rotation device allows magneto to catch up in effect spinning mag shaft faster than engine turning it the faster it turns hotter spark the bigger voltage impulse making easier starting after engine running rotational forces move spring loaded arms which make impulse coupling work at low speeds out of way the impulse coupling only works at very low engine speeds. Question 28-30
In a piston engine if ratio of air to fuel approximately 9 1 mixture Provide a stronger spark on top dead centre engine starting. Rich 9 1 correct 15 1 weak 20 1. Question 28-31
Spark plug fouling more likely to happen if The aircraft descends continuously at idle power. plug fouling can occur due to rich mixtures with low cylinder temperatures this the condition engine will be in during descent at idle power this the reason during your flight training you are told not to let engine run at idle rpm too long normally you would increase rpm to around 1000 1200 rpm. Question 28-32
To maintain a constant mixture at low and high power settings in a piston engine a carburettor fitted with A diffuser (compensating jet). As engine speed airflow through venturi increase proportion of fuel to air rises as a result of different flow characteristics of two fluids this causes mixture to become richer to overcome this effect some carburettors are fitted with a diffuser (compensating jet) as engine speed progressively increased above idling fuel level in diffuser well drops progressively uncovers more air holes these holes allow more air into discharge tube by reducing pressure differential prevent enrichment of air/fuel mixture the process of drawing both air fuel through discharge tube also has effect of vaporising fuel more readily particularly at low engine speeds. Question 28-33
A piston engine may use a fuel of a different grade than recommended Provided that grade higher. As engine speed airflow through venturi increase proportion of fuel to air rises as a result of different flow characteristics of two fluids this causes mixture to become richer to overcome this effect some carburettors are fitted with a diffuser (compensating jet) as engine speed progressively increased above idling fuel level in diffuser well drops progressively uncovers more air holes these holes allow more air into discharge tube by reducing pressure differential prevent enrichment of air/fuel mixture the process of drawing both air fuel through discharge tube also has effect of vaporising fuel more readily particularly at low engine speeds. Question 28-34
In very cold weather pilot notices during startup a slightly higher than normal engine oil pressure this higher pressure Is normal if it decreases after startup. As engine speed airflow through venturi increase proportion of fuel to air rises as a result of different flow characteristics of two fluids this causes mixture to become richer to overcome this effect some carburettors are fitted with a diffuser (compensating jet) as engine speed progressively increased above idling fuel level in diffuser well drops progressively uncovers more air holes these holes allow more air into discharge tube by reducing pressure differential prevent enrichment of air/fuel mixture the process of drawing both air fuel through discharge tube also has effect of vaporising fuel more readily particularly at low engine speeds. Question 28-35
Excessive pressure in cylinders of an engine equipped with a constant speed propeller can be caused the combination of High manifold pressure low rpm. With constant speed control pitch of variable pitch propeller changed automatically a governor after pilot sets desired engine/propeller speed with propeller speed control governor acts to keep propeller speed at same value if governor detects propeller speed increasing it increases pitch a little to bring speed back within limits if governor detects propeller speed decreasing it decreases pitch a little to bring speed again back within limits this operation may be compared to an automatic gearbox in an automobile where gears are changed automatically to keep engine operating at a reasonable speed during a power change on an engine equipped with a constant speed propeller a wrong combination of manifold pressure rpm values results in excessive pressures in cylinders this the case when one simultaneously selects a high manifold pressure low rpm. Question 28-36
When in flight a piston engine stopped and propeller blade angle near 90° propeller said to be High manifold pressure low rpm. With constant speed control pitch of variable pitch propeller changed automatically a governor after pilot sets desired engine/propeller speed with propeller speed control governor acts to keep propeller speed at same value if governor detects propeller speed increasing it increases pitch a little to bring speed back within limits if governor detects propeller speed decreasing it decreases pitch a little to bring speed again back within limits this operation may be compared to an automatic gearbox in an automobile where gears are changed automatically to keep engine operating at a reasonable speed during a power change on an engine equipped with a constant speed propeller a wrong combination of manifold pressure rpm values results in excessive pressures in cylinders this the case when one simultaneously selects a high manifold pressure low rpm. Question 28-37
The richness of a fuel/air mixture ratio the Real mixture ratio relative to theoretical ratio. As name implies mixture refers to ratio of fuel/air that goes into cylinders of an engine combustion for an internal combustion engine to operate it requires three things fuel air ignition fuel air are mixed in a ratio of approximately 15 1 (15 parts of air to every 1 part of fuel) to create combustion in a carbureted engine (non fuel injected) fuel air are mixed in carburetor before being introduced into cylinders carburetors are calibrated to operate with mixture control set to 'full rich' when operating at sea level as aircraft gains altitude it becomes necessary to reduce amount of fuel entering carburetor because amount of air automatically decreasing with altitude due to lower atmospheric pressure if pilot fails to decrease amount of fuel as altitude gained result will be an overly 'rich' mixture creating problems such as fouled spark plugs excessive fuel consumption overheating problems tend to occur when operating with an excessively lean mixture (too little fuel) a lean mixture creates better performance (to a point) as well as higher operating temperatures reduces fuel consumption the problem arises when pilots fail to enrichen mixture (add fuel) as altitude lost during a descent this results in an excessively lean mixture which can cause engine roughness fuel starvation even permanent engine damage the point to remember that fuel mixture must be decreased (leaned) as aircraft climbs increased (enrichened) as aircraft descends it also suggested to lean mixture during ground operations at higher altitude airports (generally above 3000 ft amsl) the term 'richnes refers to 'real mixture ratio' relative to 'theoretical mixture ratio'. Question 28-38
Dual ignition provides a factor of reliability and Improves combustion efficiency. As name implies mixture refers to ratio of fuel/air that goes into cylinders of an engine combustion for an internal combustion engine to operate it requires three things fuel air ignition fuel air are mixed in a ratio of approximately 15 1 (15 parts of air to every 1 part of fuel) to create combustion in a carbureted engine (non fuel injected) fuel air are mixed in carburetor before being introduced into cylinders carburetors are calibrated to operate with mixture control set to 'full rich' when operating at sea level as aircraft gains altitude it becomes necessary to reduce amount of fuel entering carburetor because amount of air automatically decreasing with altitude due to lower atmospheric pressure if pilot fails to decrease amount of fuel as altitude gained result will be an overly 'rich' mixture creating problems such as fouled spark plugs excessive fuel consumption overheating problems tend to occur when operating with an excessively lean mixture (too little fuel) a lean mixture creates better performance (to a point) as well as higher operating temperatures reduces fuel consumption the problem arises when pilots fail to enrichen mixture (add fuel) as altitude lost during a descent this results in an excessively lean mixture which can cause engine roughness fuel starvation even permanent engine damage the point to remember that fuel mixture must be decreased (leaned) as aircraft climbs increased (enrichened) as aircraft descends it also suggested to lean mixture during ground operations at higher altitude airports (generally above 3000 ft amsl) the term 'richnes refers to 'real mixture ratio' relative to 'theoretical mixture ratio'. Question 28-39
With a piston engine when detonation recognised you Reduce manifold pressure enrich mixture. The sudden release of heat energy from fuel in an aircraft engine caused the fuel air mixture reaching its critical pressure temperature detonation occurs as a violent explosion rather than a smooth burning process when detonation recognized you should reduce manifold pressure enrich mixture detonation can be caused by too lean mixture too high manifold pressure using low grade fuel an overheated engine. Question 28-40
'vapour lock' the phenomenon which Heat produces vapour bubbles in fuel line. The vapour lock a stoppage in a fuel feeding line caused a fuel vapour bubble.
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