Reciprocating Engine Induction and Cooling Systems Flashcards
The basic induction system of an aircraft reciprocating engine consists of what components?
Air scoop and ducting
What are the three major parts of a reciprocating induction system?
Air scoop, fuel delivery system, and intake manifold
What effect does induction system icing have on engine performance?
Can cause an engine to act erratically and lose power and may possibly quit
What method is used to prevent or remove induction system ice in a reciprocating engine?
Heated air
How is ice cleared in some aircraft induction systems if the carburetor heat is too low to clear the ice?
Anti-icing fluids such as alcohol are sprayed into the induction system
What engine indication can be the result of a dirty air filter?
Low power
What is the danger of using carburetor heat when operating at high power settings?
Detonation and possible engine failure
Carburetor throttle ice is most likely to form when the throttle is in which position?
Partially closed position
What are two general classifications of supercharges used in reciprocating engine induction systems?
Internally or externally driven supercharger systems
What is the purpose of a distribution impeller in a radial engine?
Break up the fuel globules and better distribution to the cylinders
How does an internally driven supercharger get its power?
They are mechanically engine driven. A high-speed impeller is driven through a gear train from the crankshaft
Where does an externally driven supercharger get its power?
By the exhaust gases that are directed against a turbine.
What unit regulates the amount of exhaust gases to the turbine of a turbocharger?
Waste gate
What type of power is used to control the position of the turbocharger waste gate on some engines?
Oil pressure to an actuating piston
What can cause the waste gate to stick?
A buildup of carbon
What are the most common ways to control a waste gate?
Mechanically or by an actuator driven by oil pressure
What causes fuel evaporation ice?
Because of the decrease in air temperature resulting from evaporation of fuel after it is introduced into the airstream
What is the function of the turbocharger waste gate?
Controls the volume of exhaust gas that is directed onto the turbine
What may be the indication of leaking intake pipes?
Engine runs rough
What may be the indication if a turbocharger waste gate will not close fully?
Aircraft may not be able to reach critical altitude
What could be the probable cause of a turbocharger engine that surges?
Waste gate or controller malfunction
What is used on many turbocharged engines for the waste gate actuator power?
Oil Pressure
How does a divergent shaped jet engine inlet affect the air flowing to the engine when an airplane is in subsonic flight?
Causes the air velocity to decrease and the air pressure to increase
Bellmouth inlet ducts are used typically on what type of aircraft?
Helicopters
The Venturi type particle separator, found on many turbine powered helicopters, utilizes what characteristic of matter to help remove debris from induction air?
Inertia
What is the most common means of regulating the cooling air flow through a reciprocating engine?
Cowl flaps
What is the purpose of the fins on engine cylinders?
Increase the surface area of the cylinder for cooling
What other engine characteristics are designed to aid in engine cooling besides cooling fins?
Engine cowlings and baffles
How is an engine designed to provide more cooling area?
The outer surface of the cylinder is increased by use of cooling fins
Why is the “open and close” adjustment during installation of cowl flaps important?
The cowl flaps are set for a tolerance that will permit them to open and close the correct amount to keep the cylinder head temperature within allowable limits
What should be done to cylinders when too much of the cooling fin area is broken off?
Cylinder should be replaced
When should cowl flaps be kept in the fully open position?
During all ground operations
What publication should be referred to before re-profiling cylinder cooling fins?
Manufacturer’s service or overhaul manual
What power sources are used to operate cowl flaps?
Electrical and hydraulic power or manually
What is the purpose of blast tubes?
Direct jets of cooling air to accessories of the engine that have high heat concentrations
What are the main reasons that excessive heat in a reciprocating engine is undesirable?
Shortens the life of the engine parts, impairs lubrication, and affects combustion
Describe the augmenter system.
Helps to keep the temperature of air-cooled engines down by using exhaust gas energy to draw cool air over the engine.
What is the source of air directed to engine bearings for cooling?
Bleed air from the compressor section
What is the purpose of insulation on the exhaust duct of a turbine engine?
Reduce the temperature of the structures in the vicinity of the exhaust duct or afterburner and to eliminate the possibility of fuel or oil coming into contact with the hot parts of the engine
What types of materials are used to make insulation blankets for turbine engines?
Stainless steel, fiberglass, silver foil and layers of aluminum foil
What areas of a turbine engine are cooled by the secondary air passing through the engine?
Combustion chamber and the turbines
What is the purpose of an engine cowling?
Streamlines the engine to reduce drag and forms an envelope around the engine which forces the airstream between the cylinders to cool them
What is the purpose of an oil cooler bypass valve?
Allows thick oil to bypass the cooler when the oil is cold
Where should cowl flaps be positioned during ground operations?
Fully open
What is the purpose of cowl air seals?
Force air to circulate around and through the baffle system
Where must most cooling air flow to cool a turbine engine?
Inside of the engine
What areas of a turbine engine are cooled by air passing through the engine?
Combustion chamber and turbine
What is the relationship between turbine engine upper temperature limits and power produced?
The higher the combustion temperatures that an engine can withstand without damage, the more power it is capable of producing
What is the approximate percentage of air passing through a turbine engine that is used for cooling rather than combustion?
75 percent
What is the unit of measure for manifold pressure?
Inches of Mercury.
Other than cooling fins, how else can you cool a reciprocating engine?
Cooling Jackets.
