Powerplant Systems & Components: Engine Cooling Systems 🔊 Flashcards
What is the most common means of regulating the cooling air flow through a reciprocating engine?
Using cowl flaps
What is the purpose of the fins on engine cylinders?
To 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
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 withing allowable limits
What should be done to cylinders when too much of the cooling fin area is broken off?
Cylinder should be replaced because it cannot cool properly and will develop hot spots
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?
The manufacturer’s service or overhaul manual should be used to obtain the allowable limits
What power sources are used to operate cowl flaps?
Electrical power, hydraulic power, or manually
What is the purpose of blast tubes?
To direct jets of cooling air to accessories of the engine that have high heat concentrations. On radial engines they prevent overheating of the ignition leads.
What are the main reasons that excessive heat in a reciprocating engine is undesirable?
It shortens the life of the engine parts, impairs lubrication, and affects combustion
Describe the augmenter system.
It is used to help 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?
To 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, layers of aluminum foil, fiber glass, and silver foil
What areas of a turbine engine are cooled by the secondary air passing through the engine?
The combustion chamber and the turbines
