d. High fuel consumption. Turbine engines are very
uneconomical when it comes to the amount of fuel they consume. The
Lycoming T53 turbine engine, for instance, uses approximately 1.5
gallons per minute of fuel. Compare it to a reciprocating engine of
approximately the same horsepower which has a fuel consumption rate
of 1 gallon per minute.
e. Cost. The initial cost of a turbine engine is very high
when compared to the cost of a reciprocating engine. For example the
T53L13B engine costs about ,000, and the cost of a reciprocating
engine of approximately the same horsepower is ,000.
The two turbine engines commonly in use today are the turbojet
and turboshaft. The turbine has surpassed the piston engine in
design efficiency. The advantages of the gas turbine are a high
powertoweight ratio, less maintenance, and low oil consumption.
Because of the small frontal area, turbines have less aerodynamic
drag. The disadvantages are foreign object damage to the compressor
vanes, high operating temperatures, and high fuel consumption. The
turbine also has a slower acceleration rate. Because of the high
operating rpm, all rotating parts must be in perfect balance. The
cost to manufacture a turbine is much higher than that of a
reciprocating engine. Aircraft designers have always been limited by
the powerplants available for use on aircraft of new design. Their
constant plea has been for higher power, less weight, and a more
compact design; the turbine engine has been the answer to some, if
not all, of their pleas.
Section III. Major Engine Sections
Because of the many types of turbine engines, it is not
possible to list all the major components and have the list apply to
all engines. Several components are common to most turbine engines,
and a knowledge of these will be helpful in developing a further
understanding of aviation gas turbine engines. This section
discusses the major engine sections individually.
Engine terminology must be explained at this point to enable
you to understand the terms used in discussing gasturbineengine