operating theory explained in this course. Directional references
are shown in figure 1.9. Table I shows engine symbols and
abbreviations commonly used.
Figure 1.9. Directional References.
a. Directional references. Front or forward cold end of
engine. Rear or aft hot end of engine. Right and left
determined by viewing the engine from the rear. Bottom determined
by the location of the combustor drain valve. Top directly
opposite, or 180 degrees from the combustor drain valve.
These directional references hold true for most gas
turbine engines. On some the power shaft is at the end where the
exhaust gas is expelled. An engine of this design is the T73
installed on the CH54 flying crane.
b. Engine station notation. The engine is divided into
stations to designate temperature (T) or pressure (P) measuring
locations. Figure 1.10 shows a T53L13, labeling the engine
stations. Any time a number is placed after the letter T or P, it
denotes a specific location in the engine.
Example: The symbol T3, denotes the relative temperature at
a specific location on the engine.