b. Operation. The engine is started by energizing the
starter, the starting fuel solenoid valve, and the ignition system.
fuel nozzles and is ignited by the four igniter plugs adjacent to the
starting fuel nozzles at the 2, 4, 8, and 10 o'clock positions. At 8
to 13 percent N1 speed, the fuel regulator valve opens, and main fuel
flows into the combustion chamber through 22 fuel atomizers and is
ignited by the burning starting fuel. As compressor rotor speed (N1)
When compressor speed increases to 40 percent N1 speed, the
starter, starting fuel solenoid valve, and ignition system should be
deenergized. Combustion gases pass through the gas producer nozzle
assemblies; impinge upon (strike) the blades of the gas producer
rotor assemblies; How through the power turbine nozzle assemblies;
and impinge upon the blades of the power turbine rotor assemblies.
Approximately 60 percent of the gas energy passing from the
compressor, while the remaining energy is extracted by the N2 power
turbines to drive the power shaft. The power turbine rotor
assemblies are splined to the power shaft and secured by the power
shaft bolt. The power shaft is splined into the sungear shaft,
which drives the output reduction gearing and, in turn, the power
output gear shaft.
The Lycoming T53 engine design was submitted to the military,
and in 1952 a contract was awarded to the Army for development of the
present T53 gas turbine engine. The basic T53 powerplant is a free
turbine consisting of two mechanically independent stages a
compressor and a power turbine. From the initial prototype version,
many models of the T53 have been developed. The following models are
currently being used by the Army.
T53L13 a secondgeneration shaft turbine engine having
all the improvements developed for the T53 L11/11A/11B versions.
It introduces combustion chamber atomizers (replacing the vaporizer
tubes), two gas producer and power turbine rotors instead of one of
each, and four atomizing type starting fuel nozzles and four igniter
T53L13A Engine model T53 L13 containing additional
modifications is designated as model T53L13A. This model
incorporates the following improvements: a 34blade second stage
compressor disc assembly; No. 2 bearing forward and aft seals, bearing