Model Comparison - AL09930220

Army Aircraft Gas Turbine Engines
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b. Operation. The engine is started by energizing the

starter, the starting fuel solenoid valve, and the ignition system.

Starting fuel flows into the combustion chamber through four starting

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)

increases, the additional fuel mixes with compressed air and burns.

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

combustion chamber is extracted by the N1 turbine rotors to drive 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.

4.5.

MODEL COMPARISON

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

plugs.

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