Tom's engine theory class 101.
The definition of any engine is. "A mechanical device that uses heat and expanding gasses to produce rotating motion."
There are only two types of engines, internal combustion and external combustion. The external combustion is a steam engine, where the combustion takes place in a boiler and the developed energy is used in a different place. The industrial revolution was driven by these engines, and our nuclear generation plants are of this type.
The internal combustion is what we have in common use today where the combustion and resulting energy is used in the same unit.
There are two theories in each type of engines, the piston theory and the turbine theory.
The piston theory uses a piston articulating rod and a crank shaft to produce rotating motion.
The turbine uses vanes to react with the air/heat and produce a rotating mass.
Both theories use the same 4 basic operations to produce and extract energy. intake, compression, power, and exhaust. The difference being the piston engine uses each process one at a time, where in the turbine engine all process are happening at the same time.
The pure turbo jet engine the sole purpose of the turbine is to keep the compressor turning, and only the escaping gasses from the rear of the engine is used to move the engine forward. (simple reaction engine)
This is how the GTC's operate, the turbine is designed only to keep the compressor turning and with just enough more horse power to drive a genset and air-conditioning boot strap blower. Removing the genset and dumping the compressed air will give you more direct horse power to drive a prop reduction gear box, but not much, because when you load the turbine the compressor slows down and when it does the temperature in the turbine rises and you burn it up for the lack of airflow. In order to gain huge amounts of horse power from a turbine engine you must extract horse power from the hot gasses escaping from the rear of the engine by using a turbine that is not attached to the compressor, In other words we have a compressor driven by a turbine that produce the hot gasses and keep the engine alive, and a separate turbine to extract the energy from those gasses to drive a prop reduction gear box. (PT-6 theory)
