Turboprop Engine Explained
How air flows through the H85-200
5 steps to understand the turboprop
Ambient air enters the engine
Air at ambient temperature and pressure is drawn into the engine through the inlet. This air contains the oxygen needed for combustion.
Air is squeezed to 20x pressure
The axial compressor stages progressively compress the air to 20 times atmospheric pressure. As the air is compressed, it heats up significantly - this is essential for efficient combustion.
Fuel burns, temperature exceeds 1,500°C
Jet-A fuel is injected into the combustion chamber and ignited. The burning fuel expands dramatically, creating high-energy hot gases that will drive the turbines.
Energy is extracted to drive the compressor
Hot gases first pass through the Gas Generator Turbine, which extracts about 70% of the available energy to drive the compressor. This keeps the compression cycle going.
Free turbine powers the propeller
The remaining energy spins the Free Turbine, which is NOT connected to the compressor. This turbine sends power through the shaft to the propeller via a 3:1 reduction gearbox, producing thrust.
Important numbers for the H85-200
The key innovation of the H85-200
The 2-shaft design allows the compressor to keep running even when the propeller is feathered. This provides better reliability and control during engine malfunctions.
The GE H85-200 powers the L410 NG with efficiency and reliability ✈️