Editing Turbojet (section)

=== Turbine ===
Hot gases leaving the combustor expand through the turbine. Typical materials for turbines include [[inconel]] and [[Nimonic]].<ref>{{Cite web|url=http://www.flightglobal.com/pdfarchive/view/1960/1960%20-%201525.html|title=1960 &#124; Flight &#124; Archive}}</ref> The hottest turbine vanes and blades in an engine have internal cooling passages. Air from the compressor is passed through these to keep the metal temperature within limits. The remaining stages do not need cooling.

In the first stage, the turbine is largely an impulse turbine (similar to a [[pelton wheel]]) and rotates because of the impact of the hot gas stream. Later stages are convergent ducts that accelerate the gas. Energy is transferred into the shaft through momentum exchange in the opposite way to energy transfer in the compressor. The power developed by the turbine drives the compressor and accessories, like fuel, oil, and hydraulic pumps that are driven by the accessory gearbox.