Inside a turbojet or turbofan, heat is the signature of thrust. Air that has been squeezed to more than thirty times atmospheric pressure leaves the high-pressure compressor at roughly 500°F (260°C), then meets atomized fuel. Ignition takes place once the mixture sits between 300°C and 400°C, but the resulting flame stabilizes at up to 2,000°C inside the combustor. Carried toward the first-stage turbine, this gas arrives with a temperature - often labeled T4 - that can brush 2,000 K, while the latest engines push the high-pressure-turbine inlet to almost 3,600°F (2,000°C) during full-power operation.
Although contemporary super-alloys begin to melt near 1,300°C, ingenious cooling keeps the hardware intact, so the flow that finally accelerates from the exhaust nozzle still measures 1,000°F (about 550°C). Pilots watch this value on the Exhaust Gas Temperature gauge, where readings normally fluctuate between 600°C and 1,000°C; in extremis, internal thermocouples may register 3,000°F (1,650VC). Together, these numbers illustrate why every modern jet engine is a precision furnace whose output is controlled, reliable thrust.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
What is the temperature of a jet engine in an aircraft?
The temperature of a jet engine has different values. Inside the combustion chamber, fuel burns at up to 2000°C (3632°F), yet the gas that meets the turbine enters between 850 and 1700°C (1562-3092°F). To protect the metal, the temperature at the exit of the compressor is held below 1000 K, while the turbine inlet temperature reaches 2000 K during full-power operation.
When the engine is operating, thermocouples mounted in the exhaust stream relay the gas temperature to the flight-deck gauge in degrees Celsius or Fahrenheit. The interstage turbine temperature, measured between the high-pressure and low-pressure turbines, is one of the indicators pilots monitor. The exhaust gas temperature at the nozzle is normally about 550°C (1022°F).
On average, internal temperature readouts during approach show 600°C (1112°F), whereas the metallic skin of the aircraft remains close to the outside air, around 38°C (100.4°F). Auto-ignition of Jet A and Jet A-1 occurs only above 210°C (410°F), so combustion is reliably sustained well below the 1700°C (3092°F) gas stream that drives the turbines.
How hot does an airplane engine get?In a jet engine, air at the tail end of the compressor gets as hot as 3,000 degrees Fahrenheit after going through the combustor. The hot section of a jet engine gas core consists of the isobaric combustor, high pressure turbine, and low pressure turbine, operating at the highest temperatures within the engine. The performance of a turbine engine is determined in large part by the maximum turbine inlet temperature that the hot section blades can sustain. Hotter temperatures make the core operate more efficiently, but simultaneously place extreme thermal stress on components like exhaust valves and valve guides, which are continually exposed to temperatures in the 1,200°F (649°C) to 1,600°F (871°C) range.
For piston engines, full-power exhaust gas temperatures (EGTs) are no higher than about 1,300°F (704°C) for normally aspirated engines and about 1,400°F (760°C) for turbocharged engines. None of the cylinder head temperatures (CHTs) must exceed 380°F (193°C) during takeoff and climb. The maximum allowable cylinder head temperature is 500°F (260°C). Steady-state CHT must be kept at or below 435°F (224°C) for models like the Lycoming O-320, though CHTs around 350°F (177°C) are better for normal cruise conditions. Normal oil temperature range is between 190°F (87.8°C), and the maximum oil temperature red line limit is established as 245°F (118.3°C). The recommended minimum operating oil temperature is 160°F (71.1°C), and oil normally gets hot enough during flight to vaporize water and most acids. Engine temperature ratio (ETR) is defined to be the total temperature ratio across the engine.
