How Many Horsepower Does A Commercial Jet Engine Have?
- Jet engines generate much more power than automobile engines, with a fully loaded Boeing 777 engine producing about 61,700 horsepower.
- Turbofan engines function through compression, combustion, and expansion to generate thrust and propel the aircraft forward.
- The power of a turbofan engine is measured in pounds of force (lbf), kilograms (kg), or Newtons (N), with one Newton equaling 0.225 pounds of force.
Jet engines are complex machines designed to generate enough power to lift an aircraft off the ground and keep it safely in the air. The power of a jet engine is denoted as thrust, whereas the power of a light-piston aircraft or an automobile can be calculated in horsepower.
Have you ever wondered how the power of a jet engine compares to an automobile engine? It is not easy to compare the two because these systems have completely different outputs. This article explains the basics of automobile and jet engine power and how they may be loosely compared, as highlighted by KLM.
Function of an automobile piston engine
A piston engine works based on energy transfer from the crankshaft to the drivetrain. The piston converts the combustion energy into mechanical action and transfers it to the crankshaft. The piston moves up and down in the cylinder. The crankshaft is connected to the drivetrain that moves the wheels and the automobile.
Photo: Gulfstream Aviation
The same principle applies to light piston aircraft, where the crankshaft drives the propeller. The power output of a piston engine is expressed in watts (W) or in horsepower (hp). One horsepower equals 746 watts.
Function of a large turbofan engine
Turbofan engines function on the principles of compression, combustion, and expansion. The large fan in front of the engine sucks a large mass flow of air and transfers it to several stages of the low-pressure (LP) and high-pressure (HP) compressors. As a result of compression, the pressure and temperature of the air increases.
When the air reaches optimal pressure and temperature, it is mixed with atomized fuel in the combustion chamber. The homogenized fuel-air mixture is ignited in the combustor, generating hot gasses. The hot gasses expand and transfer the energy to several stages of turbines before exiting through the exhaust. The exit velocity of the air increases, generating thrust and propelling the aircraft forward.
The thrust force is expressed in pounds of force (lbf), kilograms (kg), or Newtons (N). One Newton equals 0.102 kilograms or 0.225 pounds of force. By this relation, the takeoff thrust of a GE90 engine powering the Boeing 777 family aircraft, equaling 115,000 lbf, will be 514,000 Newtons.
Comparing Newtons to horsepower
The power of a turbofan engine is based on force and resistance. Meanwhile, the power of a piston engine is based on shaft power. To provide a theoretical conversion, we must loosely convert thrust to shaft power. The shaft power in watts can then be compared to the power of a crankshaft that drives the wheels of a car.
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Considering aircraft speed, weight, and resistance force (drag), a theoretical number of watts produced by the engines can be estimated. Another method is to estimate the fan power (in watts) required to drive the engine fan.
Putting it all together
An average passenger car produces 150-200 horsepower, while the two engines of a fully loaded Boeing 777 on a cruise flight generate approximately 46 Megawatts of power. One Megawatt is equal to 1341 mechanical horsepower. Therefore, the two GE90 engines in our example produce approximately 61,700 horsepower.
Similarly, four engines on a fully loaded Airbus A380 produce approximately 224 Megawatts of power at takeoff, equaling nearly 300,000 horsepower. By that estimation, each engine produces 75,000 horsepower.
What are your thoughts on the estimation of jet engine thrust in horsepower? Share your opinion in the comments section.