The engines of the large passenger planes are very big to the extent that two or more people could stand comfortably inside the engines. Particularly, the modern aircraft engines (Turbofan Engines) are remarkably huge and powerful.

How large is a Jet Engine?

The Boeing 777's GE90 engine
Is ranked among the biggest in the world. It has a diameter of approximately 3.4 meters (exceeding 11 feet).
Its height: very high, more than a man. Its engine weighs about 8 tons. There is also space even when two individuals are inside it.

The Boeing 787's GEnx engine
Its diameter is about 2.8 meters, weight: about 6 tons. A single individual could fit in it very easily.

The Airbus A380, Rolls-Royce 900
The diameter of the engine of Airbus A380, Rolls-Royce 900, is over 3 meters. It is also among the biggest and most powerful engines globally, and it can easily allow technical employees to stand in it when performing repairs.

Why are jet engines so big?

The answer is:
Turbofan is fitted to draw in more air, hence their engines are so large as far as more air is drawn in by the turbofan engine, the more thrust is created. To achieve high fuel efficiency, the bigger the fan, the higher the thrust put on minimal fuel, hence the bigger engines are economical. To reduce noise. The turbofan engines are big and make the engines less noisy since the fans provide more thrust.

Do you think people go into the engine?

During maintenance, Technicians and Engineers enter the engine to check and repair. An average person can easily stand here. Ordinary people are strictly prohibited from entering the engine as this is regarded as a very dangerous place.

The engines of the modern passenger aircraft are enormous to the extent that one can easily stand in them.
Particularly, the engines of Boeing 777, 787, Airbus A330, A350, and A380 are believed to be one of the biggest engines in the world.