How Engines Are Attached To Aircraft

Summary

This video explores the engineering behind podded engines mounted under aircraft wings, a common design for large commercial planes. The process is complex, balancing safety, weight, and accessibility. Wing-mounted engines relieve wing bending, offer easier maintenance, and enhance safety by positioning engines away from the fuselage. The engines are attached to pylons with bolts designed to withstand significant forces but are engineered to shear under extreme conditions, preventing further damage. The video also contrasts podded engines with early designs, such as the de Havilland Comet, and highlights the practicality of modern turbofan engines, which are too large for wing integration.

Takeaways

• 😀 Engines are commonly mounted in pods under the aircraft wings for large commercial aircraft.
• 😀 This design provides wing bending relief by counteracting the upward force caused by lift.
• 😀 Mounting engines under the wing also allows for easier maintenance and access.
• 😀 A downside to this design is an increased risk of foreign object damage to the wings.
• 😀 Engines are usually positioned slightly forward of the wing to prevent wing flutter and lighten the wing structure.
• 😀 Some smaller aircraft, like the Embraer ERJ family and COMAC ARJ21, have engines mounted on the fuselage tail.
• 😀 Engine pods are connected to pylons, which are securely fixed into the wing structure.
• 😀 The pylon creates a safe distance between the engine and the wing to protect against engine fires.
• 😀 Engine pods are bolted to pylons at two points: the top of the fan frame and turbine frame.
• 😀 The bolts connecting the engine to the pylon are designed to withstand extreme forces but will shear off under severe conditions to prevent fire or wing damage.
• 😀 Early aircraft, like the de Havilland Comet, mounted engines directly into the wings, but this design posed safety risks.
• 😀 As turbofan engines have grown in size, it has become impractical to mount them directly within the wing structure.

Q & A

Why are engines typically mounted in pods under the aircraft wing?

Engines are mounted in pods under the wing to provide wing bending relief, easier maintenance access, and to balance the weight distribution, which counteracts the upward bending of the wingtips caused by lift forces.

What is the downside of placing engines in pods under the wing?

One downside is that it exposes the wings to a higher risk of foreign object damage, as engines are more vulnerable to debris or impacts from the ground.

How does mounting engines slightly forward of the wing help the aircraft?

Mounting the engines slightly forward of the wing helps to prevent wing flutter and also allows for a lighter overall wing structure, improving aircraft performance.

What is the purpose of pylons in the engine mounting system?

Pylons are used to attach the engine pods to the wing structure, creating a gap between the engine and the wing. This gap is crucial for safety, especially in the event of an engine fire.

What role do bolts play in the attachment of the engine pod to the pylon?

The bolts securely attach the engine pods to the pylons at two main points, ensuring they can withstand the forward thrust and downward force of the engine’s weight during normal and extreme conditions.

What happens to the engine bolts during extreme forces like hard landings?

In the event of extreme forces, such as hard landings or engine impact with the ground, the bolts are designed to shear off. This allows the engine to detach from the pylon, reducing the risk of fire and preventing further damage to the wing.

Why is it preferable for the engine to break off from the pylon during extreme events?

It is preferable for the engine to break off from the pylon in extreme events because it prevents the engine from remaining attached, which could cause a fire risk or cause the wing to break off due to the transferred forces.

Why are modern aircraft engines not integrated directly into the wing structure?

Modern engines are not integrated into the wing structure because it poses significant safety risks, as seen in early aircraft designs like the de Havilland Comet. Additionally, the increasing size of modern turbofan engines makes this integration impractical.

What were some of the drawbacks of the early aircraft designs with wing-integrated engines?

Early aircraft designs with wing-integrated engines, such as the de Havilland Comet, faced safety issues like a higher fire risk and the potential for wing damage during extreme events, making podded engines a safer and more effective solution.

What other types of aircraft have engines mounted on the fuselage tail instead of the wings?

Smaller aircraft, such as the Embraer ERJ family and the COMAC ARJ21 regional jet, mount their engines on the fuselage tail, offering a different design approach from the common podded engine configuration.