Why Are Airplanes Engines Under the Wing?

Airbus A380 Emirates
Airbus A380 Emirates

The aviation industry has continued to be innovative over the years. The way airplanes were over 50 years ago is not the same way they are now. We do not mean they no longer fly in the air, but that extensive and continuous research has helped to improve how airplanes are designed to function.
Years back, airplanes had engines attached to the nose, above the wings, blended into the wings, and the rear fuselage. However, this has changed and most airplanes now have their engines under their wings. The reason why this is so would be made obvious in the following paragraphs.

Why Are Jet Engines Mounted Under the Wing?

The reasons why most modern airplanes have their engines under the wing is for performance, and so that the plane can function well. Engines that are under the wings ensure that they can be easily accessible for maintenance purposes. They are also under the wing for safety reasons. In addition, the two other reasons why the engines of modern-day airplanes are under the wing are engine noise and aerodynamics.
These reasons will be nicely enumerated below for a better understanding. Thus, you are advised to read along!
The designing of an aircraft is quite different from any other designing job, though they may operate under the same guidelines. Engineers often take into consideration where to place engines when they design an airplane to weigh the option that is best for the aviation industry and passengers.

  1. Maintenance
    If you ask Engine Inspectors and maintenance engineers where they would prefer having the engines located. The sure answer would be the wing, which is closer to the ground. Here, they would not require any height-Access such as a crane or high lifts to gain access to the engines.
    It is very relevant that the engines be located under the wing to aid maintenance, removal, and replacement of faulty engines in a timely and stress-free manner. What more? This also prevents any unforeseen events where a piece of equipment could be dropped on the wing.
  2. Cabin Noise
    Engine noise is one of the most dreaded problems in flying by air. And no passenger would enjoy flying and having so much noise pollution.
    Unlike the Canadian Regional Jet and others which have their engines mounted to the rear of the airplane, that has caused unspeakable noise to passengers who are unlucky to find their seats at the back. Engines mounted under the wing reduce any discomfort to passengers, as they are farther away and properly shielded by the wings.
  3. Structural Strength
    Structural strength is one of the core reasons why engines are located below the wings while fuel tanks are located in the wings. This prevents the wing from bending upward when the aircraft takes off and lift increases. This wing bending relief enables the use of bigger and heavier engines.
    In addition, the reduction in high-frequency vibration is also one of the reasons the engines are located under the wings.
  4. Aerodynamics
    The placement of the wing changed due to the increase in the size of the aircraft, and to ensure effectiveness, so that there is more lift and less drag.
    Since the engines are under the wing, the airflow over the wings works well. This is so because, at a certain angle, the air that passes over the top of the wing accelerates more quickly than the air traveling beneath it. Thus, low pressure is created which enables the aircraft to lift.
  5. Safety
    We acknowledge our fault for keeping this paramount reason the last on the list. This was not to rile you up, but we understand all the other 4 could have been summed up as amounting to safety procedures if they had not been explained above in their rights.
    In the case of a fire emergency, since the cabin and fuel tanks are apart, any fire that starts in the engine would not easily spread.
    Furthermore, say in a case where there is an engine failure, the wings will protect the cabin from any engine fragments.

Is The Aircraft Engine Always Present Below The Wings?

No! Not in all cases do we have aircraft engines that are under the wings. As a matter of fact, only a large amount of passenger aircraft has their engines under the wings. According to Aviation Stack Exchange, Fighter jets are among the aircraft that have their engines in their rear, while Small Cessnas have their engines in their nose.

Aircraft such as the Antonov An-72 have their engines above the wings and for a plane such as the Havilland DH 106 Comet, their engines are blended into the wings.

Thus, not all aircraft have their engines present below the wings. But most modern passenger airplanes have their engines under their wing as explained above.

How do plane wings not break?

The FAA has put in place stringent rules so that aircraft can survive bad turbulence, such as that given to the Boeing 787, to ensure that its wing is able to flex 26 feet while the aircraft is carrying 150% of its load capacity.

The wings of a plane will not break because it is very flexible. They are designed in a way that they can support up to 10 degrees of wing flex. And during flight, the expected degree an aircraft can flex is 7 degrees.

And the FAA has continued to ensure compliance of all new aircraft before they are useable.

What is the purpose of a wing spar?

The wing spar is one of the structural members of the wing. And its main function is to carry the bending loads in the wings generated by aerodynamic forces on the wing. En-Academic defined as spar as a structural member of the wing, that carries all the forces of both lift and the weight of the wings on the ground. They further noted that there may be more than one spar but one is responsible for the majority of the forces and is generally referred to as the Main spar.

Conclusion

Most planes now have their engines under the wings for safety, structural strength, aerodynamic, and maintenance reasons. And the common planes that have their engines under their wings are the modern-day passenger aircraft. Though this has not stopped some other aircraft from having their engines blended into the wings or at the rare fuselage. The idea is that designs best fitted for the specific aircraft aid in driving innovation. Further, the engineers know that bad turbulence may affect plane wings, therefore they demand that aircraft comply with the required degree of flex to ensure that the plane wings do not break. Finally, the article stated that the function of the wing spar is to carry bending loads in the wings. Therefore, this article has been able to provide all the information about the aviation industry as it relates to why airplane engines are under the wing.

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