How the Boeing 747 got it's hump?

How the Boeing 747 got it's hump?

How Boeing 747 got it's hump? - Pixabay


The Boeing 747 is one of the most recognizable aircraft in the world.

Even if you have difficulties in identifying different aircraft identifying Boeing 747 is very easy! That's because of that giant hump on it...

How the  Boeing 747 got it's hump?

Long ago in 1956, Boeing had studied dual deck aircraft model and model was rejected as it was too heavy!

Actually Boeing 747 was made to compete supersonic aircraft Concorde! Concorde was the Supersonic (travels faster than speed of sound) passenger aircraft. It was one of the aviation marvel.

Concorde - Wikimedia

Concorde holds record​ for quickest flight from New York to London in just 2 hours and 52 minutes. Where Boeing 747 takes approximately 7 hours for same travel.

By the entry of Concorde in aviation industry it was thought that subsonic passenger aircraft will become obsolete.

So by considering future market,
So the Boeing 747 engineers planned ahead and designed an aircraft fit for cargo, as well as people. So that even if subsonic Aircraft become obsolete, Boeing 747 can be used as Cargo aircraft.

Boeing 747 Carrying Spaceship - Wikimedia

To make it easy to load cargo in aircraft, Boeing 747 engineers made hinged door at the it's nose.

Boeing 747 with opened nose door - Wikimedia

So to make hinged door at Boeing 747 nose cockpit was shifted from nose of the aircraft to the top!

But there was lots of free space behind the cockpit hence engineers turned that space into second deck. This is the reason how Boeing 747 got it's hump!
This second deck was originally reserved for first-class passengers only! It was fully bar and lounge. But in 1973 due to fuel shortage bars and lounge on the second deck was replaced by the seats to occupy more passengers and earn more profit.

This was the story of Boeing 747 hump!

That hump has grown in its size and today the upper deck on the 747-8 is the same as the length of Boeing 737.



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Why do Boeing 737 engines have flat bottom?

Why do Boeing 737 engines have flat bottom?

Why do Boeing 737 engines have flat bottom? - wikimedia

In the beginning of 1965 Boeing launched their 737-100 and 737-200 aircraft model. Boeing 737-200 was extended version of Boeing 737-100. Those were aircraft models of Boeing 737 original series. Both of the aircraft in Boeing original series used Pratt & Whitney JT8D engines. These engines were rounded in the shape.

Boeing 737-200 - wikimedia

Then Boeing decided produce stretched and more efficient variety of their existing 737 models. Hence, After 737 original series in 1984, Boeing started production of 737 Classic series. Which consists of Boeing 737-300, 737-400 & 737-500.

Changes in 737 variant


Boeing 737 - 300 - wikimedia

Boeing 737 Classic series aircraft are extended version of Boeing 737-200. So due to extended length it was necessary to maintain location of centre of gravity of the aircraft. As location​ of center of gravity of the aircraft plays an important role in Aircraft stability. Hence, engines of Boeing 737 Classic series Aircraft were located at some distance ahead of aircraft wing to maintain Center of Gravity(CG).

To make aircraft more efficient Boeing 737 Classic series replaced Pratt & Whitney JT8D engines with CFM International CFM56 engines.

Boeing 737-500 wikimedia

CFM56 engines has high bypass ratio than JT8D engines. High bypass ratio results in higher efficiency. But there was one problem to replace JT8D engines with CFM56. CFM56 engines were much larger than JT8D engines. Replacing JT8D engines without modification in CFM56 engines resulting aircraft engines were hitting the ground. So to overcome this problem without any major changes in Aircraft design, Aircraft engines bottom were made flat. This increased the distance of aircraft engines from the ground.

It was possible to increase the length of landing gear but this will increase distance of aircraft fuselage from the ground which could increase difficulties in Cargo loading in the Aircraft.

So simplest way was to make bottom of the Aircraft engine flat.

Then in 1993 Boeing introduced Boeing 737 next generation series consisting of 737-600, 737-700, 747-800, and 737-900 even this series has CFM56 engines with flat bottom!

Do you know!
Even Newest Boeing 737 Max engine has flat bottom!

Thanks for reading!


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Boeing 747 extreme testing

Boeing 747 extreme testing

Boeing 747 - Wikimedia

(Collection of videos of Boeing 747 from youtube)

Boeing 747-8 Assembly time lapse

Here's the video of the 747-8 Freighter assembly at the Boeing Everett, Washington factory.

(Video credits Boeing)


After Boeing 747 assembly is over, it is time for testing!

Boeing 747-8 Taxiing test (High-Speed Test)

(Video Credits Derytaro)



Boeing 747-8 Tail dragging on runway test

This test of the plane is also called as the velocity minimum unstick test. By this test, the pilot can determine the lowest plane speed required for takeoff in various configurations. In this case, the plane takes off at the lower speed that expected take-off speed so that aircraft tail drags on the runway.
(Video credits Boeing)




Boeing 747-8 performs ultimate rejected takeoff

The Rejected Take-Off test is also known as RTO. It is one of the hardest tests which an airplane undergo. This test is performed under all the worst possible conditions. such as plane loaded with maximum take-off weight, without using thrust reversers, etc.
(Video credits Boeing)




Boeing 747-8 big water splash test

This test is done to know about the behavior of the plane and its engine on the runway with water on it.
(Video credits Boeing)




Boeing 747 Landing gear test

(Video credits Boeing)


Here, some of test on Boeing 747 are mentioned. Planes also undergo other tests such as stalling test, bird strike test, etc.


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