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Sunday, December 21, 2014

Iconic Planes: Boeing 747

The Boeing 747 is the most widely-recognized commercial aircraft in the world. The hump-shaped structure on the forward part of the aircraft instantly distinguishes it from other aircraft at any airport. Surprisingly, the 747 was expected to become obsolete after 400 units were sold, but till date, over 1500 have been sold.
 
A British Airways 747-400 in white, blue and red livery during takeoff with its landing gear retracting.The 747 is the most common passenger plane in the world, with quite a few being operated by every major airline in the world. The reason why Boeing introduced the hump on top was so that it could easily be converted into a cargo plane; the first-class seats can be removed and a door can be attached easily. The picture on the right shows a British Airways 747.
 
Interior view. Seats are separated by two aisles, in 3-4-3 configuration. A TV is positioned towards the front of aircraft.The plane has impressive statistics; it can fly over a distance of 13450 kilometres, can cruise at 35000 feet at 893 km/h and can carry up to 550 passengers in one go. The 747 also has many varieties, including the 747SP, 747-400, 747-8, VC-25 and the E-3. It has 4 turbo fan engines, two on each wing. The slightly swept back wings allow it to use existing hangers despite its size. (Right): The economy-class cabin on a 747-400. 
 
The Boeing 747 was produced in the early 1960s, and continues to operate today. Back then, it was one of the biggest airplanes to fly, and the main reason why it ever took off was because of the development of the Pratt and Whitney JT9D high-bypass turbofan engine, which had double to power and consumed a third less fuel than normal turbofan engines. General Electric first developed these engines, but they stuck to the military market and Pan Am and Pratt & Whitney agreed to develop these engines for the 747. Boeing promised to give the first 747 to Pan Am by the end of 1969, which left only 28 months to complete the first prototype. This was an incredible achievement, so much so that the people who worked on it were called "The Incredibles". The GIF below shows the working of a high-bypass turbofan engine.
 
Animation of turbofan, which shows flow of air and the spinning of blades.
A. Low-pressure spool
B. High-pressure spool
C. Stationary components
1. Nacelle
2. Fan
3. Low-pressure compressor
4. High-pressure compressor
5. Combustion chamber
6. High-pressure turbine
7. Low-pressure turbine
8. Core nozzle
9. Fan nozzle
 
 

Airplane assembly hall, featuring heavy machinery. Large cylindrical airplane sections and wings are readied for mating with other major components. Above are the cranes which ferry heavy and outsize parts of the 747.Back then, Boeing didn't have a factory large enough to assemble the 747, so they built a new one outside Seattle. Till today, it remains the largest plant by volume, and has been expanded to accommodate the building of other large planes. The 747 was first commercially flown in 1970, and has been substantially improved since then. It remains one of the most recognized and loved aircraft of all time, which is apparent by its nicknames "Jumbo Jet" and "Queen of the Skies". The plane of the President of the US, Air Force One, is also a extensively remodelled 747. The picture above shows the final assembly of a 747 in the Everett factory near Seattle.
 
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