The Boeing 747 Aircraft
The Boeing 747 Overview
The Boeing 747 is a wide-body commercial jet airliner and cargo aircraft, commonly known as the Jumbo Jet, had its first flight on February 9th, 1969. The iconic hump along the front of the aircraft containing the upper-deck was intended to serve as an area for a first class lounge or possibly extra seating, allowing the plane to hold the passenger capacity record for 30 years. Boeing has manufacturing 1532 units of the 747, with the 747-400 being the most commonly used model as it is an efficient passenger commercial airplane. The 747 is considered to be one of the major successes of Boeing exceeded expectations as they the company had been in debt of over $2 billion USD, where the introduction of the aircraft pulled the company out of this debt. Even today, the 747 is a commonly used passenger aircraft with many airliners still using the plane such as British Airways, Korean Air, Lufthansa and China Airlines. Development
Demand for a plane with a higher cargo capacity had came about in 1963, where the United States Air Force conducted several studies that determined that a needed for new aircraft that can carry large amounts of cargo was apparent. Thid was specifically aircraft that would have to have the cargo capacity of no other aircraft that that time. Boeing had believed that if they were to introduce the 747, it would have to be oriented toward freight purposes as supersonic passenger aircraft had just started to become popular. Due to the wide popularity of the 707 and DC-8, airports were crammed before airlines realised the problems with this. Soon, the CEO of Pan Am (Boeing's largest customer at that time) approached Boeing and asked them to build a plane that would be twice as big as the 707. Boeing soon began to work on this project as they forecasted great profits if the 747 was to be built.Powerplant
As Boeing did not have a plant large enough to assemble the giant airliner, they chose to build a new plant for which the land was bought in 1966. The construction of what was now to be called the "Everett Factory" (found in the city of Everett, Washington) was quite tricky at the start as more than 3 million cubic meters of earth had to be removed in order for Boeing to be able to lay down the foundations of the factory building. The factory became the biggest building by volume ever built that came as a result of Boeing obtaining many new permits that allowed them to expand the Everett factory to allow the production of many different wide-body commercial jets.Testing
Before final assembly, Boeing first tested the individual components of the 747 where it found the engines to be prone to several issues such as stalling and the distortion of turbine casings. To familiarise pilots with the 747 before it was even built, Boeing had constructed a training device known as "Waddell's Wagon", consisting of a mockup cockpit mounted on top of the roof of a truck. Throughout the later stages of testing, flutter testing of the aircraft had revealed that the wings suffered from oscillation. This issue had been resolved by inserting depleted uranium into the aircraft to balance and act as a ballast within the plane. In 1969, Boeing had conducted its first test flight of the 747 with test pilots Jack Waddell and Brien Wygle. The test flight had confirmed that the aircraft handled well despite a minor problem with one of the flaps. It was also found that the 747 was immune to the "Ducth Roll", something that many early jets faced. The Ducth Roll is the violent and uncontrollable swaying of the aircraft's tail. Usually an experienced pilot can easily correct this, however many trainee pilots often overcorrected their pitch axis which eventually led to the amplification of the Dutch Roll. Nearing the end of 1969, Boeing had received approval from the FAA for the 747's entry into service.
Design
Wings
The wings of the 747 have a high sweep angle of 37.5 degrees allowing for a fast and effective cruise, achieving speeds between Mach 0.84 to 0.88. Given the high sweep angle, the horizontal length of the wings are much shorter allowing the plane to fit in existing hangars without additional work to be completed. Three-part slotted flaps are located along the trailing edge of the wing, increasing the area of the wing by 21% to 90% when incrementally extended. Overall, the wing design of the 747 was one that of high efficiency and space saving, making it highly ideal for airlines over long-haul flights.Engines
The 747 utilises 4 wing mounted engines. Due to the increased weight of the 747, Pratt and Whitney had designed and manufactured the JT9D, the first high-bypass turbofan, specifically for the 747. The JT9D was able to deliver 43,500 Ibf of thrust, double the amount provided by earlier turbojets at the time whilst only consuming two thirds of the fuel needed for a turbo jet. The JT9D was built using titanium alloys and nickel alloys. It features a single stage fan, a three-stage low-pressure compressor and an eleven stage high-pressure compressor coupled to a two stage high-pressure turbine and a four stage-low-pressure turbine. Within early development of the 747, the JT9D engines had experienced multiple failures. The fault of this was later traced to ovalization, which was solved by strengthening the engine.F
Fuselage
The most iconic feature of the 747 is its double deck design. The main reason for this design is to allow airlines to maximise the passenger capacity of the aircraft while keeping the length to a considerable size so that the 747 would be able to land on major airports without any extra infrastructure required. As the cockpit is slightly raised above the main deck, a small hump is created. The raised cockpit allows for front loading of cargo on freight variants of the 747. As the 747 evolved through the years, the upper deck was stretched through first the 747-100B model, then the 747-300 and even more on the 747-8. Today, the hump found on the 747-8 is as long as the 737's total lenght.(Click For More Information)The 747's maximum takeoff weight ranges from 735,000 pounds (333,400 kg) for the 747-100 to 970,000 lb (439,985 kg) for the 747-8. Its range has increased from 5,300 nautical miles (6,100 mi, 9,800 km) on the 747-100 to 8,000 nmi (9,200 mi, 14,815 km) on the 747-8. The 747 has been designed with redundant hydraulics and four main landing gears which provide a good spread of support in case of a blow-out.
Operation
In April 1966, American Airway Pan Am had ordered 25 747-100 aircrafts for US$525 million which is adjusted to approximately US$4 billion. On January, 1970, First Lady of The United States, Pat Nixon, christened Pan Am's first 747 and in the same month, The 747 had entered service on Pan Am's New York to London route. Within the 747's introduction into service, the plane had overcame some airports' concerns that they would not be able to accommodate the aircraft. The 747 had also experienced relatively minor technical issues with the plane which were solved within a short notice. Due to the efficiency of Pan Am after it adopted the 747, other airliners had purchased the aircraft in order to remain competitive as the 747 had lowest operating cost per seat on a fully loaded flight. The global recession between 1969 and 1970 and the Oil Crisis of 1973 meant that Boeing had only sold two 747s in the years 1970 and 1971. This recession also meant that many airliners didn't have enough customers aboard each 747 flight to sustain itself economically, leading them to replace their 747s with other smaller aircraft such as the McDonnell Douglas DC-10 and the Lockheed L-1011 TriStar.
Variants
There have been many different versions/ variants of the 747 made over the years that were either targeted towards cargo delivery or passanger travel. Without doubt though, the 747-400 was the most popular and mass produced variant of the 747's ever made.747-100
The 747-100 was built with 6 upper-deck windows to accommodate the upstairs lounge areas which was later changed as airliners started to use the upper deck for premium passenger seating instead of a lounge space. Because of this, some of the 747-100s had been retrofitted to suit this new change in preference. Boeing had developed a variant of the 747-100, the 747-100 SR. The 747 SR had been built and designed specifically for the requests from Japanese airlines for a high-capacity aircraft to serve for domestic flights within Japan. The aircraft was developed as a short range version of the 747-100 with a lower fuel-load capacity but higher payload capacity. With this in mind, the 747-100 SR could hold up to 500 passengers originally and was later able to hold 550 passenger in later models. Other factors of 747-100 SR include an increased body structures and added structural support in the wings, fuselage and the landing gear. Later on, many of the 747-100s were converted into freighters as many became obsolete.747-200
The inception of the 747-200 came about when there was a large demand for longer range aircraft as long international routes were starting to become popular. To tackle this, Boeing had designed the 747-200 with General Electric's CF6-50 engines with an increased thrust of 54,000lbf higher than the previously used JT9D engines used in previous models. Boeing had produced four different versions of the 747-200, one of which being the 747-200B which was a basic passenger version of the craft with increased fuel capacity with a range on a full flight of 11,000 km. The 747-200F was a freighter model which could be fitted with or without a side cargo door and had a capacity of 105 tons. Another variation, the 747-200C was a convertible craft that could be switched between a freighter configuration and a passenger configuration. This was achieved with removable seats and a nose cargo door, making it a highly versatile aircraft. The remaining version, The 747-200M, also known as the 747-200 Combi, was a plane which allowed freight and cargo to be carried at the rear end of the main deck and also carry up to 238 passengers in a three class configuration.747-300
The 747-300 offered little difference when compared to previous versions. The aircraft features an upperdeck longer than the 747-200 by 7.11 metres. The 747-300 had some minor aerodynamic edits making it able to reach a cruise speed of Mach 0.85 slightly higher than the Mach 0.84 of the 747-100s and 747-200s. There were three different variants of the 747-300, one being oriented toward carrying passengers, the other being the 747-300 SR, an improvement other the 747-100 SR. The last variant was the 747-300M, which was an improved version of the 747-200M retaining the ability to hold as much cargo whilst still being able to carry more passengers.747-400
747-8
Specifications
| Model | 747-100 | 747-200B | 747-300 | 747-400 | 747-8 |
|---|---|---|---|---|---|
| Cockpit crew | Three | Two | |||
| Seating, typical | 366 (32F 74J 260Y) | 400 (34F 76J 290Y) | 416 (23F 78J 315Y) | 467 (24F 87J 356Y) | |
| Seating for exit limit | 440/550 | 550/660 | 605 | ||
| Length | 231 ft 10 in (70.66 m) | 250 ft 2 in (76.25 m) | |||
| Interior width | 239.5 in (608 cm) | ||||
| Wingspan | 195 ft 8 in (59.6 m) | 211 ft 5 in (64.4 m) | 224 ft 7 in (68.4 m) | ||
| Wing area | 5,500 ft² (511 m²) | 5,650 sq ft² (525 m2) | 5,960 sq ft² (554 m2) | ||
| Wing sweep | 37.5° | ||||
| Aspect ratio | 7 | 7.9 | 8.5 | ||
| Tail height | 63 ft 5 in (19.3 m) | 63 ft 8 in (19.4 m) | 63 ft 6 in (19.4 m) | ||
| Cargo capacity | 6,190 cu ft (175 m3), 30xLDI | 5,655 ft (160.1 m²) | 6,345 cu ft² (179.7 m3) | ||
| Operating empty weight | 379,500 lb (172,100 kg) | 375,100 lb (170,100 kg) | 384,000 lb (174,000 kg) | 412,300 lb (187,010 kg) | 485,300 lb (220,128 kg) |
| Maximum takeoff weight (MTOW) | 735,000 lb (333,000 kg) | 833,000 lb (378,000 kg) | 910,000 lb (412,760 kg) | 987,000 lb (447,696 kg) | |
| Cruise speed | 907km/h (490 kt) | 898-939km/h (485-507 kt) | Mach 0.855 (504kn; 933km/h) | ||
| Airspeed limit | Mach 0.92 | Mach 0.9 | |||
| Takeoff | 10,650 ft (3,250 m) | 10,900 ft (3,300 m) | 10,900 ft (3,300 m) | 10,700 ft (3,260 m) | 10,200 ft (3,100 m) |
| Range | 4,620 nmi (8,560 km; 5,320 mi) | 6,560 nmi (12,150 km; 7,550 mi) | 6,330 nmi (11,720 km; 7,280 mi) | 7,670 nmi (14,200 km; 8,830 mi) | 7,730 nmi (14,320 km; 8,900 mi) |
| Fuel capacity | 48,445 US gal (183,380 L) | 53,985 US gal (204,360 L) | 63,705 US gal (241,150 L) | 63,034 US gal (238,610 L) | |
| Turbofan Engines (x4) | Pratt & Whitney JT9D-7 or -524 or GE CF6 | PW4000 or CF6 or RB211 | GGEnx-2B67 | ||
| Thrust (per engine) | 43,500-51,600lb (193-230kN) | 46,300-54,750lb (206.0-243.5kN) | 46,300-56,900lb (206-253kN) | 62,100-63,300lb (276-282kN) | 66,500lb (296kN) |
Credit : Julie Singh
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