Since its introduction in 1970, five main production versions of the jumbo have been produced. As Key.Aero reveals, many more were proposed but didn’t make it very far from the drawing board – like the 747 Trijet…
Although the Boeing 747 has kept its unique silhouette for the duration of its more than 50-year production run, there are subtle differences between the five variants.
The first 747s, -100 series examples, were launched in 1966. They were built with six upper deck windows – three per side – to accommodate the upstairs lounge areas. As airlines began using the top floor for premium seating instead of lounge space, Boeing offered a ten-window upper deck option that some early -100s were retrofitted with.
No freighter version of this model was developed, but many of them were converted into cargo jets. A total of 168 were produced, 167 of which were delivered to customers.
The next variant to roll off the production line was the -200 which entered service in February 1971. During its first three years of production, the jet was equipped with Pratt & Whitney JT9D-7 engines. The type had increased fuel capacity and more powerful engines than the original.
A freighter model also became available and featured a hinged cargo door. A total of 393 of the 747-200s were built when production ended in 1991.
The 747-300 – the first of which was delivered to launch customer Swissair on March 23, 1983 – featured a 23ft-longer upper deck than the -200. The variant also offered a new straight stairway to the upper deck, instead of a spiral staircase on earlier variants, which created more room above and below for seats.
A total of 81 -300 series jets were delivered. In 1985, just two years after the type’s inauguration, the jet was superseded by the announcement of the more advanced 747-400. The final -300 was handed over to the Belgium flag carrier Sabena in September 1990.
The 747-400 is the most popular variant to date, having delivered 694 examples during its more than 15-year production run. The type features improved range and winglets which increase the fuel efficiency by 4% compared with previous generation examples.
The -400 introduced a new glass cockpit which was designed for a two-person flight crew instead of three, a consequence of the reduction in the number of dials, gauges and knobs which went down from 971 to 365 through the use of electronics and automation.
In March 2007, Boeing revealed it had no plans to continue to produce passenger versions of the -400. The last example was delivered in April 2005 to China Airlines.
The latest jumbo variant, the 747-8, was announced on November 14, 2005. It has been designed to be quieter, more economical and more environmentally friendly than its predecessors. The fuselage was lengthened by 19ft, marking the first stretched variant of the aircraft.
Designed to carry up to 467 passengers in a three-class configuration, the type has received a 153 total orders, including 107 for the -8F and 46 for the -8I. In July 2020, Boeing confirmed that production of the aircraft would end in 2022 after the 16 outstanding orders were produced and delivered.
Proposed Variants
Not all variants of the Boeing 747 made it past the concept stage. Here’s five designs that never existed.
Trijet
In a bid to compete with the smaller Lockheed L-1011 TriStar and McDonnell Douglas DC-10, Boeing studied the feasibility of developing a shorter 747 with three engines. The centre engine would have been fitted in the tail with an S-duct intake, like the TriStar.
If it had come to fruition, the 747 trijet would have had more payload and passenger capacity and range than both. Unfortunately, engineering designs showed that major wing modifications would be necessary and instead, Boeing decided to pursue a shortened four-engine jumbo, later resulting in the 747SP.
747-500
The American manufacturer outline preliminary studies to build a larger, ultra-long-haul version of the 747, named the -500, in January 1986. The derivative was planned to use more efficient unducted fan (UDF) engines made by General Electric and would enter service in the 1990s.
The company announce its intentions at the Financial Times’ aerospace symposium in Singapore in 1986. Joe Sutter, the then executive vice president of Boeing told the conference: “Big is better for the mid-1990s and beyond.”
747-500X, -600X and -700X
At the 1996 Farnborough Airshow, Boeing proposed three new variants of the 747 that would have combined the jet’s fuselage with a new 251ft wing derived from the 777. Additional changes included adding uprated engines and increasing the tyre count 18 to 24.
The estimated cost of the changes from previous 747 models, in particular the implementation of the new wing, was estimated to be more than $5bn. Boeing was not able to attract enough commercial interest and as a result, the plans were dropped.
747X Stretch
As Airbus moved forward with its A3XX project – which later became the A380 – Boeing offered a 747 derivative as an alternative, a more modest proposal than the previous -500X. The overall wing design remained the same, but a segment was added at the root therefore increasing the wingspan to 229ft.
A new flight deck and cabin interior based upon the 777 was proposed. Like its predecessor, the 747X was unable to garner enough support and didn’t make it off the drawing board.
747-400XQLR
Following the end of the 747X programme, the airframer continued to study improvement it could make to the type. The 747-400XQLR (Quiet Long Range) was meant to have an increased range of 7,980nm with improvements to boost efficiency and reduce its noise footprint.
Boeing assessed raked wingtips similar to those used on the 767-400ER and a sawtooth engine nacelle like those featured on the 787. Although it didn’t make it into production, many of the -400XQLR features were used on the 747 Advanced, which was later launched as the current generation 747-8.
