The Boeing 747SP By Steve Allison - Allison on Airliners Having built the 747, Boeing needed to fill another gap in the market, a medium size wide-body aircraft. Lockheed and McDonnell Douglas were well under way with the development of the L1011 and the DC10. Pan American had also approached Boeing for an aircraft to use on long and thin routes, routes that didn't have the passenger numbers to justify a 747. Boeing 747 Boeing 747SP Boeing's chief engineer Joe Sutter immediately began working on the project and decided that using an existing Boeing design would be the most cost-effective route. Several aircraft manufacturers had successfully introduced "stretched" versions of their aircraft. Sutter decided that the converse concept - a shorter version of the 747 - might be the answer here. The shortened version of the 747 would have several advantages in that it would speed up the design process and have cockpit and crew commonality with the existing 747. The concept was put to Boeing management as the 747SB, which stood for Short Body. In 1973, Boeing's board of directors approved the project, although they changed the name to 747SP, which stood for Special Performance, a rather more inspiring appellation. Boeing was convinced that they had another winner. Pan American had expressed interest in 25 aircraft, though they had only placed a firm order for 10. Boeing's research told them that there was a market for 214 SPs and they would break-even financially if they sold just 45 airframes. The SP is 48 feet shorter than a full size 747. It has a lighter wing and single slotted flaps which give a significant weight saving over the complex 3 slot flaps on the full size 747. The landing gear on the SP is also lighter as it doesn't need to support as much weight. The SP tail fin is 5 feet taller at 65 feet above ground when parked, due to the shorter moment arm. The end result is that the 747SP is significantly lighter than its big daddy. Lower weight means better fuel economy. The SP burns between 8 and 10 tons of fuel per hour compared to 12 tons that the 747-200 classic burns. Another advantage of all of this weight-saving is that more fuel can be carried which adds up to the SP being an ultra-long-range aircraft. The SP broke several distance records in its time. The first 747SP rolled off the production line in May of 1975. Jack Waddell, a Boeing test pilot, first took the SP into the air on the 4th of July of the same year. Not only did the SP outperform its design estimates, the project had been completed 10 days ahead of schedule. Due to the political situation at the time, South African Airways aircraft were not allowed to fly across several African countries. South African registered aircraft had to fly round the bulge of Africa in order to get to Europe. Thus, to compete with other airlines, SAA wanted to offer direct non-stop services to Europe, which ruled out the 747-200 models already on the fleet. The SP seemed like the answer and SAA placed an order for 4 aircraft configured for 270 passengers, compared to the 340 passenger configuration of the 747-200s. The first 747 to land in Cuba was a South African Airways 747SP although it was operating as an Air Namibia aircraft at the time. Prior to Namibian independence, 2500 Namibian young people were invited to Havana as guests of Fidel Castro to finish their education. Although the aircraft was operated by Air Namibia, the crew who were SAA staff was all issued with Namibian passports. Karl Jensen and Ben van der Spuy, set off for Havana's José Martí International Airport. Jet fuel that had been quality checked was not available at the time in Cuba so they took enough fuel to continue to Jamaica after landing in Havana. Over the years the SP continued to be a strong performer but improvements in engine technology meant that full size 747's, particularly the -400 variant could transport a lot more passengers using less fuel than the once ultra-economical SP. Boeing's order book started to look rather thin and several airlines that had expressed keen interest in the SP ended up taking just one or two. Eventually Boeing gave up on the SP and closed the production line in 1982 with only 44 airframes being built. They were persuaded to open the production to build one last SP for the United Arab Emirates, which flew for the first time in 1987, just allowing them to achieve their break-even figure. The only remaining example of a South African Airways 747 SP is at Rand Airport as a static display in the care of the SAA Museum Society. It will never fly again.

Aircraft Technical Allison on Airliners

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