Boeing 747SP should not be confused with Boeing 747SR.
The Boeing 747SP (for Special Performance) is a shortened version of the Boeing 747 wide-body airliner, designed for a longer range. It is the highest flying subsonic passenger airliner, with a service ceiling of 45,100 feet (13,700 meters).Boeing needed a smaller aircraft to compete with the McDonnell Douglas DC-10 and Lockheed L-1011 TriStar tri-jet wide-bodies, introduced in 1971/1972. Pan Am requested a 747-100 derivative to fly between New York and the Middle East, a request also shared by Iran Air, and the first order came from Pan Am in 1973.
The variant first flew on July 4, 1975, was approved by the Federal Aviation Administration on February 4, 1976, and entered service that year with Pan Am.
The SP is 184inchesft9inchesin (ftin) in length, 47feet shorter than the original 747 variants. Its main deck doors are reduced to four on each side to suit its lower capacity. The vertical and horizontal tailplanes are larger and its wing flaps have been simplified. With a 700000lb maximum take-off weight, it can fly 276 passengers in three classes over 5830nmi.One 747SP was modified into the Stratospheric Observatory for Infrared Astronomy (SOFIA).The last example was delivered in 1987; some were converted to transports of heads of state.Sales did not meet the expected 200 units, and only 45 aircraft were ultimately produced.[1]
The idea for the 747SP came from a request by Pan Am for a 747 variant capable of carrying a full payload non-stop on its longest route between New York and Tehran.[2] Joined with Pan Am's request was Iran Air; their joint interest was for a high-capacity airliner capable of covering Pan Am's New York–Middle Eastern routes and Iran Air's planned New York-Tehran route[3] (New York to Tehran was the longest non-stop commercial flight in the world for a short time). The aircraft was launched with Pan Am's first order in 1973, and the first example was delivered in 1976.[4] [5]
A shorter derivative of the 747-100, the SP was developed to target two market requirements. The first was a need to compete with the DC-10 and L-1011 while maintaining commonality with the 747,[6] which in its standard form was too large for many routes. Until the arrival of the 767, Boeing lacked a mid-sized wide-body to compete in this segment. The second market requirement was an aircraft suitable for the ultra-long-range routes emerging in the mid-1970s following the joint request. These routes needed not only longer range but also higher cruising speeds. Boeing could not afford to develop an all-new design, instead opting to shorten the 747 and optimize it for speed and range, at the expense of capacity.[7]
Originally designated 747SB for "short body", it was later nicknamed "Sutter's balloon" by employees after 747 chief engineer Joe Sutter.[8] Boeing later changed the production designation to 747SP for "special performance", reflecting the aircraft's greater range and higher cruising speed. Production of the 747SP ran from 1976 to 1983. However, a VIP order for UAE's Abu Dhabi Amiri Flight led Boeing to produce one last SP in 1987. Pan Am was the launch customer for the 747SP, taking the first delivery, Clipper Freedom, on March 5, 1976.[9] Pan Am then made the first flight of the 747SP on April 25, 1976, making a nonstop flight from New York to Tokyo.
The 747SP was the longest-range airliner available until the 747-400 entered service in 1989. Despite its technical achievements, the SP never sold as well as Boeing hoped. Increased fuel prices in the mid-1970s to early 1980s, the SP's heavy wings, high cost, and reduced capacity, and the increased ranges of forthcoming airliners were some of the many factors that contributed to its low sales. Only 45 were built, and, of those remaining, most are used by operators in the Middle East. However, some of the engineering work on the 747SP was reused with the development of the 747-300. In the 747SP, the upper deck begins over the section of fuselage that contains the wing box, not ahead of the wing box (as is the case with the 747-100 and 747-200). This same design was used in the 747-300 and newer 747-400, resulting in a stretched upper deck.
Apart from having a significantly shorter fuselage and one fewer cabin door per side, the 747SP differs from other 747 variants in having simplified flaps and a taller vertical tail to counteract the decrease in yaw moment-arm from the shortened fuselage. The 747SP uses single-piece flaps on the trailing edges, rather than the smaller triple-slotted flaps of standard 747s.
The SP could accommodate 230 passengers in a 3-class cabin or 331 (303 economy, 28 business) in a 2-class cabin, and a maximum of 400 passengers in one class.
From 2007 until 2022, a specially modified 747SP was used as the Stratospheric Observatory for Infrared Astronomy (SOFIA) astronomical observatory, operated jointly by NASA and Germany's DLR. A former Pan Am and United Airlines aircraft acquired in 1997, its airframe was modified to carry a 2.5-meter-diameter reflecting telescope to high altitude, above 99.9% of the light-absorbing water vapor in the atmosphere. The telescope and its detectors covered a wide wavelength range from the near infrared to the sub-millimeter region; no window material is transparent over this whole range, so the observations were made through a 13feet square hole in the port upper quarter of the rear fuselage, aft of a new pressure bulkhead. A sliding door covered the aperture when the telescope was not in use.[10] Astronomers took data and control the instrument from within the normally pressurized cabin. Originally delivered to Pan Am and named "Clipper Lindbergh", the name was displayed in script on the port side of the aircraft.
In September 2022, SOFIA ceased operations after the conclusion of its final mission. The retirement was made both on the grounds of cost and suitability for the requirements of the decade to come.[11] The aircraft was later flown to the Pima Air & Space Museum in Tucson, Arizona, to be put on public display.[12]
Forty-five 747SP aircraft were built between 1974 and 1987.[13] The production line was ended in 1982 but reopened in 1987 to fulfill an order for the Abu Dhabi Amiri Flight.[14]
, there are just two Boeing 747SPs remaining in active service, both operating as testbed aircraft for engine manufacturer Pratt & Whitney Canada.[15] [16] Eighteen more aircraft are stored or otherwise preserved. The remaining aircraft were either scrapped, otherwise destroyed, or abandoned. In 2016, the last 747SP in commercial service was withdrawn from service after 40 years by Iran Air.[17] [18] In 2020, the last aircraft in governmental use was stored by the Royal Flight of Oman.[19]
This list also includes organizations that used the aircraft temporarily, besides main operators.
There were three significant commercial around-the-world record-setting flights flown by 747SP: two operated by Pan Am and the other operated by United Airlines with the aircraft being "loaned" to Friendship Foundation, in order to raise money for the foundation. Those flights are:
| Model | 747SP[23] | |
|---|---|---|
| Cockpit crew | Three | |
| 2-class seats | 331 (28F + 303Y) or 343 (30F + 313Y) | |
| 3-class seats | 276 (25F + 57J + 194Y)[24] | |
| Exit limit | 400[25] | |
| Overall length | 184inchesft9inchesin (ftin) | |
| Wingspan | 195inchesft8inchesin (ftin) | |
| Wing area | 5500ft2[26] | |
| Overall height | 65inchesft10inchesin (ftin) | |
| Operating empty weight | 325260– | |
| Maximum take-off weight | 700000lb | |
| Maximum landing weight | 450000lb | |
| Engine models (x4) | Pratt & Whitney JT9D-7(A/AH/F/FW/J) Rolls-Royce RB211-524(B2/C2/D4) | |
| Engine thrust (x4) | JT9D: 46950- RB211: 49150- | |
| Maximum speed | 0.92knots km/h mphNaNknots km/h mph[27] | |
| Cruising speed | 0.86knots km/h mphNaNknots km/h mph | |
| Service ceiling | 45100feet | |
| Maximum range | 6650nmi | |
| Max fuel capacity | 50360abbr=onNaNabbr=on |
Note