Τρίτη, 5 Ιουλίου 2011

Boeing 727 [EN]

The Boeing 727 is a mid-size, narrow-body, three-engine, T-tailed commercial jet airliner, manufactured by Boeing. The Boeing 727 first flew in 1963, and for over a decade more were built per year than any other jet airliner. When production ended in 1984 a total of 1,832 aircraft had been produced. The 727's sales record for the most jet airliners ever sold was broken in the early 1990s by its younger stablemate, the Boeing 737.
The 727 followed the success of the Boeing 707 quad-jet airliner. Designed for short-haul routes, the 727 became a mainstay of airlines' domestic route networks. A stretched variant, the 727–200, debuted in 1967. In August 2008, 81 Boeing 727–100 aircraft and 419 727–200 aircraft were in airline service.

Development

The Boeing 727 design was a compromise between United Airlines, American Airlines, and Eastern Air Lines requirements for a jet airliner to serve smaller cities with shorter runways and fewer passengers. United Airlines wanted a four-engined aircraft for its flights to high-altitude airports, especially its hub at Stapleton International Airport at Denver, Colorado. American, which was operating the four-engined Boeing 707 and Boeing 720, wanted a twin-engined aircraft for efficiency. Eastern wanted a third engine for its overwater flights to the Caribbean, since at that time twin-engined commercial flights were limited by regulations to routes with 60-minute maximum flying time to an airport (see ETOPS/LROPS). Eventually, the airlines agreed on a trijet.

Production of the 727

In 1959 Lord Douglas, chairman of British European Airways (BEA), suggested that Boeing and de Havilland Aircraft Company (later Hawker Siddeley) work together on their trijet designs, the 727 and D.H.121 Trident, respectively. The two designs had a similar layout, the 727 being slightly larger. At that time Boeing intended to use three Allison AR963 turbofan engines, license-built versions of the Rolls-Royce RB163 Spey used by the Trident. Boeing and de Haviland each sent engineers to the other company’s locations to evaluate each other’s designs, but Boeing eventually decided against the joint venture. De Havilland had wanted Boeing to license-build the D.H.121, while Boeing felt the design needed to be designed for the American market, with six-abreast seating and the ability to use runways as short as 4,500 ft. In 1960 Pratt & Whitney was trying to find a customer for their new JT8D turbofan design study, based on its J52 (JT8A) turbojet, while United and Eastern were interested in having Pratt & Whitney offer an alternative engine to the RB163 Spey. Once Pratt & Whitney agreed to go ahead with development of the JT8D, Eddie Rickenbacker, Chairman of the Board of Eastern, let Boeing know that the airline preferred the JT8D for their 727s. Boeing had previously declined to offer the JT8D, as it was about 1,000 lbs heavier than the RB163, though slightly more powerful. The RB163 was also further along in development than the JT8D. Boeing reluctantly agreed to offer the JT8D as an option on the 727; it later became the sole powerplant.
The middle engine (engine 2) at the very rear of the fuselage gets air from an inlet ahead of the vertical fin through an S-shaped duct. The 727 had high-lift devices on its wing, thus being one of the first jets able to operate from relatively short runways. Later models of the 727 were stretched to accommodate more passengers and replaced earlier jet airliners such as the Boeing 707 and Douglas DC-8 on domestic routes.

 

Design


Lufthansa Boeing 727 at Paris Orly Airport in 1981

The 727 proved to be such a reliable and versatile airliner that it came to form the core of many start-up airlines' fleets. The 727 was successful with airlines worldwide partly because it could use smaller runways while still flying medium-range routes. This allowed airlines to carry passengers from cities with large populations but smaller airports to worldwide tourist destinations. One of the features that gave the 727 its ability to land on shorter runways was its unique wing design. With no wing-mounted engines, leading-edge devices (Krueger, or hinged, flaps on the inner wing and extendable leading edge slats out to the wingtip) and trailing-edge lift enhancement equipment (triple-slotted, aft-moving flaps) could be used on the entire wing. Together these high-lift devices produced a maximum wing lift coefficient of 3.6 (based on the flap-retracted wing area). The 727 was stable at very low speeds compared to other early jets, but domestic carriers learned after review of various accidents that the 40-degree flaps setting could result in a higher-than-desired sink rate or a stall on final approach. These carriers' Pilots' Operation Handbooks disallowed using more than 30 degrees' flaps on the 727, even going so far as installing plates on the flap slot to prevent selection of more than 30 degrees' flaps.
Early 727s had nose gear brakes fitted to reduce braking distance on landing, but these were soon removed from service as they provided little reduction in braking distances, while adding weight and increasing maintenance needs.

Lloyd Aéreo Boliviano 727–200 at Jorge Wilsterman Airport. The rear air stairs are visible at the 727's tail.

The 727 was designed for smaller airports, so independence from ground facilities was an important requirement. This led to one of the 727's most distinctive features: the built-in airstair that opens from the rear underbelly of the fuselage. D. B. Cooper, a hijacker, parachuted from the back of a 727 as it was flying over the Pacific Northwest. Boeing subsequently modified the design with the Cooper vane so that the airstair could not be lowered in flight. Another innovation was the auxiliary power unit (APU), which allowed electrical and air-conditioning systems to run independent of a ground-based power supply, without having to start one of the main engines. The 727 is equipped with a retractable tail skid that is designed to protect the aircraft in the event of an over-rotation on takeoff. The 727's fuselage has an outer diameter of 148 inches (3.8 m). This allows six-abreast seating (three per side) and a single aisle when 18 inches (46 cm) wide coach-class seats are installed. An unusual feature of the fuselage is the 10 inch difference between the lower lobe forward and aft of the wing as the higher fuselage height of the centre-section was simply retained towards the rear.

 

Noise

The 727 is one of the noisiest commercial jetliners, categorized as Stage 2 by the U.S. Noise Control Act of 1972, which mandated the gradual introduction of quieter Stage 3 aircraft. The 727's JT8D jet engines use older low-bypass turbofan technology, whereas Stage 3 aircraft utilize the more efficient and quieter high-bypass turbofan design. When the Stage 3 requirement was being proposed, Boeing engineers analyzed the possibility of incorporating quieter engines on the 727. They determined that the JT8D-200 engine could be used on the two side-mounted pylons, but the structural changes to fit the larger-diameter engine (49.2 inches (125 cm) fan diameter in the JT8D-200 compared to 39.9 inches (101 cm) in the JT8D-7) into the fuselage at the number two engine location were prohibitive.

Tail section of a Pan Am Boeing 727

Current regulations require that a 727 in commercial service must be retrofitted with a hush kit to reduce engine noise to Stage 3 levels. One such hush kit is offered by FedEx, and has been purchased by over 60 customers. After-market winglets kits, originally developed by Valsan Partners and later marketed by Quiet Wing Corp. have been installed on many 727s to reduce noise at lower speeds, as well as to reduce fuel consumption. Kelowna Flightcraft's maintenance division in Canada has installed winglets on Donald Trump's private 727–100. In addition, Raisbeck Engineering developed packages to enable 727s to meet the Stage 3 noise requirements. These packages managed to get light- and medium-weight 727s to meet Stage 3 with simple changes to the flap and slat schedules. For heavier-weight 727s, exhaust mixers must be added to meet Stage 3.
From September 1, 2010, 727 jetliners (including those with a hush kit) will be banned from some Australian airports due to noise.

 

Operational history


In addition to domestic flights of medium range, the 727 was popular with international passenger airlines. The range of flights it could cover (and the additional safety added by the third engine) meant that the 727 proved efficient for short- to medium-range international flights in areas around the world. Prior to its introduction, four-engine jets or propeller-driven airliners were required for transoceanic service.

Interior close-up photo of the cockpit area of a flight simulator for a Boeing 727 at the Pan Am International Flight Academy

The 727 also proved popular with cargo airlines and charter airlines. FedEx Express introduced 727s in 1978. 727s were the backbone of its fleet until recently, but FedEx is now phasing them out in favor of the Boeing 757. Many cargo airlines worldwide employ the 727 as a workhorse, since, as it is being phased out of U.S. domestic service due to noise regulations, it becomes available to overseas users in areas where such noise regulations have not yet been instituted. Charter airlines Sun Country, Champion Air, and Ryan International Airlines all started with 727 aircraft.
The 727 has proven to be popular where the airline serves airports with gravel, or otherwise lightly improved runways. The Canadian airline First Air, for example, previously used a 727-200C to service the communities of Resolute Bay and Arctic Bay in Nunavut, both of which have gravel runways. The high mounted engines greatly reduces the risk of foreign object damage.
Other companies use the 727 to transport passengers to their resorts or cruise ships. Such was the example of Carnival Cruise Lines, which used both the 727 and 737 to fly both regular flights and flights to transport their passengers to cities that harbored their ships. Carnival used the jets on its airline division, Carnival Air Lines. According to the Boeing Jetliner Databook, the Justice Prisoner and Alien Transportation System, also known as 'Con Air', currently uses four 727 aircraft to transport persons in legal custody between prisons, detaining centers, courthouses, and other places where they must be transported.

A FedEx 727 at PWM with cargo doors open

At the turn of the 21st century, the 727 was in service with a few airline fleets; however, due to changes by the U.S. FAA and the ICAO in over-water flight requirements, most major airlines had already begun to switch to twin-engine aircraft, which are more fuel-efficient and quieter than the three-engine 727. Also, the 727 was one of the last airliners in service to have a three-person flight crew, including a flight engineer, a crew member whose tasks have been largely automated on newer airliners.
Faced with higher fuel costs (although all major United States airlines phased them out immediately prior to the oil price increases since 2003), lower passenger volumes due to the post-9/11 economic climate, increasing restrictions on airport noise, and the extra expenses of maintaining older planes and paying flight engineers' salaries, most major airlines have phased 727s out of their fleets. Delta Air Lines, the last major U.S. carrier to do so, retired its last 727 from scheduled service in April 2003. Northwest Airlines retired its last 727 from charter service in June 2003. The 727 is still flying for some smaller start-up airlines, cargo airlines, and charter airlines, and it is also sometimes used as a private means of transportation. The official replacement for the 727 in Boeing's lineup was the Boeing 757; however, the smallest 757 variant, the 757–200, is significantly larger than the 727–200, so many airlines replaced their 727s with either the 737–800 or the Airbus A320, both of which are closer in size to the 727–200.

 

Variants



TAP Portugal 727–100

There are two variants of the 727. The 727–100 was launched in 1960 and placed into service in February 1964. The 727–200 was launched in 1965 and placed into service in December 1967.

 

727–100

The first 727-100 flew on February 9, 1963 and FAA type approval was awarded on December 24 of that year. The first delivery to United Airlines was made prior to this on October 29, to allow pilot training to commence. The first 727 passenger service was flown by Eastern Air Lines on February 1, 1964, between Miami, Florida, Washington, D.C., and Philadelphia, Pennsylvania.
A total of 571 727-100s were delivered (407 -100s, 53 -100Cs, and 111 -100QCs). One 727–100 was completed and retained by Boeing, bringing total production to 572.
 
727-100C
Convertible passenger cargo version. Additional freight door and strengthened floor and floor beams. Three alternate fits:
  • 94 mixed-class passengers
  • 52 mixed-class passengers and four cargo pallets (22,700 lb, 10,297 kg)
  • Eight cargo pallets (38,000 lb, 17,237 kg)
 
727-100QC
QC stands for Quick Change. This is similar to the Convertible version with a roller-bearing floor for palletised galley and seating and/or cargo to allow much faster changeover time (30 minutes).
 
727-100QF
QF stands for Quiet Freighter. A cargo conversion for United Parcel Service, re-engined with Stage III-compliant Rolls-Royce Tay turbofans.

 

727–200


Delta Air Lines 727–200

Stretched version of the 727–100. The −200 is 20 feet (6.1 m) longer (153 feet, 2 inches, 46.7 m) than the −100 (133 feet, 2 inches, 40.6 m). A ten-foot (3-meter) fuselage section ("plug") was added in front of the wings and another ten-foot fuselage section was added behind them. The wing span and height remain the same on both the −100 and −200 (108 feet (33 m) and 34 feet (10 m), respectively). The original 727–200 had the same max gross weight as the 727–100; however, as the aircraft evolved, a series of higher gross weights and more powerful engines were introduced along with other improvements, and, from line number 881, 727-200s are dubbed −200 Advanced. The aircraft gross weight eventually increased from 169,000 to 209,500 pounds (77,000 to 95,000 kg) for the latest versions. The dorsal intake of the number two engine was also redesigned to be round in shape, rather than oval as it was on the 100 series.
The first 727–200 flew on July 27, 1967 and received FAA certification on November 30, 1967. The first delivery was made on 14 December 1967 to Northwest Airlines. A total of 310 727-200s were delivered before giving way to the 727-200Adv in 1972.
 
727-200C
Convertible passenger cargo version. Only two were built.

Syrian Air 727-200Adv

A Kalitta Charters II 727–200, parked at LEX airport, Lexington, KY
 
727–200 Advanced
MTOW and range increased. Also, cabin improvements.
 
727-200F Advanced
A freighter version of the 727–200 Advanced became available in 1981 designated the Series 200F Advanced powered by the Pratt & Whitney JT8D-17A engines and featured a strengthened fuselage structure, an 11 ft 2 inch by 7 ft 2 inch forward main deck freight door and a windowless cabin. This was the last production variant of the 727 to be developed by Boeing, and 15 aircraft were built, all for Federal Express. The last 727 aircraft to be completed by Boeing was the Series 200F Advanced for Federal Express.
 
Super 27
Speed increased by 50 mph (80 km/h), due to replacement of the two side engines with the JT8D-217, which are also found on many MD-80s, along with the addition of hush kits to the center engine. Winglets were added to some of these aircraft to increase fuel efficiency. This modification was originally developed by Valsan Partners, but was later marketed by Goodrich.

A DHL 727-200F freighter at San Diego

 

Operators

As of July 2010, 398 Boeing 727 aircraft (all variants) were in commercial airline service. Most airlines have small numbers but the following operated ten or more aircraft:
  • FedEx Express (75)
  • Astar Air Cargo (26)
  • Capital Cargo International Airlines (14)
  • Kelowna Flightcraft Air Charter (13)
  • Cargojet Airways (12)
  • AeroSur (10)

Specifications

Measurement727–100727–200727-200F
Cockpit crewThree
Max. seating capacity149189N/A
Length133 ft 2 in (40.6 m)153 ft 2 in (46.7 m)
Wingspan108 ft (32.9 m)
Tail height34 ft (10.3 m)
Zero fuel weight100,000 lb (45,360 kg)155,000 lb (70,307 kg)
Maximum take-off weight169,000 lb (76,818 kg)209,500 lb (95,028 kg)194,800 lb (88,360 kg)
Maximum landing weight137,500 lb (62,400 kg)161,000 lb (73,100 kg)164,000 lb (74,389 kg)
Take-off runway length
(at 148,000 lb)
5,800 ft (1,768 m)
Landing runway length
(at max landing wt)
4,800 ft (1,463 m)5,080 ft (1,585 m)
Cruising speedMach 0.81
Maximum speedMach 0.90
Cruise altitude30,000–40,000 feet (9,100–12,000 m) Max altitude 42,000 feet (13,000 m)
Range fully loaded2,700 nautical miles (5,000 km)2,400 nautical miles (4,400 km)2,400 nautical miles (4,400 km)
Max. fuel capacity8,186 US gal (31,000 L)9,806 US gal (37,020 L)7,988 US gal (30,238 L)
Engines (3x)P&W JT8D-7, −9, −15, −17R&S

Sources: Boeing 727 Specifications

Orders and deliveries

 
Orders
1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972
111386898125133113508892119
1971 1970 1969 1968 1967 1966 1965 1964 1963 1962 1961 1960
264864661251491878320103780

 
Deliveries
1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973
81126941311361186761919192
1972 1971 1970 1969 1968 1967 1966 1965 1964 1963 1962 1961
41335511416015513511195600

B727 Orders Deliveries.jpg

 

Aircraft on display

The following museums have Boeing 727s on display or in storage:
  • Carolinas Aviation Museum 727 cockpit on display, ex-Roush 727 in storage at Charlotte-Douglas International Airport
  • Museum of Flight First 727 completed, still in restoration stage. To be flown to museum when finished. Another 727 is currently on display.
  • National Museum of Commercial Aviation, Atlanta, GA – ex-FedEx 727 in storage at Atlanta airport.
  • Museum of Science and Industry, Chicago, ex-United Airlines 727

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