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The Boeing 727 & 757

v1.0.2 / 01 mar 16 / greg goebel

* In the early 1960s, the Boeing company followed up its ground-breaking 707 jetliner with a smaller aircraft, the "727", which would prove even more popular than its predecessor. In the 1980s, Boeing introduced a replacement for the 727, the "757", which wouldn't prove quite as successful but was a still a good earner for the company. This document provides a history and description of the Boeing 727 and 757.

Boeing C-32A / 757-200


[1] 727 ORIGINS / 727-100 DESCRIBED
[2] 727-200 / 727 IN SERVICE / SPECIAL VARIANTS
[3] 757 ORIGINS / 757-200 DESCRIBED
[4] 757-200 VARIANTS / 757-300 / 757 SPECIAL VARIANTS
[5] COMMENTS, SOURCES, & REVISION HISTORY

[1] 727 ORIGINS / 727-100 DESCRIBED

* In 1956 the Boeing company, having achieved commercial success with the 707 jetliner, decided to focus on a new jetliner that could operate out of smaller airports and service the short to medium range market. Design considerations led to the selection of three engines for the aircraft, partly for safety through redundancy; partly because no two of the powerplants available at the time could get an aircraft of the desired size into the air.

There was some nervousness at selecting three engines because US Federal Aviation Administration (FAA) flight rules were more restrictive for twin-engine aircraft than for four-engine aircraft, and the FAA didn't specify which set of rules would apply to three-engine aircraft. The FAA ultimately decided that the rules for four-engine aircraft would apply to tri-jets, but the ambiguity over the matter made Boeing officials nervous at the outset.

Another source of nerves was that while Eastern and United Airlines were interested in the new jetliner, predelivery orders didn't pour in at a satisfactory rate -- but the decision was made in 1960 to proceed with development anyway. The first "727" tri-jet was rolled out in November 1962, with initial flight on 9 February 1963, the aircrew being pilot Lew Wallick, copilot Dix Loesch, and flight engineer M.K. Shulenberger. The aircrew was impressed, but getting the 727 out the door would prove more expensive than anticipated. Difficulties were resolved, and the initial production "727-100" was certified in late 1963, with Boeing then selling 727s as fast as they could be built.

* The 727 was a sleek aircraft, and in the early 1960s it appeared futuristic, a space-age machine like something out of THE JETSONS. The 727-100 was built mostly of aircraft aluminum alloy. It was powered by three Pratt & Whitney (PW) JT8D turbofans, one mounted on each side of the tail while the third was mounted in the tail, the intake being at the base of the tailfin. Each engine had a clamshell thrust reverser.

The initial engine fit was the JT8D-1, with 62.3 kN (6,350 kgp / 14,000 lbf) thrust; later the JT8D-7 -- with the same thrust, but capable of maintaining power at higher ambient temperatures -- and ultimately the JT8D-9 -- with 64.5 kN (6,575 kgp / 14,500 lbf) thrust -- were offered as options. All fuel stowage was in the wings. The 727 had an AirResearch GTC85 auxiliary power unit (APU) turbine engine, something of an innovation at the time though a standard concept these days, to provide engine starting and ground power. The APU was placed in the wing center section.


   BOEING 727-100:
   _____________________   _________________   _______________________
 
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                32.92 meters        108 feet
   wing area               157.9 sq_meters     1,700 sq_feet   
   length                  40.59 meters        133 feet 2 inches
   height                  10.36 meters        34 feet

   empty weight            36,680 kilograms    85,275 pounds
   MTO weight              64,410 kilograms    142,000 pounds

   max cruise speed        975 KPH             605 MPH / 525 KT
   service ceiling         11,400 meters       37,400 feet
   range                   3,300 kilometers    2,050 MI / 1,780 NMI
   _____________________   _________________   _______________________

All flight surfaces were swept, with a low-mounted wing and a tee tail. The two-spar wing had a sweep at quarter-chord of 32 degrees, with a dihedral of 3 degrees and an angle of incidence of 2 degrees. The wing control surface arrangement was unusually "busy", mostly to improve short-field capability. Each wing featured:

The 727 had tricycle landing gear, all gear assemblies featuring twin wheels. The nose gear retracted forward, while the main gear hinged from the wings in toward the fuselage. Maximum passenger capacity was 129 seats, but that was a "cattle car" configuration; a more reasonable single-class configuration was about 110 seats, while a typical two-class configuration was 24 first class and 72 economy class seats. There was a passenger door on the front left fuselage with a fold-out "airstair", though the airstair may have been optional; a service door ahead of the wing on the right of the fuselage; twin emergency exits over each wing; and, unconventionally, a drop-down airstair door under the tail.

727 lets it all hang out

A convertible passenger-cargo variant, the "727-100C", followed, featuring a stronger floor and a large cargo door, inherited from 707 cargo variants, on the forward left side of the aircraft. The cargo door dimensions were 2.18 x 3.4 meters (7 feet 2 inches x 11 feet 2 inches). The 727-100C was complemented in turn by a "quick change" variant, the "727-100QC", which was broadly the same, but had palletized passenger seating that could be very quickly swapped out.

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[2] 727-200 / 727 IN SERVICE / SPECIAL VARIANTS

* The 727-100 proving popular, Boeing decided to introduce a "stretched" version, the "727-200", with 3.05 meter (10 foot) plugs fore and aft of the wings, giving a length of 46.69 meters (153 feet 2 inches). Empty weight increased to 46,165 kilograms (101,775 pounds); wingspan and height remained unchanged. First flight took place on 27 July 1967.

Boeing 727-200 with -100C/QC

Initial production was in an interim configuration: at the outset, the 727-200 retained the JT8D-7 engines of the 727-100, meaning there was no increase in maximum takeoff weight, and so the bigger passenger load was at the expense of fuel load. That was a conscious tradeoff, customer input to Boeing suggesting that the company needed to introduce a larger machine for the short-haul market as soon as possible. However, Boeing soon offered the JT8D-9 as an option, followed by the JT8D-11, with 66.7 kN (6,800 kgp / 15,000 lbf) thrust, permitting higher MTO.

The 727-200 moved the right service door to the front of the aircraft, and added a service door / emergency exit on each side of the rear, providing a distinctive recognition feature for the -200 series. The "Advanced 727" was introduced in 1972, offering even more powerful engine options -- initially the JT8D-15 with 69.0 kN (7,030 kgp / 15,500 lbf) thrust, then the JT8D-17 with 71.2 kN (7,255 kgp / 16,000 lbf) thrust, and ultimately the JT8D-17R with 73.0 kN (7,435 kgp / 16,400 lbf).

Boeing 727 freighter

The final 727 model was the "727-200F", a pure freighter with no passenger windows for Federal Express. The last 727 was delivered in 1984, the final tally being:

   727-100         408
   727-100C/QC     164
   727-200       1,245
   727-200F         15
   ___________________
   
   TOTAL         1,832

* The 727 served with the vast majority of airlines in the West well into the 1990s, declining in service after that decade as fuel prices rose to the extent to make it uneconomical to fly. Some still linger in service, a few being refitted with "winglets" -- wingtip vertical fins to reduce wingtip vortex and increase fuel efficiency by a few percent.

Boeing 727-100 with winglets

A number of 727s in service were re-engined. In the 1980s, Pratt & Whitney introduced the "JT8D-200" series of turbofans, featuring substantial changes to earlier JT8Ds to provide cleaner, quieter, and more efficient operation. Federal Express updated their fleet of cargo 727s with JT8D-217 engines with 97.9 kN (9.975 kgp / 22,000 lbf) thrust -- or at least partly updated them, only replacing the two side engines and leaving the original old centerline JT8D in place, since it would have been too much trouble to refit.

Fuel consumption was cut by 10% at least; short-field performance and climb rate were substantially improved. Presumably these machines cruised with the centerline engine at a low thrust setting. Similar JT8D-200 727 retrofits ended up with service with other airlines and in private hands, some refitted with winglets and modernized avionics. The updated engine nacelles appear to be slightly reprofiled from the originals, but it's hard to make out.

Engine retrofits performed by United Parcel Service for their 727-100C/QC cargo fleet were much more easily recognized. UPS refitted their machines with quiet and efficient Rolls-Royce Tay 651-54 turbofans with thrust reversers, swapping out all three engines, resulting in an obviously bulged inlet of the centerline engine that slightly flawed the clean lines of the 727. These machines, which were redesignated "727-100QF" for "Quiet Freighter", also received avionics upgrades, the entire conversion being performed by the Dee Howard firm of San Antonio, Texas. How many upgrades to 727-100QF configuration there were is unclear, numbers cited ranging from 45 to 58, with a private conversion also mentioned. Even with re-engining, the 727 is too expensive to fly in an era of high fuel costs, and the great fleets of the type have been reduced to a handful.

Tay turbofans on 727-200QF

* There doesn't appear to have been any government "special mission" variants of the 727, though some were used as personnel or VIP transports by various nations. Six were operated by the US Air Force, including one 727-100 "C-22A" machine used by Southern Command; four 727-100 "C-22B" machines used by the Air National Guard; and one 727-200 "C-22C" machine, used by Central Command. All these machines were obtained used and were flown as personnel / staff transports; at least some of them were fitted with rearward-facing seats, the military judging that a safer configuration for accident survival. These aircraft are now all out of service. Belgium, Mexico, Panama, New Zealand, and Taiwan also operated the 727 in small numbers in the personnel / staff transport or VIP role.

In the 1980s, General Electric flew a 727-100 on lease from Boeing to test the "propfan" AKA "unducted fan" engine -- something like a halfway house between a turboprop and a turbofan -- with the propfan engine mounted in place of the right JT8D. At last notice, Raytheon operates a 727-200 as a test bed with a "pointy nose" and a widely varying range of other equipment fits for avionics trials.

Raytheon 727-200 trials aircraft

In retirement, 727s have taken on some unusual roles -- for example, as a luxury suite for a Costa Rican hotel in the woods above the beaches, the suite including wood paneling, extensive comforts, and a porch. 727s have also been used for private homes, though some of them have a derelict feel, as if being used as shelter by castaways on an island of the lost.

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[3] 757 ORIGINS / 757-200 DESCRIBED

* In the 1970s, Boeing considered development of a further elongated "727-300" variant, stretched by about 9 meters (20 feet) compared to the 727-200 and offering 35 more seats. It seems there was also consideration of more modern engine fits. However, the energy crisis of the 1970s intruded on the design process, with Boeing engineers finding that greater fuel efficiency dictated a new-design aircraft that only retained the six-across fuselage configuration of the 727.

The six-across seating configuration seemed a bit archaic to many industry observers, the trend being towards "wide body" jetliners, but airlines liked it for short-haul flights, and it was more fuel-efficient. To obtain still greater fuel efficiency for the "7N7", as it was known at the time, Boeing engineers investigated improved aerodynamics and sought more efficient engines. The 727's JT8Ds had been state-of-the-art in the early 1960s, but they were "low bypass" turbofans, with a low ratio of airflow through the fan relative to the airflow through the turbine core, and so not very efficient. In the 1970s "high bypass" engines were available that had much higher bypass ratios and greater efficiency; indeed, Boeing had a selection of attractive powerplants.

By 1978, the "757", as it had officially become known, had emerged as a twin-engine jetliner with a low-mounted swept wing, a high-bypass turbofan being mounted under each wing. Although a tee tail had been retained well into the design process, a conventional tail arrangement was chosen instead, since it provided better stall handling. The "glass cockpit" arrangement of the larger 767 jetliner, then in development, was adopted for the 757. In fact, the same cockpit design was used for both aircraft, which was why the two aircraft looked so similar in the nose; 767 aircrew had to step up to get into the cockpit, while 757 aircrew had to step down. The 757 also made extensive use of improved alloys and composite materials to reduce empty weight.

The first 757 prototype performed its maiden flight on 19 February 1982. It was powered by twin Rolls-Royce RB.211-535C turbofans with 166 kN (16,960 kgp / 37,400 lbf) thrust each, the RB.211 having been developed for the Lockheed Tristar jumbo jet. Pratt & Whitney had been working on a new series of turbofans, the PW2037 and the more powerful PW2040, but they weren't ready at the time, and so the 757 was the first Boeing jetliner to use a foreign engine at the outset.

* The initial 757 variant, the "757-200", was certificated in December 1982 and entered service in early 1983. A smaller "757-100", with a capacity of 100 seats, had been considered, but there was no customer interest and it never happened. Options for RB.211-535E4 turbofans, with 178 kN (18.185 kgp / 40,100 lbf) thrust each, or PW P2037 turbofans, with 170 kN (17,325 kgp / 38,200 lbf) thrust each, were offered a few years after initial deliveries; Pratt & Whitney then provided the PW2040, with 185.5 kN (18,910 kgp / 41,700 lbf) thrust. The General Electric CF6-32 was also considered as an option, but GE decided not to proceed with development. There was an AlliedSignal GTCP331-200 APU in the tail for ground power and engine start.

Boeing 757-200

The 757's airfoil design also leveraged off the 767, though the sweep was more moderate -- 25 degrees at quarter-chord for the 757, like the sweep of the Boeing 737 wing, opposed to the 31.5 degree sweep of the 767. The 757's wings had a dihedral of 5 degrees and an angle of incidence of 3.2 degrees. The 757 wing was less efficient in cruise flight, but more efficient in takeoff / ascent and landing / descent; since the 757 was a short-haul aircraft, it spent less time in cruise flight and so the wing sweep was an appropriate tradeoff. The wings were typically "busy" in good Boeing jetliner fashion, each wing featuring:

The tail arrangement was conventional; the tailplane had elevators but also variable incidence to help with flight trim. Each main landing gear assembly had four wheels in a 2x2 bogie configuration, hinging from the wings to retract into the fuselage, and was fitted with carbon brakes. The nose gear had two wheels and retracted forward.


   BOEING 757-200:
   _____________________   _________________   _______________________
 
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                38.05 meters        124 feet 10 inches
   wing area               185.2 sq_meters     1,994 sq_feet   
   length                  47.32 meters        155 feet 3 inches
   height                  13.56 meters        44 feet 6 inches

   empty weight            57,265 kilograms    126,250 pounds
   MTO weight              99,790 kilograms    220,000 pounds

   max cruise speed        936 KPH             605 MPH / 505 KT
   service ceiling         11,885 meters       39,000 feet
   range                   5,895 kilometers    3,755 MI / 3,180 NMI
   _____________________   _________________   _______________________

Avionics included radios, transponder, navigation and landing aids, plus a weather radar; as mentioned, the 757 had a leading-edge glass cockpit. Another leading-edge feature of the avionics system was the "Engine Indication & Crew Alerting System (EICAS)", a diagnostic system that tracked the condition of the aircraft and alerted the aircrew if it found anything wrong. Yet another was a Honeywell "inertial reference system (IRS)" based on ring laser gyros incorporated into the navigation system.

There were two passenger doors forward of the wing and one passenger door near the tail on each side of the aircraft; in some configurations, there was an emergency exit to the rear of the wing on each side, in others there were two emergency exits on top of the wing on each side. It seems plausible the variation was due to different passenger loads, an all-coach aircraft requiring more emergency exits. There were two flight crew along with cabin attendants. A typical passenger seating arrangement consisted of a first-class cabin with 16 seats, four per row, and a coach cabin with 170 seats, six per row. A high-density all-coach configuration had 239 seats. There were various arrangements of galleys and toilets placed fore, aft, or in the center. There were freight holds under the floor fore and aft of the wing, with loading doors on the right.

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[4] 757-200 VARIANTS / 757-300 / 757 SPECIAL VARIANTS

* A "757-200PF" package freighter was introduced in 1987 for United Parcel Service, featuring a large cargo door on the forward left side of the fuselage -- with the same dimensions as that of the 727 -- but no passenger capability nor windows. It could carry up to 16 pallets or containers in the main deck, as well as cargo in the two underfloor cargo holds. Maximum cargo load was just under 40 tonnes (44 tons). It was a popular item; from 2001, a fair number of 757-200 jetliners were converted to a similar configuration, the "757-200SF", or "special freighter".

A "combi" version of the 757, the "757-200M", was introduced in 1988, with the cargo door, but also retaining passenger capability. It could handle two to four cargo pallets in the forward section, and carry 123 to 148 passengers in the rear. Only one was built, for Royal Nepal Airlines, this machine being fitted with more powerful RB.211-535E4 engines to support "hot & high" operations. From 2010, several firms did offer aftermarket conversions of 757-200 jetliners to a combi configuration, typically carrying up to ten cargo pallets forward, with seating for 45 to 58 passengers in the rear. These conversions were generally intended to carry personnel along with the heavy gear they were to operate to remote locations. Two combi conversions were also acquired by the Royal New Zealand Air Force, for use in freight, passenger, VIP transport, or medical evacuation roles.

Executive / VIP configurations were sold under the designation of "77-52". VIP users included the presidents of Argentina and Mexico, as well as the Sultan of Brunei.

* Demand for a 757 variant with more capacity led to the stretched "757-300", with the initial flight of the first prototype on 2 August 1998. The 757-300 had fuselage plugs fore and aft of the wings, the fore plug having a length of 4.06 meters (13 feet 4 inches) and the aft plug having a length of 3.05 meters (10 feet), giving a total length of 54.43 meters (178 feet 7 inches). Empty weight went up to 64,950 kilograms (142,400 pounds); maximum passenger capacity was 289 seats in a single-class configuration, or a more reasonable 240 seats in a three-class configuration. Cabin accommodations were redesigned, the new arrangement being taken from the Boeing 737 Next Generation series. Like the 757-200, the 757-300 featured two passenger doors forward of the wing and one near the tail on each side of the aircraft, but featured both an emergency exit behind the wing and two emergency exits on top of the wing on each side -- for a total of twelve doors.

Boeing 757-300

The 757-300 had reinforced wings and landing gear to handle the greater takeoff weight, plus a retractable tail skid to protect against tail strikes. Powerplant options included the RB211-535-E4B with 191.7 kN (19,550 kgp / 43,100 lbf) each, or the PW2043 with 195 kN (19,900 kgp / 43,850 lbf) each.

The 757-300 went into service in 1999, but by that time the 757 program was reaching the end of the line. Sales finally went too soft to support further production, and the last 757, a 757-200, was delivered in 2005. Only 55 757-300 jetliners were built; a total of 1,050 757s, including the initial prototype, had been delivered to end of production. Sales were apparently somewhat below expectations -- not because of any real failing of the aircraft, just because competition was tough. Boeing has been talking of a "New Mid-Market" jetliner as of late, but only in general terms, the firm not being sure whether the NMA should be a long single-aisle aircraft, or a short double-aisle aircraft.

The 757 remains in widespread service. Given the increasing costs of fuel in the 21st century, a number of airlines have chosen to add winglets to their machines to improve their fuel economy. From 2012, Boeing teamed with Rockwell Collins to provide a modernized "glass cockpit" for 757s (and 767s) in service, replacing the old CRTs with flat panels and incorporating modern electronics.

* The US government obtained a number of 757s and operates them under the designation of "C-32". Four 757-200s were obtained in 1998 and 1999 as government executive transports, being designated "C-32" and painted in white and blue "presidential flight" colors; they are used to carry the vice-president and other high government officials, flying out of Andrews Air Force Base in Maryland. They feature a litter of antennas to support an extensive suite of communications gear, and they were all eventually refitted with winglets. It is said that the high-perched landing gear of the 757 is regarded as a plus for VIP flight missions, because security personnel can see underneath it so easily. These aircraft have VIP accommodations, of course, and it seems likely they have defensive countermeasures systems, though details are unclear.

Boeing C-32B tanks up

The C-32As are well understood compared to their "C-32B" brethren. There appears to be two, with rumors of four on the basis of reserved FAA tailcodes, and they were (apparently) refitted from used commercial machines. They are painted white all over, with unobtrusive national markings, and according to the story, they are used by the US government's "Foreign Emergency Support Team (FEST)", an inter-agency quick-response task force mostly intended to deal with terrorist actions. The C-32Bs don't have the same litter of antennas as the C-32As; there's not much data on their equipment fit, but it is clear that they were fitted with an inflight boom refueling socket behind the cockpit, photos and videos showing them tanking up in midair. Nobody's talking about any other specifics of these aircraft.

Honeywell 757-200 engine testbed

* The 757 has also been used as a trials machine. Boeing retained the original 757-200 prototype as a trials platform for the F-22 Raptor fighter, with the jetliner fitted with a "pointy nose" and a wing mounted on top of the aircraft behind the cockpit. Initial flight of the "Catfish", as it was known for its cluttered appearance, was in 1999; current status of this machine is unknown, but it was observed in operation as recently as 2010. Honeywell operates a 757-200 as a small turbofan testbed, with the engine unconventionally fitted to a pylon extending from the aircraft's upper forward right fuselage. It made its first flight in its new form in 2008.

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[5] COMMENTS, SOURCES, & REVISION HISTORY

* I found some illustrations of the stillborn 727-300, and got to wondering what it would have looked like had they proceeded with it. Probably by that time, trading in the old triple JT8Ds for twin large high-bypass turbofans along the lines of the RB.211 would have seemed attractive. Mounting them on the tail wouldn't seem too preposterous, there having been studies for similarly mounting high-bypass turbofans on the tailjet British Vickers VC10 jetliner as well.

727-300 with twin turbofans

* One of the ironies of the 727 and 757 is that, in comparison to other Boeing jetliners such as the 707, 737, and 747, they were only produced in a limited number of variants -- with no really exotic "special mission" variants -- and had relatively brief production lives, giving the sense that they were "also-rans". The trick here is the word "relative": with over 1,800 727s and 1,000 757s built in all, most aircraft manufacturers could only dream of building aircraft that "unsuccessful".

I may have flown on a 727 decades ago, but if so I cannot recall it at all. I did take notice of 727s flying around, however, finding their looks intriguing.

charter 727-200

* As concerns copyrights and permissions for this document, all illustrations and images credited to me are public domain. I reserve all rights to my writings. However, if anyone does want to make use of my writings, just contact me, and we can chat about it. I'm lenient in giving permissions, usually on the basis of being properly credited.

* Sources include:

Several editions of JANE'S ALL THE WORLD'S AIRCRAFT were consulted as well, and the online Wikipedia also proved useful, in particular for links.

* Revision history:

   v1.0.0 / 01 may 12
   v1.0.1 / 01 apr 14 / Review & polish.
   v1.0.2 / 01 mar 16 / Review & polish.
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