Aircraft Factfile and
Recognition Guide - Boeing 737 Series
Most 737 snaps were taken outside of my home, unless otherwise stated. Pictures taken from PHL, JFK, and LGA.
Background
In late 1958 Boeing announced a design study for "A twin engine feeder airliner to complete the family of Boeing passenger jets". In Feb 1965 the first order was placed and the project went ahead. It is now the best selling commercial aircraft in aviation history with more than 5,400 orders from 215 customers so far. Here are some statistics to illustrate its success:
Design
Design work on the 737 started in November 1964 by Joseph Sutter and Jack Steiner, Boeing wanted a true short-haul jet to compete with the Caravelle, BAC One-Eleven & DC-9 but it was way behind them. The DC-9 was about to fly, the One-Eleven was well into its flight test program and the Caravelle had been in service for 5 years. It had some catching up to do. The original 1964 specification was for a capacity of about 60-85 passengers, an economical operating range of between 100 and 1000 miles and to be able to break even at a 35% load factor. As a result of final design talks with Lufthansa the capacity was increased to 100, but the range and load factor figures still stand.
Where to put the Engines
Joe Sutter (also considered to be the father of the 747) knew that Boeing was competing against broadly the same market so needed something different, his solution was wing-mounted engines. This gave the advantages of less interference drag, a better C of G position, more usable cabin space at the rear, easier access to engines for maintenance and required less pipe work for fuel & bleeds. The weight of the engines also provides bending relief from the lift of the wings. Apparently this was benefit was over-estimated and a set of wings failed in static tests at 95% of max load and the wing had to be redesigned.
The disadvantage of wing-mounted engines was that the size of the fin had to be increased for engine-out operation over centerline thrust aircraft. Also, due to the reduced ground clearance, the engines had to be almost an integral part of the wing, which in turn necessitated a short chord. The final wing was a work of art as the spec required both good short field performance and economy at altitude.
Overall, the wing-mounted layout had a weight saving of 700Kgs over the equivalent “T-tail” design and had performance advantages. A further advantage of the wing-mounted engine design was its commonality with earlier Boeings such as the 707.
737-100
On 19 Feb 1965, Boeing announced the 737-100 after an order of 10 from Lufthansa, who became the first foreign airline to launch a US airliner. Assembly started in the summer of 1966.
The maiden flight of the 737 was on 9 April 1967, just two years after the project launch. Chief test pilot Brien Wygle and Co-Pilot Lew Wallick made the uneventful 2 1/2 hr flight from Boeing Field to Paine Field. The earliest 737's had some problems, including thrust reversers that didn't work properly, and a shimmy in the landing gear, but it was a good airplane from the start, recalls Brien. FAA certification was gained on 15 Dec 1967.
The -100 was 94ft (28.65m) long, carried 115 passengers and had an MTOW of just 42,411Kgs, less than half that of the current -900 series. The original choice of powerplant was the Pratt & Whitney JT8D-1 at 14,000Lbs thrust, but by the time negotiations with Lufthansa had been completed the JT8D-7 was used. The -7 was flat rated to develop the same thrust at higher ambient temperatures than the -1 and became the standard powerplant for the -100.
The prototype subsequently went to NASA and was in regular experimental use until 1997. It is now stored at Moses Lake and kept in an airworthy condition until it can be flown back to Boeing Field, probably in Spring 2003, where it will be put on permanent display. NASA 515 was involved in numerous pioneering flight investigations including control systems, 3D and 4D navigation, in-flight energy management, computerized flight management systems, electronic displays, Microwave Landing System (MLS) development (overrun in late development by the advent of GPS), slippery runway studies, and clear air turbulence and wind shear detection and warning. The airplane has a second flight deck, fully functional, installed in the main cabin, that was used for much of the flying. Control systems used included the original Boeing control column/wheel, Brolly handles (like bicycle handlebars), and the current side-stick controllers. Numerous glass cockpit CRT display configurations were tried, that attacked many questions regarding display arrangements, colours and symbology. Much of this work wound up on Boeing, Douglas, and Airbus airplanes as well as the Space Shuttle. The airplane has a unique fourth hydraulic system with a reservoir, pump and filter system. Other studies were performed of drag-reducing external coatings, cockpit displayed traffic information, takeoff performance monitoring, and precision flare guidance during landing touchdown.
737-200
It was immediately realized that most airlines wanted a slightly higher passenger load, to which Boeing responded with the 737-200. Two sections were added to the fuselage; a 36in section forward of the wing and a 40in section aft of the wing, giving a maximum capacity of 130 passengers. All other dimensions remained the same. The JT8D was increased to 14,500Lbs with the -9. Six weeks later on the 5 April 1965 the -200 series was launched with an order for 40 from United Air Lines. Development and production of the two series ran simultaneously.
In the face of competition from other aircraft, Boeing worked on improving fuel economy, range, drag and runway performance. To this end the wings flaps and thrust reversers were improved from aircraft number 135 and free mod kits were made available for existing aircraft. The thrust reversers were totally redesigned by Boeing and Rohr since the aircraft had inherited the same internal pneumatically powered clamshell thrust reversers as the 727 which were relatively ineffective and apparently tended to lift the aircraft off the runway when deployed! The redesign to external hydraulically powered target reversers cost Boeing $24 million but dramatically improved its short field performance which boosted sales to carriers proposing to use the aircraft as a regional jet from short runways. Drag reduction measures included extending the engine nacelles by 1.14m and widening the strut fairings. Enhanced flap, slat and panel seals were also incorporated.
737-200 Advanced
As well as incorporating all of the later -200 modifications, the -200 Adv included major wing improvements such as new leading edge flap sequencing, extension of the inboard Krueger Flap, and the addition of flap positions 2 and 10 to produce a significant increase in lift and a reduction of take-off & approach speeds for better short field performance or an MTOW increase of 2268Kg. Autobrake, improved anti-skid and even nose-brakes became available. Again, kits were available for existing operators of the -200. With the JT8D-15 at 15,500Lbs the MTOW was now up to 52,390Kgs and MLW 48,534Kgs.
In 1973 when noise was becoming a factor, the nacelle was acoustically lined by Boeing and P&W swapped one fan stage for two compressor stages in the JT8D-17 while increasing thrust to 16,000Lbs. The JT8D got up to 17,400Lbs thrust on the -17R.
For many years United remained the only major US carrier to order large numbers of 737's because although the aircraft was designed to be flown by 2 crew, the US flight-crew union ruled that aircraft in that class had to be flown by three crew. United were forced to fly their 737's with three crew until 1981. Air France had also been trying to order the aircraft for several years but were unwilling to because of staff opposition until after 1981.
737-300, 737-400, and 737-500
The 737-200 was succeeded in 1981 by the 737-300. This was a much quieter, larger and more economical aircraft and contained a host of new features and improvements. The new model featured many aerodynamic, structural, cockpit and cabin features developed for the new -generation 757/767.
Engines
The sole power plant was the CFM-56, the core of which is produced by GE and is virtually identical to the F101 as used in the Rockwell B-1. SNECMA produced the fan, IP compressor, LP turbine, thrust reversers and all external accessories. The main problem was the size of the engine for ground clearance, this was overcome by mounting the accessories on the lower sides to flatten the nacelle bottom and intake lip to give the "hamster pouch" look. The engines were moved forward and raised, level with the upper surface of the wing and tilted 5 degrees up which not only helped the ground clearance but also directed the exhaust downwards which reduced the effects of pylon overheating and gave some vectored thrust to assist take-off performance. The CFM56-3 proved to be almost 20% more efficient than the JT8D.
Airframe
The wings were extensively redesigned to enhance low speed performance and cruise efficiency. These changes were focused on a new contour for the airfoil leading edge and the addition of wing tip extensions. These two changes had the greatest impact on high speed performance and as a result, the turbulent air penetration speed changed to 280KIAS/.73M. High lift characteristics were also enhanced by re-sequencing the slats and flaps. Other changes to the wing structure included strengthened materials and corrosion protection. The span was increased by a wingtip extension of 27.9cm (11in). Rumor has it that the fin was also "given" to Shorts for use on their SD-360 as a reward for their good contract work for Boeing. Whether this is true or not, the SD-360 fin certainly looks identical, albeit scaled down.
Changes that were made to the classics over their production run include:
The last of what was known as the 737 Classic series, a Boeing 737-400 (OK-FGS, L/N 3132), was delivered to CSA Czech Airlines on 25 February 2000.
737-600, 737-700, 737-800, and 737-900
The Boeing 737-X program was launched on 29 June 1993, with a 63 aircraft order from Southwest Airlines for the 737-300X. This became the 737-700, 22cm (9in) longer than the original 737-300, seating up to 149. The main differences of the 737 Next Generation (NG) are as follows:
One of the main production differences with the NG is the single moving assembly line, this has the capacity to produce 21 aircraft a month with a flow time of just 13 days.
737-600
The 737-600 was the third of the NG's to be built and originated as the 737-500X with a similar length fuselage, seating between 108-132. The launch order came from SAS on 15 March 1995. The fuselage is essentially that of the -700, with two plugs of 1.37m (fwd) and 1.01m (aft) removed.
Other differences include:
Wing-to-body faring modified to fit aft fuselage contour.
737-700
This was the first of the NG's to fly. The QC version has a 3.4 x 2.1m side cargo door and is in use with the USAF as the C-40A Clipper. the C-40A is certified to operate in an all-passenger configuration (121 passengers), an all-cargo variant or a "combi" configuration that will accommodate up to three cargo pallets and 70 passengers on the main deck.
The first -700 was retrofitted with winglets on 11 Sept 2001 for Kenya Airways.
737-800
The 737-400X became the 737-800 but is significantly longer at 39.4m (129ft 6in) and seats up to 189. The project was launched on 5 September 1994, with commitments for over 40. First delivery was to Hapag Lloyd in April 1998.
Differences from the -700 include:
The -800 has been available with winglets either as standard or retrofit since May 2001. These reduce aerodynamic drag thereby reducing fuel consumption by up to 7%.
737-900
Boeing began work on the stretched 737-900 in April 1997 to compete with the 185/220 seat, Airbus A321. It featured a 2.4m (7ft 10in) fuselage extension giving it an overall length of 42.1m (138ft 3in), actually 40cm longer than the 707-120. The 900 has 9% more cabin floor space and 18% more cargo space than the -800; however Boeing opted to use the same NG emergency exit layout, with 4 main exit doors and 4 overwing exits, thereby still restricting the maximum passenger load to 189.
Recognizing the Boeing 737 Family
The different variants of the 737 series can be a trick to identify if you do not know any specifics between the different models. Between two different aircraft, like the A320 and the 737, the 737 can be easily identified. Here are some tips on identifying the different models of the aircraft.
| 737-100 | -100 series was the original Boeing 737, seating 100 passengers, having a length of 28.65m. |
|---|---|
| 737-200 | The -200 series was launched at the same time as the -100. The reason for the production of two series was a request from United Airlines, the launch customer for the -200 for a 737 with a higher capacity than the -100 could offer. This model is almost 2m longer at 30.53m, with a seating capacity of 124 passengers. |
| 737-200 Advanced | The -200 Advanced is an updated
version of the original -200. The aircraft received
higher rated engines and aerodynamically improvements. By
1971 the last -200 was produced, with production
standardizing on the new -200 Advanced. The model was
produced until 1985. The 737-100 and 737-200 and -200 Advanced have turbofan engines that extend out to the trailing edge of the wing and the tail arching to meet the fuselage. |
Mid-generation |
|
| 737-300 | The -300 series was the first of the 2.
generation 737. The aircraft is substantially improved
technologically from the 1. generation. The -300 is
further stretched from the -200 to meet continuous
airline demand for higher capacity 737's, and clocks in
at 33.4m. All 737-300, -400, -500, -600, -700, -800, and -900s have a tail that extends out in a "toe". Each engine is mounted on wing struts. |
| 737-400 | The -400 series is the longest model of the 2. generation, at 38.4 meters. The -400 was introduced in 1986, as airline demand for larger and larger 737s increased. This is the only 2. generation 737 with two pairs of overwing energency exits. |
| 737-500 | The -500 was the last model of the 2. generation, launched in 1987 as a replacement for aging -200 aircraft, being of similar size and capacity. The -500 is the shortest model of the 2. generation, but it features the widest aisle. |
Next Generation |
|
| In 1993, Boeing decided to
go ahead with the launch of a new generation of the 737.
The technological advances that had been made since the
introduction of the Current generation was implemented in
the new models. These new aircraft are rapidly becoming
the workhorses of the new millennium for many airlines
around the world. They feature many aerodynamical
improvements, giving them a 1.5m higher tail and 5.5m
wider wingspan. Without some experience, separating these
from the older models can be hard. |
|
| 737-600 | The -600 was the second model of this generation to be launched, with SAS of Scandinavia as the launch customer. Scandinavian is gradually phasing out its older DC-9 and MD-80 fleet for the 737s, using -600s, -700s and -800s. The -600 was sized similarly to the -500. |
| 737-700 | The -700 was the first model of the generation to be launched, and sized similarly to the -300. |
| 737-800 | The -800 was the third model to fly, and is sized a bit larger than the -400, providing a natural growth path for operators needing a replacement for their older 737s. As the -400 the -800 has two sets of overwing exits. |
| 737-900 | The -900 is the largest 737 model to date, and it has still not entered revenue service. The first prototype of the type first took to the skies in August 2000. The -900 should be fairly easy to recognize from its length, but without some practice, it can be difficult to identify, as with the rest of the 737 models. The -900 have also got two sets of overwing exits. Boeing is considering offering a higher-capacity version of the -900, where the overwing emergency exits will be replaced by an extra set of full-size exits. Having the same exit configuration as the -800 limits the -900 to the same maximum passenger capacity. The higher-capacity version, dubbed -900X is primarily targetet at charter operators and would have a capacity very close to the 757-200. |
All 737s share one feature that can only be seen from the ground - when airborne, the 737's main landing gear does not have full gear doors whereas other airliners do.
| HISTORY: | |
| First Flight | (737-100) 9 April 1967 (737-200) 8 August 1967 (737-300) February 1984 |
| Service
Entry |
(737-100) 10 February 1968 (with
Lufthansa) (737-200) 29 April 1968 (with United Airlines) (737-400) September 1988 (737-500) March 1990 (737-900) May 2001 Click here to view a list of known operators. |
| CREW: | 2 or 3 flight crew |
| PASSENGERS: | (737-100) 85 in two classes, 99 in one-class (737-200) 95 in two classes, 124 in one-class (737-300) 126 in two classes, 149 in one-class (737-400) 147 in two classes, 168 in one-class (737-500) 110 in two classes, 132 in one-class (737-600) 110 in two classes, 132 in one-class (737-700) 126 in two classes, 149 in one-class (737-800) 162 in two classes, 189 in one-class (737-900) 177 in two classes, 189 in one-class |
| ESTIMATED COST: |
unknown |
| AIRFOIL SECTIONS: | |
| Wing Root | unknown, (section 1), (section 2), (section 3), (section 4) |
| Wing Tip |
Boeing TR-8 (?) |
| DIMENSIONS: | |
| Length | (737-200) 100.17 ft (30.53 m) (737-300) 109.58 ft (33.40 m) (737-700) 110.33 ft (33.63 m) |
| Wingspan | (737-200) 93.0 ft (28.35 m) (737-300) 94.75 ft (28.88 m) (737-700) 112.58 ft (34.31 m) |
| Height | (737-200) 37.0 ft (11.28 m) (737-300) 36.50 ft (11.13 m) (737-700) 36.50 ft (11.13 m) |
| Wing Area | (737-200) 980 ft2 (91.04 m2) |
| Canard Area
|
not applicable |
| WEIGHTS: | |
| Empty | (737-200) 61,050 lb (27,690 kg) (737-300) 72,360 lb (32,820 kg) (737-600) 81,360 lb (36,900 kg) (737-700) 83,790 lb (38,010 kg) (737-800) 90,560 lb (41,080 kg) (737-900) 93,610 lb (42,460 kg) |
| Typical Load | unknown |
| Max Takeoff | (737-200) 115,500 lb (52,500 kg) (737-300) 124,500 lb (56,470 kg) (737-600) 124,000 lb (56,240 kg) (737-700) 133,000 lb (60,320 kg) (737-800) 155,500 lb (70,530 kg) (737-900) 164,000 lb (74,390 kg) |
| Fuel Capacity | internal: (737-100) 4,720 gal (17,866 L) (737-200) 4,780 gal (18,094 L) (737-300/400/500) 5,311 (20,104 L) (737-600/700/800/900) 6,875 gal (26,025 L) external: not applicable |
| Max Payload
|
unknown |
| PROPULSION: | |
| Powerplant | (737-100/200) two Pratt & Whitney
JT8D turbofans (737-300/400/500) two CFM International CFM56-3C1 turbofans (737-600/700/800/900) two CFM International CFM56-7B turbofans |
| Thrust | (737-100/200) 31,000 lb (138 kN) (737-300/400/500) 40,000 lb (177.94 kN) (737-600/700/800/900) 48,000 lb (213.52 kN) |
| PERFORMANCE: | |
| Max Level Speed | at altitude: 585 mph (945 km/h)
at 23,500 ft (7,165 m) at sea level: unknown cruise speed: 575 mph (925 km/h) at 22,600 ft (6,890 m) |
| Initial Climb Rate | unknown |
| Service Ceiling | unknown |
| Cruise Altitude | 30,000 ft (9,145 m) |
| Range | (737-200) 1,860 nm (3,440 km) (737-300) 2,260 nm (4,180 km) (737-400) 2,060 nm (3,810 km) (737-500) 2,380 nm (4,400 km) (737-600) 3,160 nm (5,840 km) (737-700) 3,300 nm (6,110 km) (737-800) 2,930 nm (5,420 km) (737-900) 2,730 nm (5,050 km) |
| g-Limits | unknown |
| KNOWN VARIANTS: | |
| 737-100 | First production model; 30 built |
| 727-200 | Stretched model for up to 124 passengers; total of 1,095 built (all -200 models) |
| 737-200C | Convertible cargo/passenger model |
| 737-200QC | Quick-change passenger/cargo convertible model |
| T-43 | Navigation training aircraft built for US Air Force with passenger cabin replaced by avionics consoles and accommodation for 12 trainees and three instructors; 19 built |
| Advanced 737-200 |
Improved 727-200 with new engines and passenger capacity up to 130 |
| Advanced 737-200C/QC |
Improved cargo models based on Advanced 727-200 |
| Advanced 737-200 Executive Jet |
Advanced 737-200 specially tailored as luxury business/executive transport |
| Advanced 737-200 High Gross Weight Structure |
Advanced 737-200 with strengthened wing structure, modified landing gear, and additional fuel tank |
| Advanced 737-200 SLAMMR |
Maritime patrol and transport model built for Indonesia equipped with side-looking airborne multi-mission radar (SLAMMR); 3 built |
| 737-300 | Second generation 737 with longer fuselage for up to 149 passengers and new engines; 1,113 built |
| 737-400 | Lengthened 737-300 for up to 168 passengers; 486 built |
| 737-500 | Shortened 737-300 for up to 132 passengers; 389 built |
| 737-600 | Third generation 737 for up to 132 passengers, replacing -500 model; 38 built by 2001 |
| 737-700 | Lengthened 737-600 for up to 149 passengers, replacing -300 model; 306 built by 2001 |
| 737-800 | Lengthened 737-600 for up to 189 passengers, replacing -400 model; 383 built by 2001 |
| 737-900 | Lengthened 737-600 for up to 189 passengers |
To date, over 4,500 737s have been ordered with nearly 4,000 delivered.
Sources: B737.org.uk History, Aerospaceweb.org Boeing 737 Factfile, Planespotter's
Encyclopedia - Boeing 737 Series
© 2004-2007 Steven
Holzinger
