I
Improved variants
Development began in 1979
for the 737's first major
revision. Boeing wanted to
increase capacity and range,
incorporating improvements to upgrade the
aircraft to modern specifications, while also
retaining commonality with previous 737
variants. In 1980, preliminary aircraft
specifications of the variant, dubbed
737-300, were released at the Farnborough
Airshow.
The 737-300 was the first Classic variant
Boeing engineer Mark Gregoire led a design team, which cooperated with CFM
International to select, modify and deploy a new engine and nacelle that would make
the 737-300 into a viable aircraft. They chose the CFM56-3B-1 high-bypass turbofan
engine to power the aircraft, which yielded significant gains in fuel economy and a
reduction in noise, but also posed an engineering challenge, given the low ground
clearance of the 737 and the larger diameter of the engine over the original Pratt &
Whitney engines. Gregoire's team and CFM solved the problem by reducing the size of
the fan (which made the engine slightly less efficient than it had been forecast to be),
placing the engine ahead of the wing, and by moving engine accessories to the sides of
the engine pod, giving the engine a distinctive non-circular "hamster pouch" air intake.
Earlier customers for the CFM56 included the U.S. Air Force with its program to re-
engine KC-135 tankers.
The passenger capacity of the aircraft was increased to 149 by extending the fuselage
around the wing by 2.87 meters (9 ft 5 in). The wing incorporated several changes for
improved aerodynamics. The wingtip was extended 9 in (23 cm), and the wingspan by
1 ft 9 in (53 cm). The leading-edge slats and trailing-edge flaps were adjusted. The tailfin
was redesigned, the flight deck was improved with the optional EFIS (Electronic Flight
Instrumentation System), and the passenger cabin incorporated improvements similar to
those developed on the Boeing 757. The prototype -300, the 1,001st 737 built, first flew
on 24 February 1984 with pilot Jim McRoberts. It and two production aircraft flew a nine-
month-long certification program.
Boeing B737
June 2017
www.alliance-airways.net
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