<P> Engines on the 737 Classic series ( − 300 , − 400 , − 500 ) and Next - Generation series ( − 600 , − 700 , − 800 , − 900 ) do not have circular inlets like most aircraft . The 737 Classic series featured CFM56 turbofan engines , which yielded significant gains in fuel economy and a reduction in noise over the JT8D engines used on the − 100 and − 200 , but also posed an engineering challenge given the low ground clearance of the 737 . Boeing and engine supplier CFMI solved the problem by placing the engine ahead of ( rather than below ) the wing , and by moving engine accessories to the sides ( rather than the bottom ) of the engine pod , giving the 737 a distinctive non-circular air intake . </P>
<P> Engines on the 737 Classic series ( − 300 , − 400 , − 500 ) and Next - Generation series ( − 600 , − 700 , − 800 , − 900 ) do not have circular inlets like most aircraft . The 737 Classic series featured CFM56 turbofan engines , which yielded significant gains in fuel economy and a reduction in noise over the JT8D engines used on the − 100 and − 200 , but also posed an engineering challenge given the low ground clearance of the 737 . Boeing and engine supplier CFMI solved the problem by placing the engine ahead of ( rather than below ) the wing , and by moving engine accessories to the sides ( rather than the bottom ) of the engine pod , giving the 737 a distinctive non-circular air intake . </P>
who makes the jet engines for the 737
who makes the jet engines for the 737
CFMI
CFMI