CFM International (GE + Safran) · Case study
CFM LEAP-1A / -1B
The CFM56's successor and a showcase of aerospace materials: woven carbon-fibre fan blades, ceramic-matrix composites in the hot section, and roughly 15% better fuel burn.
Architecture
The LEAP keeps the proven two-spool layout but rebuilds it in modern materials. Its fan blades are three-dimensionally woven carbon-fibre, made by resin transfer moulding, so the fan can grow larger and lighter and push the bypass ratio toward 11 without a weight penalty.
In the hot section, ceramic-matrix-composite (CMC) shrouds tolerate higher turbine temperatures than nickel alloys, and a higher overall pressure ratio lifts thermal efficiency. A Twin-Annular Pre-Swirl (TAPS) combustor keeps NOₓ low at those temperatures.
The cycle
Higher bypass ratio improves propulsive efficiency; higher pressure ratio and turbine temperature improve thermal efficiency. The LEAP pushes both at once, which is why it delivers about 15% lower fuel burn than the CFM56 it replaces, with lower emissions.
Engineering significance
The LEAP is now one of the two dominant powerplants on the latest single-aisle jets, sharing that market with Pratt & Whitney's geared turbofan. It marks the point where composites and ceramics moved from exotic to mainstream in a high-volume commercial engine.
Applications
Airbus A320neo · Boeing 737 MAX
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