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Turbine Edition: Jet Stream

No-blisk oblige

Turbine airplanes just seem to have a natural grace and symmetry in their lines that is sometimes hard to find in their piston-powered counterparts. And if form follows function, this shot of an Eclipse 500's Pratt & Whitney PW610F fan section says it all.

Turbine airplanes just seem to have a natural grace and symmetry in their lines that is sometimes hard to find in their piston-powered counterparts. And if form follows function, this shot of an Eclipse 500's Pratt & Whitney PW610F fan section says it all. The fan section - it's the first thing you see when you look into the engine nacelle - is made from a single piece of titanium. The individual blades are milled into a single disc, hence the popular nickname "blisk." Computer-aided design processes yield the blisk's undulating shapes, help this comparatively tiny engine to deliver up to 900 pounds of takeoff thrust, and propel the Eclipse to speeds as high as 375 knots. Blisks are not only more efficient at moving air through the engine, they save weight, reduce drag, and enhance strength. Not so long ago, turbofan engines came with fan sections consisting of multiple fan blades (inset). Each blade was attached to the hub using its own set of bolts. They get the job done, but these fan sections weigh more and are less streamlined.

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