Pratt & Whitney designed the geared turbofan to run the fan and the low-pressure turbine each at its aerodynamically optimal speed. The fan turns more slowly than the LP turbine, at about one third of the rotation speed of a conventional fan. In turn, the tensile strength requirement decreases sharply, from 200,000- to 400,000 psi to 100,000- to 150,000 psi, allowing engineers to reconsider the material used in the fan.
•The fan blades are made of aluminium alloy honeycomb structure and reinforced by Titanium leading edges.
Author – Zinhom Mohmoud – Aviation Training Consultant