The UDF blades were powered directly and gearlessly by a turbine, driven by hot gas from the engine. The two rows of propeller blades were each anchored to multiple rows of turbine blades. But what sparked the interest in developing a fuel efficient engine and aircraft became the demise of the UDF and the 7J7.
How does an unducted fan engine work?
engine layout, identified as the unducted fan (or UDF; trademark), provides a set of very high-efficiency counter-rotating propeller blades, each blade mounted on one of either of two sets of counter-rotating low-pressure turbine stages and achieving all the advantages of the arrangement without the use of a gearbox.
Why was the Boeing 727 discontinued?
The 727 could fit more passengers than the earlier models of its twinjet competition in most configurations. However, as engines became more efficient, and Boeing began to stretch the fuselage of the 737, by the time the -300 went into production, this was no longer the case.
Why do Boeing planes start with 7?
The Boeing 707 is credited with launching the beginning the “Jet Age.” It was decided that all model numbers that either began or ended in a “7” would be reserved for commercial jets.