Variable-area fan nozzle dropped as flutter fears recede

摘要

Most of the major design trades for the PW1100G are far in the past, but important tweaks to the configuration are still being made. Indeed, Pratt & Whitney confirms that it will remove a proposed feature for the PW1100G called a variable-area fan nozzle. P&W's designers once believed such a unique moving nozzle was necessary. The 81in (206cm) diameter of the engine exposes the fan blades to unusual vibrations in unstable air flow at low speeds, so closing the nozzle on take-off would smooth the air flow enough to prevent any chance of the fan blades developing a potentially disastrous flutter condition.