Wide chord
From Wikipedia, the free encyclopedia
A wide chord fan engine is a term to describe a modern turbofan jet engine having a ducted fan with a specific geometry in the inlet of the engine nacelle. In aviation terms, the meaning of "chord" is the line from the front (leading edge) of an aerofoil to the rear (trailing egde).
The main fan on a jet engine consists of a number of aerofoils mounted at the rotational center on the fandisc, and as the engine core rotates the fanblades accelerate an airmass and create the force to move forward which gives thrust (in accordance with Newton's Third Law).
In theory the larger the fan diameter (the line from the tip of one fanblade to its opposite member) the greater the thrust. In real life the fansize is limited by the fact that only a certain amount of space is available around the aircraft, and also by the increased drag (resistance) of the larger frontal area at high speeds. Aircraft propulsion engineers therefore have to find other ways to achieve higher thrust ratings, and one way of doing this is to increase the chordline (making the chord wider). By doing this the effectiveness of one fanblade becomes greater. Therefore a wide chord fan engine will have fewer fanblades, but each fanblade is greater in size and effectiveness. This also allows for lower tipspeeds which means less noise. An example of a wide chord fan engine is the Engine Alliance GP7000.
