Boeing has tweaked the engine design of its upcoming 737 MAX airliner, upping the fan size as it continues to iron out plans for the jet.
In the latest change, Boeing said the CFM LEAP-1B engines used in the updated 737 would come with a 69.4-inch fan, 1.4 inches larger that in the previous design plans released in November. A larger fan makes an engine more efficient but also creates more weight and drag.
Boeing has already made several changes to the single aisle airliner, which is based on the current-generation 737 airframe, in order to accommodate the larger engines. Those include lengthening the nose landing gear to give the aircraft more ground clearance. Boeing has said it will finalise the aircraft’s design by mid-2013.
Boeing has won more than 1000 commitments for the 737 MAX, including some 415 firm orders. The aircraft is due to begin deliveries in 2017, two years after Airbus is set to begin shipping its rival A320neo.