Boeing will not build an all new replacement for the world’s most popular airliner. Instead, the plane maker has decided to upgrade the ubiquitous 737 with new engines and a few other items to increase efficiency and extend the life of the 40-plus year old design.
The decision to ‘re-engine’ the 737 instead of coming up with a clean sheet design was made after airlines made it clear they want fuel savings now rather than later. With the recent history of the all new 787 Dreamliner, there were fears in the industry that a new design could take more than a decade. Boeing promises to deliver the 737 MAX as it is being called by 2017.
Rival Airbus has made a similar decision with its popular single aisle airliner, the A320. The European company will re-engine the airplane and deliver it as the A320neo in 2015.
Boeing says the 737 MAX family of airplanes – there are three sizes – will be 10 to 12 percent more fuel efficient than the current lineup of 737s. And it says it will be four percent more fuel efficient than the A320neo.
First introduced into service in 1968, the 737 is the most popular jet airliner in the world. More than 6,800 have been delivered and the company has a backlog of more than 2,000.
Even with the all new 787, most of the efficiency gains were made with the engines. Airlines may have gained a few more percent with a replacement for the 737, but using the existing airframe also offers advantages.
By staying with the already familiar design, the new airplane will fit well in the airlines existing maintenance and operations systems. Even the cockpit is going to be largely left alone. Small improvements are likely, but no major makeover is expected in order to keep it familiar for the large number of existing 737 pilots and minimizing any additional training time.
The 737 MAX will gain almost all of its efficiency improvements from the new engines. But adding new engines to the airplane is a big of a challenge because of the limited space available under the wing.
Current model 737s already have a flattened cowl on the bottom of the engine to keep the engines high enough off the ground. Modern hi-bypass jet engines have a significantly larger diameter than the original engines offered on the 737 in the late 1960s.
Current Boeing 737-800 with flattened cowl for ground clearance.
The 737 MAX will use engines from CFM International, a joint venture between GE Aviation and the French company, Safran. Boeing is currently deciding between using a 66 inch diameter fan or 68 inch. The company believes neither would require modifying the landing gear in order to maintain the necessary height above the ground. The larger engine is more efficient. The current 737NG uses a 62 inch fan.
The engines will have the now familiar serrated cowlings also seen on the 787 and 747-8. The design reduces the noise signature of the jet engines, making the airplanes quieter when heard from the ground.
Boeing says it already has 496 orders for the new plane from five different airlines. Airbus has more than 1,000 orders for its new A320neo.
Photos: Boeing
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