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Pratt & Whitney’s Geared Turbofan Engine: Changing the Course of Avaition

Pratt & Whitney will finally go into production this year with it’s Pure Power line of jet engines which has been heralded as everything from a “game changer” to the “future of jet propulsion”. By the addition of a gearbox the Pratt & Whitney Pure Power jet engines have been shown to reduce fuel consumption by as much as 15% and noise by 50%. By virtue of this alone, Pratt & Whitney has received thousands of orders for it’s Pure Power PW 1000G line of engines by various major players including Bombardier, Airbus, Embraer and Mitsubishi.

The 15% reduction in fuel consumption alone will be a major selling point and will result in huge savings when millions of gallons of fuel are being expended. Today’s typical airliner burns about a half gallon of fuel per mile and the resultant savings of these engines will average 1.7 million per year in operating costs for each airliner. As a result of recent price spikes over the past decade, fuel costs are now the largest single operating expense for airlines today.

With over 3500 orders as of the spring of 2013 Pratt & Whitney will recoup their R&D expenses 10 fold and it has been argued that this one product alone will double the firms profitability over the next few years. The actual engines are estimated to cost about 13 million per unit.

While the idea of fan geared jet engines is not entirely new, having made it’s appearance on a smaller scale on smaller jets over the past few decades, the size and scale of the new engines is. Pratt & Whitney has evolved the idea since the late 90s having had to deal with engineering issues associated with the enduring and dispelling of heat associated with speeds of 30,000 horse power. The 18 inch gear box weighs about 250 lbs and much effort went into engineering a gear box that could handle stress, high temperatures and effectively disperse heat.

The basic principal behind the geared turbofan engine is the gear box which allows the fan to spin at a lower speed than the turbine and low pressure compressor which in turn creates more thrust while expending less fuel. So in effect, the gear box allows these two separate and distinct components to move at optimum speeds for a greater efficiency thus the end result of 15% less fuel consumption. The new engines have a bypass ratio of 12:1 versus the typical 8:1 of conventional jet engines. This means that for each pound of air entering the engine 12 pounds of the air will bypass the core. In this way the geared turbofan engine will allow the fan to spin at slower speeds then the core turbine. To accommodate this new approach these engines will have larger fans and smaller turbines.

The new engines will have a unique set of issues most notable being a more regular scrutiny of the engines themselves and specifically the gear box for potential cracks and metal fatigue and the larger fan also means that in many cases the engines can not be retrofitted on existing aircraft designs and will more typically be used on newer planes designed with this specific engine in mind.

The initial line of PW 1000G engines that will be used by the likes of Bombardier later this year are designed for small and medium sized single isle airliners.  An even larger engine for wide bodied airliners is promised in the next few years and is said to be even more efficient than the currently available models.

Connecticut based Pratt & Whitney already has a winner with it’s Pure Power line of engines and it’s estimated that this alone will result in 400 billion in sales over the next few years with a doubling of the companies profits anticipated.

In addition to this Pratt & Whitney has been working with the University of Connecticut on the creation of an Additive Manufacturing Innovation Center on the UConn campus in Storrs, CT.  In effect a lab and research center to focus on 3D printing of metal parts which are integral to the Pure Power engines and which will become even more common over the next generation. The facility already boasts two Arcam A2X electron beam melting machines making this one of the countries most advanced facilities of it’s kind. The University of Connecticut also will be adding a degree and concentration of studies directly related to additive manufacturing (3D printing) as a direct result of this facility.

Connecticut based Pratt & Whitney is a division of United Technologies. UTC has under it’s umbrella aerospace firms, Sikorsky Helicopter, Otis Elevator, Carrier, and in September of 2011 completed a high profile 18.4 billion dollar buy out of Goodrich. The purchase of Goodrich, acknowledged as the largest aerospace acquisitions in history is perceived to be a shrewd and far sighted move. Goodrich had often been supplier of various aircraft components inclusive of brakes and landing gear to UTC and this will permit UTC to provide two thirds of the parts and components required for aircraft in house. As a direct result of the thousands of orders for it’s geared turbofan engines Pratt & Whitney is likely to be UTC’s
most profitable business unit over the next several years.

Aticle Written by:  David Mazovick

 

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