Pratt & Whitney will add another 1,000 engines to its geared-turbofan backlog this week at Paris—adding to its existing orderbook of more than 4,000—“That’s a certainty,” says President David Hess as the company begins looking towards a next-generation “Geared Turbofan Advanced.”

PW1500G and PW1700G engines for the 365 orders and other commitments announced yesterday by Embraer at the launch of its E-Jet E2 family will make up a large part of the show total, he says.

Hess says P&W expects $400 billion in OEM and aftermarket revenues from sales of the PW1000G family over the lives of the five platforms for which the GTF engine has been selected: Airbus A320NEO, Bombardier CSeries, Embraer E-Jet E2, Irkut MC-21 and Mitsubishi MRJ.

GTF sales will help P&W double its large commercial and military engine deliveries and double its revenues to more than $24 billion in 2020 from $12 billion in 2010, he says.

Hess, meanwhile, stresses that the GTF is about more than the geared fan. “Today we have a 15% fuel-burn reduction [from the V2500]—5-6% is from the gear. The other 10% is from technology improvements in all models: materials technology, component efficiency, and high-pressure core.”

He is addressing claims by CFM International that new technologies such as ceramic matrix composites (CMC) in its competing Leap-1A engine will offer lower fuel burn and maintenance costs than the PW1100G engine on the A320NEO.

Arguing that P&W is “second to none” on materials technology because of its work of the F119 and F135 combat engines, Hess says the GTF was designed deliberately to run cooler to reduce maintenance costs.

“On Leap they were compelled to drive temperatures up to get close to us on fuel burn, but running hotter drives maintenance,” says Chief Operating Officer Paul Adams. “We have 75% of the A321NEO market. Those are high-thrust engines that run at higher temperatures.”

In an interview today with Aviation Week, Embraer President and CEO Frederico Fleury Curado says the temperature reserves the engine provides by running cooler were a factor in the company’s decision to select the GTF over incumbent GE’s NG34 for the E-Jet E2.

“The engine has margins, and history shows they are often needed,” he says. “Engines run hotter over time, so those reserves were a plus for us.”

Hess says P&W has a roadmap to increase the GTF fuel savings to 20-30% from 15% by the middle of the next decade. Some of that will come from bigger fans that increase bypass ratio to 15-18 from around 12 on the PW1000G, but P&W also plans to improve the core.

This will involve increasing the overall temperature of the engine and require new materials, says Adams. “We will drive thermal efficiency. Core technology will push overall pressure ratio beyond 60, which is the next threshold for this size of engine.”

“Temperature is a value trade with cash operating cost. We will not arbitrarily drive temperatures too high to gain performance but lose on maintenance cost,” he says. “We are in a good place with the current GTF.”

Referencing CFM’s first use of additive manufacturing, in the Leap fuel nozzle, Hess says “On entry into service on the CSeries, our engine will have 25-26 parts that are additive.” The PW1500 for the CSeries will also have “around 200” composite parts, he says.

On CMCs in engines, used for the first time in the Leap, Hess says P&W had a CMC part in the F135 engine for the F-35 Joint Strike Fighter, “but we decided to replace it with an alternative composite material for lower cost and risk. We are at least as capable in composites as the competition.”