Professional Engineering

“So far, so good,” says Klapproth. “We are really happy with everything we are seeing.”

There are other similarities too: Pratt may stress its innovation, but both programmes have long research antecedents going back to the 1980s and 1990s. “We started working on the GTF in the 1980s fuel-cost crunch period,” says Adams. The work, he says, started coming to fruition at about the point a few years ago when fuel costs came back on the agenda for airlines in a big way. 

But although there are elements in which the two rivals appear to be engaging in something of a phoney war, there are real divergences too. Adams is convinced that the geared turbofan is here to stay: “For powering commercial service airlines, the regional jets, the narrow-body and the wide-body markets, I don’t think we will build a conventionally configured engine again, going forward. The geared technology is very well suited for revenue passenger service operations,” he says.

In the end, of course, whether the conventional CFM approach or the radical Pratt one wins out may depend on a set of figures that will only be verified in the longer term: operational costs and particularly the cost of maintenance. Fewer stages and lower temperatures at the core mean that Adams is confident that maintenance costs on the PW1100 could be 20% down on current engines. 

Klapproth, more cautiously, says that CFM is “committed to maintaining comparable maintenance costs on Leap, which is a more advanced engine, as we have on the current CFM-56”. 

Airbus, sitting happily in the middle while the two engine makers compete for its lucrative business, talks gently about possible 10% maintenance savings, but adds that only time will tell. Either way, it seems to have a winner on its hands: 332 firm orders in the first three months after launch for A320Neo, and all of them going for the Pratt & Whitney engine, and predictions of 4,000 Neos in time. But these are early days. 

Sharklets bite into drag

The engine contest is the real differentiator in the A320Neo, but the A320 family will have benefited by the time the new engine options come on stream from some alterations on the airframe. 

Chief among these is the addition, from 2012, of what are termed “sharklets”, a variety of blended winglet which will be available on all new A320 family aircraft. They reduce interference drag and could bring fuel savings of up to 3.5% but that, says Airbus’s John Leahy, is about as far as it goes with airframe improvements. 

There will be minor changes to accommodate the sharklets and then the new engines, but essentially the A320Neo airframe will have 95% commonality with today’s A320. “The market was very clear,” Leahy says. “It wanted a re-engined A320. If a clean sheet of paper would give us 3.5% better economy, and new engines promise 15%, it’s not so much a New Engine Option as a New Engine Obligation.”