There used to be a time when the big aircraft makers were churning out new types with astounding regularity. In the wide-body arena, there was a choice between the Tri-Star from Lockheed, the DC-10 from McDonnell Douglas and of course the 747 from Boeing. Narrow-bodies also came in a nice variety from the DC-9 through the MD-80 and the 727 to the 737. But let’s not forget that in those days a few legacy, long-range narrow-bodies were still plying the skies, just think of the DC-8 and the Boeing 707. Airbus joined the fray at the top end with the A300 which was a short-to-medium range wide-body and the first twin-engine wide-body as such. That was in 1971…
One thing was sure. Each new type brought something revolutionary, some novelty for which the airlines wanted to buy them. Safety and efficiency increased, noise decreased, passenger comfort improved…
In the meantime, the world went through a number of oil crises, stock market crashes, deregulation, 9/11 and the birth of low cost carriers and the market for narrow-body, short-to-medium range aircraft altered radically. The result? Only two types, the Boeing 737 and the Airbus 320 family survived and these days if you travel chances are you will find yourself in one of those, no matter where you are in the world.
Not that those types have not evolved over the years. In particular, the Boeing 737 had several versions with the biggest improvements coming with the New Generation (NG) series. But the 320 also improved if in less visible ways.
In spite of the improvements, the basic design of both the 737 and the 320 family has stayed much the same to this day.
When the 737 started sprouting winglets, bringing fuel efficiency improvements in the low single digits, the discussion was already going on: should the manufacturers design new aircraft to replace the existing types or should they think about re-engining the existing ones?
This was a cruel but essential question to answer for both Boeing and Airbus. The 737 and 320 are their cash-cows and the promise of a radically new, more efficient model would kill the duck with the golden eggs. But not doing anything was also not an option. The airlines were demanding better fuel efficiency and cost of ownership and Boeing and Airbus were facing down each other, waiting for the other to make the first move. Neither of them could afford not to respond to its competitor’s move.
One of the arguments against a new type from either stall was the fact that the technology required on the airframe to achieve substantial savings was just not mature enough… in fact it was and still is several years away in spite of intense research going on, on both sides of the Atlantic. A trick with new materials, if not with new shapes and airfoils, was also not in the cards since more extensive use of composites on a medium range narrow-body would bring far lower returns than on an aircraft the size of the Boeing 787 Dreamliner. In any case such radically new designs would need to go paired with radically new propulsion technology, like open rotors, the commercial application of which was seen as still further down the line.
The manufacturers argued that spending a lot of development money on a new type that would bring only incremental improvements (the only option with traditional designs) would be essentially wasted and in the end delay the introduction of the real, long term solutions, once they reached technological readiness.
In the meantime, the engine manufacturers did not stay idle. Projects seeking long term solutions carried on but alongside a number of new developments appeared that were promptly snapped up by the Russians and the Chinese for their new build aircraft types and by the likes of Bombardier for the CSeries.
With completely new types off the agenda for the time being, the pressure from the airlines grew for re-engining solutions as an interim measure. Of the two big players, Airbus was always perceived as the more likely to move but for a long time, nothing really happened. The engines that were slowly wetting the airlines’ appetite were the LEAP-X advanced turbofan from CFM International and the PW1000G geared turbofan (GTF) from Pratt & Whitney. Rolls Royce was prominent by its absence from this activity.
Of course the idea of hanging new engines on old but otherwise good designs is not new. Some of you will remember the sound of the engines of the first 707s belching smoke and making your ears hurt with their high pitched shriek. Later versions of the DC-8 were also re-engined, mainly for cargo work. But even the Tupolev 154 had an engine upgrade when the original Kuznecov NK-8-2U engines were replaced by Soloviev D30KUs on the “M” version of the 154. That this was a less successful move is another story…
But is re-engining a big deal? It is, for several reasons.
Apart from the obvious differences in terms of on-board systems, there are also structural issues that need to be considered and which add to the cost.
On the 737, the current funny looking nacelle is already something that was dictated by the engine and the new, higher diameter fans pose a real challenge in view of the limited space between wing and the ground. New main gears were first seen as inevitable but now it seems that they may not be necessary after all.
On the Airbus 320 family there is no problem with space, however, the wing will need strengthening that adds weight and reduces the achievable benefits. It appears that the new engine would be offered as an option but the beefing up of the wing (and the added weight) would be standard. So, an airline wanting to keep the old engines would in fact be penalized.
What does it cost? Estimates in Airbus’ NEO (New Engine Option) study range from 1.3 to 2 billion dollars, a hefty sum that will need to be recovered somehow before really new types come along. With the new engines promising double digit savings in fuel consumption, airlines may just order enough of the new versions to make the program pay for itself.
If the decision is made to-day, NEO aircraft from Airbus could enter into service in 2015.
In the meantime, International Aero Engines partners Rolls Royce and Pratt & Whitney are entering into a full blown war in which RR claims that Pratt has infringed its patent on swept turbine blades. As mentioned earlier, Rolls Royce has kept away from the race to develop new engines a la CFM and Pratt for reasons that left many industry watchers puzzled. But for Pratt it is absolutely essential to avoid any blemish on its Geared Turbofan offering while the race is on to get Airbus to offer the GTF as one of the options in its NEO project.
Interesting times for all concerned…
