Machine Design

First good look

The initial impressions of the controversial A380 is that it's a noteworthy achievement.

Ron Ossi
Contributing Editor

The A380 arrives at LeBourget airfield for its debut at the Paris Airshow. Visible on this view of the plane are its 22 wheels which allow it to only sport reverse thrusters on its two inboard engines. Wheel braking does the rest.

A traffic stopper. It was hard to miss the A380's 80-ft tail as it maneuvered on the ramp in Paris.

The comparative size of workers next to the A380 tail section helps provide an appreciation of the plane's massive size. New amterials, including carbon fiber-reinforced plastic and glass-fiber/aluminum laminate, account for 25% of the plane's weight.

Most people, first hearing of the Paris Air Show, think of it as a bigger version of those in which the Air Force Thunderbirds do stunts for crowds. It is much

At Paris the real business takes place in the chalets and exhibit areas but the flying and the static displays still get most of the media attention. That was certainly true this year as the show marked the public debut of the Airbus A380.

The plane's visual display was quite impressive. Big engines, huge wings, massive fuselage, 22 wheels, an 80-ft tail; that's the usual signature of this superjumbo which first flew on April 27th this year. Although the A380 is huge, it is a docile, majestic, elegant flyer. Of course, there were no Chuck Yeager maneuvers with it over France. Indeed, that would be contrary to what manufacturers want to show off nowadays. It is the total opposite of Tex Johnston's barrel roll of the Boeing 707 prototype for airline execs 50 years ago that led to that plane's first sales. (In fact, Tex might have gone to jail today for a stunt like that.)

Beyond the initial impression of a stately winged leviathan, there are technical subtleties that go into a giant that can carry 550 passengers at 570 mph for 9,300 miles. Many of these developments have been chronicled in the technical press, but the A380's demonstration showed how they combine to yield a state-of-the-art commercial plane.

For example, the A380 aerodynamic advances include superior take-off, climb and landing, reduced fuel burn, and low noise. Noise in particular is a big deal. Noise reduction is a major sales feature of the plane because it makes the A380 more acceptable in densely populated and restrictive markets where its 500 to 850-passenger capacity is most useable. As observed in Paris, the A380 certainly was quiet. But all lategeneration liners are relatively quiet. For those on the ground, the plane gave a heavy, impressive, but not irritating rumble on its breakaway from launch point. Most observers stand laterally behind the airplane on the runway. So it takes off away from the crowd and later lands behind them. Most perceived noise is forward and under the aircraft on takeoff and always in the runway center-line during take-off and landing. Nevertheless, it is clear that the plane is quiet. And in flight overhead at LeBourget airfield, the A380 was almost inaudible.

There are also advances that help boost the plane's performance. They are in the areas of new materials, dual hydraulic/electrical systems, state-of-the-art propulsion, and an advanced cockpit. But does all this add up to a justification for launching a new expensive product in an iffy market?

It's been "So far so good." At the start of the Paris Show, 154 A380s (of which 27 are freight versions) were backlogged. The nominal price for each was $290 million.

A little math shows what the market for the A380 could be. There are 299 Boeing 747-400 airliners being flown by airlines uncommitted to the A380. There are also 80 freighter versions of the 747 flying. The economic break-even target for the $11 billion A380 program is 250 aircraft. Since the A380 has come on the market, the production backlog for the 747 has diminished from 62 to 25. Over the same time period, 154 Airbus A380s and 47 Boeing 747s (of which 31 are freighters) have been ordered. Clearly, a market is there and this program will probably break even.

Airbus obviously bases its confidence in this program on more than intuition. Its studies predict a doubling of passenger miles flown annually from 2.5 to 5 trillion over the next 15 years. And airline customers already lined up for A380s say they plan on making a total of 250 weekly flights into northeast Asia with the plane by 2010.

Here is some of the cocktail chatter about the A380 overheard in Paris:
It's too big."

"Who needs it?"

"Thing of the logjam of people, 500-plus passengers. Get serious!"

Airbus officials have done their best to dispel such doubts, "In the same gate space as a 747, the A380 can take on 35% more passengers and can be turned around in the same amount of time, 90 min," says John Leahy, Airbus vice president-commercial. And this is using only a single jetway with passengers embarking just onto the main deck. Carriers can use additional jetways to speed passenger loading for a total of two on the main deck and one for the upper deck.

It takes just 70 min to service the plane on a turnaround with catering accounting for most of that time. The A380 employs four catering trucks (versus three for a 747) with one dedicated to the upper deck.

Turnarounds are expected to be even faster on high-density flights of 840 passengers which are not catered and where the plance takes on less fuel. "The A380 can deliver excellent economics even on one-hour flights of this type," claims Leahy.

It is no accident that the A380 bests the fabled 747 in metrics such as airport operations, economics , and field and flight performance. Airbus designers spent 15 years observing and reflecting on the older plane, even looking at an unconventional kind of wide-oval design, with a single deck and 19 passengers abreast. They rejected this idea early-on because it consumed too much useful wingspan and wouldn't fit in the "80 X 80 box" (263 X 263-ft airport ground operations footprint of the 747).

What came out of that effort is not revolutionary but is certainly an improvment in all respects. Its operation is aimed at being compatible with exsisting infrastructure at 60 airports worldwide. And passengers will benefit by an average of 11% more space, including a few more inches of shoulder room, and sweetened cabin amenities.

As with most human endeavors, the A380 project was not all smooth sailing. Airbus went through a major engineering reorganization in late 2000 just before the program got the go-ahead. Severe weight problems emerged early on. Use of independent cross discipline tiger teams from dispersed Airbus engineering centers helped overcome these problems.

Just as the design was to be frozen, Singapore Airlines insisted that the aircraft be able to make early morning landings at London's Heathrow Airport. The A380, as then projected, would have violated Heathrow's strict noise regulations.To meet this requirement Airbus engaged ina massive redesign of both the airframe and propulsionsystems. The nacelles and their supporting structure hadto be reworked. The diameter of the propulsion fan wentfrom 9.2 to 9.7 ft., raising the bypass ratio (BPR) topractically 9:1. While this is only a 6-in increase indiameter, it represents more than a 15% rise in torqueon the fan shaft and forced a redesign of the low spoolsection. Engine weight also rose significantly.

The engine resizing also led to bigger and heftiernacelles. Airframe modifications were required toaccommodate all the changes. Engine suppliers Rolls-Royce and General Electric/Pratt & Whitney were a bigpart of this effort which produced a plane with half theperceived noise of a 747.

Engines from both suppliers have almost identicalperformance. A380 customers pick engines based oncompetition or simply operational preference.

PLANNED FROM PREDECESSORSIt is a common practice in the jet engine business toevolve new designs from current models. This is the casewith both of the A380 engines. Rolls-Royce based itsengine on earlier Trent models. The GE/P&W team,dubbed the Engine Alliance, derived its design from theGE90 and PW4000 models, respectively. Theimprovements that both groups made come out ofnumerous studies on engine optimization for the A380and 747 starting in the mid 1990s. For example, the618-ton airplane doesnt need thrust reversers on all itsengines, just the two in-board ones. This is due to themassive braking capability of the A380s 20-wheel mainlanding gear.

The wings on the new airplane got appreciativecomments from Paris crowds. The A380 looks grand inlow-level flight thanks to a wing span that measures110% of its fuselage length. The A380 wingspan alsoexceeds that of the 747 by 24% with 56% more wingarea.

Interestingly, wings on older airliners are oftenredesigned to handle freight-carrying jobs. And freightversions have usually debuted three to five years afterpassenger models. But Airbus has designed versions ofthe A380 wings from the get-go for both passengers andheavy freight.

The A380 wing lies at the crux of the Airbus strategy.While passenger versions will continue to get most of thepress, freight versions (A380Fs) are the strategic side ofthe equation. Since 2001, 66% of all 747s ordered havebeen freighters. The current 747 backlog of 25 aircraftis 84% freighters. Small wonder, then, that Airbus islaunching its A380F version simultaneously with theA380P.

The A380F carries 165 tons. For comparison, the 747handles 121 tons. Moreover, the Airbus moves suchloads with a proportionately little engine thrust. It has15% lower in thrust/weight ratio than the 747. Topping things off, the new plane climbs faster that 747s and has a projected operating cost that is 20% lower. Much of this performance traces back to the wing design.

Finally, towards the end of the Paris Air Show, the order tally for the A380 rose by five units, thanks to an order from Kingfisher Airlines. Based in India, Kingfisher Airlines just started operating in April. At the end of June, it was operating with four narrow-body planes. But its business market in India is expanding by 25% per year and Kingfisher intends to eventually use its new A380s on routes to the U.S. To quote its Chairman, Vijay Mallya, "This is a changing, modern India...they illustrate the global situation. We will add 100 million consumer-class citizens by 2010."

From the looks of things, some of those citizens will be riding in A380s.

Comparing The A380 AND 747
WING AREA, sq ft
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