Boeing In No Hurry to Launch 747X

Boeing In No Hurry to Launch 747X

Two secret weapons are helping Boeing outperform the proposed A3XX, according to company executives.

They are the fact that an airframe becomes structurally more efficient as it stretched, conferring a substantial weight advantage to Boeing; and the extra space that designers have "found" in the 747 cabin design.

This extra space is like the attic in a house: it runs the length of the fuselage between the cabin ceiling and the top of the fuselage. And it's nearly six feet deep. That means it can be put to use as storage space, for crew rest quarters and galley carts, freeing up space on the passenger deck for up to 20 more fare-paying seats-which alone results in lowering seat mile costs by 2%.

Seddik Belyamani, Boeing's EVP for sales and marketing (who, incidentally, graduated from Toulouse where Airbus is based), calls on a famous Frenchman to help explain why he believes the 747X is superior to the A3XX.

"The Breguet Equation states the efficiency of an aircraft is based on three components: the product of propulsion efficiency times the aerodynamic efficiency, times the structural efficiency," Belyamani said.

"The engines on both are the same; we believe the aerodynamics are about the same, based on our study of their wing; which leaves structural efficiency, a double decker (as on the A3XX) is a heavier structure than a single decker-any engineer will tell you that, and it's a fact their empty weight per seat is 15% higher than for the 747X. So how do you think the performance can compare?"

Boeing is in no hurry to launch the 747X to compete with the giant Airbus A3XX. "Ours is a derivative and will not take so long to develop. We can wait until next year and still meet Airbus' entry into service date of 2005," Seddik Belyamani, executive vice-president of sales and marketing at Boeing Commercial Airplanes Group, told Show News.

That gives airlines time to study the proposals-and whether they even want them. "Many have said they are interested, but so far, none are buying," he said.

Boeing is proposing a four-aircraft family of 747Xs, all incorporating 105-inch wing root inserts that will increase fuel capacity by an extra 130,000 lbs. Compared to the current 747-400, the new wing is 17% greater in area, 8% broader in span at 229 ft, and carries 27% more fuel.

The four models are:

The 747X Stretch, seating up to 522 passengers in three classes in a fuselage 31.5 ft longer than today's 747-400 at 264 ft. Compared to today's 747-400 it will carry 100 more passengers some 435 nmi farther (up to 7,600 nmi) at Mach .87, making it the fastest subsonic airliner in the skies. (The 747-400, currently the fastest, flies at Mach .855).
747X Stretch Freighter. This version will be fitted with the short cockpit hump from the 747-100 to reduce structural weight and allow it to carry more cargo. Volume will be 23% greater-or 30 tons more-than the current 747-400F, for a total of 150 tons.
747X Stretch Domestic. This short-range, high capacity version sacrifices fuel for passengers and will carry up to 660 on high-density routes.
747X. This marries the new high-speed, long-range wing to the current 747-400 fuselage to provide the world's furthest-flying airplane. With a range of 8,975 miles it can carry up to 430 passengers non-stop between Singapore-Chicago, New York-Kuala Lumpur and Los Angeles-Singapore-and while 18 hours at a stretch might seem brutal, at least it cuts out the unpleasant experience of stopping in Narita, Japan, en route.

A fifth model, the 747-400X, provides a genealogical link between today's 747-400 and the 747X family. The new 400X will in essence be an update to today's model, featuring Boeing 777-style cockpit and interior and the stronger wing from the 747-400F. This will allow extra fuel for a range increase of 435 nm, as well as optional auxiliary fuel tanks in the cargo hold for even greater range.

"This extra capability will ensure that a full load of passengers and their baggage could be carried year round, even during adverse weather and wind conditions when airlines occasionally 'weight-limit' airplanes, meaning passengers and/or cargo are left on the ground," according to Boeing.

By John Morris