Wednesday, July 16, 2008

Jets on diets: less weight, less fuel

Aircraft manufacturers are pulling out the stops to improve fuel efficiency in jets, and they're seeing success in those efforts.

That's a key issue in Hawai'i, where close to a third of the imported petroleum goes to fuel aircraft.

(Image: Bombardier's new energy-efficient CSeries jet. Credit: Bombardier.)

The European aircraft manufacturer Airbus says aircraft fuel use has dropped 70 percent in the past 40 years, and continues to decline, with a target of another 50 percent by 2020. The planes are also decreasing noise and emissions.

“"Aircraft will only be accepted if they are efficient in terms of the environment. We have to keep technology at the heart of our programme to improve our performance,” said Airbus sustainable development chief Philippe Fonta.

At this point, improvements are coming incrementally, and with small changes that won't be immediately apparent to most passengers.

Bombardier says its new CSeries jets will cut the fuel use by 20 percent. The five-across seating jets hold 110 to 130 passengers and are scheduled to be in service by 2013.

How does it get the improved fuel performance? Cutting weight and improving wing design, Bombardier says on its website:

“Key technologies are at the heart of the CSeries advantage. Composite materials are part of the center and rear fuselages, tail cone and empennage (tail assembly) and wings. Overall, 20 per cent of the aircraft weight is in composite materials,” the manufacturer says. That, plus what it calls “its fourth-generation transonic wing design.”

Boeing is saying the latest model of its 777 has a number of design features that are cutting the cost of tanking up.

Some of the changes are small, but significant.

Boeing says its 777-200ER aircraft initially attained a 2 percent increase in fuel efficiency, and then since then, it has been able to add another 1.4 percent. For an aircaft in normal use, that 1.4 percent saves 200,000 gallons a year.

Boeing says three key things improved its plane's performance. One was modified GE engines. Another was reducing the plane's drag. And a third was cutting weight of things like the internal structure, and floor panels.

In many ways, the technologies being used for planes are the same ones being used to make cars more efficient—lighter weight, more efficient engines and aerodynamic design.

There's also an argument that in some applications, turboprop planes make more energy sense than pure jets. See:

For more on fuel prices, see:

© 2008 Jan W. TenBruggencate