Clean is mean for new plane engines

[MartinW 0]

I wonder just how much efficency we can squeeze out of the technology. And what will the next big thing be after the jet engine?

http://news.bbc.co.uk/1/hi/business/7510762.stm

For 59 of the last 60 Farnborough International Airshows, nobody really had to worry about the price of aviation fuel.

Yet now, with the underlying cost of oil having doubled since the last Farnborough in 2006, the entire industry is focusing on how to make conventional jets burn and waste less fuel.

Even the military are starting to worry about it and they don't pay a penny in tax on their fuel.

For the commercial sector, part of the answer lies with improving air traffic controls, modifying aircraft handling and fitting 'winglets' to reduce drag.

Yet, a glance round the vast technical exhibition halls at Farnborough confirmed that the focus is now moving more closely onto the features and benefits of the next generation of jet engines that will be available for the plane makers to choose from.

Particular industry hopes rest on Pratt and Whitney, part of United Technologies, which is making a big splash again this year with its "geared turbofan" engines.

The company has already invested $1bn in the technology and a test engine is also about to be tried out on an Airbus.

Innovative use of gearing allows the main front fan and the rear sections of the engine to operate at different, optimum speeds.

"The result of that is much better fuel burn, much lower noise, much lower emissions," says Todd Calman, a president at Pratt and Whitney.

[hurricanemk1c 195]

Oh dear

Kieran

[allardjd 1,853]

Innovative use of gearing allows the main front fan and the rear sections of the engine to operate at different, optimum speeds.

It's a good concept and a natural next step in making the engines more efficient. I saw a photo of that engine gearing. It looked like a pretty standard planetery gear set but the devil's in the details. It was obviously quite beefy to be able to transmit the power involved, and no doubt has an external cooling loop for the oil, but that part wasn't shown, just the gears. Some things you just can't use aluminum for.

Considering what they do with gearing in many helicopters and in the Osprey, this is not rocket science. It just needed the economics of the fuel cost to rise far enough to make it worth the cost of developing it and to make the potential buyers interested enough in fuel efficiency to be willing to pay a considerable amount of extra money for it on the front end. Gear sets which run at high torque and high speed and which have a big heat source just a few inches up the shaft from them don't come cheap.

John