More fuel-efficient airliners?

[LongTomH]

An MIT design team has produced a series of innovative commercial airliner designs that may offer as much as a 70% reduction in fuel use (with a correspondingly reduced carbon footprint):

In what could set the stage for a fundamental shift in commercial aviation, an MIT-led team has designed a green airplane that is estimated to use 70 percent less fuel than current planes while also reducing noise and emission of nitrogen oxides (NOx).

The design was one of two that the team, led by faculty from the Department of Aeronautics and Astronautics, presented to NASA last month as part of a $2.1 million research contract to develop environmental and performance concepts that will help guide the agency’s aeronautics research over the next 25 years. Known as “N+3” to denote three generations beyond today’s commercial transport fleet, the research program is aimed at identifying key technologies, such as advanced airframe configurations and propulsion systems, that will enable greener airplanes to take flight around 2035.

MIT was the only university to lead one of the six U.S. teams that won contracts from NASA in October 2008. Four teams — led by MIT, Boeing, GE Aviation and Northrop Grumman, respectively — studied concepts for subsonic (slower than the speed of sound) commercial planes, while teams led by Boeing and Lockheed-Martin studied concepts for supersonic (faster than the speed of sound) commercial aircraft. Led by AeroAstro faculty and students, including principal investigator Ed Greitzer, the H. Nelson Slater Professor of Aeronautics and Astronautics, the MIT team members include Aurora Flight Sciences Corporation and Pratt & Whitney.

Their objective was to develop concepts for, and evaluate the potential of, quieter subsonic commercial planes that would burn 70 percent less fuel and emit 75 percent less NOx than today’s commercial planes. NASA also wanted an aircraft that could take off from shorter runways. Designing an airplane that could meet NASA’s aggressive criteria while accounting for the changes in air travel in 2035 — when air traffic is expected to double — would require “a radical change,” according to Greitzer. Although automobiles have undergone extensive design changes over the last half-century, “aircraft silhouettes have basically remained the same over the past 50 years,” he said, describing the traditional, easily recognizable “tube-and-wing” structure of an aircraft’s wings and fuselage.

I has me doubts about that "when air traffic is expected to double" figure for 2035; there are a lot of factors that will probably constrain the growth of air travel.

There is also a strong possibility that these innovative designs will simply become another in a long series of, what used to be called 'viewgraph engineering': new ideas that offered fuel economy or other advantages and were never built. It may surprise some people; but, there is a conservatism in the aerospace industry and the airlines. The 'latest' designs from Boeing and Airbus are designed along the pattern established 60 years ago by the Boeing 707: swept wings and tail, and jet engines in under-wing pods. The aircraft makers have been eager to incorporate material improvements, such as composites, improved avionics (especially if they can replace flight crew members!) and improved engines.

As for the airlines, they've learned that it's more cost-effective to keep flying the same airframe decade-after-decade; just upgrade the engines and avionics on a regular basis.

Dr. Eric Drexler made a similar comment on his Metamodern blog:

A new configuration with better aerodynamics, and a reminder that hundred-billion-dollar-scale opportunities are sometimes unexploited.

On the other hand, airlines are going to have to deal with both rising costs of fuel and increased public concerns about the carbon footprint of aviation. If governments (note plural) start seriously considering a Carbon Tax, we might finally see some real innovation in aircraft design.

[RaleighNCDUer]

1. You want fuel efficient aircraft?

Try Zeppelins.

They may not be as fast as jets, but they carry far more cargo & passengers per gallon of fuel than any aircraft today. With modern computer systems they'd be far less prone to the kind of weather accidents that ended their use in the 30s, and even then they were far safer as transport than normal aircraft, if you considered total fatalities per miles flown.

I'd far rather spend 24 hours on a Zeppelin crossing the Atlantic than 6 hours on a jet.

[LongTomH]

2. Loads of problems there!

The Zeppelins were very capital and labor-intensive to build and operate. Watch one of the movies about the Hindenburg. The Hindenburg required a huge ground crew. Zeppelins were only cost-effective to operate because the German government subsidized them for propaganda purposes; they were seen as an example of German technological supremacy. Even with the subsidies, only the very rich were able to fly on the Hindenburg and Graf Zeppelin.

[Statistical]

6. So airline jets aren't capital intensive.

It doesn't take a large amount of labor to build and operate a 787?
Modern Airports don't have massive ground crews?

That being said I think airships are a dead end for passenger traffic. They simply are too slow. However for bulk cargo, mail, packages they make a lot of sense.

Where they make even more sense is moving a single extremely large component like a nuclear reactor pressure vessel, electrical turbines, or other major industrial component.

Low price of oil has made alternate aviation as popular as other alternative transportation methods. However cheap oil is ending and airships are much more energy efficient per unit of weight transported.

[LongTomH]

7. Airships are still more capital and labor-intensive

Especially when you consider the number of 'craft' handled. A ground crew for a 787 will handle several aircraft in a day. As for labor intensive in construction, just look at the size of the Hindenburg:



Find more images of airship construction at: http://www.nlhs.com/construc.htm

'Futurists' keep predicting the return of the dirigible, without really looking at the economics.

[LongTomH]

8. Here's a better image of the Hindenburg under construction

This one lets you see some of the complexity of the structure.



If you look closely, you can see the cables bracing the major frames of the airframe in a 'bicycle wheel' type structure.

[NJmaverick]

3. Can it also be quieter?

[LongTomH]

4. Read the MIT News article.

That was to be one of the design criteria.

[NJmaverick]

5. Very good!

[hunter]

9. But can you make electric planes?

http://en.wikipedia.org/wiki/High-speed_rail

Whenever possible, I'd like to travel in vehicles not fueled by BP or any other oil company.

[Statistical]

10. Jet engine will work just fine on biofuel or hydrogen.

If anything the need to power large industrial vehicles, ships, rockets, jet airliners, semi-trucks, etc all indicate that while we should invest in EV technology some other form of energy with higher density is necessary.

[hunter]

11. If we've got the hydrogen, I suspect we'd be better off making synthetic fuels with it...

...rather than using it straight up as a jet fuel.

Storing and transporting hydrogen is challenging.