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Originally Posted by NJA_Capt  If by open rotor you mean the UHB/UDF fan tests conducted by Boeing and MD. Those programs were tested and scrapped in the late 1980s. No-one to my knowledge is even considering those currently. http://www.airliners.net/search/photo.search?album=1685
I'll pass on the lower and slower/less fuel discussion. There are too many holes in that theory. People fly to save time. Comfort and class have already been removed from airlines, take away speed and you have no reason to fly.
Ever wonder where the ERJ135 originated? http://www.airliners.net/open.file/0386521/L/ |
What do you mean by "holes" in the slower/lower theory? I'm not talking about airliners flying C172 speeds, but rather somewhat slower than current jet aircraft. The shorter the sector length, the less time penalty that causes. Even if aircraft were slightly slower than now, they would still be the fastest alternative by far for trip lengths of more than, say, 500 miles (in the US without fast train service). Faster is better, of course, but fuel prices and environmental regulations will be large factors in how transportation options develop.
Open rotor research is alive and well, and is considered a critical timing factor for Boeing and Airbus to introduce their narrobody (737/A320) replacements. A large part of the reason that those older research programs into open rotor design were scrapped is because the efficiency gains were not needed with the low fuel prices of the time. There is currently great interest in open rotor technology from aircraft manufacturers and much research is going into it by the engine manufacturers. P&W is the exception, as they are trying to sell the industry on the geared turbofan (GTF), which is a technology that will be ready for primetime several years ahead of open rotor/unducted fans (UDF). If Boeing and Airbus decide to go for the GTF over the open rotor engines, they could probably introduce the next generation narrowbodies around 2014-2016 instead of 2017-2020. It remains to be seen, however, whether the GTF can deliver the efficiency gains that the UDF designs promise.
The combination of high fuel prices and new environmental regulations will very likely make the use of a new type of engine necessary. The next few years of research and testing of these new engine types should be interesting. There's a good chance that aircraft rolling off the production line around 2017 will look a lot different than the ones rolling off today.
Here are a few articles on the subject:
http://aviationweek.com/aw/generic/s...0Narrow%20Body http://www.flightglobal.com/articles...t-engines.html http://www.flightglobal.com/articles...163/pratt.html http://www.aviation.com/technology/0...t_ecojet2.html