Klaus From Germany, joined Jul 2001, 21578 posts, RR: 53
Reply 1, posted (10 years 11 months 3 weeks 3 days 21 hours ago) and read 5331 times:
The "SuperFan" engine was supposed to employ a geared fan in order to further increase the bypass ratio and overall efficiency by letting the fan rotate slower than the low pressure compressor and turbine. At the time, the concept didn´t come through and Airbus had to scale down to the lower-thrust engines used on the A340-200 and -300s. Only the re-winged A340-500 and -600 were able to use the much larger (but still conventional) RR engines.
Interestingly, though, Pratt & Whitney now seem to have solved the original problems with the geared fan concept and have proposed it for use with the 7E7. As far as I know, Boeing have rejected this proposal, but if P&W can really make it work in practice with an attractive efficiency gain and at acceptable maintenance cost, it could still be used for a new range of engines - maybe even as an alternate choice for the A340NG...
Splitzer From United Kingdom, joined Feb 2004, 151 posts, RR: 0
Reply 3, posted (10 years 11 months 3 weeks 3 days 5 hours ago) and read 5157 times:
The message you were about to post is too short and probably not of any higher value to the topic at hand. You should think long and hard before posting a message in this forum and make it detailed and a valuable addition to the topic discussed.
Avoid posting "Me Too" messages. These are messages that are posted by people who agree to a point being discussed and post a one liner, "me too!", "Good post Jim!", "I disagree" or similar message. This takes up time as readers must sort through these messages which have no real value to the group at large. Any message containing nothing more than a line or two of text is probably not worth posting.
If you have an opinion on a topic, you should in detail express why you have the opinion and what made you come to that conclusion.
Your post should be relevant to the topic discussed.