Picture of the McDonnell Douglas MD-81(UHB) (DC-9-81(UHB)) aircraft

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Visitor comments (22)   [Hide]	Post your own comments by rating the photo above!
A visitor from - posted Mon December 8, 2008: Just a prototype!
A visitor from - posted Tue August 5, 2008: I'll bet the airlines wish they had these now, with oil prices pushing 140 dollars a barrel!
A visitor from United States posted Mon May 1, 2006: I'll bet the airlines wish they had these now, with oil prices pushing 75 dollars a barrel!
A visitor from United States posted Fri April 21, 2006: I was a small part of that project and we were told that they were't able to get carriers to buy it because oil prices had dropped low enough that the costs of retooling and re-educating the maintenance crews were too high to offset the costs unvolved. It was a great deal more efficient. The core was based on a small fighter jet engine. The double row of fans in the back were counter rotating for balance. It was in-fact louder but not so loud that it couldn't be made to pass noise tests in sensitive areas with some management of the approaches and timing. It was developed in partnership with NASA
A visitor from Canada posted Sun November 20, 2005: I think its not used is because the UDF is too noisy.
A visitor from Switzerland posted Wed November 16, 2005: Engineers liked it, but birds vetoed.
A visitor from Germany posted Fri November 4, 2005: What hapened to the UDF (unducted fan), why was it never used commercially? please dont tell me, because the passengers did not like the looks of it, it was never used.
A visitor from United States posted Thu November 3, 2005: I think my Aviation professor talked about this in a systems class. If it is, its almost 90% efficient. It was not used because passengers thought it was dangerous. Same reason passangers prefer Turbofan over Turboprop.
A visitor from United States posted Mon October 31, 2005: It's really a funny engine that I never seen. But what is the actual purpose of these small wings attached to it ??? Louis, Hong Kong.
A visitor from Finland posted Sun October 30, 2005: The engine looks so strange!!!
A visitor from Germany posted Sun October 30, 2005: Looks just great! Thx!
A visitor from United States posted Sun October 30, 2005: Why did they not use it was it inefficient or dangerous or what
A visitor from United States posted Sun October 30, 2005: Effective bypass ratio is about 40:1 ! Blade containment is problematic.
A visitor from United States posted Sat October 29, 2005: I read in a book called "Airplanes of the Future" that this was planned for future planes. The design was suppost to be enviormetal by using prop's and engine. But I'm not sure. It is kind of odd though.
A visitor from Sweden posted Sat October 29, 2005: I think it's called aft-fan or an aft-duct(fan), or something like that..
A visitor from United States posted Sat October 29, 2005: Very odd
A visitor from United States posted Sat October 29, 2005: It is an experimental "un-ducted fan" engine. These were supposedly going to be more efficient than traditional jet engines, but numerous concerns kept them from going into production.
A visitor from Mexico posted Sat October 29, 2005: I remember this aircraft very well. It appears in the book "McDonnell Douglas, a tale of two giants". This engine is an experimental GE turbofan with contrapropellers. Only one of these engines was made.
A visitor from Thailand posted Sat October 29, 2005: Need an explanation, what kind of engine it is ?
A visitor from Finland posted Sat October 29, 2005: They had those GE UDF Aircraft Engines experiments mid 80s... They never got to commercial airliners.
A visitor from United States posted Sat October 29, 2005: It's an unducted fan (UDF), a type of propfan. If memory serves me correct, Air & Space Magazine recently did a full article on this three or four issues ago. I bet wikipedia also has some information, if you're interested.
A visitor from United States posted Sat October 29, 2005: Interesting. What kind of engine is it?

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