Bond007 From United States of America, joined Mar 2005, 5239 posts, RR: 8 Reply 3, posted (6 years 7 months 2 weeks 18 hours ago) and read 2476 times:
I think you are talking "ducted fan" as opposed to "unducted".
Ther Heinkel 178 had one I think .... and I'm sure others.
"July 19, 2006, Engines, CFM International is including a contrarotating ducted fan engine in studies of concepts that might provide the quantum leap in fuel efficiency, noise reduction and emissions being demanded for the next generation of single-aisle aircraft.
The engine would draw on lessons learned by CFM partner General Electric during the unducted fan (UDF) program carried out with NASA in the early 1980s, which demonstrated specific fuel burn reductions of up to 20 percent. "
I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!