Date: 24 Nov 97 03:27:48 From: Chuanga@cris.com (H Andrew Chuang) Organization: Concentric Internet Services References: 1 Followups: 1
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In article <airliners.1997.2721@ohare.Chicago.COM>, Marc Schaeffer <firstname.lastname@example.org> wrote: >I would like to know what happens in the domain of the Superfan engines. >A bit of history may be interesting. The Superfan -Ultra high bypass- >engines were initially foreseen to be mounted on the A340. IAE intended >to build a variant of the V2500 engine which incorporated a gearbox >driven, variable pitch ducted fan added to the front of the 2500 core. >Calculated fuel savings of 20% compared to classic engines were >expected. The idea came up in Dec-86 and was cancelled in Apr-87 due to >technical risks. >- What's the status on UHB engines nowadays, is it under >development/trials (PW/RR/GE/IAE/CFM ...) somewhere ? I believe PW is probably the leader in this technology due to its past experience developing a gearbox-driven propfan to compete with GE's unducted fan (UDF). PW was very interested in developing an Advance Ducted Prop (ADP) engine. However, I have not heard much about it, lately. I am not aware either GE or RR being actively pursuing this approach. >- Have similar/simplified techniques been adopted in the GE90 or Trent's >? If you are referring to gearbox-driven and variable-pitch fan, then the answer is no. >- What about reliability, weight, costs, would they not reduce the >expected cost advantage (-20% for fuel) ? I don't think weight is an issue. Even though you will have a much larger fan, there will be less fan blades and you won't need a thrust reverser because of the variable-pitch fan. However, you can find out about the reliability only when it's in the field.