withak
Posts: 219
Joined: Thu Apr 19, 2007 5:29 pm

Conta-Rotating Fan Concept

Thu Apr 26, 2007 9:19 pm

Hello everyone,

I was reading through "The Jet Engine" published by Rolls Royce and came across an interesting mechanical arrangement for a gas turbine engine called the Contra-Rotating Fan.

I was hoping that I could get some of my nagging questions answered about this rather unique looking engine:

  • What was this proposed engines advantages?
  • Why did it never get past the concept phase?
  • Was it the weirdest looking gas turbine engine ever? Big grin

Any help would be much appreciated.

Thank you in advance.

Regards

WithaK
 
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Jetlagged
Posts: 2562
Joined: Sun Jan 23, 2005 3:00 pm

RE: Conta-Rotating Fan Concept

Thu Apr 26, 2007 9:26 pm

This the kind of thing you mean?

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Maybe if fuel gets even more expensive it will make a comeback.

More efficient, but noisy and with blade containment problems.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
withak
Posts: 219
Joined: Thu Apr 19, 2007 5:29 pm

RE: Conta-Rotating Fan Concept

Thu Apr 26, 2007 9:41 pm

Quoting Jetlagged (Reply 1):
This the kind of thing you mean?

No that is not it.

The engine I was referring to is similar but the fan part was surrounded by a cowling. As far as I understand the engine was never built.

I would post a picture but the only ones I have are scanned from the book itself.

I hope this clears things up a bit.

WithaK
 
bond007
Posts: 4423
Joined: Mon Mar 14, 2005 2:07 am

RE: Conta-Rotating Fan Concept

Thu Apr 26, 2007 10:11 pm

I think you are talking "ducted fan" as opposed to "unducted".

Ther Heinkel 178 had one I think .... and I'm sure others.

But....

"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. "


Jimbo
I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
 
withak
Posts: 219
Joined: Thu Apr 19, 2007 5:29 pm

RE: Conta-Rotating Fan Concept

Thu Apr 26, 2007 10:47 pm

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