Re: GE90 Engines

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
Date:         07 Jul 95 14:26:18 
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>With the #2 engine of the L-1011 mounted along the axis of the fuselege
>using a 'S-bend' tunnel for air flow, Lockeed was unable to accomodate
>either the GE or P/W engines when the RB-211 fell behind schedule.

Lockheed could have accomodated a longer engine, and initially was
offering a choice of the RB.211 or GE's CF6.  The longer GE engine
would have required substantial redesign and the loss of several rows
of seats at the aft end of the cabin, but it could have been done.

>For a promised savings of 900 pounds per plane, Lockeed is no longer
>in the commercial transport business.

I think you're getting a bit confused there.  Lockheed preferred the
S-duct over the straight-duct, as used on the DC-10, for several
reasons, one of which was that the latter would have required several
hundred pounds of additional structure in the fin to support the #2
engine.  However, the S-duct would not have prevented them from using
the longer GE (or PW) engine, as noted above.

Lockheed's big mistake was that they badly misjudged the concerns
(justified, as it turned out) of RR's ability to deliver an entirely
new engine.  MacDAC won round one with American's DC-10 order.  Then
Lockheed won initial orders from Eastern, TWA, and Air Holdings, with
Delta's order coming a few days later.  Lockheed knew that United
preferred the L-1011, albeit with GE engines.  Lockheed was confident
that United would not split the market by buying the DC-10, and with
a number of orders already in place with the RB.211, they decided to
drop the GE engine as an option, thereby saving considerable expense.
That decision to save $100 million in development costs, not any
weigth considerations, pushed United to buy the DC-10, with GE
engines, and ultimately cost Lockheed their place in the commercial
airliner market.

>I was at a meeting within Douglas related to the addition of the RB-211/524
>engine to the MD-11 when the Rolls engineer mentioned that their engines were
>'300 pounds lighter' then their competitors.

That doesn't make sense -- the three shaft design has always resulted
in a weight penalty for the RB.211, though RR has claimed that the
increased efficiency of the design more than compensates for the added
weight.  From AW&ST, here are the weights of the GE and PW engines for
the MD-11:

    GE CF6-80C2D1F	9,634 lbs
    PW PW4460		9,400 lbs

The RB.211-524H, used on the 747 and 767, is about the same thrust,
and weighs 9,499 lbs, only 135 lbs lighter than the GE engine and a
bit *heavier* than the PW engine.

>This is well documented in an excellent book, 'The Sporty Game.'

Yes, it is, though it sounds like it's been a while since you read it.

Karl Swartz	|INet
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