Re: B747 technical questions

Date:         01 Aug 97 04:04:17 
From:         kls@ohare.Chicago.NOSPAM.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
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>: For testing, the engine being tested almost always replaces one of the
>: standard engines.  This was certainly true for GE's 747-100 engine
>: testbed, used to flight test the GE-90, and for the original 747-100
>: which Boeing used to flight test the 777's other PW and RR engines.

>On which wingstation is the new engine mounted? Those GE-90s windmills
>are huge!

Both testbeds used the #2 pylon for the test engine.  The GE-90 is
clearly snuggled up very close under the wing, using a special pylon
which is not unlike the one used on the 737-300 to get the engine as
close to the wing as possible.  The PW4084 looks like a reasonably
standard pylon in comparison.

I'm pretty sure the B-52 used to flight test the JT9D had the test
engine on the opposite side -- on the #3 pylon, that is, the inboard
pylon on the starboard side where the #5 and #6 engines would normally

Getting back to the GE-90, putting it on in outboard position (#1 or
#4) would have given them more clearance, but hanging the heavier
engine that far out on the wing might be a problem.  So might having
over twice as much thrust that far from the aircraft centerline.

Karl Swartz	|Home
Moderator of sci.aeronautics.airliners -- Unix/network work pays the bills