From: email@example.com (Ed Hahn) Organization: The MITRE Corporation, McLean, Va. Date: 18 Sep 96 13:52:15 References: 1 2 3 4 5 6 7 8 9 10
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In article <airliners.1996.1898@ohare.Chicago.COM> "David G. Davidson" <firstname.lastname@example.org> writes: >>> Let me re-state the question: "does the dgd> engine installed in the #2 position suffer a performance dgd> degradation due to the presence of the S-duct?"<< dgd> The only performance corrections that I know of for the center dgd> engine are if the 6th stage bleed system has been activated. That dgd> calls for a 0.05 EPR reduction for takeoff and GA power. dgd> The L-1011 also has no center engine performance correctiosn that dgd> I'm aware of. This is all very true. However, from what I understand, because the #2 engine in B727 sees "dirty" air from the S-duct, it is more prone to stall/surge problems than engines #1 and #3. Therefore, I think that the stall margin performance standard for the center engine is somewhat higher than those for the pod engines. Note that this does NOT mean that the center engine is of a different type, just that after being tested in the test cell after overhaul, those engines which have the best demonstrated stall margins are designated for center engine duty. This is all hazy recollection from my undergraduate engines course, however. ed -------- Ed Hahn | email@example.com | (703) 883-5988 -------- The above comment reflects the opinions of the author, and does not constitute endorsement or implied warranty by the MITRE Corporation. Really, I wouldn't kid you about a thing like this.