From: email@example.com (Gregory Wright) Organization: The 23:00 News and Mail Service Date: 10 Dec 92 02:09:23 PST References: 1 2 3
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In article <airliners.1992.113@ohare.Chicago.COM> firstname.lastname@example.org (Fred Christiansen) writes: >In article <airliners.1992.71@ohare.Chicago.COM> email@example.com (Karl Swartz) writes: >>Not surprisingly, the top 11 were all twins. > >Why "not surprisingly"? As a layman with no background in this stuff, >I would have tho't that manufacturers would keep the thrust-to-weight >in some ballpark range (for economic reasons). And that the advent >of larger twins is because more powerful engines have become available, >eliminating the need for a 3rd (or in the case of, say, MD-10 class >aircraft, the need for a 4th). >-- The reason for the this may, as you say, may not be so obvious so alow me to put in my two cents. The FAA, along with the CAA and others, require that we demonstrate a minimum climb out gradient with one engine inoperative. In the case of a two engine aircraft this requires that the airplane be able to climb out with a 50% reduction in gross thrust. For a four engine platform this one engine out condition represents only a 25% reduction in thrust. You can see then, that for a two engine plane it is required to "over" engine the plane... Hope this helps to clear things up, greg HIgh lift development >Fred Christiansen, Motorola, 2900 S Diablo Way, Tempe, AZ 85282 "Canajun, eh?" >firstname.lastname@example.org || uunet!phx.mcd.mot.com!fredch || +1 602-438-3464 > ".. I have set before you Life and Death, blessing and cursing; therefore > choose Life, that both you and your children may live" Deut 30:19 > -- ________Greg Wright____________ "Sure my YMP is fast, but if it doesn't | email@example.com | run OS2 I don't need it....." | firstname.lastname@example.org | |____uunet!bcstec!gregory_______| NOT A BOEING SPOKESPERSON.