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Old 25th Jun 2009, 05:21
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bigduke6
 
Join Date: Aug 2007
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Too many variables to give you a real accurate answer (aircraft gross weight, any slope on the ramp or taxiway, taxiing with a tailwind, airport temperature/elevation for how much thrust you have at ground idle)

But for B-744 at max gross weight, no slope on the ramp, etc you might have to use up to 40% N1 (GE-CF6 series) for 3-5 seconds to really get it rolling, then just about idle (26%) so perhaps 30% to keep the speed where you want it.

Light weight aircraft will break away and accelerate at idle thrust, and you will have to ride the brakes to slow it down, or just taxi on 2 engines instead of starting all 4.

Perhaps a more useful question is what kind of fuel burn is planned for taxi. Somehow the number that is quoted to us for planning is 45kg per minute as an average. Probably less when empty/light weight, and more if you are heavy and are using above idle thrust.
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