How much fuel is used for jet airplanes to take off?

Answer 1

It is impossible to answer this question without a more specific question. Each model design series or airframe powerplant combination is different. To start off you need to know what type of jet aircraft it is, the number of engines, and the specific model numbers of the engines installed. Example; A 1978 Hawker 700A with 2 Honeywell TFE 731C engines installed is going to use a fraction of the fuel than say a 1986 Boeing 767 with 2 Pratt & Whitney JT9D-7R4E engines installed. Yet even with this information it is not enough to supply anything more than a vague "guesstimate". Next you need to factor in the total weight of the aircraft, including fuel load, total cargo weight, and the total weight of everyone on board. The greater the weight, the more fuel required for take-off. After that comes the type/grade of fuel, specific gravity (based on the sea-level heighth of the location the aircraft is taking off from), and temperature of the fuel at the time of take off. Aircraft engines are often designed to use various grades of fuel much like like regular and ethel gasoline or ethanol in a car, some have more "umph". Specific gravity is lower at higher altitudes and this too will effect fuel economy. fuel temperature involves something called thermal expansion. At warmer temperatures the volume expands, in colder temperatures it contracts. Wind direction is another consideration. With a nose wind, it will take more power initially to overcome drag and get rolling, but the additional airflow over the wings will increase lift, so it will get airborne sooner with less runway used. A tail wind will require greater speed and more runway to take off. The next factor is whether or not the engines are equiped with after-burners. At idle throttle sitting in the chocks with all engines running, for sake of argument let's say aircraft A burns, 100lbs of fuel per minute. When it gets to End-Of-Runway preparing for take off, the pilot advances the throttles to full power. Now the engines may burn four times the amount of fuel at idle or 400lbs of fuel per minute. The longer the pilot keeps the throttles advanced while holding the brakes, the more fuel it will use, chances are even if we used the same pilot every time, each take-off will be different. If the pilot then advances the throttles to Max afterburner, the engines may burn ten times the amount of fuel as full throttle or forty times idle burn; 4000lbs per minute.