So, to be more clear I currently have an assignment about the Boeing 737-800. I have to find out the total takeoff distance of the aircraft. I'm using Anderson's book " Aircraft Performance and Design" and I'm quoting that a turbofan engine is affected from the velocity of the aircraft. Anderson uses this equation: T = k1 - k2*V + k3*(V^2) where k1,2,3 are constants from engine to engine. At his example he uses a Gulfstream IV aircraft and takes the constants as below (chapter 6, example 6.6): The constants are selected for the takeoff phase. I guess that these values come from the manufacturer but I cant find this type of info anywhere. Not even a number about the takeoff thrust. The only thing that I can find is the maximum takeoff thrust which is the max thrust available from the engines.
Developing 21,600 to 33,000 pounds of takeoff thrust, the CFM56-5B is the only engine that can power every model in the Airbus A320ceo family.