A Method Of Evaluating Power Plants For Use In Subsonic Transport Airplanes

Consideration of the requirements of a realistic power-plant evaluation for air transport operations leads to the conclusion that the criterion must include the effect of the velocity at which the transportation is accomplished and some of the operating costs. A method of evaluating power plants for transport operations based on total operating cost per ton-mile is presented. An equation is developed for the purpose of expressing the total operating cost per ton-mile with the costs appearing in the equation as constants of proportionality. Methods are outlined to aid in the application of this equation to actual power-plant-evaluation problems. An approximate method of determining the flight altitude that results in the best performance for each combination of range and velocity is presented in order to simplify the power-plant evaluation. An example is included to illustrate the use of the equations and the methods developed.