DOI link for Straight-level flight
Straight-level flight book
This chapter presents techniques to analyze the performance of an aircraft with prop-driven engine(s), either piston engine or turboprop engine, in a steady-state condition. It introduces basic equations in straight-level flight. Then the methods to evaluate the following performance criteria are discussed: specific speeds in straight-level flight, range, endurance, and ceiling. The specific speeds in straight-level flight include maximum speed, cruising speed, minimum drag speed, minimum power speed, maximum range speed, speed for absolute ceiling, and maximum endurance speed. The very basic governing principle in straight-level flight is Newton’s second law of motion. As the aircraft is flying in a long flight, the aircraft weight is reduced due to fuel consumption. The pilot needs to maintain equilibrium by using one (or more) of the following three techniques: reduction of airspeed, reduction of air density through increasing altitude, and reduction of lift coefficient.