Steady Level Flight

Steady level flight occurs when the flight path inclination angle is zero. γ = 0, and β = 0.

Various Speeds in Level Flight

The steady level flight at cruise is when the Thrust available at cruise matches the Drag to be overcome. Once the plot of D(V) vs V is available, then the horizontal line at T_cruise intercepts the curve at the cruise velocity (for jet engines). The maximum cruise velocity is determined from

For engines that are specified in terms of power, a plot of Power required versus velocity is used to determine the cruise velocity.

NOTE: If you only had a choice among limited limited engines, then the drag required at cruise may not exactly match the recommended cruise thrust. Since we are designing for a cruise speed, we should be able to locate the cruise velocity at the design point.

Maximum level flight speed is the speed corresponding to the maximum thrust available (or power available) from the engine. The intersection of the Tmax and the Velocity curve will establish the Vmax

The speeds determined are a function of the cruise altitude