Abstract:

This study develops a model for the business aircraft JetStream31 from flight data analysis in order to simulate and analyze the level cruise flight trajectory. The aerodynamic characteristics are extrapolated from flight data analysis and substituted in the longitudinal motion equations in order to trim the aircraft at any mach number. The level cruise speed is selected by drag polars analysis. The natural phugoidal motion is investigated to study its effects on the fuel consumption. The non-linear model developed is based on both elevator deflection and power inputs. Variations in the level cruise trajectory are devised to improve the JetStream31 fuel consumption.

Two periodic cruise trajectories are presented and derived from the developed model. The long period cruise trajectory is based on a change of flight level to attain the maximum endurance velocity. The second periodic cruise trajectory presented is based on a short period and simulates the natural phugoid by small changes in altitude and velocity. These two non-level periodic trajectories drives to a 3 percent fuel flow rate savings.