C Lq lift due to the pitch rate derivative C Lα lift due to the angle-of-attack rate derivative C m pitching moment coefficient C m0 zero pitching moment coefficient C mα static longitudinal stability moment with respect to the angle-of-attack derivative C mq pitching moment due to the pitch rate derivative C mα pitching moment due to the angle-of-attack rate derivative C lp rolling moment due to the roll rate derivative C lr rolling moment due to the yaw rate derivative C lβ rolling moment due to the sideslip angle derivative C lβ rolling moment due to the sideslip angle rate derivative C np yawing moment due to the roll rate derivative C nr yawing moment due to the yaw rate derivative C nβ yawing moment due to the sideslip angle derivative C nβ yawing moment due to the sideslip rate derivative C yp side force due to the roll rate derivative C yr side force due to the yaw rate derivative C yβ side force due to the sideslip angle derivative C yβ side force due to the sideslip rate derivative H altitude M Mach number α angle of attack Λ LE quarter-chord sweep angle at leading edge κ Ls stall factor in the relation for maximum lift coefficient κ LΛ sweep factor in the relation for maximum lift coefficient κ Lθ twist factor in the relation for maximum lift coefficient κ Λ1 sweep co-efficient κ Λ2 sweep co-efficient θ total twist (geometrical and aerodynamic) ABSTRACT The new FDerivatives code was conceived and developed for calcu- lating static and dynamic stability derivatives of an aircraft in the subsonic regime, based on its geometrical data. The code is robust and it uses geometries and flight conditions to calculate the aircraft’s stability derivatives. FDerivatives contains new algorithms and methods that have been added to DATCOM’s classical method, presented in a USAF Stability and Control DATCOM reference. The new code was written using MATLAB and has a complex structure which contains a graphical interface to facilitate the work of potential users. Results obtained with the new code were evaluated and validated with flight test data provided by CAE Inc. for the Hawker 800XP business aircraft. NOMENCLATURE c MAC (Mean Aerodynamic Chord) c L local aerofoil section lift coefficient c Lmax maximum aerofoil section lift coefficient q/q ∞ dynamic pressure ratio x CG distance between the centre of gravity of the aircraft and the quarter-chord point of wing MAC, parallel to MAC, positive for CG aft of MAC C D drag coefficient C Dα drag due to the angle-of-attack derivative C Dq drag due to the pitch rate derivative C Dα drag due to the angle-of-attack rate derivative C L lift coefficient C Lmax wing maximum lift-coefficient C Lα lift due to the angle-of-attack derivative THE AERONAUTICAL JOURNAL JUNE 2010 VOLUME 114 NO 1156 Paper No. 3454. Manuscript received 13 May 2009, revised version received 30 September 2009, 2nd revised version received 6 December 2009, accepted 29 January 2010. New methodology and code for Hawker 800XP aircraft stability derivatives calculation from geometrical data N. Anton, R. M. Botez and D. Popescu ruxandra@gpa.etsmtl.ca École de technologie supérieure Laboratory of Research in Active Controls, Aeroservoelasticity and Avionics Montréal, Canada . . . . . .