REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

LONGITUDINAL DYNAMIC STABILITY INVESTIGATION FOR A SUBSONIC CRUISE MISSILE USING A 3 DOF FLIGHT DYNAMICS MODEL

AHMED OSAMA MAHGOUB

Sudan University of Science and Technology, Khartoum, ah_mm_mad@yahoo.com

KHALID IBRAHIM BASHIR

Sudan University of Science and Technology, Khartoum, khalidholako@gmail.com

EIMAD ELDIN EL HADI MUSA

Karary University, Khartoum, mohandei@yahoo.com

Abstract:This paper studies the dynamic stability characteristics of a subsonic cruise missile configuration by using a 3 Degrees-of-Freedom(3DOF) nonlinear flight dynamics model.The aerodynamic data for the configuration and control surface effectiveness have been obtained using USAF digital DATCOM, and the missile static stability was checked using the data from DATCOM. The aerodynamic data and the stability derivatives obtained were used in constructing nonlinear 3 DOF longitudinal flight dynamics model to check the dynamic stability of the missile. The model was constructed using Simulink^® and the Aerospace Blockset included with the package.Two simulations with different inputs were analyzed. The initial conditions for the first simulation were non-equilibrium initial conditions without control input; the other simulation was with a double step elevator input with different initial conditions. The run time for each simulation was 500 seconds and 60 seconds respectively.Both of the longitudinal dynamic modes (Phugoid and short period) were present in the response obtained from the simulation .From the simulation results and DATCOM output it was found that the missile is both longitudinally statically and dynamically stable and that the missile response to the elevator input was proper.

Keywords:3 DOF, DATCOM, Dynamic Stability, Nonlinear Flight Dynamics, Simulink^®.