Paper: ASAT-13-FM-03 13th International Conference on AEROSPACE SCIENCES & AVIATION TECHNOLOGY, ASAT- 13, May 26 – 28, 2009, E-Mail:
[email protected] Military Technical College, Kobry Elkobbah, Cairo, Egypt Tel : +(202) 24025292 – 24036138, Fax: +(202) 22621908
Dispersion Analysis for Spinning Artillery Projectile Mostafa Khalil* , H. Abdalla** and Osama kamal† Abstract: This paper investigates the dispersion for unguided spinning projectile in order to explain the importance of the projectile production accuracy and the benefit of using guided projectiles. The total dispersion results mainly from the production inaccuracy of: (1) gun tube which can be shown in projectile's launching problems (muzzle angle, and muzzle pitching and yawing rates), (2) propellant which can be shown in projectile's muzzle velocity and muzzle spinning rate and projectile which is the projectile total mass, axial and lateral moments of inertia, and resultant center of gravity. The other causes are occurred due to free flight portion of projectile’s trajectory which may be divided to: launching problems (vibration of launch tube), wind velocity and direction (wind profile). In this study, a trajectory calculation using a 6-DOF model was developed and applied for 155 mm M107 projectiles at different projectile and flight properties. Keywords: Dispersion Analysis, Trajectory prediction, 6-DOF Model, PRODAS, 155mm M107.
Nomenclature [aN aE aD]T CA
CA
2
The acceleration vector acting on the body in Earth reference frame. Total axial force coefficient. The second order Axial force coefficient.
C lp
Damp in roll coefficient derivative.
Cmq
Pitching moment coefficient derivative with pitch rate. Pitching moment coefficient derivative with angle of attack. Normal force coefficient derivative with angle of attack
Cm CN CYp
Magnus force coefficient derivative.
C n p
Magnus moment coefficient derivative.
g
The Normal gravity on the ellipsoidal surface.
*
Assoc. Lec., Military Technical College. Assoc. Prof., Military Technical College. † Dr., Military Technical College. **
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Paper: ASAT-13-FM-03
Ix Ixy, Iyz, Izx Iy, Iz LBE M m p q r [Tx Ty Tz]T [u v w]T V T [V N E VD ]
E
The body axial moment of inertia [kg.m2]. The body mass products of inertia [kg/m2]. The body transverse moment of inertia [kg.m2]. The transformation matrix which rotate frame FE into FB. Mach number. Total mass of the body [kg]. The