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Accuracy improvement capability of advanced projectile based on course correction fuze concept.

Elsaadany A, Wen-jun Y - ScientificWorldJournal (2014)

Bottom Line: The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved.The drag ring brake is found to be highly capable for range correction.On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate.

View Article: PubMed Central - PubMed

Affiliation: Nanjing University of Science and Technology, Nanjing 210094, China.

ABSTRACT
Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course correction modules, one is devoted to range correction (drag ring brake) and the second is devoted to drift correction (canard based-correction fuze). The course correction modules have been characterized by aerodynamic computations and flight dynamic investigations in order to analyze the effects on deflection of the projectile aerodynamic parameters. The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of the drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range. On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate. In addition, the canard extension induces a high-frequency incidence angle as canards reciprocate at the roll motion.

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Basic geometrical data of the proposed projectile.
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fig1: Basic geometrical data of the proposed projectile.

Mentions: The canard aerodynamic force and moment are modeled based on [8]. The total canard aerodynamic force and moment are the sum of individual force and moment produced by each lifting canard and given by(15)FC=∑i=1NcFCXiiB+∑i=1NcFCYijB+∑i=1NcFCZikB,τC=∑i=1NcLCiiB+∑i=1NcMCijB+∑i=1NcNCikB,where Nc is the number of lifting canards. This work uses four lifting canards. Figure 1 shows a diagram of the canards used in this development. The relative aerodynamic velocity components of the ith canard are calculated according to(16)uci=u−rryi+qrzi,vci=v+rrxi−przi,wci=w−qrxi+pryi,where rxi, ryi, and rzi are the vector components from the projectile center of gravity to the computation point on the ith lifting canard resolved in the body frame. The lift and drag forces produced by the ith canard are given by(17)LCi=12ρ(uci2+vci2+wci2)SCi CLci,DCi=12ρ(uci2+vci2+wci2)SCi CDci,CLci=Clc(MCi)αCi,CDci=CDc(MCi),where Sci is the ith canard reference area. Clc and CDc are the canard lift and drag aerodynamic coefficients, respectively. αCi is the aerodynamic angle of attack of the ith canard. The canard lift and drag aerodynamic coefficients are Mach number dependent. Computationally, they are obtained by a table look-up scheme using linear interpolation. The Mach number is calculated at the computation point of each canard as follows:(18)MCi=uci2+vci2+wci2a.


Accuracy improvement capability of advanced projectile based on course correction fuze concept.

Elsaadany A, Wen-jun Y - ScientificWorldJournal (2014)

Basic geometrical data of the proposed projectile.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4109594&req=5

fig1: Basic geometrical data of the proposed projectile.
Mentions: The canard aerodynamic force and moment are modeled based on [8]. The total canard aerodynamic force and moment are the sum of individual force and moment produced by each lifting canard and given by(15)FC=∑i=1NcFCXiiB+∑i=1NcFCYijB+∑i=1NcFCZikB,τC=∑i=1NcLCiiB+∑i=1NcMCijB+∑i=1NcNCikB,where Nc is the number of lifting canards. This work uses four lifting canards. Figure 1 shows a diagram of the canards used in this development. The relative aerodynamic velocity components of the ith canard are calculated according to(16)uci=u−rryi+qrzi,vci=v+rrxi−przi,wci=w−qrxi+pryi,where rxi, ryi, and rzi are the vector components from the projectile center of gravity to the computation point on the ith lifting canard resolved in the body frame. The lift and drag forces produced by the ith canard are given by(17)LCi=12ρ(uci2+vci2+wci2)SCi CLci,DCi=12ρ(uci2+vci2+wci2)SCi CDci,CLci=Clc(MCi)αCi,CDci=CDc(MCi),where Sci is the ith canard reference area. Clc and CDc are the canard lift and drag aerodynamic coefficients, respectively. αCi is the aerodynamic angle of attack of the ith canard. The canard lift and drag aerodynamic coefficients are Mach number dependent. Computationally, they are obtained by a table look-up scheme using linear interpolation. The Mach number is calculated at the computation point of each canard as follows:(18)MCi=uci2+vci2+wci2a.

Bottom Line: The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved.The drag ring brake is found to be highly capable for range correction.On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate.

View Article: PubMed Central - PubMed

Affiliation: Nanjing University of Science and Technology, Nanjing 210094, China.

ABSTRACT
Improvement in terminal accuracy is an important objective for future artillery projectiles. Generally it is often associated with range extension. Various concepts and modifications are proposed to correct the range and drift of artillery projectile like course correction fuze. The course correction fuze concepts could provide an attractive and cost-effective solution for munitions accuracy improvement. In this paper, the trajectory correction has been obtained using two kinds of course correction modules, one is devoted to range correction (drag ring brake) and the second is devoted to drift correction (canard based-correction fuze). The course correction modules have been characterized by aerodynamic computations and flight dynamic investigations in order to analyze the effects on deflection of the projectile aerodynamic parameters. The simulation results show that the impact accuracy of a conventional projectile using these course correction modules can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of the drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range. On the other hand, the canard based-correction fuze is found to have a higher effect on the projectile drift by modifying its roll rate. In addition, the canard extension induces a high-frequency incidence angle as canards reciprocate at the roll motion.

Show MeSH