Aerodynamic Characterizations of Asymmetric and Maneuvering 105mm, 120mm, and 155mm Fin-Stabilized Projectiles Derived from Telemetry Experiments

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

Celmins

Fairfax

2012

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High maneuverability of guided projectiles enables engagement of fleeing targets, opens the area of influence of a weapon system, and allows new missions to be performed such as prosecuting targets in defilade. Gun-launched precision munitions have unique constraints that create technical barriers to achieving enhanced maneuverability. Structural integrity during the gun launch event, packaging control surfaces within the launch tube, and affordability are paramount concerns. The present work is a fundamental investigation of the flight mechanics and guidance, navigation, and control technologies necessary to optimize maneuverability of affordable precision projectiles. Detailed aerodynamic modeling and nonlinear equations of motion for the flight of a fin-stabilized airframe meeting low control authority constraints were implemented in simulation. Flight control laws were developed for various maneuver schemes with different actuator realizations. Simulations were conducted over a large parameter space to evaluate maneuverability. Results provide the optimal parameters within the distinctive scope of gun-launched munitions. Flying a skid-to-turn airframe with four canards in the "X" configuration maximizes control authority with moderate volume allocation and actuator bandwidth requirements. Examination of dynamic stability along with static stability illustrates that high-fidelity aerodynamic characterizations are required when optimizing maneuverability due to the implications on the airframe design and flight control algorithm development. NomenclatureD = diameter S = reference area m = mass t a I I I , ,  = moment of inertia tensor, axial moment of inertia, transverse moment of inertia V = total velocity of projectile Q = dynamic pressure M = Mach number    , , = pitch, yaw, total angle-of-attack Z Y X , , = forces acting on projectile N M L , , = moments acting on projectile X C = axial force coefficient N C = normal force coefficient 0 l C = static roll moment coefficient p l C = roll damping coefficient m C = pitching moment coefficient q m C = pitch damping coefficient

Section: Static and Dynamic Stabilitymentioning

confidence: 99%

Section: Airframementioning

confidence: 99%

Optimal Parameters for Maneuverability of Affordable Precision Munitions

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

Celmins

Fairfax

2012

Self Cite

“…A chart comparing linear and 6-DOF calculations of the similarly scaled q=q MAX ratios is shown in Fig. 5 One way to view the angular motion of this asymmetric projectile is to consider the time dependence of , , defined as follows [3]: Figure 6 has a chart for flight times t 30 s comparing linear theory and 6-DOF calculations along with flight-test data of the projectile modeled in the above calculations [19].…”

Section: Model Validationmentioning

confidence: 99%

Flight Stability of an Asymmetric Projectile with Activating Canards

Cooper

Journal of Spacecraft and Rockets

Costello

2012

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Driven by the creation of new smart projectile concepts with maneuver capability, projectile configurations with large aerodynamic asymmetries are becoming more common. Standard linear stability theory for projectiles assumes the projectile is symmetric, both from aerodynamic and mass properties perspectives. The work reported here extends standard projectile linear theory to account for aerodynamic asymmetries caused by actuating canards. Differences between standard linear and extended linear theories reported here are highlighted. To validate the theory, time simulation of the extended linear theory and a fully nonlinear trajectory simulation are made for a representative scenario, with excellent agreement noted. The extended linear-projectile theory offers a tool to address flight stability of projectiles with aerodynamic configuration asymmetries.

“…Within the US Army, rolling projectiles using movable lifting surfaces for maneuver control have been and are continuing to be developed. 1,2 . However, the maneuverability of such projectiles is limited as control authority can only be engaged when the projectile is in the proper orientation to move in the desired direction.…”

Section: Introductionmentioning

confidence: 98%

Effect of Projectile Aft End on Stability, Range, and Maneuverability

Silton

32nd AIAA Applied Aerodynamics Conference

2014

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A computational analysis of possible body-fin configurations, with particular emphasis on the aft end of the projectile, was completed to determine the aerodynamic coefficients. A complete grid resolution, turbulence model, and computational code version study were completed for the initial configuration. The computational aerodynamic coefficients for the body-fin configurations were integrated with previously determined canard aerodynamic coefficients for use in an aerodynamic parameterization routine. The aerodynamic parameterization routine allowed for approximate determination of necessary fin and canard characteristics to enable a highly maneuverable airframe. The artillery boattail aft end was chosen as the configuration with which to proceed. Nomenclaturespacing off wall, mm D = reference diameter, m f c = canard scaling factor f F = fin scaling factor L/D = lift-to-drag ratio M = Mach number S = reference area, m 2 q = dynamic pressure, Pa x c = axial location of canard hinge location from X cg , cal. X cg = center of gravity location, mm y + = nondimensional turbulent boundary-layer coordinate  = canard deflection angle, deg  = angle of attack, deg  trim = trim angle of attack, deg Superscripts F = fins B = body C = canards