On the trajectory of hypersonic projectiles undergoing geometry changes

Legner, Hartmut H.; Lo, Edmund; Reinecke, W. G.

doi:10.2514/6.1994-719

Cited by 9 publications

(4 citation statements)

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“…The free-flight motion of a slowly spinning elastic missile has been studied by a number of authors (1)(2)(3)(4)(5)(6). Although the theory of Murphy and Mermagen (6) is valid for large spin rates, no Magnus force is included in the aerodynamic force distribution.…”

Section: Introductionmentioning

confidence: 99%

Aero-Elastic Motion of a Spin-Stabilized Projectile

Murphy¹,

Mermagen²

2005

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) March 20052. REPORT TYPE ARL-TR-3453 SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTThe elastic flight motion of a slowly spinning finned missile has been successfully described by the finite element method (FEM). With the addition of a Magnus force distribution function, this analysis was used to describe the elastic flight motion of a spin-stabilized projectile. Transient frequencies and damping rates for a 10-cal. cone cylinder have been calculated. The elastic frequencies for a rapidly spinning projectile can be substantially different from those for zero spin. A slightly bent projectile can have a large deflection when its spin rate is near an elastic frequency. Resonant motion is demonstrated when the spin is near the first positive elastic frequency. The maximum strain associated with this motion can exceed the plastic limit. SUBJECT TERMS

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Section: Introductionmentioning

confidence: 99%

Aero-Elastic Motion of a Spin-Stabilized Projectile

Murphy¹,

Mermagen²

2005

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“…Stearns et al (1988) provides such results but details of the analysis and model are not available for verification or review. Legner et al (1994) studied the primary effects of segmentation (which is used for enhancing the penetrating characteristics of the projectile) and flexure on hypervelocity projectiles, but the details of that analysis are also unavailable. They showed effect of the fundamental bending frequency on the angle of attack and the displacement of the projectile tip and concluded that the most significant tip displacement corresponds to region in time when the angle of attack is maximized, and that increase of bending frequency leads to an increase of angle of attack.…”

Section: Static and Dynamic Aeroelastic Instabilitymentioning

confidence: 99%

A New Approach to Aeroelastic Response, Stability and Loads of Missiles and Projectiles

Hodges¹

2004

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“…Because these projectiles have to resist very large aerodynamic loads due to their high-velocity flight at sea level, designers have been concerned about the possibility of aeroelastic deformations [1][2][3][4][5][6][7]. There is some evidence that a small number of these projectiles have been forced to spin at rates close to their lowest elastic frequency and have been subject to large inelastic deformations.…”

Section: Introductionmentioning

confidence: 99%

Flight motion of a continuously elastic finned missile

Mermagen¹,

Murphy²

2001

AIAA Atmospheric Flight Mechanics Conference and Exhibit

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The motion of elastic finned projectiles has been analyzed by various approximate theories. In this report the exact equations of small amplitude motion are derived for a symmetric missile. The aerodynamic and elastic symmetries are used to allow the use of complex variables to describe the lateral motion in a non-rotating coordinate system. Although the resulting equations are both ordinary and partial differential equations, frequencies and damping rates of free oscillations are obtained from an ordinary differential equation with boundary conditions. Equations for a permanently deformed bent missile are derived, and an ordinary differential equation for the forced motion of a bent missile is obtained. Sample calculations for a finned projectile with a fineness ratio of 20 show resonant motion at the aerodynamic frequency as well as at each elastic frequency. The nonlinear roll moment associated with a bent missile is computed and the location of possible spin-yaw lock-in is determined. The flight motion of an elastic missile is shown to be the sum of two elliptical motions: a low frequency pitching motion and a higher frequency flexing motion. The induced drag coefficients for both motions are computed as functions of the missile's elasticity. u

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On the trajectory of hypersonic projectiles undergoing geometry changes

Cited by 9 publications

References 0 publications

Aero-Elastic Motion of a Spin-Stabilized Projectile

Aero-Elastic Motion of a Spin-Stabilized Projectile

A New Approach to Aeroelastic Response, Stability and Loads of Missiles and Projectiles

Flight motion of a continuously elastic finned missile

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