System Modeling of a 40mm Automatic Grenade Launcher

Transcription

1 System Modeling of a 40mm Automatic Grenade Launcher Dr. Daniel Corriveau and Mr. Alain Dupuis Flight Mechanics Group, Precision Weapons Section 4nd Gun and Missile Systems Conference & Exhibition April 3-6, 007 Defence Research and Development Canada Recherche et développement pour la défense Canada Canada

2 Presentation Overview Objectives Background Aerodynamics of a 40 mm HV grenade Error budget development Weapon system simulation results Conclusions

3 Objectives Develop an aerodynamics model for a generic 40 mm HV grenade Develop an error budget model for the MK19 AGL Drag/Mass error (%) Round-to-round muzzle velocity error (m/s) Gun dispersion (mils) Ammunition dispersion (mils) Establish the specification requirements for a new AGL gun system

4 Background AOA=30 CASW (Company Area Suppression Weapon) is a high priority procurement project for the CF 40 mm grenade launcher for various rounds: HEDP Airbursting DRDC tasked to compare the various contenders: FCS Aero and flight dynamics of rounds P hit and lethality Direct and indirect fire capability

5 Background Weapon system modeling AOA=30 Ammo: mass, CP, CG, shape, aero Weapon System representation P R O Round Characteristics at time of burst or detonation: Dispersion Probability of hit Remaining Speed Remaining Spin Angle of descent (AOD) Time of Flight D A MET data S

6 Ammo model development A/B range trial ARFDAS - Aeroballistic Range Facility Data Analysis S 6DOF Dynamic Data t, x, y, z, φ, θ, ψ Physical Properties L, M, D, I, I, I x y z Ixy, Ixz, Iyz ARFDAS Startup Atmospheric Conditions ρ, P, T, μ Complete ammo aero model Single & Multiple Fits Linear Theory Analysis 6DOF Symmetric or 6DOF Asymmetric Fit Theoretical to Experimental Aerodynamic Forces & Moments vs. Mach No. & Angle of Attack & Roll Angle C, C, C, C, C, C, C, C... Xo X X N N N Yp Yp α α α α α 5 α α C, C, C, C, C, C, C, C... m m m mq mq np np np α α α 5 α α 3 α 5 3 C, C, C, C, C, C, C... n n nr nr n m n β β 3 α γα γα 3 3 C, C, C δ δ, C... p p α γα l l l l 3

7 Ammo model development Shadowgraphs Pit View Shadow Instrumented length: 0 m Section: 6 m x 6 m 54 Stations: Indirect orthogonal shadowgraphs 4 Schlieren stations Wall View

8 Ammo model development Projectile motion DOF CALCULATED EXPERIMENTAL DATA POINTS DOF CALCULATED EXPERIMENTAL DATA POINTS X (m) DOF CALCULATED EXPERIMENTAL DATA POINTS X (m) Psi (deg)

9 0.8 Ammo model development Aerodynamic model AB - SF AB - MF A1 40 mm B1 40 mm AB - SF AB - MF 40 MM A1 40 MM B MACH MACH AB - SF AB - MF 40 MM A1 40 MM B MACH

10 Background Weapon system modeling AOA=30 Ammo: mass, CP, CG, shape, aero Weapon System representation P R O Round Characteristics at time of burst or detonation: Dispersion Probability of hit Remaining Speed Remaining Spin Angle of descent (AOD) Time of Flight D A MET data S

11 Weapon system model development Weapon system representation: Error budget model Dispersion analysis S = S + S DX TOTAL D Vx GDx + S ADx S = S + S + S DYTOTAL DVy GDy ADy

12 Error budget development MODEL B1 A1 Errors Measured LOW LEVEL MEDIUM LEVEL HIGH LEVEL Drag/Mass (%) V M round to round (m/s) V M lot to lot (m/s) Wind Std(m/s) Pressure Std (mbars) Air Temp (C) Std Dev Vert. Bore sight alignment (mils) Horz. Bore sight alignment (mils) Target range Error (m) Gun dispersion (mils) Ammunition Dispersion (mils) Fuze Error (% of time) Required as input to Prodas: Estimated based on literature and user experience Determined accurately through an accuracy trial

13 Error budget development Muzzle velocity error Determined using Radar measurements Data processed using Radar000 SHOT NUMBER V MUZ (m/s) B B B B B B B B B B Mean 4.03 Std Deviation 1.55 Std Deviation (%) 0.64

14 Error budget development Drag/Mass error SHOT NUMBER Mass C X0 (gm) B B B B B B B B B B Mean Std Deviation Std Deviation (%) σ Variation in C X0 due to non-uniform band engraving Variation in mass due to quality control C σ C X M σ M M X 0 C 0 X 0 = = M 1.0

15 Error budget development Ammunition dispersion (aerodynamic jump) Due Mainly to Initial Yaw Rate In bore Balloting CG Offset Theory States q 0 - If initial yaw rate,, is known - with aerodynamic package and physical properties - can calculate ammunition disp.

16 Error budget development Ammunition dispersion (aerodynamic jump) Angle of Attack Extrapolated to Muzzle with A/B Range Data Muzzle (.871 m) 1 st Station of Data 1 st MAX YAW X (m) SHOT NUMBER 1 st Max Yaw (deg) B01.87 B B03.85 B04.90 B B06.71 B07.46 B08.10 B09.73 B Mean.33 STD. DEV

17 Error budget development Ammunition dispersion (aerodynamic jump) S ADx = 0.40 mils S ADy = 0.40 mils First Max Yaw Average (deg):.3 Standard Deviation: 0.6 deg q 0 = 1st Maximum Yaw (deg) ( & φ & φ ) F S α max θ Inital Yaw Rate (rad/s) ( C C ) I q X d y V0 md Nα 0 aero = Cmα

18 Error budget development Gun dispersion: drop and lateral analyses DY TOTAL D Vy GDy S = S + S + S ADy DX TOTAL D Vx GDx S = S + S + S ADx Total Observed Due to Gravity drop (V MUZ, mass, C X0 ) Gun Dispersion Ammunition Dispersion

19 Error budget development Gun dispersion: total dispersion S S Measured DY = TOTAL DX = TOTAL mils mils B07 B04 B10 B01 B08 B09 B05 B03 B06 B LATERAL (m) Accuracy trial: NATO StanAg procedure

20 Error budget development Gun dispersion: drop analysis DX TOTAL D Vx GDx S = S + S + S ADx Total Observed S DX TOTAL / m Due to Gravity drop (V MUZ, mass, C X0 ) S D Vx / m Gun Dispersion = Ammunition Dispersion S ADx /m m /

21 S Error budget development Gun dispersion: lateral analysis DY D GDy = S + S + TOTAL Vy S ADy Total Observed S DYTOTAL / m Due to Gravity drop (V MUZ, mass, C X0 ) S DVy 0.00 / m S GDy = Gun Dispersion Ammunition Dispersion S ADy 0.84 /m m /

22 Error budget development Error budget model Errors SERIES D Tripod w/o sand bag, natural ground PROPOSED ERROR BUDGET For LETHALITY Study LOW LOW IDEAL HIGH Drag/Mass (%) V M round to round (m/s) V M lot to lot (m/s) Wind Std(m/s) Pressure Std (mbars) Air Temp (C) Std Dev Bore sight alignment (mils) Target range Error (m) Gun dispersion (mils) H: 0.84 V: 0.35 H: 0.4 V: 0.18 H: 0.4 V: 0.18 H: 1.05 V: 0.44 A: 0.60 A: 0.50 A: 0.50 A: 1.0 Ammunition Dispersion (mils) Fuze Error (% of time)

23 Background Weapon system modeling AOA=30 Ammo: mass, CP, CG, shape, aero Weapon System representation P R O Round Characteristics at time of burst or detonation: Dispersion Probability of hit Remaining Speed Remaining Spin Angle of descent (AOD) Time of Flight D A MET data S

24 Monte-Carlo Based Weapon System Simulations Performed using the Ground-to-Ground module of PRODAS DOF fly-out routine Hundreds of fly-out simulation with randomly varied system errors Yield dispersion at target and probability of hit Enables one to perform or determine: Scenario/Mission simulations Weapon system specifications Weapon system weaknesses

25 Scenario/Mission Simulations 1400 m 1000 m 700 m 400 m 00 m 5 standard NATO targets:.3m high X 4.6m wide 1 box of ammo: 3x

26 Scenario/Mission Simulations Assuming a P * HIT = 90% to be considered a good hit by the gunner then: where N = ln(1 P ln(1 P * HIT 1S HIT ) )

27 Weapon System Specifications: FCS Cant angle error Standard vertical NATO targets:.3m high X 4.6m wide

28 Weapon System Specifications: FCS Range error Standard vertical NATO targets:.3m high X 4.6m wide

29 Weapon System Specifications: FCS Boresight error Standard vertical NATO targets:.3m high X 4.6m wide

30 Weapon System Specifications: Ammo Time fuze error Ground target

31 Weapon System Specifications: Ammo Muzzle velocity error Standard vertical NATO targets:.3m high X 4.6m wide

32 Conclusion An aerodynamic model was developed for a 40 mm HV grenade An error budget model was developed for the MK19 AGL These models were used successfully to perform system simulations of 40mm AGL

33

34 Contact Information: Dr. Daniel Corriveau Phone: Ext Defence R&D Canada Valcartier