model, sabot design and free-flight tests of the drdc...

Model, Sabot Design and Free-Flight Testsof the DRDC-ISL A1, A2 AND A3 Models

A. DupuisM. BoivinDRDC Valcartier

M. NormandMAETEC

Defence R&D Canada – ValcartierTechnical Memorandum

DRDC Valcartier TM 2003-077July 2003

Copy No:__________

Model, Sabot Design and Free-FlightTests of the DRDC-ISL A1, A2 and A3Models

A. DupuisDRDC-Valcartier

M. NormandMAETEC

M. BoivinDRDC-Valcartier

Defence R&D Canada ValcartierTechnical Memorandum

TM 2003-077

2003-07-22

Author

A. Dupuis

Approved by

E. Fournier

Head, Precision Weapons Section

Approved for release by

E. Fournier

Head, Precision Weapons Section

Terms of release: The information contained herein is proprietary to Her Majesty and isprovided to the recipient on the understanding that it will be used for information andevaluation purposes only. Any commercial use including use for manufacture is prohibited.Release to third parties of this publication or information contained herein is prohibitedwithout the prior written consent of Defence R&D Canada.

© Her Majesty the Queen as represented by the Minister of National Defence, 2003

© Sa majesté la reine, représentée par le ministre de la Défense nationale, 2003

TM 2003-077 i

Abstract

Preliminary free - flight tests were conducted to verify the integrity of sabots and theA1, A2 and A3 DRDC-ISL model configurations launched from a powdered gun inthe velocity range of 200 to 1400 m/s. Projectiles of each configuration were fired aswell as a series of slugs for charge determination. The propellant charge mass, muzzlevelocity, maximum accelerations and drag coefficient were determined for each shotwhen fired from a 110-mm smooth bore gun and a 105-mm rifled one with andwithout a high-low pressure chamber adapter.

Résumé

Des essais préliminaires ont été effectués pour vérifier le bon fonctionnement desconcepts de sabots et des modèles RDDC-ISL A1, A2 et A3 tirés d’un canon à poudredans la gamme de vitesses situées entre 200 et 1400 m/s. Des projectiles de chaqueconfiguration ont été lancés ainsi qu’une série de balles noyaux pour déterminer lescharges propulsives. On a déterminé a charge propulsive, les vitesses à la bouche ducanon, les accélérations maxima et les coefficients de traînée pour chaque tir d’uncanon de 110 mm à âme lisse et de 105 mm rayé avec ou sans adaptateur de pressionhaute-basse situé dans la chambre du canon.

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Executive summary

Many options are being considered to improve the performance of existing weaponssystems. For example, increasing the range of artillery shells beyond the actual rangeof 40 km and providing them with some maneuverability on the battlefield to enhancethe hit probability on selected high threat targets could be of great advantage to theCanadian Forces. The use of novel controls on missiles as, for example, lateral jets,lattices fins and thrust vector control could increase their performance over classicalcontrol surfaces. The available information on how such modifications could improvethe aerodynamic performance over the classical projectile or missile shapes is ratherlimited.

As part as a joint effort between DRDC and the French German Institute under theauspices of the Franco-Canadian Accord, a project was set up to study the flightdynamic behavior of a very long range artillery shell with wings and of lattice finnedcontrols on a missile body. The objective was to conduct a fundamental study of theaerodynamic phenomena associated to these type types of control surfaces, theirmaneuverability, and to compare the results with those furnished by other means suchas lateral jets, impulse systems and classical planar control surfaces. Variousmethodologies available to each establishment such as simulations tools to predict theaerodynamics (CFD and semi-empirical/analytical), and experiments (wind tunnel,aeroballistic range and open range tests) would be utilized in a complementary fashionto avoid duplication of effort.

This memorandum presents the projectile and sabot designs as well as the preliminaryfree-flight trials that are required prior to aeroballistic range firings. The intent of thesetrials was to conduct a charge determination, to verify the model-sabot integrity atlaunch and the projectile stability of the models so as not to damage the aeroballisticrange instrumentation. Projectiles were fired from a 110-mm smooth bore and a 105-mm rifled gun with and without a Hi-Lo adapter. The propellant charge mass, muzzlevelocity, maximum acceleration and drag coefficients were determined for each shot.

Dupuis, A., Normand, M., Boivin, M,. 2003. Model, Sabot Design and Free-Flight Testsof the DRDC-ISL A1, A2 and A3 Models. TM-2003-077 Defence R&D CanadaValcartier.

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Sommaire

Plusieurs options sont entrain d’être examinées pour améliorer la performance dessystèmes d’armes existants. Par exemple, augmenter la portée d’un obus d’artillerieau-delà des 40 km actuels en leur donnant une certaine manœuvrabilité sur le terrainpour accroître la probabilité de frappe sur certaines cibles menaçantes pourraitreprésenter un avantage énorme pour les Forces canadiennes. L’utilisation de contrôlesnovateurs sur des missiles, comme, des jets latéraux, des ailettes en treillis et decontrôle de la poussée vectorielle pourraient augmenter leur performance sur lessurfaces de contrôle classiques. L’information disponible pour comprendre commentces modifications pourraient améliorer la performance aérodynamique sur lesprojectiles et missiles classiques est très limitée.

Dans un effort conjoint entre le RDDC et l’Institut de recherches franco-allemand sousles auspices de l’Accord franco-canadien, un projet a été amorcé pour étudier ladynamique du vol d’obus d’artillerie de très longue portée avec des surfaces portanteset des ailettes en treillis sur un corps de missile. L’objectif était l’étude fondamentaledes phénomènes aérodynamiques associés à l’usage de ce type de gouverne, leurpilotage par l’utilisation des connaissances nouvelles acquises et la comparaison desrésultats obtenus avec ceux fournis par d’autres moyens conventionnels de pilotagetels que jets latéraux, dispositifs impulsionnels et surfaces portantes classiques. Desméthodologies existantes aux deux centres de recherche comme les outils deprédiction de coefficients aérodynamiques (calculs numériques et semi-empiriques/analytiques) et les moyens expérimentaux (soufflerie, corridoraérobalistique et champs de tirs) ont été utilisés d’une façon complémentaire pouréviter la duplication des travaux.

Ce mémorandum présente la conception des sabots et des projectiles ainsi que lesessais préliminaires requis avant d’effectuer des essais au corridor aérobalistique. Lebut de ces essais était de déterminer la charge propulsive, vérifier l’intégrité du modèleet du sabot lors du lancement et de la stabilité des modèles en vol afin de ne pasendommager l’instrumentation du corridor aérobalistique. Les projectiles ont été tirésd’un canon 110 mm à âme lisse et d’un canon de 105 mm rayé, avec ou sans unadaptateur de pression haute-basse, situé dans la chambre du canon. La chargepropulsive, les vitesses à la bouche du canon, les accélérations maxima et lescoefficients de traînée ont été déterminés pour chaque tir d’un canon.

Dupuis, A., Normand, M., Boivin, M. 2003. Model, Sabot Design and Free-Flight Testsof the DRDC-ISL A1, A2 and A3 Models. TM 2003-077 Defence R&D CanadaValcartier.

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Table of contents

Abstract/Résumé ............................................................................................................. i

Executive summary ....................................................................................................... iii

Sommaire ...................................................................................................................... iv

Table of contents ............................................................................................................ v

List of figures ............................................................................................................... vii

Acknowledgements ........................................................................................................ x

1. Introduction ........................................................................................................ 1

2. Projectile Configuration ..................................................................................... 2

2.1 Model A1 - Artillery Shell with Wings ............................................................2

2.2 Model A3 - Missile with Grid Fins...................................................................2

2.3 Model A2 - Artillery Shell with Grid Fins........................................................3

3. Experimental Site and Instrumentation .............................................................. 4

3.1 Test Particularities ............................................................................................4

4. Model, Sabot Design and Tests for A1 Model................................................... 6

4.1 Model Design for A1 Configuration.................................................................6

4.2 Sabot Design for A1 Model ..............................................................................7

4.3 Sabot-Model Integrity Trials 1 (Oct. 99) for A1 Model ...................................8

4.3.1 Comments and Discussions ...............................................................10

4.4 Sabot-Model Integrity Trials 2 (July 00) for A1 Model .................................10


4.5 Sabot-Model Integrity Trials 3 (Nov. 00) for A1 Model ................................12


4.6 Final Sabot Design for A1 Model...................................................................14

5. Model, Sabot Design and Tests for A3 Model................................................. 15

5.1 Model Design for A3 Configuration...............................................................15

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5.2 Sabot Design for A3 Model ............................................................................15

5.3 Sabot-Model Integrity Trials 1 (Oct. 99) for A3 Model .................................16

5.3.1 Comments an Discussions .................................................................17

5.4 Sabot-Model Integrity Trials 2 (July 00) for A3 Model .................................17


6. Model, Sabot Design and Tests for A2 Model................................................. 19

7. Conclusions ...................................................................................................... 20

8. References ........................................................................................................ 21

Annex A - Measured Roll Orientations............................................................ 62

List of symbols/abbreviations/acronyms/initialisms........................................ 66

Distribution list................................................................................................. 67

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List of figures

Figure 1. Model A1 - Artillery shell concept with wings (all dimensions in caliber, 1 cal = 30mm)....................................................................................................................................23

Figure 2. Model A3 - Grid finned projectile (all dimensions in caliber, 1 cal = 30 mm) ........24

Figure 3. Model A2 - Artillery shell concept with grid fins (all dimensions in caliber, 1 cal =30 mm)...............................................................................................................................25

Figure 4. Schematic of the test site ...........................................................................................26

Figure 5. Photograph of test set up ...........................................................................................27

Figure 6. Hi-Lo 110 mm chambre adapter................................................................................28

Figure 7. Schematics of A1 projectile design ...........................................................................29

Figure 8. Sabot schematic for the A1 projectile........................................................................30

Figure 9. Photograph of sabot package for A1 model ..............................................................30

Figure 10. Photographs of A1 sabot pieces...............................................................................31

Figure 11. Sabot schematic for the slug for A1 model .............................................................32

Figure 12. Velocity and acceleration history for Slug SLA1-3.................................................32

Figure 13. Sabot separation for A1 model - Shot A1-08, VMUZ = 240.0 m/s ............................33

Figure 14. Photographs of recovered sabot pieces for A1 model .............................................34

Figure 15. Photograph of recovered polycarbonate section......................................................35

Figure 16. Modified sabot schematic for the A1 projectile - July 00........................................36

Figure 17. Photograph of modified sabot package for A1 model - July 00 .............................36





Figure 22. Sabot separation for A1 model - Shot A1-31, VMUZ = 233. m/s.............................39

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Figure 26. Schematic of final design for the A1 projectile .......................................................42

Figure 27. Photograph of A3 projectile with brass nose...........................................................43

Figure 28. Sabot schematic for the A3 projectile......................................................................44

Figure 29. Photograph of sabot package for A3 model ............................................................44


Figure 31. Sabot separation for A3 model - Shot A3-05, VMUZ = 1173.1 m/s ..........................45

Figure 32. Photograph of sabot package for A3 model - July 00..............................................46

Figure 33. Sabot separation for A3 model - Shot A3-21, VMUZ = 1158.4 m/s ..........................47

Figure 34. Photograph of A2 projectile ....................................................................................48

Figure 35. Sabot schematic for the A2 projectile......................................................................49

Figure 36. Photograph of sabot package for A2 model ............................................................49

List of tables

Table 1. Firing Conditions for A1 model - Trial 1 (Oct 99) .....................................................50

Table 2. Results from gun firing for 3.25 slugs (Oct 99) ..........................................................50

Table 3. Measured physical properties of A1 projectiles (Oct. 99) ..........................................51

Table 4. Results from gun firing for A1 Model - Trial 1 (Oct 99)............................................52

Table 5. Measured physical properties of A1 projectiles (July 00) ..........................................53

Table 6. Firing Conditions for A1 model - Trial 2 (July 00) ....................................................53

Table 7. Results from gun firing for A1 Model - Trial 2 (July 00)...........................................54

Table 8. Deduced drag coefficient for A1 Model - Trial 2 (July 00)........................................55

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Table 9. Measured physical properties of A1 projectiles (Nov. 00) .........................................55

Table 10. Firing Conditions for A1 model - Trial 3 (Nov 00) ..................................................55

Table 11. Results from gun firing for A1 Model - Trial 3 (Nov 00).........................................56

Table 12. Deduced drag coefficient for A1 Model - Trial 3 (Nov 00)......................................56

Table 13. Measured physical properties of A3 projectiles (Oct. 99) ........................................57

Table 14. Firing Conditions for A3 model - Trial 1 (Oct 99) ...................................................57

Table 15. Results from gun firing for A3 Model - Trial 1 (Oct 99)..........................................58

Table 16. Deduced drag coefficient for A3 Model - Trial 1 (Oct 99).......................................58

Table 17. Measured physical properties of A3 projectiles (July 00) ........................................59

Table 18. Firing Conditions for A3 model - Trial 2 (July 00) ..................................................59

Table 19. Results from gun firing for A3 Model - Trial 2 (July 00).........................................60

Table 20. Deduced drag coefficient for A3 Model - Trial 2 (July 00)......................................60

Table 21. Measured physical properties of A2 projectiles (Oct 99) .........................................61

Table 22. Results from gun firing for 2.2 kg slugs (Oct 99).....................................................61

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Acknowledgements

The authors would like to thank ISL for the fabrication of the models that were utilizedfor the trials as well as Drs. V. Fleck and C. Berner of ISL for their many discussionson the design of the A1 model for the aeroballistic range tests. Thanks are also due tothe CEEM-V trials team for the successful completion of these tests.

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1. Introduction

The Defence Research and Development Canada (DRDC) - Valcartier and the French-German Research Institute (ISL), in Saint-Louis, France, agreed, under the auspices ofAS 14 of the Franco-Canadian Accord, to conduct an extensive experimental andcomputational investigation on three projectile configurations. Both researchestablishments have wind tunnels, aeroballistic range facilities, open ranges andcomputational fluid dynamic (CFD) means to determine the aerodynamiccharacteristics and the stability of any projectile configuration. The aim was to use atriangular exploration (wind tunnel, free-flight and computational) to reduce as muchas possible the number of required aerodynamic tests, which tend to be quiteexpensive. Every effort was made to use the available tools at both establishments, in acomplementary fashion rather than duplicative, to maximize the efficiency.

Many options are being examined by both research establishments to improve theperformance of existing weapons platforms or by investigating novel technologies thatcould be used with present systems by increasing their current capabilities. Oneexample consists in increasing the range of artillery shells beyond 40 km by usingdeployable wings during the flight, and by providing them with some maneuverabilityon the battlefield. This would enhance the hit probability on selected high threattargets, or if a type of visual system could be mounted in the shell, it could also beused as an observing stage. The use of lattice, or grid, fins could increase theperformance of missiles over classical aerodynamic control surfaces to improvemaneuvering capability at high angles of attack. The available information on howsuch modifications would improve the aerodynamic performance over the classicalprojectile or missile shapes is rather limited. Before characterizing any enhancements,it is necessary to provide detailed and reliable information on reference test cases so asto be able to quantify any improvements over the classical projectile.

The objective of this investigation was to design the projectiles and the sabots tolaunch them, as well as to conduct the necessary trials that are required prior toaeroballistic range tests at DRDC-Valcartier. The intents of these trials were toconduct a charge determination, to verify the model-sabot integrity at launch and theprojectile stability of the models so as not to damage the aeroballistic rangeinstrumentation. The projectile configurations were fired from a 110-mm smooth boreand a 105-mm rifled gun with and without a Hi-Lo adapter. One configurationconsisted of an idealized 155 mm shell with wings and one with grid fins while thethird one was a missile body with grid fins. The propellant charge mass, muzzlevelocity, maximum acceleration and drag coefficients were determined for each shot.

This study was conducted as part of a cooperative research program between DRDCand ISL under the auspices of AS-14 entitled “Projectiles et missiles pilotés parailettes en treillis” of the Franco-Canadian Accord. This work was performed atDRDC Valcartier between October 1999 and November 2000 under Work Unit 3eb12,Flight Dynamics for Missile Performance Studies.

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2. Projectile Configuration

2.1 Model A1 - Artillery Shell with Wings

The usual method to increase the range of an artillery projectile is to reduce the dragthrough the use of devices such as a base bleed units or rocket-assist. This type ofdevices permits to extend the range of a standard 155 mm shell in the range of 30-40km. The use of the lift force in order to compensate the gravity force acting on theprojectile is another concept for obtaining an equivalent or an augmented range ofactual 155 mm projectiles. This solution requires that the projectile fly with an upwarddirected angle of attack for a very long range and to maintain a lift to drag ratio. Aspinning projectile flies during a great part of its trajectory with an angle of attack(yaw of repose). The orientation and the magnitude of this angle depend, beside otherparameters, on the moment of the aerodynamic force. This moment can be used tocontrol the angle of attack, or the yaw of repose.

A previous study [1] has shown the feasibility of using the yaw of repose in an astutefashion to maintain a continuous angle of attack in order to increase the range of anartillery shell. That study only reported on results obtained for an idealized artilleryprojectile configuration with and without lifting surfaces. An optimized configurationof a 155mm spinning artillery shell with canted lifting surfaces located slightlydownward the center of gravity is shown in Fig. 1. Critical aspects were the center ofpressure location, the angle of cant of the fins and the spin rate. The Mach numberrange of interest lied between 0.6 and 0.8.

The final projectile configuration that was chosen for the study is shown in Fig. 1. Itconsisted of a secant-ogive-cylinder projectile with an l/d of 5.65 representative of atypical 155 mm shell (Fig. 1a). The four straight profiled fins located at 1.9 cal fromthe base have a total span of 3.0 cal and a chord of 0.5 cal. The fins cants weremodified for the different trials and this will be discussed in a further section. Theogive length was 3.00 cal with a radius of 10.12 cal and a meplat of 0.088 cal.

The fins were profiled (Fig. 1b) at a radius of 1.264 cal with a mid span thickness of0.053 cal. The leading and trailing edges were rounded at a radius of 0.002 cal. Thefree-flight models were 30.0 mm in diameter. The centre of gravity positions as well asthe physical properties will be provided in later sections when discussing the design ofthe models.

2.2 Model A3 - Missile with Grid Fins

The use of grid fins as a stabilization and control device on projectiles and missilesoffers an interesting alternative to the classical fin design. Their easy storage fordeployment, low hinge moments and high angle of attack performance are their mainadvantages while their main shortcoming is a higher drag penalty [2]. The projectilesstudied [2] had an l/d of 16 with very thin webbed lattice fins oriented in a X shape.

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For this project, it was decided to simplify the configuration as much as possible sothat detailed measurements around the fins could be conducted with ease and to makesure that they could be fired at high velocities, up to Mach 4.0. Previous free-flighttests were not successful at high velocities due to structural failure of the lattice fins.

The projectile configuration that was retained for this joint project is shown in Fig. 2.The reference configuration was the Air Force Finner [3] body equipped with four gridfins, as shown in Fig. 2a. The body consisted of a 2.5 caliber tangent-ogive followedby a 7.5 caliber cylinder. The fins were placed at 0.7 calibers from the base. The totalspan is 2.4 calibers with a chord of 0.08 calibers. These last dimensions andplacements were typical of missiles systems that were studied based on a literaturesurvey on the data that was available at that time. The reference diameter for the free-flight models was 30.0 mm.

The grid fin, presented in Fig. 2b, has nine cells with thick walls. Thick walls werechosen to allow wind tunnel static wall pressure measurements on the central cell. Thisgrid fin geometry, contrary to many other papers [2, 4-8], has a vertical cell orientationinstead of a cruciform one. This was done to simplify the geometry to be able tounderstand basic aerodynamic phenomena of simple cells. Each cell is rectangularwith a width of 0.124 caliber and a height of 0.161 caliber. In order to avoid possiblestructure deficiencies during free-flight tests, a solid base was designed to mount thefins on the body. One set of fins was canted at 2.0° to provide a spin rate and one setwas deflected at 0.5° to provide a trim angle.

This configuration was tested at two different center of gravity positions and these willbe detailed in a later section. The Mach number of interest for this configuration wasfrom 0.6 to 4.0.

2.3 Model A2 - Artillery Shell with Grid Fins

As mentioned previously, the concept for the artillery shell with wings uses an astutecontrol of the yaw of repose to maintain an ideal angle of attack to increase the range.For this to occur using this principle, the center of pressure has to be moved in flightfore and aft the center of gravity. To displace the center of pressure aft of the center ofgravity, one design concept was to investigate the use of deployable grid fins at the aftend of the artillery shell, which would be controlled by the autopilot during flight.

The projectile configuration is shown in Fig. 3. The projectile body (Fig. 3a) is thesame as Model A1 and the grid fins (Fig. 3b) are the identical to the ones of the A3model, as well as their placements on the model. In this case, the center of gravity wasto be tested at one position and it was located at 3.43 cal from the nose of theprojectile. The reference diameter of the projectile for the free-flight tests was also30.0 mm and the Mach number range of interest was subsonic, i.e. in between 0.6 to0.8. The fins were also canted in the same manner as Model A3. The models weremade of steel.

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3. Experimental Site and Instrumentation

The integrity trials were conducted at two sites at DRDC-V. The first series of trialstook place at Butt 4 and the remaining ones one took place at the 2000 m precisionrange. The trial set up was basically the same at both test sites with minormodifications. A schematic of the test set-up is shown in Fig. 4. A sabot trap wasinstalled at approximately 9.2 m from the gun muzzle to duplicate the launchconfiguration at the aeroballistic range. This is particularly important for the sabotpetal separation. Two high-speed photographic stations were positioned fore and aft(6.3 m and 11.5 m from the gun muzzle) of the sabot trap to photograph the sabotseparation and model integrity. A target was situated at 150 m from the muzzle. Also,two packs of yaw cards were installed at 20 m and 30 m from the muzzle. Thisconsisted of three yaw cards separated by 0.5 m. One of the fins of each projectile waspainted blue and it was possible to obtain the roll orientation.

Two radars were utilized for these tests. One to obtain the acceleration of the sabot-model package inside the gun tube and a second to obtain the velocity history of theprojectile in flight. The detailed configuration and location of the radars are shown inFig. 4. The acceleration in the gun tube was measured by a continuous Doppler typeradar with a transmission frequency of 35 GHz. It was placed behind the gun andaimed at a metalized mylar radar signal reflecting mirror placed in front of the sabottrap. The mirror was located on the side of the firing line to avoid model disturbanceor damage, and oriented towards and inside the gun muzzle. The data analysis wasthen conducted with a Fast Fourier Transform (FFT) analyzer to obtain the velocityand acceleration history inside the gun tube.

The projectile velocity was measured with a continuous Doppler radar with afrequency of 10.492 GHz. This radar was situated passed the sabot trap (at 12.0 m)looking down range and 0.9 m below the line of fire. The projectile’s velocity historyand its muzzle velocity were obtained from this radar. The signal processing wasconducted with a FFT analyzer.

The chamber pressures were not measured in these trials since enough data wasobtained from previous similar trials.

Photographs of the test set can be seen in Fig. 5.

3.1 Test Particularities

It took three sets of trials to finalise the A1 sabot and model design, two for the A3grid fin model and the A2 model was not fired for reasons that will be explained later.The velocities of interest for the A1 and A2 projectile were of the order 210 m/s whilethose for the A3 projectile were from 210 m/s to 1360 m/s.

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The A1 model projectile was fired from a 105 mm rifled gun with a twist of 1 turn in18 calibers while the A2 and A3 projectiles were due to be fired from a 110 mmsmooth bore gun. At the low launch velocities of 210 m/s to 350 m/s, a special Hi - Loadapter (Fig. 6) was utilized in the gun chamber to obtain consistent gun pressures topropel the model-sabots at low repetitive muzzle velocities and to achieve the lowestlaunch accelerations as possible. Since these muzzle velocities are quite low, astandard 105-mm cartridge would not be suitable. The propellant mass required in astandard cartridge would be too small to obtain adequate uniform burning of thepropellant and would lead to inconsistent muzzle velocities. The Hi-Lo adapter fits inthe chamber of the 110-mm and 105-mm gun tubes to equalize the pressure in the guntube

The Hi-Lo adapter comprises several components (Fig. 6): an obturator, a diffuser, ajoining shaft, a standard M63 primer, O-ring seals on the adapter and on the diffuser,and an end nut. For these trials, the 9.525 mm diffuser was utilized. Several otherdiffusers were available but not used in this trial. A propellant charge is placed aroundthe shaft (High pressure section) between the obturator and the diffuser, and it isignited by the burning gases from the primer escaping the holes in the shaft. Thepressure in the gun tube (Low pressure section) is controlled by the escaping gasesthrough the nozzles of the diffuser.

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4. Model, Sabot Design and Tests for A1 Model

4.1 Model Design for A1 Configuration

The model design for the A1 configuration (Fig. 1) was quite a challenge since it hadto be fired in two stability conditions. With a center of gravity ( CGX ) aft of the center

of pressure ( CPX ), the projectile is statically unstable and it has to be spin stabilizedto maintain a gyroscopically stable flight. This implies that the projectile has to befired from rifled tube and the projectile has to be specifically designed for theaeroballistic range tests. The initial flight dynamic studies [1] were based on a full-scale 155 mm, which do not hold for a scaled 30 mm model. The critical aspects inthese cases are the spin rate, the center of gravity position relative to the center ofpressure and the lift to drag ratio. The gun tube that was available at DRDC-V to firesuch a projectile was the 105 mm rifled gun. It has a twist of 1 turn in 18 calibers.

There was also interest in firing the projectile, from this same gun tube, in a staticallystable condition, that is when the CGX is forward of the CPX . The reason for this isthat for full-scale operation on a 155 mm shell, as explained earlier, the shell would flyin both stability conditions. The aerodynamic properties are required to be known inthe same regime of spin rates.

The placement of the wings on the body was fixed as with [1] as shown in Fig. 1, andthe aerodynamic coefficients were predicted with four tools, numerical simulationsfrom CFD [1], and with semi-empirical/analytical tools, PRODAS [9], AP95 [10] andDATCOM [11]. The crucial parameter that the projectile had to be designed aroundwas the center of pressure location. An average of the four predicted values was takenand it was fixed at 3.03 cal from the nose. The next step was to conduct a series of six-degree-of-freedom trajectory simulations with PRODAS [9] at various center ofgravity positions (which implies modeling the model completely with various materialdensities) and fin cants to make sure that the projectile would not divert by more than1.0 m in cross range over a distance of 150.0 m. It should be noted that the availableaerodynamic data was very limited, especially the dynamic derivatives, roll dampingand roll producing moments due to fin cant. All simulations were conducted at amuzzle velocity of 210 m/s, which yielded an initial spin rate of roughly 700 rad/s.The projectile that caused the most challenge was the gyroscopically stable one.

After many 6DOF simulations, both at DRDC-V and ISL, it was decided to design thegyroscopically stable projectile with the center of gravity located at 93.6 mm (3.12 cal)from the nose of the projectile and the statically stable projectile at 81.5 mm (2.72 cal)from the nose. Both projectiles would have the fins canted at 4.0° so as to maintain therequired spin rate to have a gyroscopic stable projectile.

The detailed model designs were then made and sketches of the projectiles can befound in Fig. 7. Due to the amount of detailed drawings only schematics will be shownin this report and the full drawings are available from DRDC-V on a need to knowbasis. The statically stable projectile is shown in Fig 7a. The steel base portion of the

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model was hollowed to have the center of gravity forward. The nose section was madeof a tungsten allow. To obtain the right center of gravity position for thegyroscopically stable projectile (Fig. 7b), which is further aft the other one, thetungsten nose was hollowed out a bit and merged on a full steel base.

4.2 Sabot Design for A1 Model

Since the sub caliber projectiles have to be launched from a powdered gun to conducttests in the DRDC-V aeroballistic range, special sabots have to be designed to firethem. Since the model configuration in this case was spin stabilized, a rifled gun wasutilized. The standard gun employed at DRDC-V to fire spin-stabilized projectiles ofthese dimensions with sabots in the aeroballistic range is a 105 mm rifled gun.

Several aspects have to be considered when designing sabots and models. They are:projectile configuration, total mass, sabot separation at the sabot trap located at 9.2 mfrom the muzzle at the aeroballistic range, muzzle velocity desired, gun accelerations,etc. The last three mentioned have to be consistent from round to round. In this case,the muzzle velocity desired was approximately 210 m/s (Mach 0.6).

A schematic of the sabot design to launch the A1 projectile from the 105 mm rifledgun tube is shown in Fig. 8 and a photograph of the sabot package is shown in Fig. 9.It consists of a four solid petal aluminum shell that is split along the same direction asthe fin locations. The width of these cuts are the such that the total fin span, at 4.0°cant, has a snug fit and is in contact with both petal surface. The aluminum body iscovered with a polycarbonate material, that includes the driving band at the back end,that will protrude in the rifling of the gun tube to transmit the torque to the sabot whenfired. The aft section of the aluminum body was roughened with grooves (Fig. 10a) sothat the polycarbonate ring (Fig. 10b) does not slip with respect to the aluminum bodywhen fired. The aft end of the sabot as well as the seal were based on a standard sabotto launch an in service 105 mm projectile. Therefore, if the contact between thepolycarbonate ring and the aluminum body is successful, the full spin rate will betransmitted to the sabot during launch. The low launch velocity of 210 m/s for thiscombination was considered to be a possible problem since the petal separation iscaused by the centripetal acceleration at the muzzle. This type of sabot, even thoughsuccessful at muzzle velocities of 1500 m/s, was never tested at these low launchvelocities. This also implies that the amount of material along the saw cut lengths atthe aft end of the sabot has to be adjusted to make sure that they break evenly to havesymmetric petal separation. The sabots were manufactured at DRDC-V while theprojectiles were made at ISL. The total sabot-model mass was roughly 3.2 kg.

A roll pin was added at the aft end of the model (Fig. 9) so as to be able to measure theroll orientation of the projectile when conducting tests in the aeroballistic range.

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4.3 Sabot-Model Integrity Trials 1 (Oct. 99) for A1 Model

The main objectives of the trials were:

a. verify if the sabots and models could survive the launch loads over therequired speed regime,

b. confirm adequate sabot separation at the sabot trap,c. assure that the projectiles have adequate stability to reach the target,d. obtain some drag coefficient data

over the required speed regime. The propellant charges required to obtain the requiredmuzzle velocities were also obtained. All the tests were conducted with the N-3-1-1(0.035” web) propellant. This propellant was well suited to obtain the required muzzlevelocities of interest with the Hi - Lo adapter.

The results of all the gun launches will be given for each projectile below in individualsections. The accelerations were measured with a radar looking down the barrelthrough a reflector and only the maxima achieved are reported. The muzzle velocitiesfrom the radar aimed inside the bore and the one looking downrange are also provided.

The drag coefficient was determined for each stable projectile from the Dopplervelocity radar. It was calculated from the measured retard.

The first series of tests to verify the sabot functioning were conducted in October1999. Since the HI-LO adaptor had never been used with the rifled tube, a series ofslugs were designed and fired before firing the projectiles to obtain the right mass ofpropellant charge to obtain the desired velocity. Also the engraving force required wasnot known and the smooth bore data would be of little to no use.

A schematic of the slug is shown in Fig. 11. The aluminum shell, the polycarbonatering, the grooves and the aft base were exactly the same as the A1 sabot design. Aballast mass was inserted to approximate the mass of the A1 sabot-model package.There were no petals for this case. This would also confirm that the engraving processand that the torque from the rifling would be transmitted correctly. The mass of theslug was 3.25 kg.

The atmospheric conditions at the time of firing are given in Table 1 and the results forthe slug firings are provided in Table 2. The propellant charge mass, the maximumaccelerations achieved, the measured in bore and Doppler radar deduced muzzlevelocities are provided. The last columns gives some general comments on sabotseparation, if the projectile was stable and the impact of the projectile at the targetsrelative to the aim point. Z is positive downwards and Y is positive to the right whenlooking downrange.

Three slugs were fired. The first slug remained stuck in the barrel after a displacementof 27.0 mm with a propellant charge of 80.0 g. It was dislodged by firing a very highcharge. The driving band diameter was reduced to 107.29 mm from the original108.71mm. With these modifications, a second slug was fired at the same charge and itsuccessfully exited the gun tube at a velocity of 245.1 m/s. A third slug was fired with

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the same modifications and charge as the previous one to obtain validation. It was alsosuccessfully fired with very similar results. The desired muzzle velocity is roughly 30m/s higher then desired. A typical velocity and acceleration history in the barrel isshown in Fig. 12 for Slug SLA1-3.

The next series of tests consisted of firing the A1 model. The measured physicalproperties of each test projectile are provided in Table 3. The measured center ofgravity positions are very close to the designed parameters of 3.12 cal and 2.72 calfrom the nose. The mass of the aft and forward center of gravity projectiles wereroughly 922.0 g and 904.0 g, respectively. Unfortunately, there was an error in the fincant angle. Instead of being +4.0° they were at -4.0°. This implies that, even if thesabot achieved full spin rate at the muzzle, the spin rate of the model would decay veryrapidly and spin to an equilibrium negative steady spin rate. Six-degree-of-freedomtrajectory simulations confirmed this also. This means that all the models with the aftcenter of gravity positions (Models A1-01 to A1-05) could not be fired, as they wouldbe gyroscopically unstable and unsafe to fire. It was decided that the models with theforward center of gravity positions could be fired, as they were statically stable. Theeffect of the very rapid change in spin rate was of a concern on the flight dynamicsperformance, but it was deemed necessary to launch them to at least verify sabotseparation, integrity and to confirm that the full spin rate could be transmitted.

The firing conditions are provided in Table 1 and the results in Table 4. The sabot ofthe first shot (A1-10) was modified so that the driving band was the same as the twoslugs that were successfully fired. The shot was fired with 80 g of propellant and thesabot did not open at exit, but the muzzle velocity was good.

It was decided to modify the sabot for the second shot (A1-09) by cutting the slotsfurther in the base till there was 5.33 mm of wall left. The saw cuts were filled withresin. Again the sabot did not open but the muzzle velocity was correct.

The sabot of the third shot (A1-08) was modified by still cutting deeper in the backend till there was 2.3 mm of wall left and by cutting the slots in the polycarbonate upto the driving band. The sabot opened very quickly and more than the sabot trapdimensions (1.22 m x 1.22 m) at 9.2 m from the muzzle. The projectile was unstable atthe target and it entered at 90.0°. The muzzle velocity was similar to the other shots.Photographs of the sabot separation for this shot can be seen in Fig. 13.

For the next shot, A1-07, the polycarbonate ring was only split halfway to the drivingband and all the other conditions were as the prior shot. The results were very similarto shot A1-08, that is, a quick sabot opening and the projectile unstable, with a slightdrop in muzzle velocity. The recovered sabot pieces indicated that there was impactbetween the sabot and the model at launch.

The last shot, A1-06, was a repeat of A1-08, with a slightly lower charge. The resultswere the same as the A1-08, but with a muzzle velocity of 213.0 m/s. Again therecovered sabot pieces showed impact of the model on the sabot and these are shownin Fig. 14. The arrows point out where the impact occurred during separation at themuzzle and this was probably the cause for the projectile being unstable. A recovered

10 TM 2003-077

polycarbonate ring (Fig. 15) shows the imprint of the rifling indicating that the torquefrom rifling was transmitted to the sabot to produce the required spin rate.

4.3.1 Comments and Discussions

The action of the sabot in the gun tube is correct. It transmits the torque to themodel and propels it to the muzzle without breakage. The problem exists atseparation where there is impact of the sabot petals with the model at themoment when the petals rotate. This rotation speed has to be reduced byreducing the mass of the petals combined with a slight modification at thebase of the sabot where there is contact, and possibly by adding a pusher pad.The desired muzzle velocities were obtained. The fins on the models will alsohave to be oriented in the right direction.

4.4 Sabot-Model Integrity Trials 2 (July 00) for A1 Model

A series of wind tunnel tests were conducted on the A1 projectile [12] and the resultsshowed that the CPX was very close to the predicted values and therefore the samecenter of gravity positions were kept for this second series of tests. The wind tunnelroll producing moment due to the fin cant was quite different from the predicted one,higher by a factor of 5.0. But since the value of the roll damping moment was notknown, it was decided to keep the angle of the fins at 4.0°.

Six projectiles were requested for the second series of tests, three with a forwardcenter of gravity and three with an aft center of gravity. The physical properties ofeach test projectile are provided in Table. 5. The fins were all canted at +4.0°.

The modifications to the sabot that were made during the first trial were kept and itwas additionally modified as follows for the second series of tests as shown in theschematic of Fig. 16 and in the photograph of Fig. 17. The first modification consistedin lightening the sabot petals by drilling out some material in the center of each petal.The second modification was to remove some material at the base of the sabot wherethe impact was noticed. The option of using an aluminum cylindrical spacer betweenthe model and the sabot was retained. The total mass of the modified model-sabotpackage was 2.76 kg.

The second series of tests occurred in July 2000 and the firing conditions are providedin Table 6 and the results in Table 7. The first shot was a forward CGX projectile(A1-21), which is a statically stable projectile, with a propellant mass of 70.0 g. Thecylindrical pad was not used. The sabot separation was good, the projectile was stableat the muzzle, but there was a slight impact trace on one of the recovered sabot petal.The projectile was unstable at 150.0 m. The muzzle velocity is a bit high.

The second projectile fired, A1-24, an aft CGX projectile that is gyroscopicallystabilized, was fired with a reduced charge to lower the launch velocity. The launchwas successful and the projectile was stable at the muzzle, and at the yaw card at 30.0

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m, but it was unstable at 150.0 m. The velocity was reduced to roughly 215 m/s. Aphotograph of the projectile in flight can be seen in Fig. 18 at the first camera position.

A second statically stable projectile, A1-22, was fired. The launch was very good andthe projectile was stable up to the target. The muzzle velocity at this charge wasrepeatable. The in bore data was not determined. The sabot separation can be seen inFig. 19 at the first camera position.

A second aft CGX projectile was fired, A1-25, and a very bad launch occurred asshown in Fig. 20. There is no doubt that there was a very adverse sabot separation andthat there was contact.

This shot was followed by the remaining statically stable projectile, A1-23, and a goodlaunch was achieved and the projectile was stable all the way to the target. Aphotograph of the model in flight can be seen in Fig. 21 at the second camera position.

The last projectile available was fired (A1-26), and in this case the cylindrical spacerwas installed. The sabot opening was a lot less than the other ones and again theprojectile was unstable at the muzzle. The recovered sabot pieces again showed tracesof impact between the model and sabot.

The drag coefficient was determined from the Doppler radar velocities for two shotsthat reached the target. It was calculated from the measured retard and they areprovided in Table 8. The DC is roughly 0.25 at Mach 0.6.

The roll orientations of the projectiles on the yaw cards were also determined for fourof the shots. These are giving in Annex A. The spin rates were deduced whereapplicable.


An asymmetric sabot separation occurs with the present sabot design firedwith a propellant charge of 60.0 g since there is still too much material at theend of the sabot to break. The present 2.3 mm of wall thickness left should befurther reduced to 1.52 mm. As proof that the breakage is uneven, acomponent of two polycarbonate segments were recuperated un-separated.This has the effect that the aluminum petals impact the sabot trap randomly,that is, two petals impact the sabot trap at a different radius from the firingline while the other two miss the sabot trap completely.

The consequence of having two petals non separated on the model while itflies along the firing line with one fin stuck in between them would be tragicon the trajectory.

The engraving of the driving band from the rifling of the tube has to also bedone in a symmetric fashion. As there are 28 grooves in the gun tube and thatthere are four polycarbonate segments on the sabot, special care has to be

12 TM 2003-077

taken to make sure that 4 grooves (multiple of 7) coincide with the four sawcuts of the petals when loading the gun.

The amount of material to break from the polycarbonate ring should also beweakened by increasing the slot to halfway along the driving band and at halfthickness to make sure that the breakage be even from one segment toanother.

With some roll data and spin rate available, it was possible to obtain the roll-damping coefficient by holding the roll producing moment to the wind tunnelvalues. This was first done with the statically stable models where theprojectile was stable over 150.0 m. Afterwards, 6DOF trajectory simulationswere conducted with the aft center of gravity projectile, and it was shown thata fin cant in between 7.0° and 8.0° was necessary to obtain a gyroscopicallystable projectile over 150.0 m. These results coincide with the results forprojectile A1-24 which was stable at 30.0 m and unstable at the target,showing a loss of gyroscopically stability since the required spin was notmaintained at a fin cant of 4.0°.

After discussion with ISL personnel, it was decided to fire more projectiles inanother series of tests with minor sabot modifications. Two projectiles withthe forward CGX with a fin cant of 4.0° would be fired and two projectiles

with the aft CGX with a fin cant of 8.0°.

4.5 Sabot-Model Integrity Trials 3 (Nov. 00) for A1 Model

The sabot design was basically the same as the last series with the slight modificationsthat were suggested in the last section. The physical properties of the tested projectilesare given in Table 9. The trials took place in November 2000 and the firing conditionsare provided in Table 10 and the results in Table 11.

The first shot fired, A1-31, provided very good results. Good sabot separation wasachieved and the projectile attained the target with no large yaw. The velocity was abit higher than the previous trial at the same charge since there is less resistance due todriving band being thinner. A photograph of the projectile in flight at the secondcamera station is show in Fig. 22. A small amount yaw is discernable. The imprints onthe yaw cards also showed very little yaw.

An aft CGX projectile with a fin cant angle of 8.0°, A1-33, was then fired at the samecharge. There was a good sabot separation and pictures of the separation are shown inFig. 23. At the first camera position the yaw angle is very low while it is very high atthe second camera position. It did not impact the target at 150.0 m.

A second projectile with a forward CGX , A1-32, was fired at a slightly reducedcharge. There was sabot-model impact and high yaw angles at both camera positions,

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as seen in Fig. 24. At the yaw card positions, the angles were low and there was noimpact on the target at 150.0 m. The measured roll orientations are given in the annex.

The last available shot, A1-34, was fired with similar results as shot A1-33 (Fig. 25).The sabot separation was good but there appears to have been some model-sabotcontact.

The deduced drag coefficients for two shots are given in Table. 12. The drag at Mach0.7 is a bit higher than at Mach 0.6 partially due to a standard Mach number rise in thisregion and possible also to higher angles of attack. The second shot definitely had veryhigh angles of attack to produce such a high drag.


The modifications to the sabot have made the separation of the sabotsymmetric but it is still missing the dimensions of the sabot trap. To alleviatethis, a special set up will be required at the aeroballistic range to make surethat the sabot petals are captured. The separation of the petals was measuredby putting a cardboard at 7.3 m from the muzzle. The separation of the petalswas very symmetric, for two consecutive shots, and at a radius of 65 cm fromthe firing line.

The results show that there is still some contact between the sabot and themodels and it seems to be happening more with the model with the aft CGX

than the forward one. As a matter of fact, all the aft CGX models fired had a

very poor flight dynamic behavior. The fact that the aft CGX has a solid base(Fig. 7b) and the forward one has an opening at the base (Fig. 7a) might shedsome crucial information. As the sabot opens, the pivot point of the openingwill be at the base of the petals close to the model. In the first test, impactswere noticed at the base of the petals over a small region. A small amount ofmaterial was removed from the sabot for the second series of tests and therewas some success with the forward CGX models and none with the aft one.

But some sabot impacts were still noticed on one shot of the forward CGXand all of the aft ones. The last trial again functioned relatively well for theforward CGX and not for the aft CGX . Therefore it is possible, and veryprobable, that the contact between the sabot and the model still occurs at thepivoting point of the sabot opening when the petals rotate. The last trialshowed that, at least, with the latest sabot modifications that the sabot wasopening in a symmetric fashion.

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4.6 Final Sabot Design for A1 Model

With the comments of the last section, a final sabot design was brought forward andthe schematic is shown in Fig. 26. The major modifications are at the base of the sabot.More material was removed from the sabot in the section just aft of the model. Theprime objective of the new sabot design was to displace the pivot point of the openingprocess further back, on a plastic ball bearing, rather than at the junction of the fourpetals of the previous designs. This will have the effect of momentary retard theangular rotation and the opening of the sabot with respect to the contact point at thebase of the model with the sabot. This will permit a prolonged time for the axialseparation of model. This should also help in enforcing a symmetric separation of thesabot petals. All the other modifications to the driving band were kept. This will be thesabot that will be used for the aeroballistic range tests.

After discussion with ISL, it was agreed that the first three models to be fired in theaeroballistic range program would be the configuration with the forward CGX with afin cant of 4.0°. For security reasons the movable butt in the aeroballistic range will belocated at 130.0 m form the muzzle to stop the projectiles. If these launches are asuccess, two projectiles with the aft CGX location with a fin cant of 8.0° would thenbe fired. The propellant charge mass is 55.0 g to obtain a velocity of 210.0 m/s.

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5.1 Model Design for A3 Configuration

The main concern in the model design for the A3 grid finned configuration (Fig. 2)was the possibility of structural failure of the fins at the base. The expected launchaccelerations were of the order of 30 000 gn at Mach 4.0. Since the body of the A3configuration is the Air Force Finner [3] and that some aeroballistic range tests hadbeen conducted also at DREV on that configuration [13], it was decided to keep thesame center of gravity position for the grid finned model. This would allow an easiercomparison of the aerodynamic results, especially for the dynamic derivatives. Thecenter of gravity position for the Air Force Finner projectile was 4.8 cal from the noseof the projectile [3, 13].

Therefore the body was made of an aluminum alloy with a brass nose. A photographof the model is shown in Fig. 27. The aft end of the projectile demonstrating the gridfin attachments to the model body is shown in Fig. 27b. The fins were made of highproof steel and they were glued in slots in the aluminum body. The placement of theroll pin to measure the roll orientation in the aeroballistic range tests is easily seen.The physical properties of the A3 projectiles for the first series of tests are given inTable 13. The center of gravity is located at about 4.84 cal from the nose and the massof the projectile is roughly 665 g.

5.2 Sabot Design for A3 ModelSince this model configuration in this case is fin stabilized, a smooth bore gun wasutilized. The standard gun employed at DRDC-V to fire fin-stabilized projectiles ofthese dimensions in the aeroballistic range is a 110-mm smooth bore gun.

A schematic of the sabot design for the A3 projectile is show in Fig. 28. It is a two-petal sabot design made of aluminium. It had four projectile centering screws at thefront of the sabot. The lengths of the saw cuts on each side were adjusted to obtainadequate petal separation for the expected velocities. A sabot base seal pad was alsoused to prevent gas leakage past the sabot body.

A pivot pin, which is in line with the saw cuts, was added to force the sabot opening atthat point. A polycarbonate ring with a 5° angle is positioned at the aft end of thesabot. There are two reasons for this. The first one, is to have a good pressure sealbetween the sabot and the gun tube so as to be able to have a known shot start pressurewhich helps in having consistent muzzle velocities at the same propellant charge mass.The second reason is that, as the sabot leaves the gun tube, the high radial pressureacting on the rear ring relative to the front part, causes the pivoting action at the pivotpoint of the sabot petals. The mass of the combined sabot-projectile wasapproximately 2.7 kg.

16 TM 2003-077

A photograph of the sabot-model package is shown in Fig. 29

5.3 Sabot-Model Integrity Trials 1 (Oct. 99) for A3 Model

The first series of tests to verify the sabot functioning for the A3 model wereconducted in October 1999. Since model-sabot combinations of this mass were firedpreviously, a charge determination was not necessary since enough data was available.The velocity of interest for the A3 projectile was from 210 m/s (Mach 0.6) to 1200 m/s(Mach 3.5).

Just prior to the free-flight trials for the A3 projectile, some wind tunnel results [14and 15] became available. Those results showed that this projectile, with the presentcenter of gravity position, was statically unstable for all Mach numbers below 2.5. Thetest plan was modified so as to test the sabot-projectile configuration at Mach 2.5 andabove.

The firing conditions at the time of firing are provided in Table 14 and the results inTable 15. The propellant type that was used was NQM-044. The first shot, A3-01, wasfired as close as possible to Mach 2.5. The sabot separation was correct and the petalsimpacted the sabot trap. The projectile was unstable for the reasons explainedpreviously.

The second shot, A3-04, was fired at a reduced charge to obtain a velocity of about675.0 m/s. This was done to make sure the wind tunnel results were correct and thefree-flight trials confirmed that the projectile was unstable. The sabot separation wascorrect.

The third shot fired, A3-03, was fired at the same charge as the first tests. The velocityobtained as slightly higher than the first shot, and the projectile was stable and itimpacted the target at 150.0 m. This also confirms the wind tunnel results that staticstability occurs just above Mach 2.5. A photograph of the projectile in flight isprovided in Fig. 30 at the second camera position.

The last shot fired for this configuration, A3-05, was at a velocity of about 1173 m/s(Mach 3.5). The maximum accelerations measured were roughly 25 000 gn and thefins survived the launch loads. The projectile was stable and it impacted the target. Thesabot separation is show in Fig. 31 at the first camera position.

The reduced drag coefficients from the Doppler measured velocity are provided inTable 16 and, as expected, they are high compared to planar fin.

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5.3.1 Comments an Discussions

The separation and functioning of the sabot at 860.0 m/s and 1175 m/sperformed as designed. The main concern is, unexpectedly, that the projectileis unstable below Mach 2.5 at the present center of gravity position. The windtunnel results [14 and 15] show that it would be impractical to try to fire theA3 projectile subsonically. To increase the Mach number range, the onlyoption was to displace the center of gravity location forward on the projectile.

Based on the wind tunnel results and a stability analysis, it was shown that,replacing the brass nose by a tungsten one would displace the center ofgravity position forward by about one caliber. This would allow having astable projectile from about Mach 1.4 and higher.

It was therefore decided to have a second series of tests with the tungstennose projectile to verify that the stresses at the base of the model would notbe surpassed at the higher velocities.

5.4 Sabot-Model Integrity Trials 2 (July 00) for A3 Model

There were no sabot design changes for the second series of tests. The nose section ofthe model was replaced with a tungsten one. A photograph of the sabot-model packageis shown in Fig. 32. The total mass was roughly 2.9 kg.

The physical properties of the projectiles with the tungsten nose are furnished in Table17. The center of gravity location is at 4.03 cal of the nose, about 0.8 cal more than thebrass nose projectile. The mass of the projectile increased by about 200 g, to 880.0 g

Three projectiles were fired in the second series of tests conducted in July of 2000.The firing conditions are provided in Table 18 and the results are presented in Table19. The chamber pressures were measured in these trials. The first shot fired at aboutMach 3.5, A3-21, was completely successful. The sabot separation is shown in Fig. 33.

The second shot, A3-22, fired at a velocity of 675.1 m/s, or Mach 2.0, was alsosuccessful in all the aspects.

The third shot, A3-23, was not successful since the sabot did not open enough. Theamount of material along the saw cuts at the base of the sabot will have to be reducedtill there is about 0.13 mm to 0.38 mm of material left.

The deduced drag coefficients for the two successful shots are supplied in Table 20.The DC are basically the same as the first series of tests

18 TM 2003-077


Overall, the sabot functioning is very satisfactory from Mach 1.5 to 3.5 withthe tungsten model. The model is stable at Mach 1.5 and above, and the finssurvive the launch loads.

It is planned to fire about 10 projectiles in the aeroballistic from Mach 1.5 to3.5 to obtain the aerodynamic coefficients and stability derivatives of this gridfin configuration

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The Mach number of interest of the A2 projectile configuration (Fig. 3) was about 0.6.Since the A3 model was unstable subsonically it was highly likely that the A2projectile configuration would also be unstable. Wind tunnel tests confirmed thishypothesis. Therefore, it was not possible to fire this projectile at that Mach numberand at the center of gravity position of the fabricated projectiles. For completenesspurposes, the sabot design will be presented as well as the test results for two slugs ofthe same mass.

The models were made of steel and the measured physical properties are supplied inTable 21. The center of gravity position is located at 3.4 cal from the nose and themass is about 730.0 g. A photograph of the A2 projectile is shown in Fig. 34. The finswere made of high proof steel and they were glued in slots in the steel body.

A schematic of the sabot design is illustrated in Fig. 35 and a photograph of the sabotpackage is shown in Fig. 36. The sabot pieces and functioning are the same as the A3projectile. The total mass of the sabot and model was around 2.18 kg.

The gun tube to be utilized was the 110 mm smooth bore gun with the HI-LO adaptor.There were no data for the HI-LO adaptor at this sabot-projectile mass. Therefore, twoslugs were fabricated at mass of 2.21 kg. The results of this test are provided in Table22. The muzzle velocities obtained for propellant charge masses of 40.0 g and 80.0 gwere 170.7 m/s and 263.9 m/s, respectively.

The wind tunnel results showed that the center of pressure was located at 0.8 cal fromthe nose at Mach 0.6. It was deemed impossible, based on those results, to displace thecenter of gravity position ahead of this location and to have a statically stableprojectile and a structurally sound one. Therefore, the aeroballistic range trials for theA2 projectile were not pursed any further.

20 TM 2003-077

7. Conclusions

The model and sabot design of the A1, A2 and A3 projectile configurations for thejoint DRDC-ISL project were presented.

The initial free-flight trials to test the sabot concepts to launch the three configurationswere successfully completed. The velocity of interest, depending on the configuration,ranged from 210 to 1200 m/s. A 110-mm smooth bore and 105 mm rifled gun tubeswith and without a special Hi-Lo adapter were used to launch the projectiles. A seriesof slugs were fired to obtain the required propulsive charge to obtain a specificvelocity in some cases. The propellant charge mass, muzzle velocity, maximumacceleration were determined for each shot and the drag coefficient was deduced fromthe stable projectiles.

Three trials were necessary to obtain a safe sabot to launch the A1 projectileconfiguration. A total of eighteen shots were fired. The design of the sabot and theprojectile proved to be quite a challenge. The engraving process, the symmetric petalseparation, as well as avoiding model sabot contact at separation at a velocity of 210m/s and at high spin rates simultaneously, were finally resolved.

The sabot concept for the A3 projectile worked as expected. The projectile wasmodified to have its center of gravity position more forward than the first design. Thiswas done since the latticed finned projectile was statically unstable. The new projectiledesign will allow testing from Mach 1.4 to 3.5.

The A2 projectile was never fired since the projectile was unstable at the Machnumber range of interest of 0.6. It was believed impossible to displace the center ofgravity position to obtain a statically stable projectile and a structurally sound one.Therefore, the aeroballistic range trials for the A2 projectile will not be pursed.

The next step in the project is to fire the two different configurations in the DRDCValcartier aeroballistic range to determine their aerodynamic characteristics andstability derivatives (static and dynamic) with the goal of establishing a reliabledatabase.

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8. References

1. Fleck, V., Berner, C., "Increase of Range for an Artillery Projectile by Using theLift Force", Proceedings 16th International Ballistics Symposium, San Francisco,CA, USA, 23-27 September 1996, ISL Report PU 355/96

2. Abate, G., Winchenbach, G. and Hathaway, W., “Transonic Aerodynamic andScaling Issues for Lattice Projectiles Tested in Ballistic Ranges”, 19th

International Symposium on Ballistics, 7-11 May, 2001, Interlaken, Switzerland.

3. West, K. O., "Comparison of Free-flight Spark Range and Wind Tunnel TestData for a Generic Missile Configuration at Mach Numbers From 0.6 to 2.5",AFATL-TR-81-87

4. Washington, W.D., Miller, M.S., "Experimental Investigations on Grid FinAerodynamics: A Synopsis of Nine Wind Tunnel and Three Flight Tests", RTO-MP-5 AC/323(AVT)TP/3, November 1998

5. Simpson, G.M., Saddler, A.J., "Lattice Controls: A Comparison withConventional Planar Fins", RTO-MP-5 AC/323(AVT)TP/3, November 1998

6. Abate, G.L., Duckerschein, R.P., Hathaway, W., "Subsonic/Transonic Free-Flight Tests of a generic Missile with Grid Fins", AIAA Paper 2000-0937, 38th

AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, USA, Jan. 2000

7. Fournier, E., “Aerodynamic Coefficients Measurements of a High L/D Projectilewith Grid Fins”, DREV TM 2001-035, April 2001, UNCLASSIFIED

8 DeSpirito, J., Edge, H., Weinacht, P., Sahu, J. and Dinavahi, S., “ComputationalFluid Dynamics (CFD) Analysis of a Generic Missile with Grid Fins”, ARL-TR-2318, September 2000

9. "Projectile Design Analysis System (PRODAS), P2000 V 2.2.17", Arrow TechAssociates Inc., 2000.

10. Moore, F. G., McInville, R., M. and Hymer, T., "The 1995 Version of the NSWCAeroprediction Code: Part I - Summary of New Theoretical Methodology",Naval Surface Weapons Center, NSWCCDD/TR-94/379, February 1995

11. Burns, K. A., Deters, K. J., Stoy, S. L., Vukelich, S. R. and Blake, W. B,"Missile Datcom Users Manual - Revision 6/93", WL-TR-93-3043, June 1993

12. Dupuis, A.D. and Berner, C., “Wind Tunnel Tests of a Long Range ArtilleryShell concept”, AIAA-2002-4416, August 2002.

22 TM 2003-077

13. Dupuis, A. D. and Hathaway, W., “Aeroballistic Range Tests of the Air ForceFinner Reference Projectile”, DRDC Valcartier TM 2002-008, May 2002,UNCLASSIFIED

14. Berner, C., and Dupuis, A., “Wind Tunnel Tests of a Grid Finned ProjectileConfiguration”, AIAA 2001-0105, 39th Aerospace Sciences Meeting and Exhibit,8-11 January 2001, Reno, Nevada (ISL PU346/2000)

15 Dupuis, A. and Berner, C., “Aerodynamic Aspects of a Grid finned Projectile atSubsonic and Supersonic Velocities”, 19th International Symposium on Ballistics,Interlaken, Switzerland, 7-11 May 2001

TM 2003-077 23

R 10.12

0.50

1.00

1.00

5.65

1.90

0.088

δδδδ

3.00

Figure 1a. General geometry

0.053

0.50

R 1.264

R 0.002

Figure 1b. Fin details

Figure 1. Model A1 - Artillery shell concept with wings (all dimensions in caliber, 1 cal = 30

mm)

24 TM 2003-077

10.00

2.50

R 6.53

1.00

R 0.007

0.7

0.7

0.44

Figure 2a. Overall geometry

0.44

0.55

0.70

0.13

0.124

0.16

1

0.017

0.017

0.075

0.08


Figure 2. Model A3 - Grid finned projectile (all dimensions in caliber, 1 cal = 30 mm)

TM 2003-077 25

R 10.12

1.00

5.65

0.088

3.00

0.70

0.70

0.44

3.43

CG

Figure 3a. Overall geometry

0.44

0.55

0.70

0.13

0.124

0.16

1

0.017

0.017

0.075

0.08


Figure 3. Model A2 - Artillery shell concept with grid fins (all dimensions in caliber, 1 cal = 30

mm)

TM

2003

-XX

26

6.3

m

11.5

m

9.2

m

150.

0m

Bal

listi

cSy

nchr

oC

amer

a

35G

Hz

RA

DA

R 110

mm

gun

Bla

stgu

age

1m

7.2

m

Sabo

ttr

ap

12.0

m

ED

-85

0R

adar

Ref

lect

ing

mir

ror

1.2

m

Yaw

card

pack

sat

20.0

man

d30

.0m

Fig

ure

4.S

chem

atic

of

the

test

site

26 TM 2003-077

TM 2003-XX 27

Figure 5a. View 1

Figure 5a. View 2

Figure 5. Photograph of test set up

TM

2003

-XX

28

1-

M-6

3pr

imer

5-

Dif

fuse

r2

-O

btur

ator

6-

“O”

ring

3-

“O”

ring

7-

Nut

4-

Shaf

t

Fig

ure

6.H

i-L

o11

0m

mch

amb

read

apte

r

28 TM 2003-077

TM 2003-XX 29

Figure 7a. Statically stable projectile; CGX = 2.72 cal from nose

Figure 7b. Gyroscopically stable projectile; CGX = 3.12 cal from nose

Figure 7. Schematics of A1 projectile design

30 TM 2003-077

1 - Base seal 3 - Aluminium sabot body2 - Polycarbonate ring 4 - A1 Projectile

Figure 8. Sabot schematic for the A1 projectile

Figure 9. Photograph of sabot package for A1 model

TM 2003-077 31

Figure 10a. Grooved portion of sabot body

Figure 10b. Polycarbonate section

Figure 10. Photographs of A1 sabot pieces

32 TM 2003-077

1 - Polycarbonate sabot 3 - Ballast2 - Retaining pin 4 - Seal

Figure 11. Sabot schematic for the slug for A1 model

0.0

50.0

100.0

150.0

200.0

250.0

-5000.0

0.0

5000.0

10000.0

15000.0

20000.0

25000.0

30000.0

35000.0

-0.035 -0.030 -0.025 -0.020 -0.015 -0.010 -0.005 0.000 0.005

Time (s)

Figure 12. Velocity and acceleration history for Slug SLA1-3

TM 2003-077 33

Figure 13a. Camera 1

Figure 13b. Camera 2

Figure 13. Sabot separation for A1 model - Shot A1-08, VMUZ = 240.0 m/s

34 TM 2003-077

Figure 14a. View 1

Figure 14b. View 2

Figure 14. Photographs of recovered sabot pieces for A1 model

Model sabotcontact

TM 2003-077 35

Figure 15. Photograph of recovered polycarbonate section

36 TM 2003-077


5 - Optional cylindrical pad

Figure 16. Modified sabot schematic for the A1 projectile - July 00

Figure 17. Photograph of modified sabot package for A1 model - July 00

TM 2003-077 37



38 TM 2003-077



TM 2003-077 39

Figure 22. Sabot separation for A1 model - Shot A1-31, VMUZ = 233. m/s




40 TM 2003-077




TM 2003-077 41




42 TM 2003-077


5 - Pivot ball bearing

Figure 26. Schematic of final design for the A1 projectile

TM 2003-077 43

Figure 27a. Plan view

Figure 27b. Rear view

Figure 27. Photograph of A3 projectile with brass nose

44 TM 2003-077

1 - 5.0° polycarbonate ring 4 - Aluminium petal2 - Centering screws 5 - Seal pad3 - A3 projectile 6 - Pivot pin



TM 2003-077 45



46 TM 2003-077

Figure 32. Photograph of sabot package for A3 model - July 00

TM 2003-077 47




48 TM 2003-077

Figure 34. Photograph of A2 projectile

TM 2003-077 49

1 - 5.0° polycarbonate ring 4 - Aluminium petal2 - Centering screws 5 - Seal pad3 - A2 projectile 6 - Pivot pin



50 TM 2003-077

Table 1. Firing Conditions for A1 model - Trial 1 (Oct 99)

ModelNumber

DateFired

AtmosphericTemperature

(°C)

AtmosphericPressure(mBar)

A1-10 25/10/99 0.6 996.0A1-09 25/10/99 1.6 996.2A1-08 26/10/99 1.3 991.8A1-07 26/10/99 3.8 989.6A1-06 27/10/99 2.2 1004.8

Table 2. Results from gun firing for 3.25 slugs (Oct 99)

105 mm HI-LO – 9.525 DIFFUSERPROPELLANT TYPE: N-311 – 0.035

MTOT = 3.25 kg

ModelNumber

PropellantMass

MaxAcc.

In boreMuzzleVelocity

DopplerRadar

MuzzleVelocity

Comments

(g) (gn) (m/s) (m/s)

SLA1-1 80.0 - - -

Slug stuck in barrel after 27mm displacement

Slug pushed out with highpropellant charge

SLA1-2 80.0 3245 240.5 245.1

Driving band diameterreduced to 107.29 mm from108.71 mmGood resultsImpact at 150 m

Z = -2.5 mY = -0.2 m

SLA1-3 80.0 3361 240.5 241.5

Repeat of SLA1-2Good resultsImpact at 150 m

Z = -1.5 mY = +1.0 m

TM 2003-077 51

Table 3. Measured physical properties of A1 projectiles (Oct. 99)

ModelNumber

d

(mm)

l

(mm)

CGfromnose(mm)

CGfromnose(cal)

CGfromnose(cg/l)

m

(g)

IX

(g-cm2)

IY

(g-cm2)

A1-01 30.00 169.520 93.983 3.133 0.554 921.9 1131.33 15881.01

A1-02 30.00 169.545 93.899 3.130 0.554 922.0 1131.04 15892.80

A1-03 30.00 169.672 93.980 3.133 0.554 923.1 1130.44 15945.12

A1-04 29.99 169.622 94.008 3.134 0.554 922.6 1129.36 15947.20

A1-05 30.00 169.647 94.155 3.139 0.555 921.2 1130.58 15874.12

A1-06 29.99 169.571 81.788 2.727 0.482 903.5 1088.96 13312.95

A1-07 29.99 169.545 81.742 2.726 0.482 905.3 1093.09 13341.18

A1-08 29.99 169.571 81.715 2.725 0.482 905.6 1093.72 13348.39

A1-09 30.00 169.622 81.826 2.728 0.482 903.1 1089.28 13324.29

A1-10 29.99 169.571 81.648 2.722 0.482 904.7 1090.70 13342.53

52 TM 2003-077

Table 4. Results from gun firing for A1 Model - Trial 1 (Oct 99)


MTOT = 3.15 kg

ModelNumber

PropellantMass

MaxAcc.


DopplerRadar

MuzzleVelocity

Comments

(g) (gn) (m/s) (m/s)

A1-10 80.0 3354 247.0 250.0

Driving band diameter at107.29 mm

Sabot did not open- To much plastic to break

A1-09 80.0 2553 247.5 251.3

- Sabot modified by sawcutting deeper5.33 mm wall left

- Slots filled with resin- Sabot did not open

A1-08 80.0 2496 240.0 see note1

- Saw cuts made deeperleaves 2.3 mm wall

- Slot split to driving band- Sabot opened very fast

more than sabot trap size- Projectile unstable- Impact at 150 m

Z = +1.8 mY = -0.5 m

(90° orientation impact)

A1-07 80.0 2448 229.1 see note 1

- Slots split halfway todriving band

- Results similar to A1-08- Evidence of impact of sabot

and model

A1-06 70.0 1813 213.0 see note 1- Repeat of A1-08- Same results- Evidence of impact of sabot

and model1 since projectile was unstable, unable to obtain accurate muzzle velocity

TM 2003-077 53

Table 5. Measured physical properties of A1 projectiles (July 00)

ModelNumber

d

(mm)

l

(mm)

CGfromnose(mm)

CGfromnose(cal)

CGfromnose(cg/l)

m

(g)

IX

(g-cm2)

IY

(g-cm2)

A1-21 30.00 169.583 81.410 2.714 0.480 900.3 1089.73 13147.72

A1-22 29.97 169.622 81.593 2.722 0.481 902.1 1091.06 13273.21

A1-23 29.99 169.672 81.689 2.724 0.481 906.4 1096.38 13385.87

A1-24 29.97 169.634 93.835 3.131 0.553 922.6 1130.67 15914.94

A1-25 29.98 169.660 93.846 3.130 0.553 922.5 1130.94 15934.61

A1-26 29.98 169.533 93.820 3.129 0.553 921.1 1130.40 15862.55

Table 6. Firing Conditions for A1 model - Trial 2 (July 00)

ModelNumber

DateFired


(°C)


A1-21 10/07/00 19.5 983.4

A1-24 10/07/00 23.3 983.1

A1-22 11/07/00 16.6 989.5

A1-25 11/07/00 16.7 989.9

A1-23 11/07/00 18.3 990.1

A1-26 11/07/00 18.8 990.3

54 TM 2003-077

Table 7. Results from gun firing for A1 Model - Trial 2 (July 00)


MTOT = 2.76 kg

ModelNumber

PropellantMass

MaxAcc.


DopplerRadar

MuzzleVelocity

Comments

(g) (gn) (m/s) (m/s)

A1-21 70.0 2440 250.0 245.7

Good sabot separationStable at muzzleUnstable at 150 mImpact traces on sabot petal

due to modelImpact at 150 m

Z = +1.9 mY = -1.7 m

A1-22 60.0 - - 215.7

Good sabot separationProjectile stableImpact at 150 m

Z = 1.6 mY = -0.1 m

A1-23 60.0 2055 210.0 212.7


Z = 2.1 mY = -0.05 m

A1-24 60.0 1960 220.0 218.1

Good sabot separationStable at 30 mUnstable at 150 mImpact at 150 m

Z = +2.2 mY = -2.0 m

A1-25 60.0 2215 215.0 205.2Bad launchProjectile unstable at muzzleNo impact at 150 m

A1-26 60.0 1945 205.0 204.5

Install base bad in sabotSabot opened a lot less

than other shotsProjectile unstable at muzzleNo impact at 150 mTraces of impact between

model and sabot

TM 2003-077 55

Table 8. Deduced drag coefficient for A1 Model - Trial 2 (July 00)

ModelNumber

MachNumber DC

A1-22 0.63 0.248

A1-23 0.62 0.254

Table 9. Measured physical properties of A1 projectiles (Nov. 00)

ModelNumber

d

(mm)

l

(mm)

CGfromnose(mm)

CGfromnose(cal)

CGfromnose(cg/l)

m

(g)

IX

(g-cm2)

IY

(g-cm2)

A1-31 29.98 169.520 81.471 2.718 0.481 904.2 1086.47 13223.75

A1-32 29.98 169.558 81.556 2.721 0.481 904.1 1087.00 13254.61

A1-33 29.97 169.571 93.574 3.122 0.552 928.6 1132.70 16130.19

A1-34 29.97 169.583 93.626 3.124 0.552 928.8 1132.77 16137.92

Table 10. Firing Conditions for A1 model - Trial 3 (Nov 00)

ModelNumber

DateFired


(°C)


A1-31 14/11/00 6.1 983.3

A1-33 14/11/00 5.8 982.8

A1-32 15/11/00 3.1 973.7

A1-34 15/11/00 3.8 973.0

56 TM 2003-077

Table 11. Results from gun firing for A1 Model - Trial 3 (Nov 00)


MTOT = 2.74 kg

ModelNumber

PropellantMass

MaxAcc.


DopplerRadar

MuzzleVelocity

Comments

(g) (gn) (m/s) (m/s)

A1-31(δ=4.0°)

60.0 2240 232.3 233.9

Sabot opening more thansabot dimensions


Z = +2.2 mY = -0.6 m

A1-32(δ=4.0°)

55.0 2300 210.0 213.8

Contact sabot - modelHi yaw on Camera 1 and 2Projectile stable at yaw cardsNo impact at 150 m

A1-33(δ=8.0°)

60.0 2220 223.6Projectileunstable

Good sabot separationNo yaw at Cam 1High yaw on Cam 2No impact at 150 m

A1-34(δ=8.0°)

55.0 2135 208.9Projectileunstable

Good sabot separationNo impact at 150 m

Table 12. Deduced drag coefficient for A1 Model - Trial 3 (Nov 00)

ModelNumber

MachNumber

DC

A1-31 0.70 0.347

A1-32 0.64 1.606

TM 2003-077 57

Table 13. Measured physical properties of A3 projectiles (Oct. 99)

ModelNumber

d

(mm)

l

(mm)

CGfromnose(mm)

CGfromnose(cal)

CGfromnose(cg/l)

m

(g)

IX

(g-cm2)

IY

(g-cm2)

A3-01 30.00 299.848 145.044 4.835 0.484 663.7 742.93 48403.08

A3-03 29.99 300.000 145.011 4.835 0.483 664.0 742.30 48464.71

A3-04 30.00 299.975 145.034 4.835 0.483 664.2 744.64 48448.90

A3-05 30.00 299.975 145.034 4.835 0.483 663.9 743.18 48489.65

Table 14. Firing Conditions for A3 model - Trial 1 (Oct 99)

ModelNumber

DateFired


(°C)


A3-01 13/10/99 5.7 995.6

A3-04 13/10/99 6.9 990.9

A3-03 14/10/99 4.2 985.4

A3-05 14/10/99 4.4 987.0

58 TM 2003-077

Table 15. Results from gun firing for A3 Model - Trial 1 (Oct 99)

110 mmPROPELLANT TYPE: NQM-044

MTOT = 2.7 kg

ModelNumber

PropellantMass

MaxAcc.


DopplerRadar

MuzzleVelocity

Comments

(kg) (gn) (m/s) (m/s)

A3-01 2.72 11450 832.8 833.8Good sabot separationProjectile unstableMissed target at 150 m

A3-04 1.81 7318 674.0 674.5Good sabot separationProjectile unstableMissed target at 150 m

A3-03 2.72 12134 859.2 859.4

Good sabot separationImpact at 150 m

Z = +0.1 mY = -0.1 m

A3-05 4.08 24593 1174.5 1173.1

Good sabot separationImpact at 150 m

Z = -0.1 mY = -1.0 m

Table 16. Deduced drag coefficient for A3 Model - Trial 1 (Oct 99)

ModelNumber

MachNumber DC

A3-03 2.57 0.945

A3-05 3.51 1.080

TM 2003-077 59

Table 17. Measured physical properties of A3 projectiles (July 00)

ModelNumber

d

(mm)

l

(mm)

CGfromnose(mm)

CGfromnose(cal)

CGfromnose(cg/l)

m

(g)

IX

(g-cm2)

IY

(g-cm2)

A3-21 29.98 299.911 120.874 4.031 0.403 879.9 953.26 64349.39

A3-22 29.96 299.873 120.765 4.031 0.403 878.3 950.19 64270.32

A3-23 29.96 300.013 120.973 4.037 0.403 877.2 949.81 64292.91

Table 18. Firing Conditions for A3 model - Trial 2 (July 00)

ModelNumber

DateFired


(°C)


A3-21 5/07/00 18.0 989.8

A3-22 5/07/00 17.3 990.0

A3-23 6/07/00 19.7 993.3

60 TM 2003-077

Table 19. Results from gun firing for A3 Model - Trial 2 (July 00)

110 mmPROPELLANT TYPE: NQM-044

MTOT = 2.9 kg

ModelNumber

PropellantMass

ChamberPressure

MaxAcc.


DopplerRadar

MuzzleVelocity

Comments

(kg) (MPa) (gn) (m/s) (m/s)

A3-21 4.08 104.5 23385 1158.0 1158.4


Z = -0.3 mY = 0.0 m

A3-22 1.81 23.4 - - 675.1


Z = -0.2 mY = -0.2 m

A3-23 1.36 - 4880 555.0 556.4Bad sabot separationSplit sabot more

along sawcuts

Table 20. Deduced drag coefficient for A3 Model - Trial 2 (July 00)

ModelNumber

MachNumber

DC

A3-21 3.39 0.902

A3-22 1.98 1.179

TM 2003-077 61

Table 21. Measured physical properties of A2 projectiles (Oct 99)

ModelNumber

d

(mm)

l

(mm)

CGfromnose(mm)

CGfromnose(cal)

CGfromnose(cg/l)

m

(g)

IX

(g-cm2)

IY

(g-cm2)

A2-01 29.98 169.495 103.030 3.437 0.608 727.4 777.43 12225.85

A2-02 29.98 169.444 102.967 3.434 0.608 727.2 776.77 12201.67

Table 22. Results from gun firing for 2.2 kg slugs (Oct 99)


MTOT = 2.21 kg

ModelNumber

PropellantMass

MaxAcc.


DopplerRadar

MuzzleVelocity

Comments

(g) (gn) (m/s) (m/s)

SLA2-1 40.0 1250 171.3 170.7 Good shot

SLA2-2 80.0 - - 263.9 Good shot

62 TM 2003-077

Annex A - Measured Roll Orientations

TM 2003-077 63

MODEL A1-21 (cg forward)

Vmuz = 245.7 m/s; muzφ′ = 190.4 °/m

X(m)

Roll Angle(deg)

Delta 1(°/m)

Delta 2(°/m)

19.0 167154.0

19.5 244 144.0134.0

20.0 311

30.0 71112.0

30.5 127204.0

31.0 229


Vmuz = 215.7 m/s; muzφ′ = 190.5 °/m

X(m)

Roll Angle(deg)

Delta 1(°/m)

Delta 2(°/m)

19.0 107136

19.5 175 129122

20.0 236

30.0 129110

30.5 183 126144

31.0 255

64 TM 2003-077

MODELE A1-23 (cg forward)

Vmuz = 212.7 m/s; muzφ′ = 190.5 °/m

X(m)

Roll Angle(deg)

Delta 1(°/m)

Delta 2(°/m)

19.0 155138

19.5 224 134130

20.0 289

30.0 220118

30.5 279 133148

31.0 353

MODEL A1-24 (cg aft)

Vmuz = 218.1.0 m/s; muzφ′ = 190.5 °/m

X(m)

Roll Angle(deg)

Delta 1(°/m)

Delta 2(°/m)

19.0 73166

19.5 156 138110

20.0 211

30.0 205120

30.5 265 136152

31.0 341

TM 2003-077 65


Vmuz = 233.9 m/s; muzφ′ = 190.4 °/m

X(m)

Roll Angle(deg)

Delta 1(°/m)

Delta 2(°/m)

20.0 273138

20.5 342 133128

21.0 406.0

30.0 335176

30.5 423 155134

31.0 490


Vmuz = 213.8 m/s; muzφ′ = 190.4 °/m

X(m)

Roll Angle(deg)

Delta 1(°/m)

Delta 2(°/m)

20.0 311128

20.5 375 122116

21.0 433

30.0 231129

30.5 -

31.0 0.0

66 TM 2003-077

List ofsymbols/abbreviations/acronyms/initialisms

CD drag coefficient

DRDC-V Defence Research and Development Canada - Valcartier

d cylindrical diameter of models (mm)

I IX Y, axial and transverse moments of inertia (g - cm2)

l length (m)

m mass (g)

CGX center of gravity from nose (cal or m)

CPX center of pressure from nose (cal or m)

TM 2003-077 67

Distribution list

INTERNAL DISTRIBUTION

1 – Director General1 - Deputy Director General3 - Document Library1 - A. Dupuis (author)1 - M. Boivin (author)1 - F. Lesage1 - É. Fournier1 - N. Hamel1 - A. Jeffrey1 - M. Lauzon1 - P. Harris1 - Maj. Côté1 - R. Bélanger1 - D. Sanschagrin1 - R. Stowe1 - F. Wong1 – D. Corriveau1 – Munitions Test and Evaluation Center - Valcartier

EXTERNAL DISTRIBUTION

1 - DRDKIM (unbound copy)1 – Defence Research and Development Canada1 – Director Science and Technology Land1 – Director Land Requirement1 – Director Air Requirement 51 – Director Naval Requirement1 – Director Science Technology Air1 - Director Science Technology Naval1 – Directorate of Technical Airworthiness 61 - Directorate of Technical Airworthiness 6-3-71 – Director Ammunition Program Management (ES) 4-31 – Defence Research and Development Canada - Suffield

68 TM 2003-077

1 - M. M. Normand (author)MAETEC6161, route FossambaultVille de Fossambault, QCG0A 3M0

1 – Dr. C. Berner1 - Dr. V. FleckInstitut de recherches franco-allemands de Saint-Louis5, rue du Général CassagnouSaint-Louis, France, 68301

dcd03f

SANS CLASSIFICATIONCOTE DE SÉCURITÉ DE LA FORMULE

(plus haut niveau du titre, du résumé ou des mots-clefs)

FICHE DE CONTRÔLE DU DOCUMENT

1. PROVENANCE (le nom et l’adresse)

DRDC Valcariter

2. COTE DE SÉCURITÉ

(y compris les notices d’avertissement, s’il y a lieu)

UNCLASSIFIED

3. TITRE (Indiquer la cote de sécurité au moyen de l’abréviation (S, C, R ou U) mise entre parenthèses, immédiatement après le titre.)

Model, Sabot Design and Free-Fligth Tests of the DRDC-ISL A1, A2 and A3 Models

4. AUTEURS (Nom de famille, prénom et initiales. Indiquer les grades militaires, ex.: Bleau, Maj. Louis E.)

Dupuis, Alain D., Normand Marcel, Boivin Marco

5. DATE DE PUBLICATION DU DOCUMENT (mois et année)

July 2003

6a. NOMBRE DE PAGES

82

6b. NOMBRE DE REFERENCES

15

7. DESCRIPTION DU DOCUMENT (La catégorie du document, par exemple rapport, note technique ou mémorandum. Indiquer les dates lorsque le rapportcouvre une période définie.)

Technical Memorandum

8. PARRAIN (le nom et l’adresse)

9a. NUMÉRO DU PROJET OU DE LA SUBVENTION

(Spécifier si c’est un projet ou une subvention)

9b. NUMÉRO DE CONTRAT

10a. NUMÉRO DU DOCUMENT DE L’ORGANISME EXPÉDITEUR

TM 2003-077

10b. AUTRES NUMÉROS DU DOCUMENT

N/A

11. ACCÈS AU DOCUMENT (Toutes les restrictions concernant une diffusion plus ample du document, autres que celles inhérentes à la cote de sécurité.)

Diffusion illimitéeDiffusion limitée aux entrepreneurs des pays suivants (spécifier)Diffusion limitée aux entrepreneurs canadiens (avec une justification)Diffusion limitée aux organismes gouvernementaux (avec une justification)Diffusion limitée aux ministères de la DéfenseAutres (préciser)

12. ANNONCE DU DOCUMENT (Toutes les restrictions à l’annonce bibliographique de ce document. Cela correspond, en principe, aux données d’accèsau document (11). Lorsqu’une diffusion supplémentaire (à d’autres organismes que ceux précisés à la case 11) est possible, on pourra élargir le cerclede diffusion de l’annonce.)

SANS CLASSIFICATIONCOTE DE LA SÉCURITÉ DE LA FORMULE


dcd03f

SANS CLASSIFICATIONCOTE DE LA SÉCURITÉ DE LA FORMULE


13. SOMMAIRE (Un résumé clair et concis du document. Les renseignements peuvent aussi figurer ailleurs dans le document. Il est souhaitable que lesommaire des documents classifiés soit non classifié. Il faut inscrire au commencement de chaque paragraphe du sommaire la cote de sécuritéapplicable aux renseignements qui s’y trouvent, à moins que le document lui-même soit non classifié. Se servir des lettres suivantes: (S), (C), (R) ou(U). Il n’est pas nécessaire de fournir ici des sommaires dans les deux langues officielles à moins que le document soit bilingue.)

Preliminary free - flight tests were conducted to verify the integrity of sabots and the A1, A2 and A3 DRDC-ISL model configurations launched from apowdered gun in the velocity range of 200 to 1400 m/s. Projectiles of each configuration were fired as well as a series of slugs for charge determination. Thepropellant charge mass, muzzle velocity, maximum accelerations and drag coefficient were determined for each shot when fired from a 110-mm smoothbore gun and a 105 mm rifled one with and without a high-low pressure chamber adapter.

14. MOTS-CLÉS, DESCRIPTEURS OU RENSEIGNEMENTS SPÉCIAUX (Expressions ou mots significatifs du point de vue technique, qui caractérisent undocument et peuvent aider à le cataloguer. Il faut choisir des termes qui n’exigent pas de cote de sécurité. Des renseignements tels que le modèle del’équipement, la marque de fabrique, le nom de code du projet militaire, la situation géographique, peuvent servir de mots-clés. Si possible, on doitchoisir des mots-clés d’un thésaurus, par exemple le “Thesaurus of Engineering and Scientific Terms (TESTS)”. Nommer ce thésaurus. Si l’on ne peutpas trouver de termes non classifiés, il faut indiquer la classification de chaque terme comme on le fait avec le titre.)

FREE-FLIGHT TESTS

SABOT DESIGN

PROJECTILE DESIGN

SABOT SEPARATION

RADAR

DRAG COEFFICIENT

LATTICE FINNED PROJECTILE

ARTILLERY SHELL WITH WINGS

GUN LAUNCHED

CHARGE DETERMINATION

SMOOTH BORE GUN

SUBSONIC

TRANSONIC

SUPERSONIC

FLIGHT DYNAMICS

SANS CLASSIFICATIONCOTE DE SÉCURITÉ DE LA FORMULE


model, sabot design and free-flight tests of the drdc...

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