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I've noticed there is no repository for ballistic science documents the way there is for the Mechanized or the infantry forums (for example) so I decided to fix this. 

 

My first offering is dtic stuff from the past on some weird and novel ways to extend the L/D ratios of spin stabilized projectiles.   I originally learned about this from someone I was having a discussion with years back and hunting lead me to one of those discussions about bringing back the battleships on navweaps discussion boards where one of the posters (Zenmastur) laid out his master plan for Battleship resurrection.  Which included the aforementioned 'higher than 6:1 L/D ratio spin stabilized projectiles'.    It took awhile to hunt down but I eventually found some of the original documents that focused on novel projectile shapes (for a large improvement) and non-conical boat tails (for a much smaller improvement)   

 

Obviously this went nowhere insofar as I am aware, and I suspect they had drawbacks nobody addressed (like most do) but it's an interesting thing to look at anyhow.   Much of this is the work of one Anders S. Platou, who seems to be as prolific as the RAVEN guy. 

 

AN IMPROVED PROJECTILE BOATTAIL

 

Quote

A series of projectile boattails have shown improved aerodynamic performance over the standard conical boatail. These boattails have equal or lower drag and an improved gyroscopic stability. Their Magnus and damping characteristics appear to be satisfactory so that the projectile should be dynamically stable. Also, these boattails increase the projectile wheel base considerably, thereby decreasing the balloting in the gun tube. The improved aerodynamic performance could lead to longer ranges, longer projectiles or lower spin rates for future projectiles.

 

AN IMPROVED PROJECTILE BOATTAIL. PART II.

 

Quote

A series of projectile boattails have shown improved aerodynamic performance over the standard conical boattail. These boattails have equal or lower drag and an improved gyroscopic stability. Their Magnus and damping characteristics appear to be satisfactory so that the projectile should be dynamically stable. Also, these boattails increase the projectile wheel base considerably, thereby decreasing the balloting in the gun tube. The improved aerodynamic performance could lead to longer ranges, larger payloads, or lower spin rates for future projectiles.


Improving the Flight Performance of Projectiles 

 

Quote

The BRL has been conducting experiments on spin stabilized projectiles using a new boattail shape called the Non-Conical Boattail. This boattail improves the aeroballistic characteristics of the projectile so that longer ranges are attained and heavier payloads can be flown to the target with good accuracy. Many of these experiments have been carried out on 155mm diameter full bore projectiles, but the aerodynamic characteristics can be applied to this configuration in any diameter including subcalibered projectiles.

 


 

The new boattail also provides a better configuration than a conical boattail for imparting spin as well as forward velocity to the projectile through a saboting system. In this report, the aerodynamic and aeroballistic characteristics of the new projectile as obtained from aeroballistic ranges, wind tunnels, and full range flights are summarized and compared to a similar conical boattail projectile.
 

 

 

MUZZLE-BLAST-INDUCED TRAJECTORY PERTURBATION OF NONCONICAL AND CONICAL BOATTAIL PROJECTILES

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Muzzle-blast loadings on spin-stabilized projectiles are analyzed and used to compute resultant trajectory deviations. Both conical and nonconical boattail rounds are treated. Approximations are made that permit the expression for the force on the projectile to be integrated; the resulting equation is used to develop a universal momentum transfer function that can be directly related to projectile jump. Although nonconical boattail configurations are more sensitive to muzzle blast than conical designs, the computed trajectory deviation in either case is small compared to the total measured dispersion of typical systems

 

THE EFFECT OF VARIOUS BOATTAIL SHAPES ON BASE PRESSURE AND OTHER AERODYNAMIC CHARACTERISTICS OF A 7-CALIBER LONG BODY OF REVOLUTION AT M = 1.70

 

Quote

Models, 7 calibers long, with a variety of conical, ogival (convex) and concave boattails were free-flight tested at M = 1.70, for drag and other aerodynamic characteristics. The total drag decreases monotonically for boattails longer than 0.5 calibers. For shorter boattails, the drag is higher than that of the square based body. For boattail lengths between 0.5 and 1.5 calibers, conical boattails have lower drag than either the ogival or concave configurations. The base pressure decreases with boattail length but increases with the boattail angle at the base. Among other aerodynamic characteristics, the boattailing appears to cause the most significant change in the Magnus torque coefficient. For certain boattails, this change may be sufficiently large to make the configuration dynamically unstable.

 

 

 

 

 

YAWSONDE FLIGHTS OF 155MM NON-CONICAL BOATTAIL PROJECTILES AND THE 155MM M549 PROJECTILE AT TONOPAH TEST RANGE-OCTOBER 1977

 

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As part of the BRL program to develop the non-conical boattail projectile, twenty 155mm projectiles were fired from an M185 gun tube on 18 and 21 October 1977 at the Sandia Corporation, Tonopah Test Range, Nevada. This is the second phase of a planned three phase test program at Tonopah on the nonconical boattail projectiles. The report describes the experimental plans and presents the data records and some of the results obtained during the projectile flights.

 


YAWSONDE FLIGHTS OF 155MM NON-CONICAL BOATTAIL PROJECTILE-B CONFIGURATIONS AT TONOPAH TEST RANGE--MARCH 1978

 

Quote

As part of the BRL program to develop the non-conical boattail projectile, twenty 155mm projectiles were fired from an M185 gun tube on 14 and 16 March 1978 at the Sandia Corporation, Tonopah Test Range, Nevada. This is the third phase of the non-conical boattail program . This report describes the experimental plans and presents the data records and some of the results obtained during the projectile flights.

 

AEROBALLISTICS OF 9ORKSCRE1 PROJECTILES (12 page document)


 

Quote

During the development and exploitation of the BRL NonConical Boattail Projectile, it became evident that a new projectile shape which combines a triangular nose with a triangular boattail would have low drag and a long wheel base for low balloting in the gun barrel. No aerodynamic data were available on the configuration (nicknamed the corkscrew) at the beginning of this program, so it was deemed advisable to conduct wind tunnel and range tests to determine its drag and stability characteristics.

 

 

AEROBALLISTICS OF CORKSCREW PROJECTILES (36 page document)

 

Quote

~ Preliminary wind tunnel and aeroballistic range tests on a new and novel exterior projectile shape have shown that this S-caliber to 8-caliber long shape has extremely good aerodynamic characteristics. It not only has very low drag, but also low pitching and Magnus moments which in turn yield good gyroscopic and good dynamic stability. Extrapolation of the data to longer lengths indicates that 10-caliber to 12-caliber long projectiles having this shape can be flown with satisfactory stability.


 

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A UNIFIED THEORY OF PENETRATION (U)

Quote

Today's weapons employ compact fragments as well as long rods and shaped)charge jets. From the viewpoint of an armor designer, it is desirable to have a method of dealing with all three types of penetrator both in theory and in practice, This report presents an equation of motion which in its most general form describes penetration by a forming, stretching, eroding jet. In various specialized forms, it describes penetration by pre-formed rods and compact projectiles. One specialized form reduces to the classical jet penetration formula according to which penetration in a semi-infinite target is proportional to the square root of the ratio of the jet and target densities. A correction for target hardness is automatically included. The solutions of the various forms of the equation of motion are given explicitly in closed form and are profusely illustrated by numerical examples and comparisons with experimental data.

 


 

In this report we restrict ourselves to one dimension and to finite or semi-infinite targets made of one material. The chapter on jets is also limited to descriptions of a standard 81mm, 420"copper cone device. These restrictions will be removed in future reports.)

 

 

MECHANICS OF PENETRATION: ANALYSIS AND EXPERIMENT

 

Quote

This paper reviews available analytical methods for the study of kinetic energy (inert) projectile-armor interactions at ordnance velocities (0.5-2 kms ). Particular emphasis is placed on three-dimensional numerical simulation of perforation and results of two-dimensional plane strain and threedimensional finite element computations are compared with experimental results for impact situations leading to perforation and to ricochet. Problem areas and requirements for improved materials characterization are discussed.

 

IMPACT DYNAMICS: THEORY AND EXPERIMENT

 

Quote

A review is presented of the state of the art in the analysis of materials and structures subjected to intense impulsive loading. Emphasis is placed on the penetration and perforation of solids and current development its in three-dimensional finite element and finite difference simulation of impact phenomena. The need for adequate characterization of material response and failure at high strain rates is emphasized and current capabilities highlighted. An assessment is made of anticipated developments and advances in high speed computers, high strain rate materials characterization, and in numerical simulation techniques which will contribute to improved design and reduced vulnerability of materials and structures to impact loading.

 

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On 4/13/2018 at 2:43 AM, Collimatrix said:

Finally got around to looking at this. It's a blow forward.

I forget what other GL design of that era was messing with that system of operation, but I know there was one.

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On 6/10/2018 at 5:46 PM, Meplat said:

Finally got around to looking at this. It's a blow forward.

I forget what other GL design of that era was messing with that system of operation, but I know there was one.

 

Meplat, the one Chinn was working on was blow forward. This one is a long recoil constant react/FOOB (firing out of battery) gun designed by Russell S. Robinson, it even lists him as the design engineer in this proposal.

 

A whole bunch of Colt's proposals in this era came from them buying his company. (Robinson Improved Conventional Armaments / RICA) The SAR archives seem to have a pretty substantial chunk of them too including the CR-26 26mm gun/cannon, the lightning system, both his .50/.30 and 9x19 or .45 ACP SSB designs (but not his .30/.15 stuff), and I'm pretty sure that the GPAM had heavy involvement by Robinson and are all in the SAR archives.

 

GPAM gun

 

CR-26 feed system patent illustration

 

CR-26 gun picture

 

 

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Some random recoil impulse figures.  This stuff is interesting/important if you want to deal with guns from the back end rather than the front end, I find. 

 

Fire out of Battery Test results - a discussion of soft recoil/Fire Out of Battery recoil mitigation technologies (In the quest to put bigger guns on lighter frames)   It provides a number of Ogorkiewicz ratio figures for various armored vehicles (ratio of tank gun recoil impulse to its mass.  Rule of thumb  is 900 ns/ton as I recall)  


Ogorkiewicz Ratio [1], Round Impulse/Vehicle Mass, is often used when analyzing recoil effects on fighting vehicles, a ratio of 900 N*sec/M. ton is recommended as an upper design limit. The following table, (tablekl) is a comparison of Ogorkiewicz Ratio for a number of armored vehicles designed in the later half of the twentieth century compared to the FSC vehicle design concept.

 

Here is the list of 105mm 120mm and the Sheridan's 152mm gun:

 

https://imgur.com/a/MtAyVok

 

Designer's Dilemma - recoil, what to do with it?  Covers towed/field artillery rater than sPG:

 

155mm towed gun figures:

 

https://imgur.com/a/7bCBkzm

 

Also a bit on FCS and tank guns, it includes a few interesting tidbits like recoil force and energy comparisons between 120mm and 140mm guns:

 

DOD: DEVELOPING SCIENCE AND TECHNOLOGIES LIST SECTION 9: GROUND COMBAT SYSTEMS TECHNOLOGY

 

A future MBT concept can be expected to have the following features:



 

(1) Crew Extensive automation of basic functions—driving, navigation, reconnaissance, and operation—will enable the MBT to be operated by a two-man crew in a more compact fighting compartment (Hilmes, 1999).

 

(2) Weight The combat weight should not exceed MLC (Military Load Class) 60, or about 55 tons. The possible reduction of crew from four to two and the realization of a compact fighting compartment—with a net volume of about 3 m3 versus 10–12 m3 for current MBTs—will have a positive effect on weight reduction. And a similar effect will be realized by volume reductions in engine technology. For example, the Euro power pack is about 35 percent smaller than the Leopard 2 engine, but delivers the same power; however, the new armament system will increase weight. Increasing gun caliber to 140 mm—these rounds are about twice as heavy as 120-mm rounds—will increase overall ammunition weight even with a one-third reduction in the ammunition reserve. Weight gain will result from a bigger overall installation to accommodate higher recoil energy (from 155 to 270 kJ) and braking force (from 600 to 1,200 kN). The autoloader will weigh at least 600 kg. The greatest increase in weight is expected from demands for increased protection:

 

Future requirements are expected to specify protection levels for the fighting compartment area of [about] 1000 mm rolled homogeneous armor (RHA)-equivalent against 125 mm kinetic energy (KE) threats, and 1200 mm RHA-equivalent against shaped charge threats. If the KE threat is to be met with the use of purely passive protection elements, it would be necessary to think in terms of an area density of over 4 tons/m2 . It remains doubtful as to whether the KE threat can be effectively mastered in the medium-term (up to the year 2015) through the use of stand-off active protection systems. Protection against the shaped charge threat is less of a weight-related question. Here the use of reactive armor provides an obvious solution, through which a reduction of the penetration performance from 400-600 mm can be expected (e.g. Russian MBTs). Alternatively it is also possible to maximize the depth of protection through the use of passive armor technology, as adopted for instance in the turret area of the Leopard 2A5. Without significant developments to the basic protection concepts and protection technologies, combat weights in the region of 70 tons have to be expected for the next generation of MBTs. There could thus be no question of remaining within MLC 60 limits. (Hilmes, 1999, p. 74)

 

It's about 15 years old by now, but its still interesting. 

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On 10/12/2018 at 12:23 AM, N-L-M said:

 

Back in 2009, I stumbled across a site hosting the annual command histories for the Commander in Chief Pacific (CINCPAC) from 1960 through the mid-'80s. I found an interesting tidbit in the 1974 history regarding an examination of establishing South Vietnamese production of the Lazy Dog munition for the VNAF.

 

Quote

“Commander in Chief Pacific Command History 1974 - Volume I, pp 248-249”
 

LAZY DOG Weapon System as an Aircraft Area Munition


Scientific Analysis Group Report No. 1-74 on the LAZY DOG system was requested by the Defense Attache in Saigon as part of his effort to cut down on the cost of the continuing war in Vietnam. He was specifically looking for items that RVN industry could produce at lower cost than comparable U.S. items. Air delivered munitions, all produced in the United States, were one of the single items of greatest expense. LAZY DOG was believed to be a highly effective but unsophisticated anti-personnel weapon. It had been purged from both USAF and Navy systems, but there remained many “assets,” missiles, dispensers, drawings, studies, etc., located in the Air Force and Navy R&D community that were considered useful. Further assessment was to be made to determine the feasibility of developing a LAZY DOG manufacturing capability in the RVN, and a capability for the VNAF to deliver it. 1
 

1. J35 HistSum Aug 74; Scientific Analysis Group Report No. 1-74 , 25 April 74, Subj: A Review of the LAZY DOG Weapon System as an Aircraft Area Munition.

 

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16 hours ago, Vicious_CB said:

 

Comparing Advertised Ballistic Coefficients with Independent Measurements

 

http://www.dtic.mil/dtic/tr/fulltext/u2/a554683.pdf

 

If anyone needs a reference for "real" BCs. 

 

>Nosler’s advertised ballistic coefficients showing the largest overestimates.<

 

Nosler's BCs are in fact so outrageous that I can tell by looking at them that they are wrong.

 

I've been calling them out for deceptive figures for years.

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Basing on what principle users post materials in this thread? I have hundreeds of reports\theses\presentations about weapon design, most of them are from dtic. Here is list of aerodynamics folder:

 

Spoiler

19.02.2016  09:34           866я419 A DRAG COEFFICIENT, KD, BASED ON THE 155MM SHELL, HE, M 101.pdf
09.04.2018  10:58         2я811я666 A SIMPLIFIED METHOD FOR PREDICTING AERODYNAMICS OF MULTI-FIN WEAPONS.pdf
22.11.2017  17:53         4я403я623 Aeroballistic Evaluation of KineticEnergy (KE) Penetrators for Electromagnetic (EM) Gun Applications.pdf
23.11.2017  10:58         1я055я587 Aerodiynamic Properties Of 60-MM Mortar Shell, T24.pdf
06.04.2018  16:17         1я379я472 AERODYNAMIC CHARACTERISTICS OF FIN- AND FLARE-STABILIZED 25 mm XM910 PROTOTYPES.pdf
23.11.2017  15:51         3я069я948 Aerodynamic Characterizations of Asymmetric and Maneuvering 105-, 120-, and 155-mm Fin-Stabilized Projectiles Derived From Telemetry Experiments.pdf
19.02.2016  14:53         4я928я084 AERODYNAMIC DATA FOR SPINNING PROJECTILES.pdf
16.01.2017  10:03           657я757 AERODYNAMIC HEATING OF MISSILEROCKET - CONCEPTUAL DESIGN PHASE.pdf
06.04.2018  16:04         4я849я231 AERODYNAMIC PROPERTIES OF THE 152MM XM617 PROJECTILE.pdf
29.06.2017  11:51         4я430я262 AERODYNAMICS OF GUIDED AND UNGUIDED WEAPONS. PART 1. THEORY AND APPLICATTON.pdf
11.10.2017  13:20         1я620я113 AERODYNAMICS OF THE 120-MM M831A1 PROJECTILE ANALYSIS OF FREE FLIGHT EXPERIMENTAL DATA.pdf
15.02.2017  15:06         9я285я594 AERODYNAMICS, DIMENSIONS, INERTIAL PROPERTIES, AND PERFORMANCE OF ARTILLERY PROJECTILES.pdf
23.11.2017  10:31           586я696 An Approximate Method for Pitch-Damping Prediction.pdf
29.06.2017  11:24         2я895я739 ANALYSIS OF THE DRAG COMPONENTS OF THE ANGLED ARROW PROJECTILE.pdf
27.09.2014  12:28           305я064 Analysis of the Rolling Moment Coefficients of a Rockets with Wraparound Fins.pdf
25.12.2014  10:44         1я794я928 Anti-Tank Spike-Nosed Projectiles With Vortex Rings Steady and Non-Steady Flow Simulations.pdf
06.02.2017  11:14         2я150я583 Artillery precision guided munition airframe definition.pdf
16.08.2018  16:04    <DIR>          basic finner
27.09.2014  12:46         3я507я804 CFD Computation of Magnus Moment and Roll Damping Moment of a Spinning Projectile.pdf
22.02.2017  10:59         1я197я804 CFD Prediction of Magnus Effect in Subsonic to Supersonic Flight.pdf
25.01.2018  13:32           871я492 COMPARISON ANALYSIS OF DRAG COEFFICIENTS FOR SUPERSONIC MORTAR PROJECTILES.pdf
22.11.2017  17:15         1я617я954 COMPUTATION OF THE ROLL CHARACTERISTICS OF FINNED PROJECTILES.pdf
22.11.2017  11:10         1я222я596 COMPUTATION OF THE ROLL CHARACTERISTICS OF SEVERAL FIN DESIGNS FOR A LONG ROD PENETRATOR.pdf
29.10.2017  11:38         1я482я540 COMPUTATION OF THE ROLL CHARACTERISTICS OF THE M829 KINETIC ENERGY PROJECTILE AND COMPARISON WITH RANGE DATA.pdf
28.02.2018  14:00         2я812я793 COMPUTATIONAL STUDY OF SWEPT-FIN AERODYNAMIC HEATING FOR THE 105MM M774.pdf
04.12.2015  15:17           420я661 COMPUTATIONS OF UNSTEADY AERODYNAMCS OF A SPINNING BODY AT TRANSONIC SPEEDS.pdf
26.07.2017  09:47         2я954я174 DRAG AND STABILITY PROPERTIES OF THE 105MM SHELL, HE.pdf
29.06.2017  11:20         3я274я697 DRAG AND STABILITY PROPERTIES OF THE XM144 FLECHETTE WITH VARIOUS HEAD SHAPES.pdf
06.02.2017  15:55           826я407 DRAG PREDICTION AND VALIDATION OF STANDARD M549, 155mm PROJECTILE.pdf
10.07.2018  10:41         1я408я484 DRAG PREDICTIONS FOR PROJECTILES AT TRANSONIC AND SUPERSONIC SPEEDS.pdf
06.04.2018  16:10         2я638я243 ESTIMATION OF THE STATIC AERODYNAMIC CHARACTERISTICS OF ORDNANCE PROJECTILES AT SUPERSONIC SPEEDS.pdf
25.12.2015  09:49           297я175 Experimental Results on the Feasibility of an Aerospike for Hypersonic Missiles.pdf
10.07.2018  13:16           260я335 Experimental Validation of Elliptical Fin Opening Behavior.pdf
22.11.2017  15:55         1я154я590 EXPERIMENTAL VALIDATION OF ELLIPTICAL FIN OPENING BEHAVIOUR.pdf
26.04.2016  09:59         1я441я341 Flow Field Investigation around Body Tail Projectile.pdf
26.04.2016  09:56           865я681 Flow Field Investigations and Aerodynamic Characteristics of Artillery Projectile.pdf
17.10.2016  16:31         1я637я762 FLOW SIMULATION AND DRAG COMPONENTS FOR HEAT PROJECTILES WITH SPIKE AND CONE NOSES.pdf
23.11.2017  15:51           813я945 High-Capacity Artillery Projectile (HICAP) Fin Characteristics.pdf
05.04.2018  16:16         1я277я907 INCREMENTAL DRAG DUE TO GROOVES AND THREADS FOR KE PROJECTILES.pdf
17.11.2017  13:57         1я802я697 Instability estimation of irregularly shaped bodies moving through a resistive medium with high velocity.pdf
03.02.2019  15:27                 0 list
24.02.2016  12:16         4я789я000 MC DRAG - A COMPUTER PROGRAM FOR ESTIMATING THE DRAG COEFFICIENTS OF PROJECTILES.pdf
31.08.2017  13:11        13я198я322 naca1135.pdf
22.11.2017  17:19         3я063я561 Navier-Stokes Computations of Finned Kinetic Energy Projectile Base Flow.pdf
09.06.2018  11:10         1я119я013 Nose-Cone-Fin-Optimization.pdf
01.11.2017  17:24         5я513я533 Notes on a Theory of Spinning Shell.pdf
17.11.2017  14:14         3я007я940 NTREM_2012-Numerical_simulations_for_prediction_of_aerodynamic_drag_on_high_velocity_fragments_from_naturally_fragmenting_HE_warheads-web.pdf
22.11.2017  17:59         2я130я606 Numerical Prediction of Pitch Damping Stability Derivatives for Finned Projectiles.pdf
06.02.2017  11:41         1я604я131 Numerical Simulations on Aerodynamic Characteristics of a Guided Rocket Projectile.pdf
21.11.2015  15:02         1я256я292 NumericalSimulationofBulletFlowFields1.pdf
21.11.2017  16:39         1я253я267 Obliczanie charakterystyk aerodynamicznych  obiektow latajacych z wykorzystaniem programow Prodas i Fluent.pdf
05.04.2018  17:49         2я016я639 ON ESTIMATING THE DRAG COEFFICIENT OF MISSILES.pdf
22.11.2017  16:48         1я929я511 Parabolized Navier-Stokes Computation of Surface Heat Transfer Characteristics for Supersonic and Hypersonic KE Projectiles.pdf
22.11.2017  17:57           386я860 Prediction of the Pitch-Damping Coefficients Using Sacks' Relations.pdf
17.11.2017  13:39         2я335я693 Prediction of the trajectory of an irregularly shaped body moving through a resistive medium with high velocities.pdf
29.06.2017  11:19           693я121 PROJECTILE SUPERSONIC DRAG CHARACTERISTICS.pdf
23.05.2017  10:38         2я029я458 Recent Applications of CFD to the Aerodynamics of Army Projectiles.pdf
27.09.2014  12:34         1я489я006 Roll Damping for Finned Projectiles Including Wraparound, Offset, and Arbitrary Number of Fins.pdf
06.06.2018  14:20           429я604 simplified aerodynamic heating of rockets.pdf
23.05.2017  10:35         1я282я676 SPIKE-NOSED PROJECTILES COMINPUTATIONS AND DUAL FLOW MODES IN SUPERSONIC FLIGHT.pdf
22.11.2017  17:30         1я631я350 SPIN CHARACTERISTICS OF THE 60-mm HIGH EXPLOSIVE M49A4 PROJECTILE WITH MODIFIED M2 FIN ASSEMBLIES.pdf
20.11.2017  15:37         3я139я264 SPIN-73.pdf
23.11.2015  16:19         1я383я327 Static Aerodynamics CFD Analysis for 120-mm Hypersonic KE Projectile Design.pdf
23.11.2017  10:55           589я883 THE EFFECT OF FIN SLOTS ANDFIN TABS ON THE DYNAMIC STABILITY CHARACTERISTICS OF THE NAVY LOW DRAG BOMB.pdf
22.11.2017  11:35         1я901я485 The Effect of Sabot Grooves on Lift Force for Kinetic Energy Projectiles.pdf
23.11.2016  12:45         3я915я320 The Effects of Base Bleed on Plug Nozzles.pdf
17.06.2016  10:35           856я883 THEORETICAL AERODYNAMIC COEFFICIENTS OF TWO-DIMENSIONAL SUPERSONIC BIPLANES.pdf
20.10.2017  11:20         3я113я824 THREE-DIMENSIONAL BOUNDARY LAYER RESEARCH AS APPLIED TO THE MAGNUS EFFECT ON SPINNING PROJECTILES.pdf
04.12.2015  15:17           411я242 VIRTUAL FLY-OUT SIMULATIONS OF A SPINNING PROJECTILE FROM SUBSONIC TO SUPERSONIC SPEEDS.pdf

 

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Because (as far as I know) we don’t have a material science section of this forum, I’ll link this here: 

 

https://apps.dtic.mil/dtic/tr/fulltext/u2/a405973.pdf

 

“Depleted Uranium: a case study of good and evil” 

 

tl;dr, DU is no more harmful than other heavy metals used by armies across the world, like tungsten and lead. The fears and concerns proposed by people regarding DU’s toxicity are caused by misunderstandings and a lack of critical thinking / fact checking. 

 

In other words: water is wet. 

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https://apps.dtic.mil/dtic/tr/fulltext/u2/a168578.pdf

 

ferro-aluminide alloys. 

 

The best are alloys with niobium, chromium, and tantalum - followed by titanium, copper, and the base line FeAl (not in order). 

 

Surprisingly, FeAl + silicon alloys perform (nearly 3 times) better at 600 C than at room temp. 

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I don’t know where to ask this, but I have a question: 

 

https://apps.dtic.mil/dtic/tr/fulltext/u2/609554.pdf 

 

“Development of a structural uranium alloy” 

 

 

What advantages would uranium alloys have over steel or aluminum? It’s rarer, much heavier without a significant increase in strength, difficult to work with, and I can’t think of anything (off the top of my head) that a high density material would perform better than common structural materials, except maybe the mass dampener in Taipei 101. 

 

PS. The article refers to Niobium as ‘Columbium’, Cb. 

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Posting more stuff I find on the internet that may be of interest:

THE THEORY OF HIGH SPEED GUNS

 

Abstract



This monograph summarizes the gas dynamics of high-speed guns, utilizing a gas of low molecular weight at high temperature. Theory and test results are presented. The reader is assumed to be an advanced student in engineering. The fundamental ideas and equations are fully developed.

 

In other words really fast guns that aren't railguns. 

 

INTERIOR BALLISTICS OF GUNS

 

Preface

This handbook, Interior Ballistics of Guns, presents fundamental data, followed by development of the theory and practice of interior ballistics, with application to rifled, smooth-bore and recoilless guns. Included in the presentation are studies pertaining to heat transfer, temperature distribution and erosion, together with standard and experimental methods of measurements. Finally, ignition, flash and other special topics are explored. 



 

This handbook has been prepared as an aid to scientists and engineers engaged in military research and development programs, and as a guide and ready reference for military and civilian personnel who have responsibility for the planning and interpretation of experiments and tests relating to the performance of military materiel during design, development and production.

 

Optimisation of small arms defeat via dynamic jacket removal (pdf download link) 

 

Abstract

The majorities of studies into penetration by small arms have neglected the contribution of the jacket to the penetration event due to its small mass compared to the rest of the bullet. Recent research has suggested that the jacket does actually play a measurable role in the penetration of a target. This project has focused on the concept of dynamic jacket removal as an approach to optimise small arms defeat. This approach was envisaged to address the gap in current knowledge with regards to the role of the bullet jacket in the penetration of a target. Here, jacket stripping techniques were employed, elucidating underling mechanisms where armour piercing (AP) rounds were fired at target materials. Forward ballistic experiments were conducted, utilising conventional ballistic testing on an indoor small arms range as well as 30 mm and 50 mm smooth bore single stage light gas guns. To compliment this work, reverse ballistic experimentation was also undertaken on a 50 mm single stage light gas gun. Impact events were interrogated via a series of diagnostics including high speed video imaging, flash X ray radiography and depth of penetration testing. Experimental results were complimentary, providing insight into two key competing effects with regards to the jacket on penetration. These were the potential for the jacket to cushion / damp the impact, as well as the physical confinement resulting from the presence of the jacket itself around the bullet core. Further, these experiments also identified a potential optimum in terms of stripping plate design. In addition, to further investigate the role of the bullet jacket, sample cores and jacket materials were loaded both together and in isolation using a split Hopkinson pressure bar, with results in particular highlighting the cushioning effect of the jacket material. Limited numerical simulations were also produced using Ansys® Autodyn. These numerical results further elucidated the experimental work – again highlighting the importance of the jacket in terms of cushioning the impact event / reducing the subsequent pre-loading of the penetrating AP core. Overall, both experimental and numerical results showed that the bullet jacket does indeed aid in penetration. In corollary, in practical terms, jacket removal has the potential to aid in armour performance – with the experiments conducted herein providing insight into dynamic jacket removal. In terms of such stripping mechanisms, it was demonstrated that a plate thickness comparable to the calibre of the bullet appeared optimal. Further, results have also shown the importance of hardness and other material properties when considering the final defeat of an incident projectile through spallation.



 

Ballistic protection efficiency of composite ceramics/metal armours

 

Abstract

Some theoretical aspects of ballistic protection testings of composite armours concerning test methods and criteria of armour efficiency estimation, have been considered. The experimental results of performed ballistic tests of the composite ceramics/metal armours, depending on composite armour type, bullet type and target (composite armour) distance have been presented. The corresponding analysis of test results, concerning ballistic protection effects and ballistic efficiency of the composite armours, have been also given. The composite armours are composed of Al2O3 ceramic plates (facing side) adhered to aluminium alloy or armour steel (backing side).



 

Ballistic resistance of high hardness armor steels against 7.62mm armor piercing ammunition

Abstract



Although advanced lightweight composite based armors are available, high hardness steels in military vehicles are often used to provide ballistic protection at a relatively low cost and is an interesting material due to its widespread usage in vehicle structure. In this study, ballistic limit of 500 HB armor steel was determined against 7.62 mm 54R B32 API hardened steel core ammunition. Lagrange and smoothed particle hydrodynamics (SPH) simulations were carried out using 3D model of bullet and high hardness armor target. Perforation tests on 9 and 20 mm thickness armor were performed to validate simulation methodology. Also material tests were performed for armor steel and ammunition hardened steel core to develop Johnson–Cook constitutive relations for both strength and failure models. Finally, results from 3D numerical simulations with detailed models of bullet and target were compared with experiments.

 

The study indicates that the ballistic limit can be quantitatively well predicted independent of chosen simulation methodology, but qualitatively some differences are seen during perforation and fragmentation. As shown in results, good agreement between Ls-Dyna simulations and experimental data was achieved by Lagrange formulation with the full bullet model.

 

Impact dynamics of tool steel penetrators

 

From the introduction:



This study treats only certain aspects of “physical impacts”, define as the process involved in the collision of two or more objects. Thus impact encompasses a wide range of processes as exemplified by the game of billiards, automobile accidents, air blast upon structures and eve molecular collisions. However, the number of collisions must be restricted to a relatively small incidence, as otherwise a condition of repeated loading would prevail. Moreover, common terminology limits the term “impact” to collisions in which the mass effect of both impinging bodies must be taken into account. The concept of impact is further differentiated from the case of static loading by the nature of its application. Forces created by collisions are exerted and removed in a very short interval of time and initiate stress waves which travel away from the region of contact. Impact of bodies with curved or pointed surfaces is accompanied by penetration of one member into the other. On the other hand, static loading is regarded as a series of equilibrium states and requires no consideration of accelerating or wave effects. Rapid loading is usually not produced by means of a collision, and normally involves longer loading times than found in impact processes. The transient nature of the stresses generated by static (or rapid) loading may thus frequently be neglected.

 

Perforation resistance of five different high-strength steel plates subjected to small-arms projectiles

 

Abstract



Thin plates of high-strength steel are frequently being used both in civil and military ballistic protection systems. The choice of alloy is then a function of application, ballistic performance, weight and price. In this study the perforation resistance of five different high-strength steels has been determined and compared against each other. The considered alloys are Weldox 500E, Weldox 700E, Hardox 400, Domex Protect 500 and Armox 560T. The yield stress for Armox 560T is about three times the yield stress for Weldox 500E, while the opposite yields for the ductility. To certify the perforation resistance of the various targets, two different ballistic protection classes according to the European norm EN1063 have been considered. These are BR6 (7.62 mm Ball ammunition) and BR7 (7.62 mm AP ammunition), where the impact velocity of the bullet is about 830 m/s in both. Perforation tests have been carried out using adjusted ammunition to determine the ballistic limit of the various steels. In the tests, a target thickness of 6 mm and 6 þ 6 ¼ 12 mm was used for protection class BR6 and BR7, respectively. A material test programme was conducted for all steels to calibrate a modified Johnson–Cook constitutive relation and the Cockcroft–Latham fracture criterion, while material data for the bullets mainly were taken from the literature. Finally, results from 2D non-linear FE simulations with detailed models of the bullets are presented and the different findings are compared against each other. As will be shown, good agreement between the FE simulations and experimental data for the AP bullets is in general obtained, while it was difficult to get reliable FE results using the Lagrangian formulation of LS-DYNA for the soft core Ball bullet

 

Ballistic behavior of high hardness perforated armor plates against 7.62 mm armor piercing projectile

 

Abstract



In this paper, some of the important defeating mechanisms of the high hardness perforated plates against 7.62 54 armor piercing ammunition were investigated. The experimental and numerical results identified three defeating mechanisms effective on perforated armor plates which are the asymmetric forces deviates the bullet from its incident trajectory, the bullet core fracture and the bullet core nose erosion. The initial tests were performed on the monolithic armor plates of 9 and 20 mm thickness to verify the fidelity of the simulation and material model parameters. The stochastic nature of the ballistic tests on perforated armor plates was analyzed based on the bullet impact zone with respect to holes. Various scenarios including without and with bullet failure models were further investigated to determine the mechanisms of the bullet failure. The agreement between numerical and experimental results had significantly increased with including the bullet failure criterion and the bullet nose erosion threshold into the simulation. As shown in results, good agreement between Ls-Dyna simulations and experimental data was achieved and the defeating mechanism of perforated plates was clearly demonstrated.

 

The Mechanical Metallurgy of Armour Steels

 

Abstract

Armour steels have historically delivered optimised ballistic performance against a range of battlefield threats and continue to be highly competitive armour materials. The relationship between armour steel mechanical properties, specifically their mechanical metallurgy, and ballistic performance is explained, where such performance is primarily determined by material strength, hardness and high strain rate behaviour. Other important topics such as toughness; the adiabatic shear phenomenon; structural cracking; and dual hardness and electroslag remelted armour steels are also discussed along with armour steel specifications and standards.




 

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