Meyer R., Koehler J., Homburg A. Explosives. Wiley-VCH, 2002 / Explosives 5th ed by Koehler, Meyer, and Homburg (2002)

Combustible Cartridge Cases	60

Combustible Cartridge Cases

Verbrennbare Kartuschhülsen; douilles combustibles

The propellant charge used for the shot from a weapon is introduced into cases or bags (“cartouche bags”); for metallic cartouche cases, the projectile is combined with the propellant charge and the propellant Charge igniter to form a “cartridge”.

Now, combustible cartridge cases serve the purpose of making the case material contribute to the ballistic performance and to render unnecessary the removal of inert material from the weapon affer the shot. Such case material has to be adapted to the combustion process of the powder. It consists of high-energy material, e.g. nitrocellulose, a structure-reinforcing additive, e.g. kraft-paper pulp, binders of plastic material, and further additives, e.g. stabilizers such as contained in the powder itself. The cases are made by filtration from a pulp, pressing, molding and drying.

Caseless ammunition is also available for infantry weapons; as the ejector mechanism can be dispensed with, it is possible to raise the number of shots in machine guns.

W “Caseless Ammunition”

Combustion

Verbrennung; brˆulage

Any oxidation reaction, including those produced by introduction of atmospheric oxygen; many explosives are capable of burning without detonation if unconfined. Moreover, the oxidation reaction taking place in propellants without introduction of oxygen is also designated as combustion: it is preferable to denote this process as burning (W Burning Rate; W Deflagration).

Combustion Chamber

Brennkammer; chambre de combustion; case

In rocket technology, the chamber in which the reaction of the propellants takes place.

In solid fuel rockets, the propellant container also serves as the combustion chamber; in liquid fuel rockets it is the chamber in which the injected liquid components of the propellant are made to react with one another. The combustion chamber must withstand the predetermined working pressure and the temperatures developing at the chamber walls. In liquid fuel rockets the chamber wall is externally cooled in most cases; in solid fuel rockets, in which internal charges

61	Composite Propellants

bonded to the chamber walls are often employed, the required protection is afforded by the propellant itself. These conditions determine the choice of a suitable chamber material. Since the weight of the combustion chamber has a decisive effect on the range of the rocket, the walls should be as thin as possible. The use of thermally insulating and reinforced (e.g., with fiberglass) inserts made of plastic materials has already proved successful.

Standard combustion chambers and laboratory combustion chambers*) have been developed for testing the behavior of solid rocket fuels and for the determination of their characteristic properties.

Commercial Explosives**)

Gewerbliche Sprengstoffe; explosifs pour usage industriel

Explosives designed, produced, and used for commercial or industrial applications other than military.

Commercial Waterproof Primers

Trade name of a W Pentolite priming charge used for the initiation under wet conditions.

Compatibility**)

Verträglichkeit; compatibilit´e

Ability of materials to be stored intimately without chemical reaction occurring.

Incompatibility may result in a loss of effectiveness or may be very hazardous. For example, W Chlorate Explosives and W Ammonium Nitrate Explosives are not compatible (formation of self-decomposing ammonium chlorate). For compatibility testing W Vacuum Test.

Composite Propellants

Verbundtreibsätze; poudres composites

Composite propellants are solid rocket fuels, consisting of oxygendonating inorganic salts and a binder made of plastic.

The high-polymeric binders in use today include polysulfides (PS), polybutadieneacrylic acid (PBAA), polybutadiene-acrylonitrile (PBAN),

* E. Haeuseler and W. Diehl, Explosivstoffe, Vol. 15, p. 217 (1967). ** Text quoted from glossary.

Compositions A; A-2; A-3	62

polyurethane (PU) and carboxyland hydroxyl-terminated polybutadiene (CTPB and HTPB).

Nitrates and perchlorates, W Ammonium Perchlorate in particular, are used as oxidizers.

These propellants can be manufactured by casting or by pressing. The grain fineness of the salt employed affects the combustion properties to a significant extent. The mechanical (preferably rubber-elastic) properties of the plastic binders must satisfy special requirements.

CDB Propellants are combinations of composites with W Double Base Propellants, which achieve “plateaus” (W Burning Rate) otherwise difficult to attain.

For details about composite propellants see:

Zähringer, A. F.: Solid Propellant Rockets, Wyandotte, New York 1958

Barr`ere, Jaumotte, Fraeijs de Veubeke, “Vandekerckhove”: Rocket Propulsions, Elsevier Publ. Amsterdam 1961

Dadieu, Damm, Schmidt: Raketentreibstoffe, Springer, Wien 1968

Compositions A; A-2; A-3

Pressed charges made of phlegmatized W Cyclonite (RDX) differing from each other only by the various kinds of wax they contain.

detonation velocity, confined: 8100 m/s = 26 600 ft/s at r = 1.71 g/cm3

Compositions B; B-2

Hexolite; Hexotol

Castable mixtures of Cyclonite (RDX) and TNT in the proportion of 60 : 40; some of them contain wax as an additive. They are used as fillings for bombs, mines and W Hollow (Shaped) Charges.

density: about 1.65 g/cm3*)

detonation velocity, confined: 7800 m/s = 25 600 ft/s at r = 1.65 g/cm3

Composition C; C-2; C-3; C-4

Military plastic explosives, consisting of W Cyclonite (RDX) and a plasticizer, which itself may or may not be explosive. The respective formulations are:

* Can be raised to > 1.7 g/cm3 by application of special casting techniques.

63			Confined Detonation Velocity
Table 4.
Composition	RDX	Plasticizer	Type
	%	%
C	88.3	11.7	non-explosive
C-2	80.0	20.0	explosive
C-3	78	22.0	explosive
C-4	90	10.0	polyisobutylene
	(selected
	grain
	fractions)

(W also Plastic Explosives)

Composition I; II

Eutectic mixtures of ammonium nitrate, sodium nitrate, dicyanodiamide and guanidine nitrate.

Table 5.

	Composition
	I	II
ammonium nitrate	65.5	60
sodium nitrate	10.0	24
dicyanodiamide	14.5	8
guanidine nitrate	10.0	8

Confined Detonation Velocity*)

Detonationsgeschwindigkeit unter Einschluss; vitesse de d´etonation sous confinement

The detonation velocity of an explosive or blasting agent in a container such as a borehole in contrast to detonating in the open (W Detonation Velocity).

* Text quoted from glossary.

Confinement	64

Confinement

Einschluss

Confinement is understood to mean an inert material of some strength and having a given wall thickness, situated in the immediate vicinity of an explosive. Priming or heating the explosive materials produces different results, according to whether they are located in a stronger or a weaker confinement. If confined by thick steel, almost any explosive will explode or detonate on being heated; on the other hand, they burn on contact with an open flame if unconfined (W Combustion; W Mass Explosion Risk), except W Initiating Explosives.

The destructive (fragmentation) effect of an explosion becomes stronger if the explosive is confined (stemmed) in an enclosure such as a borehole. In the absence of natural confinement, the explosive charge is often embedded in an inert material such as clay. See also

W Mud Cap and W Stemming.

Contained Detonating Fuze*)

Sprengschnur mit Schutzmantel; cordeau d´etonant gain´e

Mild detonating fuze completely contained within a shock-absorbing sheath to prevent damage to the surroundings when the fuze is detonated.

Contour Blasting

Profilsprengen; saulage en profil

The purpose of controlled blasting is to produce an excavation contour, while leaving behind an intact, fissure-free formation (“prenotching”, “pre-splitting off”, “notching”, “contour blasting”). This is done by the application of diminished-strength explosive charges, using numerous boreholes driven exactly in parallel (vacant boreholes; firing in a cavity; charge diameters small as compared to the total diameter of the borehole; fissurefree roof firing in salt mines).

For further details see: Rune Gustavson: Swedish Blasting Technique. SPI, Gothenburg, Sweden (1972)

Copper chromite

Kupferchromit; chromite de cuivre

(CuO)x(Cr2O3)y

* Text quoted from glossary.

65	Coyote Blasting

dark brown to black powder

Copper chromite is the reaction product of copper oxide and chromium oxide. It is an important catalyst for the burning of rocket propellants and pyrotechnical compositions.

Specifications

sieve analysis:
through mesh width 0.07 mm: at least	98 %
through mesh width 0.04 mm: at least	90 %
net content
CuO: at least	79 %
not more than	85 %
Cr2O3: at least	13 %
not more than	19 %
Fe2O3: not more than	0.35 %
water-soluble matter: not more than	0.5 %

Cordite

Designation for double base (nitroglycerine-nitrocellulose) gun propellants in the United Kingdom.

Coruscatives

This is the name given by the American worker Zwicky to pairs of materials (other than the well-known thermites, W delay compositions) which react with each other without formation of gas.

The exothermal nature of certain components may be surprisingly high; the mixture Ti : Sb : Pb = 48:23:29 is primed at 570 °C (1060°F), and the reaction temperature attains 1000 °C (1830°F). Other combinations include magnesium-silicon, magnesium-tellurium, magne- sium-tin and magnesium-phosphorus.

Coyote Blasting

Kammerminensprengungen; sautage par grands fourneaux de mines

In coyote blasting, which is practiced in open-pit mining and in stone quarries, tunnels are driven into the mined face and chambers are drilled which can accommodate large quantities (up to several tons) of explosives. The chambers – usually several chambers at once – are charged, stemmed and detonated. They must be primed with the aid of a W Detonating Cord.

Crawford Bomb	66
Coyote blasting	has now been almost completely displaced by

W Large Hole Blasting, because the spaces accommodating the explosive can be produced more rationally in this way.

Crawford Bomb

A bomb used to determine the W Burning Rate of solid rocket propellants.

The propellant grains are in the form of thin rods (“strands”) which may have been cut or extruded and protected against surface burning by mantle insulation. The strand is placed in a bomb and electrically initiated at one end, after which its combustion rate is recorded with the aid of wire probes. Using compressed nitrogen, the pressure at which the combustion take place is adjusted in the bomb; standard values are 20, 40, 70, 100, 130, 180, 250 bar at a temperature between – 40 °C and 60 °C.

Crimping*)

Anwürgen; sertir

The act of securing a blasting cap to a section of safety fuse by compressing the metal shell of the cap against the fuse by means of a cap crimper.

Critical Diameter

Kritischer Durchmesser; diam`etre critique

The critical diameter is the minimum diameter of an explosive charge at which detonation can still take place. It is strongly texture-depend- ent, and is larger in cast than in pressed charges. Finely dispersed gas inclusions considerably reduce the critical diameter.

In the case of very insensitive materials – ammonium nitrate, for example – the critical diameter may be very large.

Cumulative Priming

Kumulative Zündung

Counter-current priming, in which the explosive charge is simultaneously primed at two or more places, so that the detonation waves travel to meet one another, and their effect becomes additive.

* Text quoted from glossary.

67	Cutting Charges

Curing*)

Härten; aushärten; maturer

Polymerization of prepolymer or monomer component of mixed propellants to increase mechanical strength.

Cushion Blasting*)

Hohlraumsprengen; fir avec chambres d’expansion

A method of blasting in which an air space is left between the explosive charge and the stemming, or in which the blast hole is purposely drilled lager than the diameter of the explosive cartridge to be loaded; W Contour Blasting.

Cut Off

Abschlagen einer Sprengladung; de capitation

Separation of a part of a borehole charge by the blast effect of another shot in electrical delay firing circuits. Cut off can also occur to the whole burden of the borehole charge by previous shots; W Permitted Explosives.

Cutting Charges

Schneidladungen; charge creuse pour d´ecoupage

Cutting charges serve to cut through iron plates, cables, bridge trusses etc. They are constructed on the principle of W Shaped Charges, but are not rotationally symmetrical; their shape is that of long channels (grooves).

The cutting depth of these charges depends to a considerable extent on the thickness and lining material of the angular or semi-circular groove; in addition, the optimum distance from the target must be determined in advance.

As in rotationally symmetrical hollow charges, a jet of highly accelerated gases and metal fragments is produced.

* Text quoted from glossary.

Cyanuric Triazide	68

Cyanuric Triazide

Cyanurtriazid; triazide cyanurique

colorless crystals empirical formula: C3N12 molecular weight: 204.1

energy of formation: +1090.3 kcal/kg = +4561.9 kJ/kg enthalpy of formation: +1072.9 kcal/kg = +4489.2 kJ/kg oxygen balance: – 47 %

nitrogen content: 82.36 % N

melting point (under decomposition): 94 °C = 201°F lead block test: 415 cm3/10 g

detonation velocity, unconfined: 5500 m/s at r = 1.02 g/cm3 deflagration point (explosion): 200 – 205 °C = 390 – 400°F

friction sensitivity: 0.01 kp = 0.1 N pistil load

This compound is prepared by slowly introducing powdered cyanogen chloride into an aqueous solution of sodium azide with efficient cooling.

Cyanuric triazide is an effective initiating explosive. It is not employed in practice owing to its high vapor pressure.

Cyclonite

cyclo-1,3,5-trimethylene-2,4,6-trinitramine; Hexogen; Trimethylentrinitramin; hexog`ene; RDX; T 4

colorless crystals

empirical formula: C3H6N6O6 molecular weight: 222.1

energy of formation: +96.0 kcal/kg = +401.8 kJ/kg enthalpy of formation: +72.0 kcal/kg = +301.4 kJ/kg oxygen balance: – 21.6 %

nitrogen content: 37.84 %

volume of explosion gases: 903 l/kg

69	Cyclonite

heat of explosion calculated*)

(H2O liq.): 1350 kcal/kg = 5647 kJ/kg (H2O gas): 1266 kcal/kg = 5297 kJ/kg

heat of detonation**)

(H2O liq.): 1510 kcal/kg = 6322 kJ/kg specific energy:

140 mt/kg = 1375 kJ/kg density: 1.82 g/cm3

melting point: 204 °C = 399°F

heat of fusion: 38.4 kcal/kg = 161 kJ/kg

vapor pressure:

Pressure	Temperature
millibar	°C	°F
0.00054	110	230
0.0014	121	250
0.0034	131	268
0.0053	138.5	281

lead block test: 480 cm3/10 g detonation velocity, confined:

8750 m/s = 28 700 ft/s at r = 1.76 g/cm3 impact sensitivity: 0.75 kp m = 7.5 N m friction sensitivity: 12 kp = 120 N pistil load critical diameter of steel sleeve test: 8 mm

Cyclonite is soluble in acetone, insoluble in water and sparingly soluble in ether and ethanol. Cyclohexanone, nitrobenzene and glycol are solvents at elevated temperatures.

Cyclonite is currently probably the most important high-brisance explosive; its brisant power is high owing to its high density and high detonation velocity. It is relatively insensitive (as compared to, say W PETN, which is an explosive of a similar strength); it is very stable. Its performance properties are only slightly inferior to those of the homologous W Octogen (HMX).

The “classical” method of production (Henning, 1898) is the nitration of hexamethylene tetramine (C6H12N4) to “Hexogen” (C3H6O6N6) using concentrated nitric acid; the concentrated reaction mixture is poured into iced water, and the product precipitates out. The structural formula shows that three methylene groups must be destroyed or split off by

* computed by “ICT-Thermodynamic-Code”.

**value quoted from Brigitta M. Dobratz, Properties of Chemical Explosives and Explosive Simulants, University of California, Livermore.