Propellant casting

Propellants cast into rockets are commonly case-bonded to the motors to achieve maximum volumetric loading density. The interior of the motor is thoroughly cleaned, coated using an insulating material, and then lined with a composition to which the propellant binder adheres under the environmental stresses of the system. The insulation material is generally a mbber-type composition, filled with siUca, titanium dioxide, or potassium titanate. SiUca-filled nitrate mbber and vulcanizable ethylene—propylene mbber have been used. The liner generally consists of the same base polymer as is used in the propellant. It is usually appHed in a thin layer, and may be partially or fully cured before the propellant is poured into the rocket. 

First propellant casting was cured 12 days at 110°F., washcoated with BISA, and subsequently cast with second propellant. 

Holahan et al, Research on Rocket Propellant-Cast Double Base-Non Explosive Plasticizers which are Solvents for Lead Salicylate , PATR... 

Trimethylolethane trinitrate (metriol trinitrate) is not satisfactory as a plasticizer for nitrocellulose, and must be used with other plasticizers such as metriol triacetate. Mixtures with nitroglycerin tend to improve the mechanical properties of double-base cast propellants at high and low temperatures. Metriol trinitrate has also been used in combination with triethylene glycol dinitrate as a plasticizer for nitrocellulose. Its physical properties are Hsted in Table 7 (118-122). 

W. G. Clark, Evaluation of 1,2,4-Butanetriol Trinitrate as the EiquidExplosive Plasticiserfor Cast Double Base Propellant Report 4, PTA, Dover, N.J., 1960. 

Table 10. Composition and Properties of Nitrocellulose-Based Cast Propellants...

Fig. 9. Batch process for cast-composite polymer-based propellants. QC = quality control.

Uses. Uses for copper—siUcon alloys are siUcon bronze, UNS C 87200, as bearings, pumps, valve parts, marine fittings, and corrosion-resistant castings siUcon brass UNS C 87400 as bearings, gears, impellers, valve stems, and clamps and siUcon brass UNS C 87500 as small propellers, valve stems, gears, and bearings. 

Amongst the products made by polymerisation casting are propellers for small marine craft, conveyor buckets used in the mining industry, liners for coal washing equipment and main drive gears for use in the textile and papermaking industries. 

This type consists of a propeller or disk-type wheel within a mounting-ring panel or cage. The wheel or housing is constructed from either sheet metal, cast aluminium, plastic, or plastic-coated material. It may be a direct drive with the wheel on the motor shaft or belt driven. 

Typical marine propellers are fixed pitch and small in diameter with veiy thin, but broad, blade sections. They are made from either cast metal, corrosion-resistant metal alloys such as copper, or composite materials. Marine propellers normally operate at 60 percent efficiency due to the proximity of the ship s hull, which limits the overall diameter of the propeller and disturbs the efficient flow of water through the blades. As a result, the blades have to be veiy wide to produce adequate thrust. Marine propeller designers use innovations such as overlapping blades and wheel vanes to offset those problems and improve efficiency. 

Jacketed cast iron hemispherical bottom vessel Propeller—no baffles T/D = 2.5 U-Type impeller—no baffles. T/D = 1.05 0.67 1... 

Copper alloys in wrought or cast form are used for other purposes in ships and other marine installations, such as for propellers bearings, valves and pumps. One widespread application of aluminium-brass is its use for heating coils in tankers carrying crude oil or petroleum products. Some corrosion problems encountered in this and other applications on board ship have been described by Gilbert and Jenner . 

Penta-erythritol Diacetate Dipropionate", ERDE 11/M/58 (Oct 1958), AD 206266 (DDCSTI users only) 6) V. Pasquale, Feasibility Study on Using Low Acetyl Cellulose Acetate Inhibitor for Production Cast Grains , NOSIH TR 317 (10 July 1970), AD 510578 (Conf) 7) CPIA Solid Propellant Manual , CPIA/M2 (28 Jan 1974), unit 1069 (Conf)... 

Trinitrotoluene DNT Tetryl Primer materials < s Nitrocellulose j Nitroglycerin 1 j NC-based propellants j Ball Powder j 0> > o PL. -o ra 55 Acid manufacture J Filling of warheads Mfg of extruded rocket grains j Mfg of cast rocket grains... 

Toluene is continuously nitrated to mononitrotoluene in a cast-iron vessel, 1 m diameter, fitted with a propeller agitator 0.3 m diameter rotating at 2.5 Hz. The temperature is maintained at 310 K by circulating 0.5 kg/s cooling water through a stainless steel coil 25 mm o.d. and 22 mm i.d. wound in the form of a helix, 0.80 m in diameter. The conditions are such that the reacting material may be considered to have the same physical properties as 75 per cent sulphuric acid. If the mean water temperatute is 290 K, what is the overall coefficient of heat transfer ... 

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