Smoke rockets

Gun Propellents. Although the stresses on individual gun propellant grains are less severe because of the small size, these propellants must withstand much higher weapon pressures and accelerations. Formulation options are usually more limited for gun propellants than for rocket propellants because the products of combustion must not foul or corrode a gun, should have a low flame temperature, and should exhibit minimum flash and smoke characteristics. Gun propellants are examined microscopically for porosity, are tested for mechanical characteristics, and fired in closed bombs to determine the burning characteristics. 

The proplnts described above are in the realm of prior art and depict those NC proplnts with low smoke potential that are used primarily as gun proplnts. Recent research and development work has been concentrated on creating both gun proplnts and rocket proplnts with reduced smoke output in order to foil countermeasures. Lavitt (Ref 76) found that the concurrent use of optimum proportions of lead stearate and sodium barbiturate in double-base proplnts resulted in a marked reduction in smoke output. This was attributed to the synergistic interaction of the two salts to produce more complete oxidation of the exhaust products. The importance of using the optimum ratio of the two catalysts is demonstrated by the higher smoke values shown in Table 4 for Propellants 105, 106 and 107, when compared to other... 

FIGURE 15.23 The white smoke emitted by the shuttle booster rockets consists of powdered aluminum oxide and aluminum chloride. 

Excluding tobacco and tobacco smoke (lf f3), the largest known human exposure to N-nitrosamines is in the industrial sector (4). The area or process air samples containing the largest amount of nitrosamines are in a tire factory, NMOR at the 250 yg/m level (5, a leather tannery, NDMA at the 47 ]xg/wr level (jy, and a rocket fuel factory, NDMA at the 36 yg/m level (7). 

The thunderous roar of a rocket s engines and the tremendous white clouds of smoke that accompany lift-off—these sensations evoke powerful emotions in any one viewing a Space Shuttle launch. The chemistry of the propellant mixture is responsible for the billowy clouds as the Shuttle soars into the sky. 

Pyrotechnics are often used in the production of fireworks and primers. A pyrotechnic contains both a fuel and an oxidizer formulated to produce a lot of energy. The energy is then used to produce a flame or glow (matchstick) or combined with other volatile substances to produce smoke and light (fireworks) or large quantities of gas (firework rockets). 

When a fuel-rich pyrolant burns in the atmosphere, oxygen molecules from the atmosphere diffuse into the initial combustion products of the pyrolant. The combustion products burn further and generate heat, light, and/or smoke in the atmosphere. A typical example is the combustion process in ducted rockets fuel-rich products generated in a gas generator are burnt completely in a combustion chamber after mixing with air pressurized by a shock wave that is taken in from the atmosphere. 

Titanium (Ti) is used as a major component of Ti alloys, which are used as heat-resistant Ught metals for the construction of aircraft and rockets. Though Ti is also used as an anti-acid metal, it bums in air when heated above 1500 K. TiCl4 is a Uquid used to form colored smoke in air. 

The smoke characteristics of three types of pyrolants, namely nitropolymer pyrolants composed of NC-NG with and without a nickel catalyst, and a B-KNO3 pyrolant, have been examined in relation to the use of these pyrolants as igniters of rocket motors. Though nitropolymer pyrolants are fundamentally smokeless in nature, a large amount of black smoke is formed when they burn at low pressures below about 4 MPa due to incomplete combustion. Metallic nickel or organonickel compounds are known to catalyze the gas-phase reaction of nitropolymer pyrolants. 

The smoke characteristics and the ignition capabilities of igniters are evaluated by using a micro-rocket motor. Ignition delay time and rate of pressure rise are... 

HCl molecules form visible white fog when water vapor is present in the atmosphere. An HCl molecule acts as a nucleus, becoming surrounded by HjO molecules, which forms a fog droplet large enough to be visible. When the combustion products of an AP composite propellant are expelled from a rocket nozzle into the atmosphere, a white smoke trail is seen as a rocket projectile trajectory whenever the relative humidity of the air is above about 40%. Furthermore, if the temperature of the atmosphere is below 0 °C (below 273 K), the HjO molecules generated among the combustion products form a white fog with the HCl molecules even if the relative humidity is less than 40 %. Thus, the amount of white fog generated by the combustion of an AP composite propellant is dependent not only on the humidity but also the temperature and pressure of the atmosphere. 

Thus, AP is a valuable oxidizer for formulating smokeless propellants or smokeless gas generators. However, since the combustion products of AP composite propellants contain a relatively high concentration of hydrogen chloride (HCI), white smoke is generated when they are expelled from an exhaust nozzle into a humid atmosphere. When the HCI molecules diffuse into the air and collide with H2O molecules therein, an acid mist is formed which gives rise to visible white smoke. Typical examples are AP composite propellants used in rocket motors. Based on experimental observations, white smoke is formed when the relative humidity exceeds about 40 %. Thus, AP composite propellants without any metal particles are termed reduced-smoke propellants. On the other hand, a white smoke trail is always seen from the exhaust of a rocket projectile assisted by an aluminized AP composite propellant under any atmospheric conditions. Thus, aluminized AP composite propellants are termed smoke propellants. 

Uses. In ultraviolet stabilizers and smoke depressants for polymers to increase the burn rate of rocket propellants to prevent erosion of space capsule shields to improve the viscosity of lubricants to catalyze polymerization reactions to catalyze combustion some derivatives used as hematinic agents... 

In 1963 Pains was amalgamated with the Wessex Aircraft Engineering Company (WAECo) who were based at High Post near Salisbury and who were, in turn, owned by the British Match Company. Within two years Pains Fireworks had relocated from Mitcham to High Post in a move that extended the Factory s product base from fireworks to distress flares, signalling smokes, line carrying rockets and munitions simulators trading under the name of Pains-Wessex. 

Table 1.2 lists the current applications of black powder. In general, as the balance of the ingredients in the composition shifts from the near stoichiometric 75 15 10 mix, the rate of burning decreases but is still fast enough to be of major importance in hrework rockets, delay fuses, igniters and pyrotechnic smokes. 

The largest RYUSEI rocket is said to be 18 m in length and weighs around 40 kg (sic). Built in three sections the head or payload section holds sequential fireworks and smoke dragons attached externally, while the combustion chamber is made from split pine logs, gouged out and then re-assembled to make a cylinder. 

---