Bottle rocket

A bottle rocket is a very small skyrocket. A typical bottle rocket consists of a rocket engine attached to a stabilizing stick. The user can place the stick in an empty bottle (hence the name), and ignite the rocket engine; the mouth of the bottle guides the stick, stabilizing the rocket in its first moments of flight.

These rockets have been made at least since the early decades of the 20th century, and in many countries, including Japan, China, and Macao. The older type of bottle rocket was typically a black powder skyrocket with a motor about two inches (5 cm) long and up to 0.375 inch (9 mm) diameter, mounted on a thin bamboo splint and often having a small report charge.

Modern bottle rockets are small and very cheap. They are often sold by the gross, for less than $US 0.20 each, and have known to have been as little as $1.50 for 144 bottle rockets. Thailand's Isan region, many are made by hand and sold in conjunction with Rocket Festivals, which feature similar appearing rockets that may pack as much as 250 kg of black powder.

In India, bottle rockets are set off during the Hindu festival of Diwali, and are sold in the millions.

Bottle rockets are specifically illegal in many jurisdictions, even those where most other consumer fireworks are legal. They are sometimes considered to present a unique hazard, due to their ability to fly in many different directions other than vertically. Bottle rockets are illegal in several states [ [http://www.dailyinterlake.com/articles/2008/06/25/news/news01.txt http://www.dailyinterlake.com/articles/2008/06/25/news/news01.txt] ] in America, but they are cheap and easy to obtain.

Construction

A bottle rocket consists of three major parts:

*The rocket engine. This will typically use a black powder-type fuel, possibly with additives to produce a decorative spark trail as the rocket ascends, but they have also used chemical reactions (eg. vineger and baking soda) for thrust. The fuel is pressed to form a solid grain inside a cardboard tube; this tube is sealed at the top, but open at the bottom. When the fuel is ignited from the bottom, hot gases are expelled downwards, propelling the rocket upwards. Other fuels are possible. A common alternative choice is whistle mix, to produce a whistling rocket.

*The nose cone. In addition to serving its aerodynamic role, the nose cone typically contains the rocket's payload. This may include exploding fireworks, colored stars, a parachute, confetti, or other decorative items.

*The guide stick. A typical bottle rocket, with no fins or other stabilizers, relies entirely on its stick for stability in flight. The stick's length and weight are chosen to achieve this.

External links

* [http://www.pyroguide.com/index.php?title=Bottle_rocket A pyrowiki on pyrotechics] - more information on bottle rockets.