High-powered rocket
From Wikipedia, the free encyclopedia
High-power rocketry is a hobby similar to model rocketry, with the major difference being that higher impulse range motors are used. The NFPA definition of a high-power rocket is one which has a total weight of more than 1500 grams and contains a motor or motors containing more than 62.5 grams of propellant or more than 160 Newton-seconds .
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[edit] Types
High-power rockets are defined as rockets flown using commercially-available motors ranging from H to O class. While NFPA1122 dictates guidelines for model rocketry, NFPA1127 is specific to high-power rockets.
[edit] Associations
The Tripoli Rocketry Association and the National Association of Rocketry are the major sanctioning bodies for the hobby in the USA, providing member certifications, and criteria for general safety guidelines.
In most other countries, where HPR is supported, the regulations are very similar to the TRA and the NAR.
In Canada the Canadian Association of Rocketry is appointed as regulator for the hobby.
In South Africa the controlling body for Rocketry is SAASA. SAASA is an acronym for South African Amateur Space Administration.
The United Kingdom Rocketry Association or UKRA has been featured on BBC's Top Gear.
[edit] Construction
High-power rockets are predominantly powered by commercially-available APCP-based motors or nitrous oxide-based hybrid motors.
High-power rocket designs can vary widely as do anticipated altitudes and performance but altitudes of 10,000' and velocities in the supersonic ranges are not uncommon. A combination of (often) larger mass and higher apogees may require sophisticated recovery systems. High-power rockets are frequently flown with sophisticated electronic devices used for recording flight data (altitude, velocity, acceleration/deceleration, G-forces) and for deploying recovery methods or devices.
High-power rockets are constructed from materials such as phenolic resin, fiberglass, carbon fiber, and other composite materials and plastics. Motor casings are normally machined aluminium with ablative phenolic or paper liners and are reloadable, i.e. can be used multiple times.
[edit] Recovery
In model rocketry, a parachute, streamer or other recovery device or method deploys at apogee, but high-power rockets may employ more complex recovery systems since altitudes can be much higher than their counterparts. In a high-power rocket, an altimeter or electronic timer may deploy a drogue parachute (which stablizes the rocket in descent) or a controlled freefall (where the fore and aft sections are merely separated by a tether or umbilical cord, often made of tubular nylon). These recovery events can be brought about by small explosive charges (black powder or Pyrodex) or pressurized gasses (e.g. CO2). At an altitude predetermined by the hobbyist, an altimeter deploys a main parachute which slows the rocket to a safe recovery speed. The most common varieties of altimeter use accelerometers, barometric sensors or a combination of both.
