Model rocket motor classification

As propellant is called a pre-assembled drive for model rockets. Propellant charges for model rockets always consist of a propellant charge and usually also from a delay charge and an ejection charge. As fuel is usually transmitted in small propellant charges of black powder used. For larger propellant charges a much modern and more powerful composite fuel used.

The propellant charge which is ignited electrically safety reasons in general, takes the function of the acceleration of the missile model. If the propellant burned, the delay charge begins to burn. It accepts no drive function, but allows through their smoke cargo to follow the model better. After combustion of the delay charge ignites the ejection charge. This charge ejects the recovery system forward by the rocket body.

Legal

In Germany are treated (more than 75 grams) solid rocket boosters either as pyrotechnic articles (up to 75 grams of fuel), or as explosives. Pyrotechnic articles of Classes I, II, III, and PT1 and PT2 must be approved by the BAM and wear according to national guidelines, a BAM number, explosives must undergo a type approval according to EU directives and then obtain a CE mark. Pyrotechnic articles of Class IV are subject to a so-called quality control. Fireworks must - in spite of their structural similarity - can not be used for the propulsion of model rockets. In Germany may (for people over 18 years -the-counter ) propellant charges have a maximum of 20 grams of propellant. A license, the T2 form ( see below) for the purchase of stronger propellant charges is necessary. This note is in Germany also needed to launch model rockets legally with multiple stages or bundled propellants allowed.

In all other countries, such as Switzerland, Austria, Great Britain, Sweden, France, Poland and the United States and Canada, propellant charges may be sold freely with much larger loads and used without proper government approval. Also, no special government license is needed there for the launch of model rockets with multiple stages or bundled propellants. Instead the focus on self-regulation within the local model rocketry organizations by so-called high-power certification systems in which the access to larger engines via a multistage testing and certification system is carried out. However, the Hand-made propellants ( the so-called Experimentalraketenbau ) is forbidden in these countries without a license.

Authorization according to § 27 Explosives - The " T2 bill " (Germany only)

Depending upon completion of the exam and the resulting entries in the corresponding certificate, may various pyrotechnic articles of Class T2 ( propellant charges for technical purposes with more than 20 grams of propellant weight) as well as black powder be purchased with a permit under § 27 Explosives in Germany. Also, in order to concentrate on model rocket propellant charges or more stages to fly this appearance is necessary.

A permit under § 27 SprengG normally not eligible for the production of pyrotechnic articles, fuel mixtures or explosives and burning of fireworks with more than 20 grams effect charge, provided that these acts are not registered there explicitly, which is possible only through the presentation of a corresponding technical qualifications.

To obtain a license pursuant to § 27 of Explosives Act, you can be ( Proof must be at least 21 years old (in exceptional cases 18 years ), physically suitable and reliable effected by the presentation of a corresponding clearance certificate of the competent authority and should not be confused with the police certificate ) and an appropriate examination to the competent authority, such as the labor inspectorate or a nationally recognized training institute, have been passed. Furthermore, it is also a so-called need, such as membership in a model rocket club, a prerequisite for the grant.

Courses are conducted in Germany by several rockets clubs. A course lasts i.d.R. several days and imparts all the knowledge necessary for the construction and launch of missiles with more than 20 g of fuel weight.

Designation

There are different types of propellant charges. They are usually according to a scheme that has the American National Association of Rocketry (NAR ) originally developed called. This consists of one letter and two numbers, with the following meaning:

A G64 -7 thus has between 80 and 160 Ns pulse, 64 N average thrust and by the end of firing a free-flight phase of 7 seconds before the parachute is ejected.

Basically you should only use this for use in model rockets as possible the manufacturer's recommended propellant charges, otherwise may crash the model. The solid rocket boosters most commonly used for the propulsion of model rockets are blowing sets of categories C and D.

Differences fireworks propellants

Propellant charges of fireworks meet in their strength as propellants category A to C. In contrast to model rocket propellants there are at blowing sets of fireworks no delay and propellant charges in the proper sense. The propellant ignites after it is burned directly for the name of the peak effect sentence. For model rockets can be exchanged in principle, the propellant charges while they are connected firmly with this in fireworks. Also model solid rocket boosters are always shipped without fuse. Model rockets may also - in contrast to fireworks - are flown throughout the year.

Micro- motors

Model rockets with very small engines are also known as mini model rockets or model rockets with micro - motors. The term Micro-motor was introduced in the 1990s by Czech Micro- motors from Delta, which had a diameter of only 5.1 mm and a length between 10 and 18 mm. The engines were designated as role models for the Micro Maxx Micro- motors of the U.S. manufacturer Quest Aerospace.

Micro Maxx rockets were always delivered as a finished model. They can be started only with electric ignition and reach peak heights of up to 60 meters. The Micro -Maxx product line has since been reinstated by the manufacturer.