Archive-name: model-rockets/general Rec-models-rockets-archive-name: rockets-faq/part01 Posting-Frequency: weekly Last-modified: 1998 November 16 URL:
http://www.ninfinger.org/~sven/rockets/rmrfaq.toc.html Rec.Models.Rockets FAQ (Frequently Asked Questions): PART 1 OF 14 GENERAL INFORMATION This portion of the r.m.r FAQ is maintained by Buzz McDermott, at
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Comments, criticisms, suggestions and corrections for this section should be sent to that email address. 1.1 What, exactly, is a 'model rocket' versus a 'high power' rocket? Where do liquid fueled and homemade rocket motors fit in? What about amateur rockets? 'Model', 'high power', 'advanced', and 'amateur' are all terms which have many definitions, depending to whom you are speaking. In r.m.r., and in the FAQ documents, the definitions (if any) accepted by the NFPA, National Association of Rocketry, and Tripoli High Power Rocketry Association are used. If these definitions conflict the NAR definition is used. 'Model rockets' are rockets that conform to the guidelines and restrictions defined in the NFPA 1122 document. These rockets weigh less than 1500 grams, contain less than 125 grams of total fuel, have no motor with more than 62.5 grams of fuel or more than 160 NS of total impulse, use only pre-manufactured, solid propellant motors, and do not use _meta_l body tubes, nose cones or fins. One inconsistency with this is the CPSC definition of a model rocket motor, which by their definition must contain no more than 80NS total impulse. NFPA document 1127-94 contains the most complete definition of a model rocket and the model rocket safety code. This is the same safety code as adopted by the NAR. 'Large Model Rockets' is a term used in the FAA FAR 101 regulations. It refers to NAR/NFPA model rockets that are between 454 and 1500 grams (1 to 3.3 pounds) total liftoff weight or contains more than 113 grams but less than 125 grams of total fuel. 'High power rockets' are rockets that exceed the total weight, total propellant or single motor total impulse restrictions of model rockets, but otherwise conform to the same guidelines for construction materials and pre-manufactured, commericially made rocket motors. High power rockets also allow the use of _meta_l structural components where such a material is necessary to insure structural integrity of the rocket. High power rockets have no total weight limits, but do have a single motor limit of no more than O power (40,960NS maximum total impulse) and have a total power limitation of 81,920NS total impulse. NFPA document 1127-1985 contains the most complete definition of a high power rocket and also the high power rocketry safety code. This safety code has been adopted by both the NAR and TRA. _meta_l bodied rockets are allowed by NFPA 1127 where _meta_l is required to insure structural integrity of the rocket over all of its anticipated flight. 'Amateur' rockets covers all other non-professional rockets that do not meet the criteria for model or high power rockets. This includes _meta_l bodied rockets, liquid or hybrid fueled rockets, and rockets with any type of homemade rocket motor. 'Experimental' rockets is an ambiguous term. In the early 1980's it was used (reportedly coined by the magazine 'California Rocketry') to describe rockets that exceeded the model rocket limit at that time (1 pound total liftoff weight and no motor above F power). More recently, it has been used by the Tripoli Rocketry Association to describe the class of rockets that use pre-manufactured solid or hybrid rocket motors but that do not qualify as high power rockets. This includes _meta_l bodied rockets and those with more than 80,000NS of total power. 'HPR-lite' is not any type of 'official' rocket designation but has been used to refer to rockets that exceed the old NFPA model rocket limit of 1 pound but still qualify as NFPA model rocket under current guidelines. These rockets typically use E through G power and are built with much the same techniques as high power rockets. This term originated in the internet 'rec.models.rockets' newsgroup. It should be noted that this term refers to legal model rockets, not any type of high power rocket, and might therefore be misleading to many. The term 'Large Model Rocket' should be used instead. Another term that has no formal definition but is more and more being used in the literature is 'hobby rocketry'. This term includes both model and high power rockets, but excludes amateur rockets. The term 'consumer rocketry' has also been used, and means the same thing. The term 'non-professional rocketry' encompasses all forms of model, high power and amateur rocketry. Finally, the editor of this document wishes to get on his soapbox for just one moment and add the term 'stupid rocketry' to cover all those who attempt to casually produce their own rocket fuel and/or motors without the benefit of very serious study, and implementation, of the processes involved and safety measures required. Especially note that this comment is NOT aimed at serious amateur rocketry organizations, college level research, etc. End of soapbox.
Favoured: 0
