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- X-Last-Updated: 1998/11/27
- From: wolf@netheaven.com (Wolfram v.Kiparski)
- Newsgroups: rec.models.rockets,rec.answers,news.answers
- Subject: rec.models.rockets FAQ Part 01 - General Information
- Followup-To: rec.models.rockets
- Organization: none
- Distribution: world
- Reply-To: wolf@netheaven.com
- Summary: This posting contains a list of Frequently Asked Questions
- (and their answers) about Model and High Power Consumer Rocketry
- Approved: news-answers-request@MIT.EDU
- Originator: faqserv@penguin-lust.MIT.EDU
- Date: 11 May 2004 10:50:39 GMT
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- 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
- bmcdermo@ix.netcom.com. 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 metal
- 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 metal 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. Metal bodied rockets are allowed by NFPA 1127 where metal 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 metal
- 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
- metal 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.
- -------------------------------------------------
- 1.2 NFPA, FAA, DOT, ... Who are all these organizations and how do they
- affect the rocketry hobby?
-
- DOT (Dept. of Transportation) regulates shipping of rocket motors and
- reloads.
- CPSC (Consumer Products Safety Commission) regulates what may and not
- be sold as a 'consumer' items at the retail level.
- FAA (Federal Aviation Administration) is responsible for airspace
- control and regulates flights of rockets that exceed 1 pound and
- enter FAA regulated airspace.
- NFPA (National Fire Protection Association) makes recommendations for
- use of non-professional rocket motors. Although the NFPA only
- makes recommendations, most state and local laws concerning the
- use of model rockets are based, at least in part, on NFPA
- recommendations; especially NFPA 1122. The NFPA also has a draft
- definition and safety code for High Power rockets, NFPA 1127.
- BATF (Bureau of Alcohol, Tobacco and Firearms) has responsibility for
- regulations concerning storage and use of explosives. This agency
- has taken a recent interest in looking into how high power rocket
- motors are stored and used.
- ATC (Air Traffic Control) You must notify the nearest FAA ATC center
- prior to flying Large Model Rockets or High Power Rockets.
- -------------------------------------------------
- 1.3 What is the current legal status of model and high power rocketry in the
- U.S.?
-
- A. FAA Regulations:
- * Rockets containing less than 113 grams of total fuel and weigh
- less and one (1) pound do not require any type of FAA notification
- and are not restricted by the FAA except where they pose a threat
- to aircraft.
- * FAA "large model rockets" (see the definition in #1, above)
- require that the nearest Air Traffic Control center (ATC) be
- notified of the launch between 24 and 48 hours prior to the
- launch. This is notification and not permission. In the U.S., try
- calling 1-800-WX-BRIEF to get the number of the ATC center nearest
- you.
- * FAA High power rockets (weighing more than 3.3 pounds, containing
- HPR motors, or containing a total of more than 125 grams of
- fuel) require a formal waiver be approved by the FAA and activated
- prior to the launch. Refer to the full r.m.r FAQ (dated 1 Oct 94
- or later) for more complete details.
- * NOTE THAT THE FAA DOES NOT PLACE ANY RESTRICTIONS ON FUEL-PER-
- MOTOR OTHER THAN THE TOTAL LIMIT OF FUEL. HOWEVER, MOTORS WITH
- MORE THAN 62.5 GRAMS OF FUEL ARE HIGH POWER ROCKET MOTORS AND
- REQUIRE HIGH POWER CERTIFICATION TO FLY. This does allow HPR
- certified flyers to conduct low-end HPR launches (with up to about
- 240NS composite motors) without having to obtain a waiver.
- * Remember that HPR waivers, ATC notification and high power
- certification are all separate issues and must all be properly
- followed.
- B. CPSC Regulations/Restrictions:
- * G class model rocket motors (80.01-160.00NS total impulse) have been
- classified as high power by the CPSC. They are considered model
- rocket motors by the NFPA. These motors are now restricted for sale
- to buyers 18 years of age or older. This includes the sale of G
- reloadable motors.
- C. DOT Shipping Restrictions:
- * Most single use rockets motors with less than 62.5 grams of
- propellant are now classified as UN 1.4s and can be shipped via
- UPS (with a HAZMAT fee) or regular parcel post.
- * Most reloadable rocket motor fuel grains weighing less than 62.5
- grams each are now classified as 'flammable solids' and may be
- shipped via UPS (with HAZMAT fee) or regular parcel post.
- * The UPS HAZMAT fee is now $10
- * Any single use rocket motor containing more than 62.5 grams of fuel,
- and any reloadable motor fuel grain weighing more than 62.5 grams
- are classified as UN 1.3c, or Class B, explosives. These motors and
- reload grains may be shipped ONLY via Federal Express to certain
- designated shipping points.
- * Aerotech has announced it has received an exemption for single use
- motors up to K class and reload grains for at least L, and possibly
- M class motors, which allow these motors and reload grains to be
- shipped UPS ground in the same manner as motors containing less
- than 62.5 grams of propellant. Aerotech says these are now shippable
- as class 4.1 flammable solids.
- D. BATF Restrictions:
- * Any rocket motor or reloadable fuel grain containing more than 62.5
- grams of propellant is now classified by the ATF as a Class B Low
- Explosive. This includes Aerotech reloads from J power and up.
- * You must have a federal Low Explosives Users Permit (LEUP) to
- legally purchase Class B rocket motors, reloads, and thermalite except
- under certain restricted circumstances.
- * You must have a federal LEUP to legally store rocket motors or reload
- grains which contain more than 62.5 grams of propellant.
- * You must comply with federal low explosives regulations when
- transporting and storing Class B rocket motors.
- * You must be 21 years of age to obtain an LEUP.
- E. Other High Power Restrictions:
- * You must be 'high power certified' to fly high power rockets.
- * The NAR and Tripoli both have programs for obtaining high power
- certification. You need to join one or both of these organizations if
- you want to fly high power rockets.
- * You must be at least 18 years of age to become high power certified.
- -------------------------------------------------
- 1.4 I would like to get into Large Model Rockets. What are my options?
- Who has NAR certified E, F and G motors today?
-
- The following manufacturers currently have NAR certified E, F and G motors,
- as indicated.
-
- Motor Class Manufacturer Propellant Type
-
- E Flight Systems, Inc. Black Powder
- E Aerotech/Apogee Composite (ammonium perchlorate)
- F Flight Systems, Inc. Black Powder
- F Aerotech/Apogee Composite (ammonium perchlorate)
- G Aerotech Composite (ammonium perchlorate)
-
- There are 18, 21, 24, 27 and 29 mm diameter motors available. One
- manufacturer (Aerotech) has reloadable motor casings for 18, 24, and
- 29 mm motors.
-
- Several manufacturers sell rockets designed for E through G powered
- flight. Refer to the previous list of addresses and get a few catalogs.
- R.m.r readers have recommended kits from NCR, THOY, LOC, Aerotech,
- Vaughn Brothers, and others. Look for the following
- minimum features in E through G powered kits:
- - plywood or fiber centering rings rather than paper or cardstock
- - plywood, thick plastic, or G10 fins rather than balsa
- - thicker motor tubes
- - cloth rather than plastic parachutes
- - thicker-walled body tubes
-
- Remember to build these models stronger than smaller model rockets. Use
- CA and epoxy rather than white or yellow glue. These rockets will
- have to survive much higher stresses than smaller model rockets.
- -------------------------------------------------
- 1.5 Is the proper term rocket 'engine' or rocket 'motor'?
-
- I don't know. I don't really care. And neither should you! In this
- document 'motor' and 'engine' are taken to mean the same thing and both
- refer to "the thing in the rocket which makes it go 'whoosh!!' (or 'roar',
- if flying high power :-)". If you want a sure way to start a fight with
- a fellow rocketeer, just argue that whatever term he/she uses is the wrong
- one.
- -------------------------------------------------
- 1.6 What do the letters and numbers on a model rocket motor mean?
-
- The NAR has developed a motors classification scheme which has been
- mandated by NFPA 1122 and most state regulations. This system
- specifies the motors total impulse class, average thrust, and ejection
- charge delay. This is printed on any motors certified by the NAR.
- the pieces are as follows, given the example:
-
- E15-10W
-
- The first letter indicates the power range, as specified in the table
- below. The number to the left of the dash is the average thrust of
- the motor, in newtons. The number to the right of the dash is the
- approximate ejection delay in seconds starting at the time of motor
- burnout. The final letter is an optional manufacturer designation
- for motor or fuel type. Note that letter designating total impulse of
- the motor specifies an impulse *range*, not an exact total impulse. For
- example, there are G motors that have anywhere from 90 to 160 NS of total
- impulse....an Aerotech G42 is rated at 90NS and a G40 is rated at 120NS.
- Motors with more than either 62.5 grams of total propellant or have more
- than 160NS of total impulse are considered High Power motors. You must
- be certified to purchase and fly these motors. Soon, it may also become
- necessary to have a license to store high power motors.
-
- Andrew Mossberg (aem@hypertek.com) recently posted this chart to
- rmr, which includes approximate propellant weights for maximum impulse
- motors for each class:
-
- P
- O
- W Low High Low High 200 ISP Propellant
- E Limit Limit Limit Limit Weight
- R (NtSec) (NtSec) (lbsSec) (lbsSec) (grams) (lbs)
- = ======= ======== ========= ========= ======== =======
- A 1.26 2.5 0.28 0.56 1.3 0.0028
- B 2.51 5.0 0.56 1.12 2.5 0.0056
- C 5.01 10.0 1.13 2.25 5 0.0112
- D 10.01 20.0 2.25 4.5 10 0.02
- E 20.01 40.0 4.5 9 20 0.04
- F 40.01 80.0 9 18 41 0.09
- G 80.01 160.0 18 36 82 0.18
- H 160.01 320.0 36 72 163 0.36
- I 320.01 640.0 72 144 326 0.72
- J 640.01 1,280.0 144 288 652 1.44
- K 1280.01 2,560.0 288 575 1,305 2.88
- L 2560.01 5,120.0 575 1,151 2,609 5.75
- M 5120.01 10,240.0 1,151 2,301 5,219 11.5
- N 10240.01 20,480.0 2,301 4,602 10,438 23.0
- O 20480.01 40,960.0 4,602 9,204 20,875 46.0
- P 40960.01 81,920.0 9,204 18,409 41,751 92.0
-
- Currently, consumer rocketry stops at rockets with a total of no more
- than 81,920NS of total impulse. Anything larger than that is by
- definition an amateur rocket.
- -------------------------------------------------
- 1.7 What is a CATO? Is it CATO pronounced KAY-TO or CAT-O?
-
- The following definition has been posted to r.m.r. by Jack Hagerty,
- (jack@rml.com) editor of the excellent r.m.r Glossary. For even more
- complete information on the term CATO, refer to the glossary.
-
- A motor failure, generally explosive, where all the propellant
- is burned in a much shorter time than planned. This can be
- a nozzle blow-out (loud, but basically harmless), an end-cap
- blow-out (where all of the pyrotechnic force blows FORWARD
- which usually does a pretty good job of removing any internal
- structure including the recovery system) or a casing rupture
- which has unpredictable, but usually devastating, effects.
- Another form of CATO is an ejection failure caused by either
- the delay train failing to burn or the ejection charge not
- firing, but the result is the same: the model prangs.
-
- Opinions on the meaning of the acronym range widely. Some
- say it's not an acronym at all, but simply a contraction of
- 'catastrophic' and should be pronounced 'Cat-o' (which sounds
- better than 'cata' over PA systems :-). Others maintain that
- it is an acronym but disagree on the meaning, offering a
- broad spectrum of 'CAtastrophic Take Off,' 'Catastrophically
- Aborted Take Off,' 'Catastrophe At Take Off' and the self
- referential 'CATO At Take Off.' The acronym crowd pronounces
- it 'Kay-Tow', like the Green Hornet's side kick. It has been
- pointed out, though, that all of the above are 'post-hoc'
- definitions since LCO's were using the term over range PA
- systems long before any formal acronym was established.
- -------------------------------------------------
- 1.8 When a consumer rocket motor fails (i.e., CATOs) does it explode or
- detonate?
-
- To be precise, consumer rocket motors do NOT 'detonate'. Black powder
- rocket motors 'deflagrate'. Detonation involves the creation of super-
- sonic shock waves. Use the term 'explode' when discussing CATOs involving
- split motor casings, holes blown out the sides of models, etc.
- -------------------------------------------------
- 1.9 Why don't I just make my own model rocket motors? Shouldn't I be able
- to custom-make better, more powerful motors at a cheaper price?
-
- This subject has been hotly debated on r.m.r. It is one of those
- 'emotional' subjects that find people either firmly for or against.
-
- The bottom line is that rec.models.rockets is primarily a newsgroup for
- discussing *consumer* rocketry (which covers model rocketry and high
- power rocketry). Some amateur issues are discussed, but these are not
- the primary focus of the group. Manufacturing your own rocket motors can
- be a very dangerous thing to do, unless done properly, and with extreme
- care. The odds are you will not make motors that are of any higher quality,
- total impulse, reliability, or cost less than pre-manufactured consumer
- rocket motors.
-
- It is the opinion of the editor(s) of this FAQ that you should NOT try
- to manufacture your own motors. If, however, you insist on partaking
- in amateur rocketry, then the editor(s) of this FAQ urge you to get in
- contact with an established amateur rocketry group for guidance and
- assistance.
- ---------------------------------------
- Copyright (c) 1996, 1997, 1998 Wolfram von Kiparski, editor.
- Refer to Part 00 for the full copyright notice.
-
-
-