What is "Consumer Rocketry"?
Consumer rocketry is a term used to describe rocketry activities pursued by hobbyists, teachers and other people who are not involved in the commercial applications of rocketry. These activities involve enthusiasts in constructing, flying and recovering lightweight models of real rockets. These models are normally described as either 'model', 'advanced', 'high power', or amateur and experimental rockets.
'Flying model rockets' come in various shapes, sizes and configurations. There are simple model rockets, scale model rockets, multi-stage rockets, rockets which are powered by more than one motor (clusters), rocket-boosted gliders, rocket-boosted radio-controlled gliders, and rotorocs - rockets recovered by helicopter type rotors.
What is the difference between a "model rocket", "advanced model rocket" , "high power" rocket and an experimental rocket?
The two regulations governing rocketry in New Zealand (The HSNO Regulations and the Civil Aviation Rule Part 101), are normally concerned with the total rocket vehicle, that is, rocket airframe and motor combined.Back
Generally speaking however, when rocketeers refer to a 'model rocket' or low power motor they are referring to rockets with no metal structural parts powered by commercially manufactured motors in the power ranges A through D. A 'large' or 'advanced model rocket' motor means a rocket with no metal structural parts, powered by a commercially manufactured motor in the ranges E through 2G's.
[Note that the Civil Aviation Rules define a 'large' model rocket as:
• using between 25 and 125 grammes of propellant (about E to H power);
• producing between 20 and 320 Newton Seconds of total impulse (about E to H power);
• using a slow burning propellant
• made of lightweight materials;
• having no airframe parts made from metal; and
• having a gross liftoff mass not exceeding 1.5 kg].
A 'high power rocket' refers to a rocket with no metal structural parts powered by a commercially manufactured motor in the power ranges H to N. An amateur or experimentalrocket is anything that falls outside of the above categories.
All the above types of rocket are flown from a launch pad, use electrically ignited rocket motors (which are purchased separately from the rocket kit itself), and are designed to be recovered by various means, eg parachute, to enable them to be flown time and time again.
To fly a model rocket you require a launch pad, a launch controller to ignite the motors, flameproof recovery wadding and a selection of model rocket motors (which include igniters).
Where can I buy model rockets in New Zealand?
Model rocket kits and model rocket motors and model rocket parts are freely available in New Zealand from AEROSPACE EDUCATION, Box 13 368 Onehunga Auckland, who market Quest, Aerotech, MRC, Estes, Rouse-Tech, Entacore, Jolly Logic and Public Missiles brands of rocket kits, motors, avionics and parts.
Catalogue prices are:
|Public Missiles (High Power)||$4.50|
|Quest (Model Rocketry)||$3.50|
|Estes (Model Rocketry)||$3.50|
|MRC (Model Rocketry)||$2.00|
How old do I have to be to purchase a model rocket motor?
Model Rocketry motors are recommended for ages 10 to adult with adult supervision recommended for ages 12 years and under. Advanced Rocketry motors are recommended for ages 16 to adult with adult supervision recommended under this age group. High Power Rocketry motors are recommended for age groups 18 and over again with adult supervision recommended under this age limit.
What regulations currently govern the use of model and high power rocketry in New Zealand?
Users of modelrockets and large (advanced) model rockets must legally abide by the Model Rocket Safety Code (published with each rocket kit or motor pack).
There are no Civil Aviation Restrictions on flying 'model rockets' however users of 'large', 'highpower' and experimental rockets need to abide by Civil Aviation Rule Part 101. Briefly, these rules state:
Large, High Power and Experimental Rockets
You cannot operate these rockets above 400 feet AGL (AGL means "above ground level") within 8km of an aerodrome boundary; and:
You cannot operate them, within 4km of an aerodrome boundary, without the permission of the airport operator or Air Traffic Control.
You cannot, without prior permission, launch into prescribed prohibited, restricted, danger or low flying areas, nor into controlled airspace without authorisation from the Air Traffic Control unit responsible for that area.
'Controlled airspace' differs from location to location. To determine whether your launch will breach controlled airspace you need to either refer to an aeronautical map or contact the ATC supervisor in your area (phone 0800 626 756, ask to speak to the supervisor).
You cannot fly or drop an object from a rocket in a manner hazardous to aircraft, persons or property.
You cannot fly when there is less than 4/8ths cloud coverage, or the horizontal visibility is less than 8km, or fly a rocket into any cloud.
High Power and Experimental Rockets
You must submit a pre-launch notice to the NOTAM office at least 24 hours before the launch. This notice must provide your name, address and phone number, or, for multiple launches:
the name, address and phone number of the coordinator of the launchings
the location, date, time and duration of the operation
the estimated number of rockets to be operated
the estimated size and weight of each rocket
the estimated highest altitude to which each rocket will be launched.
(The fax number of the New Zealand NOTAM office is 03 358 9192).
You cannot operate these rockets at night.
Readers wishing to obtain a copy of Part 101 of the Civil Aviation Rules may contact Publishing Solutions Ltd, Box 983, Wellington 6015, Ph: 0800 800 359.
Summary of CAA Procedures to Follow When Launching
What motors are available in New Zealand?
There are 13, 18, and 24mm diameter black powder single use motors available for model rockets in the motor power ranges A to D . These cost from $21 to $40 for a pack of 3 or 4.
There are 18, 24, and 29mm diameter ammonium perchlorate motors available for 'model'' and 'advanced model' rockets, in both single use and reloadable form, in the power ranges B to G. These cost from between $11 to $55 for one or three.
For reloadable motors you need to make a one-off purchase of a metal motor casing for between $79 and $120 depending on the size.
There are 29, 38, 54 and 98mm diameter ammonium perchlorate motors available for high power rockets, in reloadable form, in the power ranges H to N. These cost between $180 and $1800 for the motor casing and $54 to $2560 per flight for the propellant.
In a model rocket catalogue or price list, model rocket motors and propellant kits are referred to by a series of letters and numbers. What do these letters, which are sometimes stamped on the rocket motor itself, mean?
This coding system specifies the motor's total power class, it's average thrust and the delay time between propellant burnout and the ignition of the ejection charge, and in some cases the nature and type of the propellant grain. The first letter refers to the range in which the total impulse (power) of the motor falls. Each succeeding letter can have up to twice the power of the preceding letter.
Using the example G64-10W, the letter G indicates the power range of the motor as specified in the table below (that is, this motor generates between 80 and 160 Newton Seconds of thrust). Note that this letter refers to a power range and not an exact total impulse.
For example a Quest C motor would have a power rating closer to 5 Newton Seconds whereas an MRC C motor would have a rating closer to the 10 N/sec parameter. The total impulse is essentially the area enclosed by a "thrust/time curve":
Rocket Motor Classifications
|Limit (N/Sec)||Limit (N/Sec)||Weight (grams)|
The first number, that is the number 64 in the example above, specifies the average thrust produced by the motor in Newtons. The average thrust is defined as the total impulse produced by the motor divided by the combustion period or thrust duration of the motor. Conversely, the total power of the motor is found by multiplying the average thrust by the motor's burn time. In the example above, the G64 motor has a 2 second burn, so 64 * 2 secs = 128 N/secs of total impulse.
Generally speaking, the higher the average thrust, the faster the rocket's speed when it leaves the launch pad. That is, most of the thrust produced by the motor is developed at the front end or beginning of the burn. So a G80 white lightning motor leaves the pad approximately twice as fast the G40 motor installed in the same rocket. The average thrust rating of the motor is used by the rocketeer to determine which motors of the same total impulse should be used in a rocket, depending on whether it has a high lift off weight or low liftoff weight.
The second number in the motor code, ie the number 10 in the example above is the delay time. This refers to the time lapse in seconds between propellant burnout and the ignition of the ejection charge. The higher this number the longer the period the rocket will travel before the ejection charge fires. High power rocket motors normally have a letter and not a number to indicate the delay time, eg S(mall),M(edium),L(arge). Unfortunately for the rocketeer these letters do not always mean the same for all types of high power rocket motors, so you need to check your motor documentation carefully to determine the exact seconds of delay time.
Some motors specify a second letter to indicate the type of propellant. In the example above, an Aerotech motor, the W stands for White Lightning, T means Blue Thunder, J stands for Blackjack and H stands for Hybrid. The T grain propellants are customarily high average thrust (speed), and the J grains low average thrust (speed).
On some motors the letter can signify that the motor has no ejection charge and is plugged, eg D11-P, F14-P. These types of motors are normally used in rocket-boosted gliders where no ejection charge is necessary, or in very big high power motors where it is very difficult to accurately predict the rocket's coast time. In this latter case, the ejection charge is built by the modeller, placed in the rocket separately from the motor and is activated electronically, perhaps by an altitude sensing device, timer or by radio control.
The Oct 2000, and April 2001 issues of the NZ Rocketry Assn's "INCOMING" publication contain a comprehensive article on model rocket motors.
Are different makes of rocket motor interchangeable?
Although kit and motor manufacturers may recommend otherwise, different brand rocket motors can fit and be launched in any other manufacturer's rocket as long as the engine mount diameter and thrust ring position is the same. Engines and mount diameters are standardised in the sizes 12.7mm, (mini motor), 18mm, 24mm, 29mm, 38mm, 54mm, 75mm, and 98mm. The Aerotech 18mm (composite) motor has the greatest flexibility, allowing a rocket with an 18mm motor mount to be flown with either B, C, D or E power. The Estes D and E engines however have a different diameter than the smaller power (18mm) motors and the E engine is longer than the D. High power rocket engine mounts normally do not have a thrust ring fitted so different length motors of the same diameter can fit in the engine mount depending on it's length.
What are "hybrid" motors?
A hybrid rocket employs a combination of a liquid oxidiser and a solid fuel. The liquid oxidiser is customarily nitrous oxide and the solid fuel a cellulose composition. Since the fuel and oxidizer are separate, both are inherently safer than solid rocket motor propellant. The Aerotech hybrid rocket motor for use in model rockets is available in New Zealand. Users require a 54mm 1280 N/sec reloadable motor and a rocket that can accommodate a 600mm long by 54mm diameter engine mount, and which has an electronically activated recovery system. The solid cellulose propellant and pre-heater grain are loaded into the 54/1280 motor casing which is then screwed into the 54mm liquid tank which contains the nitrous oxidiser. Between the two is a small solid propellant disc which, when ignited, permits the flow of nitrous oxide into the solid portion of the motor. The motor's impulse is rated in the J power range and it has an average thrust of 122 N/seconds. A 38mm and a 98mm hybrid motor are presently under development.
How do I get started in model rocketry?
Your best bet is to purchase a low power "starter kit" for between $79 and $119. A starter kit contains a rocket kitset, a launch pad, an electrical launch controller, recovery wadding, and a number of rocket motors and igniters. The rocket can be used again and again by purchasing additional motors for between $21 to $30 for a three or four pack (A-D power). An Aerotech advanced model rocketry starter kit is available and costs about $395 with single use motors and $495 with reloadable motor. The Summer 1995 issue of AEROSPACE EDUCATION has a good article on beginning in model rocketry. Tips for first time rocketeers.
Are there any national-level rocketry organizations which I might join?
The NZ Rocketry Association has affiliated Clubs which organise two-monthly rocketry meetings for both low power and high power launches. A feature at some of these meets is the opportunity for visitors to build and fly their own rocket.. Fees (at 1 January 2012) are: $10 per year. To join, go to: NZ Rocketry Association.
What are some good books to read to learn more about model and high power rocketry?
Handbook of Model Rocketry, Sixth Edition.
G. Harry Stine
This book covers most things you need to know get started, plus good tips for experienced modellers. The sixth edition was published March 1994. Check your local library.
The Model Rocketry Handbook
Stuart Lodge. Argus Books 1990,ISBN 1-85486-047-X.
This book targets the beginner, but also contains some good tips for more experienced rocketeers. Paperback , 128 pages.
The Rocket Files
200 black and white pages, this book is best suited for those beginning in rocketry through those making the transition from high power to experimental rocketry. Fully illustrated and contains over 200 pictures and diagrams.
Are there any rocketry publications available?
Journal of the National Association of Rocketry, published bi-monthly.
$US 3.95 ? per issue.
Contact Sport Rocketry, Box 177, Altoona, WI 54720, USA.
Web: http://www.nar.org Note:
All subscriptions mentioned above can change at any time.