Australian rocketry education
Some basic information for people new to the hobby

The codes are broken down into 4 sections:

  • G - This specifies the TOTAL IMPULSE of the motor and is measured in Newton seconds
  • 40 - This number specifies the average thrust of the motor in Newton's
  • 7 - This is the ejection charge delay in seconds. Faster rockets want longer delay times.
  • T - This is the propellant type

TOTAL IMPULSE

This is an indicator of the total power potential of the motor. Each letter has twice the power potential as the previous letter as you will see in the following table.


TOTAL IMPULSE
POWER RANGE
(N/sec)
APPROXIMATE MOTOR WEIGHT
A
1.26 - 2.5
1.3g
B
2.51 - 5.0
2.5g
C
5.01 - 10
12g
D
10.01 - 20
15g
E
20.01 - 40
20g
F
40.01 - 80
41g
G
80.01 - 160
82g
H
160.01 - 320
163g
I
320.01 - 640
326g
J
640.01 - 1280
652g
K
1280.01 - 2560
1.305kg
L
2560.01 - 5120
2.609kg
M
5120.01 - 10,240
5.219kg
N
10,240.01 - 20,480
10.438kg
O
20,480.01 - 40,960
20.875kg
P
40,960.01 - 81,920
41.751kg

AVERAGE THRUST

This, as the name implies, tells you how much thrust the motor generates during it's burn as an average. The G40 generates 40 newtons of thrust on average. It also provides an indication of the rate at which the motor burns. A higher number equates to a faster burn and a lower number to a slower burn. In our example of a G-40 motor, we can see that this is a fairly slow burn motor. You can get an idea of the rate at which a motor will burn, by dividing the total impulse by the average thrust. We could expect our example motor to burn for about 4 seconds *(3 seconds is normal). If it were a G80 we could expect it to burn for about 2 seconds *(1.5 seconds). So we can see that the higher the number, the higher the initial thrust, but a shorter burn time results.

Sometimes you will see a motor that has a higher average thrust than the total impulse for that motor - like an F100 for example. A full F motor has a potential of 80N/sec of thrust. This does NOT mean it can generate no more than 80 newtons of thrust. It means that an F100 will generate 100 newtons of average thrust and burn for less than a second.


* Because most motors fall short of their total power potential, most burns times are actually less than what you work them out to be - as with everything related to rocket motors, there is only a fine line of 'certainty'.

EJECTION CHARGE DELAY

This is the time in seconds between motor burn out and the ejection charge. As a basic rule, if a rocket is fast or flies high, you'll want a longer ejection charge delay. If the rocket is slow and heavy, you'll choose a short delay. If it's a booster for a staged rocket, you don't want any delay at all.

PROPELLANT TYPE

There are three common types of propellant:

  1. Black powder
  2. Amonium Perchlorate
  3. Plastic / N2O

Most motors in the "A" through "C" range are black powder. You can also get "D" and "E" black powder motors. Black powder motors are typically low thrust motors and are relatively inexpensive compared to composite amonium perchlorate motors.

Amonium perchlorate (AP) composite)) propellant is the standard propellant used in mid and high power rocketry. In Australia, you need a license to posses composite motors. Amonium perchlorate motors range from the 18mm D21, right up to 98mm "P" impulse motors (which cost thousands of dollars each)

Aerotech Propellant Types

 

AeroTech motors come in 10 different propellant formulations, described below:

White Lightning™ (W)

A brilliant white flame, dense bright white exhaust and a throaty roar are the hallmarks of this popular propellant. Easy to track. Exciting to watch! White Lightning looks and sounds like actual sounding rockets and launch vehicles. Special effects professionals and aerospace companies specify the AeroTech White Lightning propellant to achieve realistic simulation.

Blue Thunder™ (T)

Produces a bright violet-blue flame with a minimum of exhaust smoke. These motors provide a higher level of thrust than White Lightning or Black Jack motors of the same total impulse. Blue Thunder is the perfect propellant for high lift-off acceleration.

Black Jack™ (J) and Black Max™ (FJ)

Provides the high visibility tracking of dense black exhaust. In addition to a distinctive lift off roar, Black Jack motors give your models lower acceleration and longer powered flight than White Lightning or Blue Thunder motors of the same total impulse. Black Max provides slightly higher acceleration than White Lightning Propellant.

Redline™ (R)

Distinctly different from its propellant relatives, Redline provides unique visual and thrust characteristics for larger airframes and performance oriented flyers. The proprietary AeroTech formulation imparts Redline with its signature vivid scarlet flame. Redline's burning rate lies midway between that of White Lightning and Blue Thunder. Photos don't do justice to the "laser-beam" intensity and color of Redline… you have
to see it to appreciate it!

Warp-9™ (N)

If you blink you'll miss it! Displaying a prominent yellow-orange flame studded with "mach diamonds", Warp-9 is AeroTech's fastest-burning propellant. Originally developed for Orbital's Pegasus® fin motors, Warp-9 is perfect when you need the highest thrust possible from a given motor size. Alternatively, when used in an "endburning" grain configuration, Warp-9 delivers unique thrust curve profiles such as that produced by the new G69N model rocket reload.

Mojave Green™ (G)

Mojave Green™ is one of AeroTech's newest propellants designed for its single use and RMS reloadable motors. Named for an infamous green rattlesnake with two types of venom that roams the Mojave desert, Mojave Green produces a brilliant green exhaust plume with a moderate amount of smoke. Mojave Green's high density and specific impulse delivers a higher total impulse in each motor size than any other AeroTech propellant. Motor burn times using Mojave Green are similar to those produced by Redline™.

Metalstorm™ (M)

Metalstorm is AeroTech’s latest propellant designed for its single-use and RMS reloadable motors. It has completely different visual, audible and performance characteristics than the other sparky propellants currently on the market. Metalstorm ignites easily and produces a large, brilliant white exhaust plume, a much longer yellow-orange dense spark tail, plentiful white sparks that fan out in flight and an ample volume of white smoke.

Metalstorm’s high density and relatively high specific impulse results in a higher delivered total impulse for a given volume than some other sparky propellants. This characteristic makes Metalstorm "the performance sparky". Motor burn times using Metalstorm propellant are slightly longer than those produced by White Lightning, but the total impulse is only slightly lower.

Metalstorm motors assemble in an identical fashion to other AeroTech reloads fitting the same hardware. Cleanup is easy with none of the problems plaguing earlier sparky motors.

As with all rocket motors using spark-generating propellants, special precautions must be taken to avoid fires around the launch pad by clearing the immediate area of all combustible materials in accordance with
applicable fire and safety codes.

Dark Matter (DM)

Dark Matter is a sparky propellant but unlike Metalstorm with it’s higher ISP and white smoke, Dark Matter is the black smoke sparky. These remind me of the old black powder Rocketflite Silver Streaks, which were legendary in the early days of high-power rocketry.


As with all rocket motors using spark-generating propellants, special precautions must be taken to avoid fires around the launch pad by clearing the immediate area of all combustible materials in accordance with
applicable fire and safety codes.

Propellant X (X)

Proplellant X is a new high ISP propellant. It is a fast burning propellant with a long yellow/white flame and low smoke.
                    

Our example motor has a T designation, which makes it a Blue Thunder. There is also a  'sparkling' propellant

Plastic / N2O or Hybrid motors as they are commonly referred to, have a small bottle of nitrous oxide connected to a fuel grain of plastic (or just about any other material (rubber and cellulose also being popular)). The plastic is the fuel and the N2O is the oxidizer. All components of a hybrid motor are totaly inert and they are intrinicly safe and can only be deemed 'dangerous' when the right sequence of ignition events take place. Hybrids are usualy low thrust motors and require expensive ground support equipment (GSE) and they take longer to prepare for flight. They must also use electronic deployment (altimeter) because they do not have a motor initiated ejection charge. One of the great things about hybrids is once you have the GSE, the fuel grains are much cheaper than AP motors and you can buy them over the net because they are an inert substance.

COMPOSITE SINGLE USE MOTORS & RELOADS

Composite motors come in three different types - Single use, loadable and reloadable. It should be noted that black powder motors burn from the nozzle up, while all composite motors burn from the top down. With composite motors, you are required to slide the ignitor into a slot - the ignitor rests against the delay element. It should also be noted that composite motors vary greatly in length, unlike black powder motors. This is why most mid and high power rockets don't have any form of motor retention (thrust ring & motor clip)- this gives you greater flexibility in what sort of motor you can use. Retention is usually via a commecial solution available from rocketry vendors.

Single Use: These are similar to standard black powder motors but are typically three times more powerful. Single use motors are convenient and quick to prep but they are a bit expensive. Most people stepping up from black powder to composites will start off flying on single use motors, but it won't be long before you start looking at reloads.

Loadable Motor System (LMS): These are a cross between single use and reloadable motors. They are a single use motor and all parts are disposed of after use, however you are required to perform some assembly of the motor before you can use it.

DMS (Disposable Motor System)

New DMS series of High-Power Single-Use motors! No hardware to buy, load, clean or lose
High strength, light weight filament-wound fiberglass casing User adjustable time delays in 2 second increments

The time delay of DMS motors is shortened using AeroTech's new Universal Delay Adjustment Tool DMS motors feature a glass-reinforced composite phenolic nozzle, a new molded plastic bulkhead and ship with a FirstFire igniter and bondable thrust ring

Reloadable otor Cases and Systems (RMS): Reloads consist of two parts:
The reload casing. This is the 'shell' for the motor and they are available to suit different levels of total impulse. You only need one reload case for any given impulse range and a reload motor system mnumbering system as follows:

RMS 29/40 - 120
The '29' stands for a 29mm motor. The 40 - 120 stands for the maximum system impulse range in Newton seconds.

RMS 29/60
Again, the 29 stands for a 29mm motor. The 60 stands for the maximum total impulse of the case in Newton seconds.


Reload Type
Motor
Total Impulse (N/sec)
29/40 - 120
E16-W
40
29/40 - 120
E23-T
40
29/40 - 120
F22-J
65
29/40 - 120
F40-W
80
29/40 - 120
F52-T
80
29/40 - 120
G33-J
100
29/40 - 120
G64-W
120
29/60
F37-W
50
29/60
F62-T
50

As you can see from the above table, if you purchase a 29/60 as opposed to a 29/40 - 120 you will be putting severe limits on the type of reloadable motor you can use as it is only suitable for motors in the 60 N/sec range.

2) The reload motor. This is the actual motor that goes into the reload case and is the part that you replace after each launch. It actually consists of a number of components such as O rings, the propellant grain, the delay element plus some other parts that are essential to the motor. All the parts of the motor are assembled into the reload case and it is important that you follow the instructions carefully and assemble the motor in the correct order. Both the reload case and reload motor will have instructions on how to do this. It should also be noted that different motors have different assembly requirements, so do not presume that because you've reloaded a 29mm F motor that the assembly for a G motor is going to be exactly the same, because it probably won't be.

Reloadable Systems are pretty expensive: A 29/40 - 120 will set you back about AU$120.00 Individual cases (such as the 29/60) are a little cheaper but the initial expense is worth it because the motors are cheaper and in the long run you will save money. Provided you look after your reload case and take care so that it doesn't get ejected from your rocket and lost, it should last you many years. The downside of reloads is that it can take 15mins to 45mins to reload the motor after each flight but this is good in it's own way because you get better value out of your day out. You could burn $100 worth or single use motors in an hour or burn the same in reloads over the whole day. You also need to clean the reload case after every launch. Failure to do so can result in a CATO (catastrophic take off).


 

Loadable Motor System
                  Typical contents of an LMS                     Completed LMS Motor
SELECTING A MOTOR

When selecting the right motor to use, many people who are new to rocketry only tend to look at the total impulse of the motor - after all, a G has to be better than an F right? Not always. As you can see from the chart above, a G impulse motor has a power range of 80 - 160 n/sec. Most motors don't come anywhere near the top range of the motors potential power - 80 - 160 n/sec is quite a range and it gets far worse, to the point of being totally meaningless, as you get into high power motors such as L and M impulse.

The average thrust is more important. Let's say you have a rocket and you have the choice of using a D12 or an E9. The E9 motor will have a much greater total impulse, almost double that of the D12. The D12 however, has greater average thrust at 12 N/sec compared to the 9 N/sec of the E motor. What this means to you is that in some situations the D12 will launch a heavier rocket more safely than the E9. This is because the higher initial thrust the D12 supplies will help get the rocket stable before it leaves the launch rail. Once in the air, though, you can guarantee that the E9 motor would lift your rocket higher. "

 The reality of selecting a motor is to consider the the entire motor code and match it to your rocket's weight and/or diameter. Most rockets come with a recommended motor chart and it is advisable that you stick to these recommendations. If it's a scratch built rocket, well, we hope you've done your homework and remember to advise the range safety officer that you intend to launch an unproved scratch built rocket.



MOTOR CASES AND RELOADS

Following is a table of Aerotech RMS cases (excluding R/C cases) and the reloads that can be used in them. If you can not find the motor you are looking for check the Aerotech products list click * HERE *


RMS
HARDWARE
MOTOR
TOTAL
IMPULSE
PROPELLANT
WEIGHT
LOADED
WEIGHT
AVAILABLE
DELAYS
RMS 18/20 D13W 20 N-sec 9.8g 33g 4,7,10
RMS 18/20 D24T 20 N-sec 8.7g 31g 4,7,10
 
RMS 24/40 D9W 20 N-sec 10.1g 45g 4,7
RMS 24/40 D15T 20 N-sec 8.9g 44g 4,7
RMS 24/40 E11J 35 N-sec 25g 61g 3
RMS 24/40 E18W 40 N-sec 20.7g 57g 4,7
RMS 24/40 E28T 40 N-sec 18.4g 55g 4,7
RMS 24/40 F12J 43 N-sec 30g 67g 3,5
RMS 24/40 F24W 50 N-sec 25.3g 62g 4,7
RMS 24/40 F39T 50 N-sec 22.7g 59g 6,9
 
RMS 29/40-120 E16W 40 N-sec 19g 107g 4,7
RMS 29/40-120 E23T 40 N-sec 17.4g 104g 5,8
RMS 29/40-120 F22J 65 N-sec 46.3g 133g 5,7
RMS 29/40-120 F40W 80 N-sec 40g 126g 4,7,10
RMS 29/40-120 F52T 80 N-sec 36.6g 123g 5,8,11
RMS 29/40-120 G53FJ 92 N-sec 60g 147g 5,7,10
RMS 29/40-120 G64W 112 N-sec 60g 151g 4,7,10
RMS 29/40-120 G71R 108 N-sec 56.9g 145g 4,7,10
 
RMS 29/60 F37W 50 N-sec 28.2g 112g S,M,L
RMS 29/60 F62T 50 N-sec 25g 109g S,M,L
RMS 29/100 G54W 90 N-sec 46g 141g S,M,L
RMS 29/100 G104T 90 N-sec 40.8g 136g S,M,L
RMS 29/120 G77R 105 N-sec 55.4g 155g S,M,
RMS 29/120 G79W 115 N-sec 58.6g 158g S,M,L
RMS 29/180 G75J 155N-sec 105.6g 228g S,M
RMS 29/180 H128W 175 N-sec 92.2g 215g S,M,L
RMS 29/180 H165R 170N-sec 83.1g 205g S,M,L
RMS 29/180 H238T 175 N-sec 79.8g 202g S,M,L
RMS 29/240 H97J 200 N-sec 140.9g 282g S,M
RMS 29/240 H180W 230 N-sec 123g 264g S,M,L
RMS 29/240 H210R 220 N-sec 110.8g 251g S,M,L
RMS 29/240 H220T 220 N-sec 106.4g 239g S,M,L
RMS 29/360 I200W 330 N-sec 175g 364g S,M,L
RMS 29/360 H268R 320 N-sec 166g 346g S,M,L
 
RMS 38/120 G61W 120 N-sec 60.9g 194g S,M,L
RMS 38/120 G67R 110 N-sec 57.6g 191g S,M
RMS 38/120 G69N 137 N-sec 62.2g 195g PLUGGED
RMS 38/120 G339N 110 N-sec 48g 181g PLUGGED
RMS 38/240 H73J 180 N-sec 125g 293g S,M
RMS 38/240 H123W 230 N-sec 125g 293g S,M,L
RMS 38/240 H148R 220 N-sec 115.1g 283g S,M,L
RMS 38/240 H242T 230 N-sec 110.8g 279g S,M,L
RMS 38/240 H669N 220 N-sec 96g 252g PLUGGED
RMS 38/360 H112J 280 N-sec 187.5g 385g S,M
RMS 38/360 I161W 350 N-sec 187.5g 385g S,M,L
RMS 38/360 I218R 330 N-sec 172.7g 370g S,M,L
RMS 38/360 I357T 350 N-sec 166.2g 364g S,M,L
RMS 38/360 H999N 320 N-sec 144g 331g PLUGGED
RMS 38/480 I154J 360 N-sec 250g 476g S,M
RMS 38/480 I211W 460 N-sec 250g 476g S,M,L
RMS 38/480 I225FJ 360 N-sec 241.7g 486g S,M,L
RMS 38/480 I285R 420 N-sec 230.2g 456g S,M,L
RMS 38/480 I300T 440 N-sec 221.6g 441g S,M,L
RMS 38/480 I1299N 430 N-sec 192.1g 422g PLUGGED
RMS 38/600 I195J 478 N-sec 312.5g 582g S,M
RMS 38/600 I284W 590 N-sec 312.5g 568g S,M,L
RMS 38/600 I305FJ 450 N-sec 302.1g 581g S,M,L
RMS 38/600 I366R 550 N-sec 287.8g 543g S,M,L
RMS 38/600 I435T 600 N-sec 277g 527g S,M,L
RMS 38/720 I600R 640 N-sec 323.7g 617g M
RMS 38/720 J350W 700 N-sec 375g 665g S,M,L
RMS 38/720 I364FJ 560 N-sec 362.5g 678g S,M,L
RMS 38/720 J420R 650 N-sec 345.3g 635g S,M,L
RMS 38/1080 J570W 1060 N-sec 527g 908g S,M,L
RMS 38/1080 J575FJ 805 N-sec 519g 932g S,M,L
RMS 38/1080 J825R 970 N-sec 497g 878g S,M,L
 
RMS 54/426 I115W 412 N-sec 219g 545g S,M,L
RMS 54/426 I117FJ 361 N-sec 243g 566g S,M,L
RMS 54/426 I215R 399 N-sec 208g 527g S,M,L
RMS 54/426 I229T 407 N-sec 196g 514g S,M,L
RMS 54/426 I599N 410 N-sec 186g 505g PLUGGED
RMS 54/852 J90W 770 N-sec 391g 834g S,M,L
RMS 54/852 J180T 800 N-sec 398g 841g S,M,L
RMS 54/852 J275W 850 N-sec 440g 883g S,M,L,X
RMS 54/852 J250FJ 731 N-sec 487g 907g S,M,L,X
RMS 54/852 J315R 780 N-sec 415g 844g S,M,L,X
RMS 54/852 J460T 850 N-sec 390g 833g S,M,L,X
RMS 54/852 J1299N 850 N-sec 373g 834g PLUGGED
RMS 54/1280 J135W 1200 N-sec 587g 1126g S,M,L
RMS 54/1280 J415W 1280 N-sec 660g 1199g S,M,L,X
RMS 54/1280 J401FJ 1094 N-sec 730g 1267g S,M,L,X
RMS 54/1280 J540R 1180 N-sec 622g 1154g S,M,L,X
RMS 54/1280 J800T 1280 N-sec 595g 1134g S,M,L,X
RMS 54/1280 J1999N 1150 N-sec 515g 1100g PLUGGED
RMS 54/1706 K185W 1500 N-sec 783g 1418g S,M,L
RMS 54/1706 K513FJ 1467 N-sec 974g 1647g S,M,L,X
RMS 54/1706 K550W 1700 N-sec 880g 1515g S,M,L,X
RMS 54/1706 K695R 1520 N-sec 830g 1450g S,M,L,X
RMS 54/1706 K1100T 1500 N-sec 733g 1368g S,M,L,X
RMS 54/2560 K700W 2400 N-sec 1232g 2059g PLUGGED
RMS 54/2560 K828FJ 2120 N-sec 1373g 2223g PLUGGED
RMS 54/2560 K1275R 2230N-sec 1170g 1990g PLUGGED
 
RMS 75/1280 K1499N 1340N-sec 604g 1741g PLUGGED
RMS 75/2560 K560W 2560N-sec 1341g 2774g PLUGGED
RMS 75/2560 K780R 2360N-sec 1268g 2701g PLUGGED
RMS 75/3840 L850W 3840N-sec 2011g 3741g PLUGGED
RMS 75/3840 L1150R 3560N-sec 1902g 3632g PLUGGED
RMS 75/5120 L1420R 4610N-sec 2535g 4562g PLUGGED
RMS 75/5120 M1297W 5417N-sec 2681g 4708g PLUGGED
RMS 75/6400 M650W 5964N-sec 3351g 5125g PLUGGED
RMS 75/6400 M1315W 6700N-sec 3351g 5675g PLUGGED
RMS 75/6400 M1550R 5700N-sec 3156g 5480g PLUGGED
RMS 75/7680 M1850W 7500N-sec 3979g 6871g PLUGGED
 
RMS 98/2560 K458W 2560N-sec 1325g 3106g PLUGGED
RMS 98/2560 K650T 2560N-sec 1176g 2957g PLUGGED
RMS 98/2560 K680R 2358N-sec 1254g 3035g PLUGGED
RMS 98/2560 K1999N 2560N-sec 1195g 2989g PLUGGED
RMS 98/5120 L952W 5120N-sec 2650g 5027g PLUGGED
RMS 98/5120 L1300R 4567N-sec 2508g 4884g PLUGGED
RMS 98/5120 L1500T 5120N-sec 2351g 4728g PLUGGED
RMS 98/7680 M1419W 7680N-sec 3975g 6931g PLUGGED
RMS 98/7680 M1600R 7085N-sec 3762g 6717g PLUGGED
RMS 98/7680 M2400T 7680N-sec 3527g 6483g PLUGGED
RMS 98/10240 M750W 9325N-sec 5300g 8776g PLUGGED
RMS 98/10240 M1939W 10240N-sec 5300g 8845g PLUGGED
RMS 98/10240 M2000R 9218N-sec 5016g 8429g PLUGGED
RMS 98/10240 M2500T 10240N-sec 4531g 8025g PLUGGED
RMS 98/15360 N2000W 14000N-sec 7676g 12412g PLUGGED