Lets take an example so you can see how to read the charts. As an example, we'll look at the "E28-4T" motor.
Breaking it down, we have four bits of information. "E," "28," "4," and "T"
The first letter, "E," in our example, is the power level classification of the motor. If you look at the chart at the right, you can see that "E" motors range between 20 and 40 Newton-seconds of "Total Impulse". Each letter's maximum total impulse is twice that of the prior. For a full chart of impulse classification levels, check out the Wikipedia page.
In our example, the E28-4T has 39.69 N-s of total impulse per the manufacturer, so it would considered a "Full" E motor since it is so close to the maximum of 40 N-s.
The first number after the power letter is the average thrust level of the rocket measured in Newtons, equivalent to 0.225 pounds of force. That means in our example, the motor has an average thrust of 28 Newtons.
The number after the dash is the length of time in which the "delay" charge burns before it allows the ejection charge, which deploys your parachute, to go off. Delay allows time for the rocket to coast and slow down so the parachute doesn't rip out of the tube at ejection. In our example, the rocket would coast for 4 seconds before deployment.
Most single-use motors give a hard number for the delay, and you will need to purchase the appropriate one for your kit. Some loadable, larger single use or reloadable motors will often have a maximum delay that, with a specially designed tool, you can use to shorten the delay to what is best for your rocket. Look at the "Max Delay" statistic for that particular motor. If it is an N/A, or not listed, you cannot adjust the delay.
The letter after the delay* denotes the propellant type, aka color, of the motor. Each brand uses a different lettering scheme. Our example is an Aerotech motor, and the "T" tells us that it is a Blue Thunder propellant. Propellant type doesn't affect the way your rocket flies, it just affects the way it looks at takeoff. See the image below to get an idea of what the flame will look like for the different chemical formulations. For more information on motor flame-color, see Peak-of-Flight Newsletter #217.
Note: The "T" for the Blue Thunder formulation can cause a little confusion, since Estes use the "T" designation to indicate the size of the motor as being 13mm in diameter. See Estes Items for more about the "T."
*The propellant type may also come immediately before the dash on some high-power reloads. In the example of H123W-M, the ordering goes (Total Impulse)(Average Thrust)(Propellant)-(Delay)
The following propellant descriptions are courtesy of Aerotech:
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 newer 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 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.