Estes Motors

Estes Industries makes a variety of different motors and sizes. The ones shown here are "Black Powder propellant." Black powder is also called gun powder and has only three ingredients: charcoal, potassium nitrate, and sulfur. The advantage of black powder propellant is that it is cheaper compared to more exotic propellants. The downside is that it doesn't create a lot of energy per kilogram of fuel. The easy way to tell a black powder motor from other motors is that it comes in a paper casing. That is one reason it is so inexpensive compared to other fuels.

Black powder motors are easy to ignite. When they burn, they produce a orange/reddish color flame, and light grey smoke. In general, they have low-to-moderate amount of thrust, so the rockets that use them take off slower than other types of rocket propellants. This makes them easier to photograph at lift-off because they rocket isn't moving fast. But you should take care that the rocket leaves the launch pad at a sufficient speed that it doesn't go unstable. A good rule of thumb is that the rocket should be going at least 30 miles per hour when it leaves the launch rod. You can find out this information using a computer software program to simulate your launches. We recommend the RockSim software.

There are different size black powder motors, as shown in the picture below. For reference, the typical model rocket engine that comes with most starter sets is the 18mm diameter X 70mm long variety (shown 2nd from the left). If you want more power, you'd probably select a bigger motor, and if you have a small launch field, you might want to choose a motor with less power.

Do you need help picking a motor? Don't panic! We're here to help you.

1. If you purchased the kit from us, look at the recommendations on the kit's page. It's near the bottom. We have a chart on every kit page showing which rocket motors it can accept.
2. If you didn't purchase from Apogee, then take a look at your kit. The packaging or the instructions will often have a list of motors that can work with the rocket.
3. For advance rocketeers, we recommend using the RockSim software to select engines. That is what we do here at Apogee to pick rocket engines. It will generate a quick list of rocket engines that could work in the design with just a couple of clicks of your mouse once the basic dimensions of the rocket are entered into the program.

Do you have a motor already, and want to know which rocket kit it could be used in? See our tool that specifically tells you this type of information. Select the motor you have from the menu, and it will spit out a list of kits that can be used with that rocket engine. You'll find this FREE tool here.

Let's take an example so you can see how to read the charts. As an example, we'll look at the "1/2A3-2T" motor. 

Breaking it down, we have four bits of information. "1/2A," "3," "2," and "T"

The first letter, "1/2A," in our example, is the power level classification of the motor.  The "1/2" power band, as the chart to the right shows, is greater than .625 Newton-seconds of Total Impulse, and less than 1.25 Newton-Seconds. The maximum power doubles from one letter to the next. So a "B" motor can have twice the power of an "A" motor; which means it will fly approximately twice as high.

Remember, think of power as the size of the fuel tank. The tank doesn't have to be totally full. So An "E" motor isn't required to have the maximum of 40 N-s of total power to still be classified as an "E". It just has to have greater than 20 N-s but less than 40 N-s. This gives us the power-bands (shown as the colors in the chart to the right).

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 3 Newtons during the entire burn time. If you were driving a car, you could relate average thrust to the amount of pressure you push on the accelerator pedal. The harder you push, the higher the average thrust of the motor, and hence the higher you'll accelerate the rocket. If you want to go fast, choose a high thrust motor. If you want to get good economy (longer travel distance), choose a lower average thrust motor. 

For example, a B6 and a B4 would have the same amount of fuel in the tank. But the B6 burns it faster, and hence the rocket will reach a higher speed. The B4 motor burns the fuel slower, and like in your automobile, you'll get more distance out of the fuel that is burned.

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. The 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 2 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.

For black powder motors, the letter after the delay time is meaningless. Estes put the "T" designation to refer to "tiny." When Estes first produced the "T" size motors, they only had two sizes. At this point in time, the "T" just causes confusion, because a letter is used on composite and high-power motors to designate the type of propellant and the color of the flame produced by the motor. Since these are black powder motors, a letter isn't really needed. The "T" size motor are sometimes referred to as Estes mini-motors.

Engine Diameter and Length

Unfortunately, the engine diameter and length are not included in the type code printed on the side of the rocket. So before you can pick an engine from the charts, you have to refer back to the rocket kit itself and see which engine diameter it can use. Do that first. Most kits can accept different length motors, so that is not an issue. The most important thing when selecting a rocket engine is the diameter, and then the "type" designation.

What are the advantages of single-use motors?

1. They are simple and reliable. Just put the motor into the rocket and launch it!
2. They're readily available and, in an emergency, you can pick some brands up at local hobby shops.
3. Fastest turn-around times between flights of the same rocket means you can get a ton of flights done on the same day!
4. If you lose your rocket due to the wind, extreme altitude, or other, you're not out the investment of the much more expensive reloadable casing.
5. Safer to use by younger children, as the propellant and ejection charge are all sealed within the casing.

What is the disadvantage of single-use motors?

1. Single-use motors cost a little more per-flight than reloadable.
2. Larger single use motors, particularly with E class or higher, you often have to pay a HAZMAT fee, which can cause shipping to be upwards of $45. This is because only so much propellant can be in a continuous chunk before there is an assumed risk. Any motors that require the fee are marked.

You have to weigh the advantages versus the extra cost. We believe that there are a lot of cases where it makes sense to use them, which is why we carry so many different ones. We also offer "reloadable motors" in which the casing can be cleaned out and used over and over. These are especially cost effective when the motor is G-size or bigger.