The 38mm diameter motors are the first stop on your way to your high power certification. In the 38mm category, you can fly from a G-size engine to a J-size. That means it is possible that you can get your Level 1 and Level 2 high power certification with the same rocket! This is what brings great glee to many rocketeers, as it simplifies the certification process and saves them a lot of money. That is probably why the 38mm size engine mount is the most popular size for high power.

The other advantage of 38mm motors is that they still come with delay and ejection charges. You do not need to invest in electronics and other equipment to pop the parachute out of the rocket. This fact simplifies construction of the rocket and makes it easier to gain experience with building high-power engines. When you first get into high power rocketry, you'll probably want to focus all you attention on building the rocket strong enough to handle the higher forces that occur with big rockets. You don't want to worry about getting the electronics to work properly too, do you? Just one step at a time, right?

The case holds the propellant inside. It is anodized yellow to make it easy to find if it ever should fall to the ground.

The forward closure screws onto the front end of the case. It serves multiple purposes. First, it holds the hot gases of the burning propellant and keeps them from shooting forward into the body of the model rocket. It also holds the special slug of propellant called the "delay grain." Finally, it has a small receptical at the tip to hold the black-powder ejection charge.

The aft closure screws onto the base of the aluminum case. Like the forward closure, it is a bulkhead that holds the hot gases inside the case so the motor can produce thrust. In the middle of the part there is a big hole, which allows the nozzle to protrude out the back end of the assembly.

Their is another feature of the aft closure that makes it convenient for use in most rockets. The diameter is bigger than the case. When you push the motor into the engine tube of the rocket kit, it stops when it butts up against the aft closure. In effect, it acts as the engine block. This way you can leave the engine block out of the kit if you want to use it with different length reload motors!

In fact, theses cases have the exact same specs as the one from Aerotech, because Aerotech licensed Rouse-Tech to make them for consumers. The only difference is the anodized color on the outside of the motor.

Step 1: Pick the diameter of the engine. Clicking on the diameter will take you to more information about each diameter motor so you can select the correct casing.

• 24mm Dia. Motors (power: E - F )
• 29mm Dia. Motors (power: F - G )
• 29mm HPR Motor (Power: G - I )
• 38mm Dia. Motors (power: G - J )
• 54mm Dia. Motors (power: I - K )
• 75mm Dia. Motors (power: K - M )
• 98mm Dia. Motors (power: K - N )

Step 2: Pick the Aerotech Propellant kit that you want to fly in your rocket. To be honest, this is the most time-consuming step. Contact us if you need help. We'll direct you to the RockSim software that we use to help pick the right rocket engines for your vehicle. Technical Publication #28 gives you a step-by-step procedure for picking the motors that might work in your rocket.

Step 3: Match the propellant kit that you just selected in step 2 to the appropriate Rouse-Tech Monster Motor Case.

Q. Where do I buy the propellant kits that go into the motor cases?

A. Give us a call at: 719-535-9335 and we can give you further directions.

Q. Are there any special tools that are needed to assemble these motors?

A. No. You will only need a tube of grease (white lithium grease or vasoline will work fine) to put on the threads to provide a little lubrication.

Q. Don't I need to be high-power certified to buy these motors?

A. No. You can buy the aluminum casings without being certified. However, you do need to be high-power certified to buy the propellant kits (H size and larger).

Q. Where do I go to get High Power Certified so I can buy the propellant kits?

A. In the United States, there are two organizations that can certify you to fly high power motors. They are the National Association of Rocketry, and Tripoli Rocketry Association. If you are outside of the USA, please click here.

Q. Why isn't there a "one-size-fits" all reloadable-case?

A. Great Question! It has to do with the physics of rocket motors. To make such an motor case, you would have to design it to fit the largest engine. Then smaller motors would have a lot of empty space in them. First of all, this would be inefficient because you're carrying excess weight into the air. The extra space that should be filled with propellant causes problems with the rest of the propellant burning. There are vibrations and acoustics that resonate in the empty chamber that make sustaining thrust difficult. It is a delicate balancing act to design efficient motors. That is why it is called "rocket science" after all. Fortunately, the hard part is done for us by the manufacturers, and we get to enjoy the smooth operation of each well designed motor.

Q. Why would Aerotech license Rouse-Tech to make these motors?

A. The casings are expensive to manufacture, and it ties up a company's money to make all the necessary inventory. By licensing the case production to Rouse-Tech, Aerotech frees up its cash to invest in new motors and propellant -- which is good for consumers as it offers them more choices of motors.

Q. How easy is it to assemble a reloadable rocket motor?

A. It will take you about 5 minutes to put one together. If you want to see how easy it is, watch our YouTube video where we put one together (click here).

Q. What kind of hook should I use to hold the 38mm reloadable engines in my rocket? I noticed that the Apogee web site doesn't have long engine hooks.

A. Aero Pack Engine Retainers. These are useful on rockets that use the 38mm diameter reloadable motors.

Cesaroni (also known as CTI) is a manufacture of reloadable rocket motors. These motors are made in the standard diameters, so they will fit into your current fleet of rockets without having to do any further modifications. Note: the cases are not compatible with Aerotech Reload Propellant.

"I am satisfied with how the order was handled. Everything arrived quickly and in good condition. It will take me some time to get through the book and using the software but will pass along any comments. I will be passing along information about Apogee Components as I found the web site helpful, provideing links to many resources (materials and information)." - Sebastien LeBel