Q. Is it simple to use a reloadable motor?

A. Like anything in rocketry, there is a learning curve. There is a proper sequence of assembly steps, each with a verification step (to check for quality control). If you follow these steps (for both assembly and disassembly) with proper cleaning, you will find that it is fairly easy to assemble a reloadable rocket engine. Watch the video on this web page and judge for yourself if it is easy or not. We think you'll find that it is straight-forward if you follow the instructions.

Q. It is safe and reliable?

A. Yes, if you use them as prescribed by the detailed instructions.

Reloadable rocket motors are designed to be rugged and safe. If you assemble them incorrectly, they are designed to spit out the aft closure (where the nozzle is held in place). Once this happens, the pressure inside the motor is released, and most times the propellant will completely stop burning.

Q. When should I switch from single-use motors and use the reloadable variety?

A. As soon as you are sure you won't stop flying rockets (we all know how addictive they are). The metal case, into which you insert the propellant grains, takes a commitment to purchase because of the initial expense. You must look at it as an investment that pays for itself over time (like the RockSim software), because of the reduced cost per flight for the reload propellant grains.

Q. When should I avoid using a reloadable motor?

A. Reloadable motors are not for everyone. If you're under 18 years old, you may not use them.

There are also some situations where it is advisable to use a single-use motor, like the Apogee Medalist or Econojet motors. The biggest reason to use a single-use motor is in a rocket where there is a higher than average chance that the rocket will be lost after the flight. For example, launching the high-flying Apogee Aspire kit, which can easily go over 1 mile high and become a tiny speck in the sky, is a good place to use a single-use motor. This is the major reason why we at Apogee Components, do not sell the 18mm reload casing; there is just too high of a chance of losing the rocket on each flight.

Other "not-recommended" situations are when the launch area is surrounded by thick forests and/or lots of water. If you lose the rocket, you've lost the expensive metal reload casing.

You might not want to use a reloadable motor in contests, where you want to keep the rocket light. Typically, a single-use motor will be lighter in weight, and should allow the rocket to fly higher and stay in the air longer.

Finally, if you are in a time-crunch, such as working on a school project where you have to fly the same rocket multiple time in a single day, you might want to avoid a reloadable motor. The reason is that it can take a significant amount of time to clean and reload the casing after each flight. The weather may change quickly on you during those periods of prepping for flight. Also, when you are stressed for time, you are more apt to make an assembly mistake that could cause you to crash the rocket.

Q. How do you select the right reload motor to use?

A. You select a reload motor based on the rocket you intend to fly and it's mission objective. This is exactly the same way you'd choose a single-use motor.

Start by using the RockSim software. Create or load-in your rocket design, then try out various motors until you find the right one that will keep the rocket safe and will meet the mission objectives. I highly recommend reading Technical Publication #28, which describes the procedure for selecting motors.

Q. Why doesn't Apogee Components carry bigger reload motors from Aerotech?

A. At this time, we are only carrying the motors that can be shipped through the mail. We are not yet set up to ship the bigger ones that require a hazmat fee and must be shipped by UPS or FedEx. This is limited to rocket motors with less than 30 grams of propellant.

Q. Can I make my own metal cases?

A. Not recommended. Each reloadable case is precision engineered and manufactured to exact specifications using high-grade aerospace materials. They are made this way to be safe and reliable. Why? Because, if they should fail because of improper assembly, they need to burst open in a pre-designed manner that won't cause harm to spectators. Safety is everything in model rocketry!

Q. Is the rocket fuel (propellant grains) interchangeable between motor casings?

A. No. Each type of propellant grain is made to be loaded in a specific metal case. The reason is that the grains are different geometries (some have holes, some have slots) and are different sizes. They each burn differently which affect how much thrust they create. Additionally, the grains must be matched to the correct rocket nozzle so they create the proper amount of pressure inside the metal case. Too much pressure and the case will burst the aft bulkhead. Too little pressure and the motor will not make enough thrust to lift the rocket safely into the air. In other words, there is no such thing as a "generic" reload case.

Q. Can I make my own reload propellant (such as black-powder) and put it into the metal reload casing?

A. No. Black powder is classified as an explosive. The metal reload case is not designed to hold explosives like black powder. It will burst open in an uncontrolled manner. This is highly dangerous!

Q. Can I reload a single-use motor with the reloadable propellant grains?

A. No. During the "burn," the inside of a single-use case is severely charred and eaten away. The nozzle also erodes and changes shape. Should you try to reload the case, it will burst open and could cause you harm. This is why the NAR safety code prohibits modelers from doing this dangerous activity.

Q. What does "Easy Access" mean?

A. It is Aerotech's designation for reloadable rocket motors where the individual propellant grains weigh 30 grams. Why is 30 grams an important number? That is the maximum amount of propellant that is shippable through the postal system. If the fuel grains weigh over 30 grams, they cannot be shipped through the postal system; they would have to go via UPS or FedEx. These companies charge a hazmat fee ($20 per box) for shipping flammible items like rocket propellant. By keeping the propellant grains under 30 grams, you save money by avoiding a hazmat fee.

Note: the 30 grams is the maximum weight of the individual propellant grains. Many of the Easy Access™ motors use multiple grains (two or more slugs of propellant); which is why the total propellant weight inside the motor is greater than 30 grams.

Q. Why don't you ship rocket motors to countries outside the USA?

A. There are too many shipping regulations. We're a small company, and we don't have the manpower to track the regulations for each country in the world. So to keep our prices as low as possible, we only ship motors to USA customers.

Q. Can you ship motors to me by this weekend?

A. All rocket motors must be shipped by surface transportation (truck). While we ship the motors usually the same day the order comes in, you should plan extra time for the postal service to deliver them via third class mail (Parcel Post).

Q. How is maximum lift-off weight determined?

A. The maximum recommended lift-off weight for each delay depends on the size of the rocket, its drag coefficient, launch angle, and the wind conditions at launch. We recommend running a RockSim computer simulation for each rocket design and launch conditions to select the proper motor delay. For help selecting the correct delay time, see Apogee Technical Publication #28.