What Is Inside a Model Rocket Engine?

Before we even begin to explain what is inside a model rocket engine, it must be stressed that you should never try to disassemble one, because they contain a propellant that is highly flammable and, once that propellant has been removed from the engine casing, it can be very easily ignited.

It is also not advisable for anyone to try to make their own engines, unless they are 100% sure that they know what they are doing. Some expert enthusiasts do make their own rockets and engines, but it is much safer for the amateur to stick with mass-produced model rocket kits and engines.

In the early days, before Vern Estes invented Mable, the very first machine for mass producing model rocket engines, early enthusiasts made their own motors, which led quite a lot of accidents, some of which were fatal. Fortunately, today, engines for model rockets are widely available and they are very affordable.

The most common type of propulsion unit is the single-use, solid propellant type of motor. Here are the components of a standard model rocket engine.


The casing is a simple tube made out of strong cardboard. Cardboard is used because it is cheap, strong and it is lightweight.


At the rear end of an engine, you will find the nozzle, which is usually made of clay or a ceramic material. The nozzle compresses the hot exhaust gasses as they are powered through it by the propellant, and that is what creates the thrust that will lift the rocket off the ground. Clay or ceramics are used for the nozzle, so that it can withstand the high temperature of the exhaust gasses.


In most standard rocket motors, the propellant that is used is black powder. When the propellant is ignited by electric igniter, or starter, it burns from the bottom up, expelling the thrust-creating exhaust. Black powder is made from sulfur, charcoal, and potassium nitrate. In the larger types of engines, a composite propellant is used, which is usually made of ammonium perchlorate, aluminum powder and a rubber-like binding material.

Delay Charge

Once the propellant has been used up, the delay charge, which is located immediately on top of the propellant, will be ignited. At this point in the flight a model rocket will just be coasting and the delay charge will be emitting smoke and flame, but it will not be creating any thrust. The length of time that the delay charge burns will be about 3 to 8 seconds.

Ejection charge

Once the delay charge has burned through to the top, it will ignite the ejection charge. The ejection charge is what will blow the nose cone off of the top of the casing and then the recovery system will be deployed, which is usually a parachute. When the ejection charge ignites, hot gasses are expelled, which is why recovery wadding is used to protect the recovery system from damage.

A modern model rocket engine is perfectly safe to handle and …

What Equipment Do You Need to Launch a Model Rocket?

When you see the advertisements for model rockets, it's easy to overlook the fact that you need to buy launch equipment as well. In fact, terms like "ready to fly rockets" and "almost ready to fly rockets" are actually quite misleading, because you can't fly them unless you also purchase a launch system and some consumables.

That, of course, can lead to a lot of disappointment on a Birthday or at Christmas and it's a common mistake that many people make. The extra equipment and the consumables needed to launch a model rocket are not excessively expensive, but it is frustrating if you did not know that you needed them.

So, if you are thinking of buying someone a model rocket kit for a gift, here are the additional pieces of equipment and consumables that they will need to be able to fly their rocket and that are not usually included as a part of a standard kit .

Launch Pad

The launch pad is a part of what is known as the launch system and it is a relatively simple piece of equipment that provides a stable base from which to launch a model rocket. A launch pad will cost you in the region of $ 15- $ 20 and it is reusable.

Launch Controller

The launch controller is the other element of what is known as the launch system and it is a small, hand-held electronic device that heats up the rocket igniter which, in turn, ignites the rocket engine. Launch controllers cost in the region of $ 20.

Rocket Engines

You will usually have to purchase the engines, or motors, for you model rocket separately too. Rocket engines come in a large variety of different sizes, so it is important that you check what type of engine is recommended for the rocket that you have bought. Rocket engines vary in price, but most start at around $ 10 for a pack of three.

Rocket Igniters

Rocket igniters, which are sometimes called rocket starters, are what are used to ignite the rocket engine. These are consumables, so they are not usually included with a model rocket kit. A packet of 6 Estes rocket starters will cost approximately $ 5.

Recovery Wadding

Recovery wadding is another consumable that you will need to launch a model rocket. Recovery wadding is made of a flame retardant material and it is used to protect the recovery system, which is usually a parachute, from the heat of the ejection charge. Recovery wadding is an essential consumable, but it only costs about $ 5.

Modeling supplies and tools

Depending on the type of model rocket that you buy, you may need some sundry modeling supplies, such as sandpaper, wood glue and plastic cement, as well as some basic modeling tools.

Model rocket kits are classified by skill levels; ready to fly, almost ready to fly, easy to assemble, and skill levels 1 through 5.

Ready to fly models need virtually no assembly and no …