How Does a Model Rocket Engine Work?

This article is obviously just a basic introduction tothe ground and into the air. Once this charge has
model rocketry. With the Carlisle brothers'burned off, your rocket will have reached a
development of the pre-packaged model rocketsub-atmospheric altitude (usually between 1,000 and
engine, this is a hobby that can be safely enjoyed by1,500 feet). The first charge will burn through and ignite
all. I encourage you to get out there and launch yourthe second charge or Delay Charge during the
first rocket. Once you do, you'll be hooked.coasting phase of the rocket's flight. During this phase,
If you're interested in becoming a model rocketthe delay charge emits smoke, enabling you to spot
enthusiast, you'll probably want to learn a little bit aboutthe rocket in the sky. The final phase, the Ejection
the history and workings of the model rocket. This funCharge, activates the recovery system for the model
hobby can provide years of entertainment androcket. The ejection charge produces a small
education for you and your family.explosion which ejects the nose cone and deploys the
Who Invented the Model Rocket Engine?parachute for recovery of the rocket.
The modern model rocket engine was created in 1954Model Rocket Performance
by Orville and Robert Carlisle. Orville was aHow fast the rocket travels, how high it ascends, and
pyrotechnics expert and his brother, Robert, was ahow far it goes depends on the type of model rocket
model airplane hobbyist. Although small rockets hadengine used. Model rocket engines are not all the
been designed in previous years by scientists forsame. The weight of the case, the amount of
research purposes, the Carlisle brothers were the firstpropellant or the pattern of the burn, and the length of
to develop the modern model rocket for the amateurcoasting time for the delay charge all affect the way
market. Up until that time, many young rocketthe rocket will perform.
enthusiasts had been injured (or even killed) trying toWhen purchasing model rocket engines, you will notice
create their own model rocket engines. Thethat each engine is given a number. The format for the
development of the pre-packaged engine changed thetypes of engines is the same. It is letter
hobby from one that had inherent dangers to one thatnumber-number (example C6-4). The letter indicates
was safe. It also made rocketry an affordable hobby.the rocket engine's total impulse range (with A being
The current price for model rocket engines is about $5the lowest and O being the highest). This range is
for a pack of three engines at local hobby and toydefined in newton-seconds, which is a measure of
stores.momentum. The first number indicates the engine's
Parts of the Model Rocket Engineaverage thrust (measured in newtons). If you have a
Most model rockets have pre-manufactured single-useheavier rocket, you should use an engine with a higher
engines. These have become popular because theythrust. The second number indicates the length (in
allow people to fly their model rockets without havingseconds) of the delay charge phase. In our example
to handle the dangerous propellants. The engineengine, C6-4, the delay charge would burn for four
consists of the casing (typically paper or lightweightseconds. It's important to know the length of the
wood) with a clay or ceramic nozzle at one end and acoasting phase of the flight so you don't eject the
clay end cap at the other end. Between the nozzleparachute while the rocket is still ascending, or you
and the end cap are three different charges. Thedon't eject the parachute too close to the ground on
Propellant Charge is what gets your model rocket offthe descent.