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 sulphur, charcoal, and potassium nitrate. In the larger types of engines, a composite propellant is used, which is usually made of ammonium perchlorate, aluminium powder and a rubber-like binding material.

Delay Charge

Once the propellant has been used up, the delay charge, which is situated 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 to use and, if stored properly it will last for a long time too. It’s thanks to Vern Estes and his machine called Mable that we can now all enjoy flying model rockets safely.

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3 Great Benefits of Getting Involved With Cosplay

Cosplay is a combination of costume and play and first started to gain popularity in the early 1990’s in Japan. This is a practice of dressing up as a fictional character while acting much like that character to give a touch of authenticity to the experience. Many of the people who get involved see cosplay as a unique display of performance art and is associated with characters that appear in video games, anime, or comic books. Plus, it is also popular for many individuals that attend the major conventions related to film or comics.

There are plenty of reasons why people get involved with cosplay which can range from creating an elaborate costume that portrays a favorite character to the overall social experience.


A major aspect of getting involved with cosplay is the ability to promote socialization and meet others that hold a similar interest. By meeting up with other like-minded individuals it helps to create an environment that makes it possible to socialize without judgment. Plus, this safe environment can do a lot for the personal self-esteem, as well as to help with academic and social success. Also, by sharing an activity with others with the same interests, it can help to create immediate familiarity with a complete stranger, and it is much easier to make friends in a shared community.

Most groups that choose to cosplay get a lot less negative reactions than was experienced in the past, with more and more people open to this pastime as it grows in popularity.


The use of cosplay can help and support the quiet type, who might not normally feel they are able to expose their inner needs. However, with the ability to dress up differently many of these same people are able to come out of their closets.

Cosplay can be used as an efficient method to help improve self-esteem, which over time can make it possible to even overcome anti-social disorders and stage fright, while giving a great ego boost and increase in energy.

Creative skills

Creative skills are certain to be learned when it comes to building the wide range of costume and props. Many people who started out with creating the costumes for cosplay have gone on to build a professional career in costume fabrication. The costume making process helps to learn about crafts, fabric and sewing, as well as staying in touch with the latest costume styles and techniques.

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5 Unusual Places to Metal Detect

Whether you’ve been metal detecting for many years or are just learning how to use a metal detector, finding the best treasures that have been carelessly dropped or left, should always be the passion of your quests. While hunting for metal goodies in commonly known areas, like pastures of land, around houses, beaches, parks, school yards or playgrounds, it’s important to consider five places where the average metal hunter may not typically consider.

1. Old Trees

Metal detecting enthusiasts should be drawn to large trees that have been standing for many years, even centuries. These natural landmarks are potential places to look around for coins, jewelry and other personal items, because people tended to congregate beneath them for social activities. Also, relics from the American Civil War can be found around trees where both Union and Confederate soldiers rested from war, preparing for future skirmishes. It’s also possible that these trees got hit by bullets as soldiers hid behind them for protection. So, bullets are probably still lodged in those trees.

2. Uprooted Trees

Hurricanes and tornados can cause large, old trees to topple and fall to the ground. In the process, roots are pulled up from the ground and soil that has not seen sunlight in many years, is exposed. Within the ground beneath the root systems you might be able to find old metal relics that were dropped before or while the tree was growing.

3. Basements of Old Houses, Taverns, and Inns

You are likely to find many kinds of lost objects where houses and taverns were located many years ago. Although these structures may no longer be standing, large deep holes that were once basements are all that remains. To locate these structures, you probably need to do some historical research because houses were typically built off the beaten path, mainly in forests. In the Northeastern part of the United States you will discover older foundations that date to the 18th century when they were parts of England’s colonies. In the past few years, many historical items have been recovered, such as: rare colonial coins, bullets, buttons, lead smoking pipes, tokens and even gold and silver rings.

4. Outhouses

Over one hundred years ago, people used thin wooden outdoor closets called outhouses for bathroom purposes. Nobody had flushing systems then, so waste simply went into a previously dug pit in the ground. When people used outhouses, coins might have fallen out of unbuckled pants as they crouched over an opening to the pit. Outhouses were also used as trash collectors, because no trash collection services existed then. So people threw old bottles, horseshoes, and many other used household items into them. Digging outhouses can lead to many great finds, but you have to be willing to dig out old feces! Eww! Locating old outhouses usually takes research. You can usually find them by searching for old houses because owners built that extra “shed” to do their private “business.”

5. Swimming Holes, Rivers and Streams

Camping, swimming, kayaking are a few activities that many outdoor enthusiasts do in the summer and fall. Many lose personal items when they are having fun in the water, especially coins, keys, iPhones, and wallets which drop out of people’s pockets as they move about in the water. Rivers and streams have also played parts in the American Revolutionary and Civil Wars. Soldiers who fought, crossed and camped have lost bullets, guns and rifles, buttons, box plates belt buckles and coins.

Successful metal detecting often leads treasure hunters to “out of the way” or naturally hidden locations. Searching through historical data can lead hunters to locations that have been abandoned for years, such as old house foundations and outhouses. Old trees, uprooted ones and popular swimming areas are natural spots that draw people for having fun. Of course, when necessary, always ask for permission to hunt. You aren’t guaranteed to find anything, but the fun in metal detecting is the search itself.

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