An Introduction to Rockets Part I

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sambo
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An Introduction to Rockets Part I

Post by sambo »

An Introduction to Pyrotechnic Rockets Part I

Contents

1. Introduction
2. Rocket Types
3. Rocket Tooling
4. Rocket Tubes
5. Nozzles
6. Rocket Fuels
7. Coreburner - 10 minute rocket
8. Hotter Fuels
9. Troubleshooting : C.A.T.O.s
10. Headings
11. Thrust Testing
12. Pressing Rockets
13. Whistle Rockets
sambo
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Re: An Introduction to Rockets Part I

Post by sambo »

1. Introduction

This series aims to take those wishing to start making their own pyrotechnic rockets through from first steps to some of the more advanced techniques. As is so often said, you'll never get a room full of pyrotechnicians to all agree on a single way of doing things and there isn't only ever one right way. However, there are many things, often learned through trial and error and sometimes even through mistakes, that can prove invaluable when starting to make your own devices. Hopefully, this goes someway to help in that regard.

We will take a look at some of the different rocket types but this introductory series is really concerned with coreburners. Why ? - largely because as we are wishing to lift a payload for an effect these would be a good choice with reproducible results. Also, In my opinion, you can't beat the whoosh from a coreburner !

Whilst it's true that you can take a tube, ram in some cat litter with a mallet for a nozzle and screen together some Potassium Nitrate, Charcoal and Sulphur and ram that in and you're away, it can be difficult to obtain consistency. Consistency = predictability and this goes someway to ensuring safety and so if you choose to follow these methods we are really assuming you have the following :

1. A decent tooling set - the best tooling in the UK in fact comes from PyroGear ! I would seriously recommend in investing in a set as it will pay dividends. My size of choice would be 3/4 inch as a good all-round workhorse ( more about sizes later )

2. A Ball mill - if you don't have one, plainly you need to get one as this really governs the quality and consistency of your mix and everything else depends on this.

3. A wooden mallet. Not rubber, Not metal. You can obtain Raw Hide mallets from ebay, these seem to be popular in the US. I've never used one.

4. A Ramming Post. Actually, this is really important and something I initially overlooked. A Ramming Post governs the way in which your powder consolidates in the tube by dampening the "bounce" from the mallet. As you build more rockets you'll realise what I mean by this bounce as this is what hinders you from fashioning a good, solid, crack free grain ( again, more about that later )

5. Decent charcoal. Ideally homemade.

6. Bentonite clay, buy it - don't use cat litter ( I've just upset thousands by saying this ) but when starting off you want as little additional variables and hassles as you can. A kilo will cost you a tenner and last you for over a hundred rockets.

Of course, there are a multitude of other items I could add to the list but this will be enough to get you good consistent results.
sambo
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Re: An Introduction to Rockets Part I

Post by sambo »

2. Rocket Types

Learning to build rockets is obviously inherently risky and as with all things pyrotechnic it helps to read a lot before you begin. Don't just take this tutorial as the be-all and end-all, have a look at some of the links posted in the appendix at the end, as well as the rockets section of this forum. The more you read, the more jargon you will invariably encounter and so it helps to have a basic idea of what we are really talking about...

This guide is principally concerned with Black Powder rockets, ie potassium nitrate, charcoal and sulfur compositions. Sometimes an additional metal may be used for sparking tail effects but there are some important rules to follow when doing this which we will touch upon later. Later on we will discuss whistle, briefly. There are, however, many other types, here are just a few :

a) Black Poweder
b) Whistle
c) Magnalium Rockets - invented by Doc Steinberg and Doc Barr in the 1990s, these are very powerful and very sensitive magnalium fueled coloured rockets. Never to be rammed.
d) Strobe Rockets

The rocket may also be "packaged" in different ways, for example :

a) Core Burner - contains a pressed core formed by using a central spindle
b) Super Core Burner / De Laval Nozzle - convergent-divergent nozzle for increased exhaust efficiency
c) End Burner - no formed central core, nozzle only.
d) Nozzleless - what is says on the tin
sambo
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Re: An Introduction to Rockets Part I

Post by sambo »

3. Rocket Tooling

There are a number of places to obtain rocket tooling and you can even make your own. Due to the tapering on the spindle, it is more difficult to make a D.I.Y. coreburner tool and really something best done by someone with a lathe. Ken here at pyro-gear can get you started or you can try and pick up a deal second hand by posting on this and other forums. What I would say is avoid cheap tooling from ebay, especially those with a wooden base, they won't last. Tooling also needs to be made from non-sparking brass or aluminium for safety.

If your feeling very flush you can purchase a "branded" set from the U.S. from either Rich Wolter and Wolter Tools or Ben Smith at firesmith tools. Both can easily be found by searching online. My preference would be Ben Smith's tools here as they have a slight edge. My preference would always be towards a brass spindle as they tend to be tougher and more resistant to bending.

Then there is the question of tube supports.... If you're hand ramming this isn't strictly necessary, although if you get really good at giving it a good whack you will notice that the base of most tubes will start to flare - certainly if you're using cheaper spiral wound tubes ( not recommended - see tubes section ) and these may in fact burst altogether. Your options are either to

a) hit it less hard, which will reduce some performance and can lead to problems with not consolidating the grain properly which can cause CATOs ( Catastrophic Take Offs ) with the rocket exploding before leaving it's guide tube.
b) support the tube in someway. Wood hardener treating the nozzle end of the tube can help to reduce flare but isn't brilliant. Tube supports can be as simple as a stack of adjustable metal hose clamps overlying a section of PVC tube that has been cut longitudinally and then re-closed to fit the outside diameter of the tube, or as complicated as an aluminium case or one of the systems offered by the experts such as Ben Smith.
sambo
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Re: An Introduction to Rockets Part I

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4. Rocket Tubes
sambo
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Re: An Introduction to Rockets Part I

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5. Nozzles
sambo
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Re: An Introduction to Rockets Part I

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6. Rocket Fuels
sambo
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Re: An Introduction to Rockets Part I

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7. Coreburner - 10 minute rocket
sambo
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Re: An Introduction to Rockets Part I

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8. Hotter Fuels
sambo
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Re: An Introduction to Rockets Part I

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9. Troubleshooting - C.A.T.O.s
sambo
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Re: An Introduction to Rockets Part I

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10. Headings
sambo
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Re: An Introduction to Rockets Part I

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11. Thrust Testing
sambo
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Re: An Introduction to Rockets Part I

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12. Pressing Rockets
sambo
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Re: An Introduction to Rockets Part I

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13. Whistle Rockets
Jolyon
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Re: An Introduction to Rockets Part I

Post by Jolyon »

hello, im new to this forum and wanted to say thanks for this post, the first part of this was really usefull and i think the last bit may have been deleted as it does not appear to be there? some of the headings look very intresting

many thanks jolyon
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Pyro-Gear
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Re: An Introduction to Rockets Part I

Post by Pyro-Gear »

Sort of re read it makes sense, but any questions ask away.
sambo
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Re: An Introduction to Rockets Part I

Post by sambo »

errrr

:oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops:

that'd be my lazy 'A'

Apologies one and all, I kinda didn't see the footfall to justify continuing with it. But, I haven't read it back in a while and if you'd like me to write another specific section let me know.
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Boophoenix
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Re: An Introduction to Rockets Part I

Post by Boophoenix »

Common Sambo get some free time and desire and write a hole book. I'd purchase a copy I do believe.

Great start by the way.
Tyvole
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Re: An Introduction to Rockets Part I

Post by Tyvole »

But Sam, it was just starting to get to the interesting stuff! Please, do go on...
"If you don't learn anything, what's the point?"
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Pyro-Gear
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Re: An Introduction to Rockets Part I

Post by Pyro-Gear »

And Sam don’t forget Dave F’s shim brass trick for support tubes.
Crwinter
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Re: An Introduction to Rockets Part I

Post by Crwinter »

Hi Sambo

If you could find the time to finish off the tutorial- I for one, would really appreciate it. I'm sure others would too. I was just getting in to it!!!
Many thanks
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Pyro-Gear
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Re: An Introduction to Rockets Part I

Post by Pyro-Gear »

Here is a video we made years ago https://www.youtube.com/watch?v=oJaZOgY75R4
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