ROCKETS AND CANNONS

ROCKETS AND CANNONS coutesy of Jolly Roger

Rockets and cannon are generally thought of as heavy artillery.

Perpetrators of violence do not usually employ such devices, because they are

difficult or impossible to acquire. They are not, however, impossible to

make. Any individual who can make or buy black powder or pyrodex can make such

things. A terrorist with a cannon or large rocket is, indeed, something to

fear.

ROCKETS

Rockets were first developed by the Chinese several hundred years before

the myth of christ began. They were used for entertainment, in the form of

fireworks. They were not usually used for military purposes because they were

inaccurate, expensive, and unpredictable. In modern times, however, rockets

are used constantly by the military, since they are cheap, reliable, and have

no recoil. Perpetrators of violence, fortunately, cannot obtain military

rockets, but they can make or buy rocket engines. Model rocketry is a popular

hobby of the space age, and to launch a rocket, an engine is required. Estes,

a subsidiary of Damon, is the leading manufacturer of model rockets and rocket

engines. Their most powerful engine, the "D" engine, can develop almost 12

lbs. of thrust; enough to send a relatively large explosive charge a

significant distance. Other companies, such as Centuri, produce even larger

rocket engines, which develop up to 30 lbs. of thrust. These model rocket

engines are quite reliable, and are designed to be fired electrically. Most

model rocket engines have three basic sections. The diagram below will help

explain them.

_________________________________________________________

|_________________________________________________________| -- cardboard

\ clay | - - - - - - - - - - | * * * | . . . .|c| casing

\_______| - - - - - - - - - | * * * | . . . |l|

_______ - - - thrust - - - | smoke | eject |a|

/ clay | - - - - - - - - - | * * * | . . . .|y|

/________|_____________________|_______|________|_|_______

|_________________________________________________________| -- cardboard

casing

The clay nozzle is where the igniter is inserted. When the area labeled

"thrust" is ignited, the "thrust" material, usually a large single grain of a

propellant such as black powder or pyrodex, burns, forcing large volumes of

hot, rapidly expanding gasses out the narrow nozzle, pushing the rocket

forward.

After the material has been consumed, the smoke section of the engine is

ignited. It is usually a slow-burning material, similar to black powder that

has had various compounds added to it to produce visible smoke, usually black,

white, or yellow in color. This section exists so that the rocket will be

seen when it reaches its maximum altitude, or apogee.

When it is burned up, it ignites the ejection charge, labeled "eject".

The ejection charge is finely powdered black powder. It burns very rapidly,

exploding, in effect. The explosion of the ejection charge pushes out the

parachute of the model rocket. It could also be used to ignite the fuse of a

bomb...

Rocket engines have their own peculiar labeling system. Typical engine

labels are: 1/4A-2T, 1/2A-3T, A8-3, B6-4, C6-7, and D12-5. The letter is an

indicator of the power of an engine. "B" engines are twice as powerful as "A"

engines, and "C" engines are twice as powerful as "B" engines, and so on. The

number following the letter is the approximate thrust of the engine, in

pounds. the final number and letter is the time delay, from the time that the

thrust period of engine burn ends until the ejection charge fires; "3T"

indicates a 3 second delay.

NOTE: an extremely effective rocket propellant can be made by mixing aluminum

dust with ammonium perchlorate and a very small amount of iron oxide.

The mixture is bound together by an epoxy.

BASIC ROCKET BOMB

A rocket bomb is simply what the name implies: a bomb that is delivered

to its target by means of a rocket. Most people who would make such a device

would use a model rocket engine to power the device. By cutting fins from

balsa wood and gluing them to a large rocket engine, such as the Estes "C"

engine, a basic rocket could be constructed. Then, by attaching a "crater

maker", or CO2 cartridge bomb to the rocket, a bomb would be added. To insure

that the fuse of the "crater maker" (see sect. 4.42) ignited, the clay over

the ejection charge of the engine should be scraped off with a plastic tool.

The fuse of the bomb should be touching the ejection charge, as shown below.

____________ rocket engine

| _________ crater maker

| |

V |

_______________________________V_

|_______________________________| ______________________

\ | - - - - - -|***|::::| /# # # # # # # # # # # \

\__| - - - - - -|***|::::| ___/ # # # # # # # # # # # \

__ - - - - - -|***|::::|---fuse--- # # explosive # # )

/ | - - - - - -|***|::::| ___ # # # # # # # # # # # /

/___|____________|___|____|____ \_______________________/

|_______________________________|

thrust> - - - - - -

smoke> ***

ejection charge> ::::

Duct tape is the best way to attach the crater maker to the rocket

engine. Note in the diagram the absence of the clay over the ejection charge

Many different types of explosive payloads can be attached to the rocket, such

as a high explosive, an incendiary device, or a chemical fire bottle.

Either four or three fins must be glued to the rocket engine to insure that

the rocket flies straight. The fins should look like the following diagram:

| \

| \ <--------- glue this to rocket engine

| \

| |

leading edge |

-------> |

| |

| | trailing edge

| | <--------

| |

\_____/

The leading edge and trailing edge should be sanded with sandpaper so

that they are rounded. This will help make the rocket fly straight. A two

inch long section of a plastic straw can be attached to the rocket to launch

it from. A clothes hanger can be cut and made into a launch rod. The segment

of a plastic straw should be glued to the rocket engine adjacent to one of the

fins of the rocket. A front view of a completed rocket bomb is shown below.

fin | <------ fin

| | |

| __|__ |

V / \ V

---------------| |---------------

\_____/

|o <----------- segment of plastic straw

| <------ fin

By cutting a coat hanger at the indicated arrows, and bending it, a

launch rod can be made. After a fuse is inserted in the engine, the rocket is

simply slid down the launch rod, which is put through the segment of plastic

straw. The rocket should slide easily along a coathanger, such as the one

illustated on the following page:

____

/ \

| |

cut here _____ |

| |

| / \

V / \

_________________/ \________________

/ \

/____________________________________________\

and here ______|

Bend wire to this shape:

_______ insert into straw

____________________________________________

\ <--------- bend here to adjust flight angle

| <---------- put this end in ground

LONG RANGE ROCKET BOMB

Long range rockets can be made by using multi-stage rockets. Model

rocket engines with an "0" for a time delay are designed for use in

multi-stage rockets. An engine such as the D12-0 is an excellent example of

such an engine. Immediately after the thrust period is over, the ejection

charge explodes. If another engine is placed directly against the back of an

"0" engine, the explosion of the ejection charge will send hot gasses and

burning particles into the nozzle of the engine above it, and ignite the

thrust section. This will push the used "0" engine off of the rocket, causing

an overall loss of weight.

The main advantage of a multi-stage rocket is that it loses weight as

travels, and it gains velocity. A multi-stage rocket must be designed

somewhat differently than a single stage rocket, since, in order for a rocket

to fly straight, its center of gravity must be ahead of its center of drag.

This is accomplished by adding weight to the front of the rocket, or by moving

the center of drag back by putting fins on the rocket that are well behind the

rocket. A diagram of a multi-stage rocket appears on the following page:

___

/ \

| |

| C |

| M | ------ CM: Crater Maker

| |

|___|

| |

| C | ------ C6-5 rocket engine

/| 6 |\

/ | | | \

/ | 5 | \

/ |___| \ ---- fin

/ /| |\ \

/ / | | \ \

/ / | C | \ \

| / | 6 | \ |

| / | | | \ |

| / | 0 | \ |

|/ |___| \|

| / \ |

\______/ ^ \______/ ------- fin

C6-0 rocket engine

The fuse is put in the bottom engine.

Two, three, or even four stages can be added to a rocket bomb to give it

a longer range. It is important, however, that for each additional stage, the

fin area gets larger.

-= Exodus =-

'94