# The Naked Scientists Forum

### Author Topic: shooting people from cannons  (Read 10127 times)

#### paul.fr

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##### shooting people from cannons
« on: 01/05/2007 23:45:25 »
when someone is shot from a cannon, how do they work out where to put the net? why does he not get hurt or burned, and why does he have a beard? they all do!

#### ukmicky

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##### shooting people from cannons
« Reply #1 on: 02/05/2007 00:08:36 »
They weigh the person and use some form of scientific calculation to see how far a certain amount of powder will shoot it at different angles or something like that.

Nearly forgot the beard is used to seal the barrel of the cannon to prevent the expanding gases from leaking out before they have been used to propel the idiot inside. :-)

#### another_someone

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##### shooting people from cannons
« Reply #2 on: 02/05/2007 00:10:42 »
I imagine the only purpose of the beard is to demonstrate that only crazy people get shot out of cannons, and having a beard makes him look crazier.

Calculating the trajectory of a cannon shell is very important in battlefield conditions if you are going to hit your target.  It is easier to do with a cannon shell that is rigid and of a simple shape designed for its purpose than it is for a human body that might wriggle (no doubt they do try and wriggle as little as possible), and of highly irregular shape; but then, they are only trying to predict the trajectory over a few tens of yards and not over a 20 miles range that is done in battlefield conditions (but then, there is also the simplification that it is being fired indoors, and so you don't need to worry about wind).

If you know the mass of the projectile (the human being), the charge used, and the length of the barrel, and how well the barrel is seeled, you can predict what speed the projectile will leave the barrel.  If you know the speed and angle of the projectile, its aerodynamic qualities, and its mass, the flight path will be determined by the force of gravity and the aerodynamic drag, both of which can be calculated.

The biggest headache is that a human being is a very complex aerodynamic shape, and that the charge will have to be adjusted if the guy being blasted out significantly changes weight.  All of that said, as I said, the firing range is very short, so the scope for error is limited.

It is easy enough to put some wad between the charge and the projectile, just as is used with shot guns, and would have been used with muskets in the past.  The wad will improve the seal between the charge and the lining of the barrel, and by preventing the gas escaping forward will also protect the projectile from the heat of the gas.

#### neilep

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##### shooting people from cannons
« Reply #3 on: 02/05/2007 00:12:07 »
They weigh the person and use some form of scientific calculation to see how far a certain amount of powder will shoot it at different angles or something like that.

Nearly forgot the beard is used to seal the barrel of the cannon to prevent the expanding gases from leaking out before they have been used to propel the idiot inside. :-)

LOL....the beard thing is very funny !!!...LOL

#### paul.fr

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##### shooting people from cannons
« Reply #4 on: 02/05/2007 00:13:59 »
They weigh the person and use some form of scientific calculation to see how far a certain amount of powder will shoot it at different angles or something like that.

Nearly forgot the beard is used to seal the barrel of the cannon to prevent the expanding gases from leaking out before they have been used to propel the idiot inside. :-)

i hate it when they use some form of scientific calculations, but i can live with it. I also notice other fairground performers have beards! it could just be a requirement. or sign of madness.

#### paul.fr

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##### shooting people from cannons
« Reply #5 on: 02/05/2007 00:18:57 »
I imagine the only purpose of the beard is to demonstrate that only crazy people get shot out of cannons, and having a beard makes him look crazier.

lol, we all think the same about the beard.

The biggest headache is that a human being is a very complex aerodynamic shape, and that the charge will have to be adjusted if the guy being blasted out significantly changes weight.  All of that said, as I said, the firing range is very short, so the scope for error is limited.

It is easy enough to put some wad between the charge and the projectile, just as is used with shot guns, and would have been used with muskets in the past.  The wad will improve the seal between the charge and the lining of the barrel, and by preventing the gas escaping forward will also protect the projectile from the heat of the gas.

a silly way to put this. but, if the man had an itch on exiting the barrel and tried to scratch it. would he change the trajectory and miss the net?

#### ukmicky

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##### shooting people from cannons
« Reply #6 on: 02/05/2007 00:39:53 »
Quote
Calculating the trajectory  of a cannon shell is very important in battlefield conditions if you are going to hit your target
Trajectory, thats the word . Don't you just hate it when you know the word but it just wont reveal itself to your thought process until its to late.
Quote
Calculating the trajectory of a cannon shell is very important in battlefield conditions if you are going to hit your target.  It is easier to do with a cannon shell that is rigid and of a simple shape designed for its purpose than it is for a human body that might wriggle

These days its a lot easier to hit your target with an artillery shell as the new generation coming in now have built in Satnav and can steer themselves onto their targets even if they have been fired in a direction which should take them ten miles of course.

#### another_someone

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##### shooting people from cannons
« Reply #7 on: 02/05/2007 01:14:36 »
a silly way to put this. but, if the man had an itch on exiting the barrel and tried to scratch it. would he change the trajectory and miss the net?

If he happened to curl up during the flight, his aerodynamic profile would be totally changed, and he would very probably tumble out of the air well short of the net.  A slight fidget may only bring him from one end of the net to the other, but bending over would be a real problem.

#### another_someone

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##### shooting people from cannons
« Reply #8 on: 02/05/2007 01:19:32 »
These days its a lot easier to hit your target with an artillery shell as the new generation coming in now have built in Satnav and can steer themselves onto their targets even if they have been fired in a direction which should take them ten miles of course.

This would only be possible with shells fired from smooth bore guns, although the trend is to move from rifled bore to smooth bore.

In any case, I would be very nervous about using a technology based on SatNav unless I owned my won SatNav satellites (which at present amounts to USA, and Russia, and some time in the future, also the EU).  On the other hand, if every country tries to launch its own SatNav system, space might start getting a bit full.

#### ukmicky

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##### shooting people from cannons
« Reply #9 on: 02/05/2007 01:44:01 »
Not sure if these are the same as the ones i heard about but their similar
Trajectory Correctable Munition (TCM)
http://www.globalsecurity.org/military/systems/munitions/tcm.htm

http://www.globalsecurity.org/military/systems/munitions/m982-155.htm

XM982 Excalibur
Precision Guided Extended Range Artillery Projectile

« Last Edit: 02/05/2007 01:50:09 by ukmicky »

#### Karen W.

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##### shooting people from cannons
« Reply #10 on: 02/05/2007 01:57:58 »
Hey !! This last year at the fair I watched a very beautiful Blond bombshell without a beard  be propelled through the air out of the cannon at the fair here! Well It was really Awesome,Extremely loud and I think she was crazy !!!
« Last Edit: 02/05/2007 07:39:59 by Karen W. »

#### another_someone

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##### shooting people from cannons
« Reply #11 on: 02/05/2007 02:09:48 »
Not sure if these are the same as the ones i heard about but their similar
Trajectory Correctable Munition (TCM)
http://www.globalsecurity.org/military/systems/munitions/tcm.htm

http://www.globalsecurity.org/military/systems/munitions/m982-155.htm

XM982 Excalibur
Precision Guided Extended Range Artillery Projectile

As far as I can read, it is combined SatNav and inertial guidance, so at least they have some capability even if the satellites are shut down.

I would also expect that the shells would have to be fired from sabots, to protect the fins, and those will have to be fired from smooth bore canon.

It also appears at present still to be in development rather than an available product.
« Last Edit: 02/05/2007 02:14:09 by another_someone »

#### ukmicky

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##### shooting people from cannons
« Reply #12 on: 02/05/2007 04:23:01 »
Its designed to be fired from standard 155 artilery piece and the us military  are already recieving there first orders. I saw a program about them last month.

#### daveshorts

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##### shooting people from cannons
« Reply #13 on: 02/05/2007 08:08:44 »
I think most human cannons are actually powered by big springs, the explosion is just for effect. I guess you test it with something about the same weight as a human and start off firing the person not very far, then crank up the spring slowly as you move the net outwards..

#### lightarrow

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##### shooting people from cannons
« Reply #14 on: 02/05/2007 12:44:08 »
I think most human cannons are actually powered by big springs, the explosion is just for effect. I guess you test it with something about the same weight as a human and start off firing the person not very far, then crank up the spring slowly as you move the net outwards..
Ah! I believed they shooted the man and then some very fast people run with a net to match is point of fall!

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##### shooting people from cannons
« Reply #14 on: 02/05/2007 12:44:08 »