"a dumb question about artillery!" Topic

Gents ,
Talking about 12 pounders the cannonbal weight around 6 kilos? greetings serge joe

Not so dumb. It would actually be about 5.5 kilos. However, weights differed between different countries and you might find that '12 pounds' is heavier in one country than another. You need to check which country's artillery you are talking about.

What might be helpful is to use one nation's weight system, say the English weight for a pound, and then compare the others to it.

For example, the French 8-pounder is almost 9 English pounds, and the Austrian 6-pounder is less than a French 6-pounder.

All pounds are not equal. There is a table of national weights and measures in Tousard's American Artillerist's Companion which is now available on Google Books.

I have found it to be very helpful.

B

For what it's worth, from the old naval rules "Don't Give Up the Ship":

Various tests made have proved beyond reasonable doubt that U.S. shot was lighter than it should be. To reflect this, deduct 7% from the number of points of low damage scored … Likewise French shot was at least 10% heavier than its poundage. If the Firing Speed Rule is employed, add 10% to French hits scored …

Artilleryman is quite correct. That's why it is
really difficult to compare the throw weight of
Naval broadsides on large ships of the period,
especially when both the French and the British
fidgeted with their 'standard' armaments.

We(Liverpool Wargames Association) play the board game "Wooden ships and Iron men" with 1:1200 ships.
We were very unhappy with all fire being done at the end of a movement and just giving crew quality a bonus.

So we introduced sequel movement and a rate of fire based on the crew quality (ie some crew can fire twice in a turn).

We looked at the broadside of each class of vessel, working out the weight of shot from each broadside and calculating for each nation pound weight.

This makes a Frence 80 has a better broadside than a British 98.

We carried out a great many changes to the original rules,
the Crew quality we broken it down with Gunnery, Seamanship, boarding and morale.

This give us a more interesting Game a nations play to there strengths.

We call them "Wooden Legs and Iron Lungs".

But you then need to reduce the French broadside as it used lower quality powder, add a greater chance of misfires after the opening shots due to uses matches rather than locks and….

A 12-pdr ball weighs differtly depending upon the country as the calibre varied with the bore from 110mm to 125mm. So the weight would vary from 5.4kg to 6.0kg.
Stephen

FreddBloggs

Having a gunnery as a quality in the crew timings sorts most of it out.

The rules have always had a first time fire bonus for each broadside.

In spite of its name, the designation x-pounder was just a name for a cannon ball of a certain caliber. The actual weight could and did vary (due to variations in the quality of the iron used, and other inexactitudes caused by the cast).

Before the cannon ball was accepted to be used as ammunition in the artillery, first its diameter was checked, with a very tiny allowance admitted.

If the caliber was OK, the weight was measured.

As an example, in 1829 (surely the same applied before), in the Prussian artillery, a

Prussian 3pounder ball had to weight at least 2,75 pounds, and maximum 3,25 pounds.
Prussian 6pounder ball had to weight at least 5,5 pounds, and maximum 6,5 pounds.
Prussian 12pounder ball had to weight at least 11 pounds, and maximum 13 pounds.
Prussian 24pounder ball had to weight at least 22 pounds, and maximum 26 pounds.

(the "pounds" here are Prussian pounds of 467,711 gramms)

Thes means, the cannon balls could weight 1/12 (ca. 8%) less or more than what their denomination indicated.

Gents,
I thought this was short topic but to my surprice a longer one no just a yes or no one greetings serge joe

By the way are there tables to give the windige for 12 pounders? greetings serge joe

Is that the correct word?
greetings serge joe

Is that the correct word?

I think you mean "windage" – the amount of difference between the size of the ball and the diameter of the bore.

G'Day Gents

It is my understanding that the performance of the British 6 pounder and French Long 4 pounder were near enough that they could be used on the same artillery table for a game design.

Is this a fair enough assumption?

Best Regards
Art

There is good information on windage in Louis de Tousard's American Artillerist's Companion. The measurements for both British and French windage on various gun calibers is given.

For the three calibers (4-, 8-, and 12-pounders of the Gribeauval System, the windage was uniform for all three field pieces. That always was not the case for the field pices of other nations' artillery systems, the Austrian field pieces of the Liechtenstein System, for example.

B

But stil are there any diagrames? greetings serge joe

Yes i did the"windage" got greater depending on the use of the barrel overheating during the battle? greetings serge joe

Serge,

You can look up all th edimensions you want here :
Tomas de Morla. Tables des principales dimensions et poids des bouches la feu de campagne, de silege et de place, avec leurs affuts et avant-trains, des projectiles etc: ainsi que des charges, des portees etc. des bouches la feu des artilleries principales de l'Europe …. Leipzig: Barth, 1827. 25 pages:
link
(windage for all the pieces is among the data)
(the data is given in local measures and converted to Frenhc measures, whihc you can then further convert to modern metric measures or English measures if you like)

Wear of a barrel would increase widage.
Heating of a barrel would reduce windage (the metal expands in all dimension).

We really don't know precisely the weight of the ball rounds. They were made by size, and the exact composition of the iron varied (by nation, over time, by location of mining, by location of manufacture, etc., etc.) Hence you see the large ranges of weights such as posted above for the Prussians. Unless you know the specific gravity of the cast iron used, you really just don't know the exact weight.

- Sasha

Heating barrel reduces the size of the bore?

Naw…………physics ain't like that. The bore increases……heat a metal tyre to shrink on a wooden wheel as it cools?

Sasha got something wrong…at last………taken long enough mind you! Does not happen often….

Glad you are still around though.

I do not think also the arrelout side wdiameter wil in creaze Heating barrel reduces the size of the bore?

Naw…………physics ain't like that. The bore increases……heat a metal tyre to shrink on a wooden wheel as it cools?

Sasha
got something wrong…at last………taken long enough mind you! Does not happen often….

Glad you are still around though.only the outside of zhe barrel wil increase in diameter greetings serge joe

Nope. So will the inside. If you have a metal plate, with a hole in it…and you heat the plate….what happens?

The plate expands of course.

Does the hole get smaller, bigger, or stay the same?

The hole gets bigger……..as though it was made of the same metal!

It's physics……..long time ago mind (1970)

and Serge Joe does it again, he gets us talking!

I thought yesterday we would have to start all over again when the site crashed. I could then ask whether Napoleon was a little guy, or the Prussians did nothing at " Waterloo", or anything that produces hundreds of irate responses……….

Then I guess we should be talking about mass, not weight. A cannonball weighs nothing in space orbit (microgravity) but has a heck of a mass. If it hits you at a given velocity down here, its weight means nothing (as it is heading horizontal to the pull of the earth)…its mass does (it's….woops no apostrophe… velocity matters even more of course….squared for the kinetic energy….velocity is everything, not mass, when on the receiving end….hence M16 and AK74s).

It weighs one sixth as much on the moon, but if it hits you at the same speed, it packs the same punch there as on a Belgian ridge. Mass is unchanged. Spoils your day still.

Can this get any worse? My apologies. I have been working much overtime due staff shortages……….I need a break

I am so tempted right now to post a "Can you actually fire a cannon on the moon" topic :) ;)

(Yep, too many hours here too :) )

Mass does indeed matter considerably in ballistics, negating even the numerous variables, e.g. wind, pressure, humidity, altitude.

Momentum is what deadhead is speaking of, mass x velocity. But since velocity does decrease due to the for mentioned, so does the momentum. Thus a larger mass with an initial lower velocity can and does impart a larger amount of its momentum into a target, in addition to its energy. Also a larger mass has a greater amount of inertia, or ability to stay on track, thus even at a low velocity, a more massive body tends to not deviate. Although one can argue a faster projectile is not in the air long enough to succumb to this.

A while back I commented on something similar using concrete numbers:

TMP link

On a side note, there is a reason why a large caliber rifle can hit a target over 2 miles away, with the same initial, or even final momentum as a smaller rifle…it stays on track, is more accurate, and maintains its energy for a longer period of time.

The debate over the AK47 (not the AK74 which has the same caliber and lower velocity to the M16, thus would have a smaller initial and final energy and momentum) vs. M16 is an old and never ending one which does not really address the issues of each weapon.

The AK47 has a larger caliber, and powder chamber, however the initial momentum of the two projectiles is roughly the same, given the M16's projectile travels more quickly. In fact, claims made about the AK47's inherent inaccuracies are only true because the platform, or the weapon itself is so light compared to the momentum of the projectile released…it does not absorb enough of the energy.

If you securely strap both weapons down, fire a shot, the AK47's projectile will travel further, hit harder, and will be more accurate. This has nothing to do with the cycling of either weapon.

There is an optimum powder charge for each weapon. One cannot continue to add more powder to a smaller caliber weapon and have the projectile travel further. Thus in order for projectiles to travel further, and hit harder, a larger caliber is needed.

There is a reason why an army used 12lbers on the battlefield, in addition to 6lbers, and it is not just a matter of some sort of phallic competition. Rather one is speaking of small arms, artillery, battle ships or even rail guns, there is a very real advantage of a larger caliber, so long as the logistics of maintain such a weapon is not compromised…history has seen enough of this.

ilodic.

Yes, you could fire a cannon on the moon, but with gunpowder as a source, I am not certain there is enough passive oxygen available. Certainly one could devise such a contraption if necessary.

'But why does the Sun "burn", there is no oxygen there?' "And why are mountains colder at the top if they are closer to the Sun?"

REALLY off topic here… three days off teaching in the classroom due to weather.

I know it is just me….but I do love physics still (and hate chemistry). Kinetic energy is what makes all the difference when you are hit, not momentum. Kinetic energy is equal to half mass X square of velocity. The velocity squared contributes massively to ruining your entire day. That is how the smaller rounds in the later AK74 and the M16 could evolve and allow the soldier to carry more ammo, but retain the stopping power,……… higher velocity I had always understood.

Once a round leaves the muzzle it cannot increase its velocity. In a vacuum it carries on regardless, in air it is slowed, in a gravity field it drops. There is no further force to accelerate it (granted changing direction under gravity is strictly acceleration)

Just lighting a cannon on the moon would be impossible. Hadn't thought of that! Rockets only work by supplying their own oxygen.

The inertia argument is quite fascinating. Mass does count then! May just be me, but thanks to all and to Serge Joe for starting something yet again.

Can anyone explain why spin makes something more likely to continue in a straight line?….that I have never fathomed. Quantum physics is easy by comparison

Mass always counts. Firing a weapon on the moon only requires a difference in pressure. As the moon has no atmosphere, there is no pressure. Any compressed gas, if given a path to a lower pressure, will move the mass in that direction. Once it enters the vaccuum of space (zero atmosphere) momentum takes over per Sir Issac Newton's Laws. Physics is fun.

True, but even on the little moon, the round will still strike the "earth" influenced by gravity. It is not like in space. I am sticking with velocity being everything.

I am now convinced by the above, that mass determines the chance that it will hit you, if aimed correctly (still not sure I understand why…even before spin comes into it….but not sure anyone really understands spin effect). I like inertia…..sounds right. Not so sure about the round still accelerating after leaving the barrel….impossible.

Velocity determines how much of you is left to bury or burn or mourn. The energy transmitted into your anatomy is proportional to the square of the velocity. Imagine that…the "speed" multiplied by itself. It's like Einstein and E equals etc.

Whether the cat is alive or dead is beyond me. Even Heisenberg was uncertain, Schroedinger…odd chap…….

I need a break. Even Saturday I have to work as a colleague, rota-ed to, has gone skiing and I am the only person in town to take call. Hang on, I retired 18 months ago!

1,000 Kg vehicle at 3m/s = 9,000 Joules (Neglect the 1/2, it is to preserve the derivative, and is a constant, so it does not matter in this example.)

100 Kg person at 10m/s = 10,000 Joules.

Fast person vs. slow, smallish vehicle…vehicle wins despite having a smaller kinetic energy. If you are not sure, try it;-)

Because of conservation of momentum, the vehicle will move only 1/3 the amount of distance, given the momentum is 3 times that of the person, all thing being equal, free bodies, no coefficient of friction etc.

Historically mass was defined by its tendency to stay put, what we call "inertia." The idea of mass coinciding with "matter" or amount of stuff was not widely accepted during Newton's time. This is the first law of motion.

To question why a law is a law, is to question why are things the way they are and not something else. Why is the speed of light "that" speed in a vacuum and not something else?

Laws by definition are accepted as is, and are not mutable. Even the term theory is thrown about too casually, when it is about as close to fact as one can get, hence, the Heliocentric Theory…the Earth revolves around the Sun. It is true, but not "true enough" to be a law.

The other, or "left" hand side of the E = .5mv^2, is Force times distance. A more massive object can vary its kinetic energy, but the potential remains the same, given force and mass are proportional on Earth…we call the force the Earth exerts on a mass weight. Thus a heavier object which weighs more, traveling the same distance, will carry more energy with it, given force and distance are linear in this regards.

We really do not know what mass is, other than it is in direct proportion to the number of protons, relativistic effects neglected (a neutron is simply a dormant hydrogen atom having not decayed, plus an anti-neutrino to preserve intrinsic angular momentum, i.e. "spin.")

Though this begs the question, what gives matter its mass, or inherent attraction to any other massive body in the Universe, despite distance? Numerous gauge particles have been postulated over the years, the "Higgs" seems to be the most promising, though acts differently than any other gauge particle, given gravity is so pervasive, even upon gauge particles themselves. Thus a Higgs particle would be necessary to give the Higgs particle mass, thus an irreducible system of particles, something physicists are not happy with.

The Schrodinger's cat thought experiment is widely misquoted as the poster child for ambiguity in science. Neither Schrodinger nor Heisenberg, or any person on the gravitational or quantum side of physics prescribed to the notion of "chance", only that knowing something so precisely is not practical.

By definition, the Schrodinger equation, as a second order differential equation has a unique set of solutions given a set of initial conditions… so no ambiguity, it is just not realistic to go probing for really small things, with really big tools without distorting stuff.

Sorry to get so nerdy, but questions were asked:-)

ilodic.

"it is just not realistic to go probing for really small things, with really big tools without distorting stuff."

AH….thanks, I now know where i went wrong in my first attempt at brain surgery….

I need to find a smaller chainsaw (and a new subject) :)

TM

PS..I always thought that spin/gyroscopic stabilization worked on the conservation of momentum principal, that is that there is MORE momentum (forward and spin) and therefore "more conservation"….admittedly my only real physics experience is that of demonstrating 10mps per second with my physics books from the top balcony of my school on the last day!! And even that is 35 years ago now.

Genuinely absolutely fascinating…….

I am very grateful and did learn much from both responses. The example of the car and the runner is brilliant.

and conservation of momentum principle for spin…….

This is of relelvance to artillery projectiles however obtuse it all seems

Heh? In physics and quantum mechanics people are used to using two equivalent expressions for kinetic energy. In physics, you usually start with the total energy of a system being an operator (Hamiltonian)= (K +P) or kinetic energy plus potential energy operating on a wave function which describes the system that you are dealing with. K, the kinetic energy can be usually described by either expression:

1/2 x mass x velocity squared or

Momentum squared divided by 2 x mass = (MV)x(MV) / 2M

They are the same thing- the only difference is the math convenience of using one expression or the other.

By the way, the example of the car and the runner is a little inaccurate. It is more an illustration of the difference between an inelastic and an elastic collusion. An inelastic collusion is something like bouncing a marble on a big piece of granite. All the energy of the collision is retained in the marble and it bounces almost back to where it started. An elastic collusion is a bug hitting your teeth while you are motorcycling. The energy of the bug's part of the collusion goes to transforming the bug to the puree going down your throat. The energy loss to each party is the same (remember the law about conservation of momentum? which could also have been called the conservation of kinetic energy except for the experiments that are used to explain it).

In the situation of our wargaming understanding, we really should be looking at a different set of laws of physics. One is that the "air resistance" to a projectile moving through it increases by something related to the 4th power of the velocity, so small very fast projectiles slow down quickly as they quickly lose their energy to pushing air out of the way, faster than the air can move out of the way. (its called the sound barrier). A heavier slower projectile of the same initial energy doesn't pay this penalty so it can move further without losing as much kinetic energy into heating the air it passed through. (If one has some background in non-equilibrium statistic mechanics, playing math games with this is a fun exercise)

The matter of a spun on-axis of projection of a bullet (or of a roundball) does not have a signficiant component of gyroscopic stabilization. The physics has more to do with the fact that the rapid spinning averages out any effect of air eddies and irregularities in the surface of the projectile, so the forces that might cause the projectile to drift in one direction (with an multiplying effect) is averaged over the entire 360 degrees. Look up some references on how big-bore long-range rifle black powder rifle shooters prepared their bullets in the 1880 or so eras. Goggle topics like "how does a baseball kunckleball work" or "how does a curveball really curve and break near the plate" for good explanations that are transferable.

There will be a small amount of spiral path added to the trajectory- a couple of inches at hundreds of yards for a rifle bullet and quiet a bit for a 16" diameter bullet. (Amazing is that all this plus the rotation of the earth while the 16" is in flight are perfectly calculated by 1930 era mechanical-electric analog computers on battleships!)

In reality quantum mechanics has little to do with visible bodies, let alone large ones such as cannon balls…the wave packet is too small to have any kind of measureable affect, as is relatively. I was merely commenting on the misuse of the Schrodinger's Cat thought experiment.

When dealing with the three classical units, mass, length, an time, (and charge, though not relevant here), one can see dE/dv is p. (Thanks for reminding me, I forgot the change in energy is momentum with respect to velocity…thus the correlation between energy and momentum is preserved, not linear mind you, but squared…well, kind of…how precise do you want to be when reality is quantized?)

I am not certain where this 2 x m stuff comes from, and have not seen this derivation before… it looks a bit "forced" to preserve units. When I took a graduate level quantum mechanics course…over twenty years now (the most difficult course you could possibly imagine in terms of the tedious math…pre-internet…not fun to do by hand), I do not recall showing both sides are equivalent using classical units, we just used the del operator.

Delta E and Delta t cannot be found simultaneously, nor Delta p or Delta x… given they are related by the derivatives in the second order differential equation. The old having energy and time, or momentum and position pun.

Agreed the example of a human and a car was a bit skewed, though one could use the example of a smaller vehicle with a larger speed, and a larger vehicle with a smaller speed. Assuming same construction, negating elasticity, one can have a higher energy and still be "pushed" back due to conservation of momentum…think two differently massed balls.

The 4th power issue I assume is given by inverse square velocity and its relation to the cross sectional area of a projectile?, e.g. v^2 + x^2 is something like v^2ish? Kind of fuzzy, but yes, that is another variable…cross sectional area.

Area does matter, as this is why really small birds have small wings compared to their bodies, where as large birds, which fly, have very large wings in comparison…area and volume are not proportional in similar objects.

A cube with a volume of 1 has an area of 6, but a cube with a volume of 8, has an area of 24.

So what you have is a non-linear relationship between volume and area. Since we are speaking of balls here, the volume and area ratio given 4/3Pir^3 vs. 4Pir^2 is r/3…better than the x/6 for a cube, but not optimal.

I will need to check on what the difference is for conical projectiles, smaller cross sectional area is ideal, hence sabots in tanks (and early renaissance artillery if you care to look. Search for "musket arrows" if you can find it.)

Took people a while to realize a ball has really, really poor ballistics, and aerodynamics, but is easy to make, and is nice in a fouling barrel.

It is really neat how scientists were able to stabilize things on battleships with gyroscopes. But, a 2,000lb+ round going really fast does not have much time to deviate once set. The math is really messy, but knowing your latitude, and some spherical (elliptical) trig helps out a lot.

In terms of artillery, what is ideal, if logistics are not compromise, is size of the round, and length of the barrel. You have the best of both worlds…high potential energy, and kinetic energy along with momentum.

ilodic.

Oh. Gyroscopic stabilization. Yes, this does not make much difference in a ball. This has to due with the fact a spinning ball for all intensive purposes, is a stationary ball. If you were to encase a bar inside a shell, and then rotate it, you would achieve a gyroscopic effect.

Many years ago I recall having seen an experiment where two disks were placed on an inclined plane. They had the same mass, the same diameter, but one was a solid piece of wood, the other a piece of aluminum(?) with it's center bored out…so I guess a disc and a washer (this was an integral method…calc. pun anyone?)

To my surprise the less dense piece of wood reached the bottom first. So on an incline plane, two objects with the same shape and mass can reach the bottom at different times. The point is the metal disc was more stable, and hence a bit slower due to its mass mostly distributed towards the outside, but achieving a gyroscopic effect, at least in a passive way. Now we are getting into classical mechanics…there was a lot of messy math there as well.

ilodic.

I may be the only one still reading this……but I think it is fascinating. Hell, if we do not know whether the cat is alive or dead, the tree in the forest may still be standing and an electron can interfere with itself without getting arrested…….macroscopic physics should be easy.

You are not the only one still reading it.

link

…….Consider a bullet fired at some angle on a long range trajectory. The bullet starts out with its spin axis aligned with its velocity vector. As the trajectory progresses, gravity accelerates the bullet down, introducing a component of velocity toward the ground. The bullet reacts like a spiraling football on a long pass, by 'weather-vaning' it's nose to follow the velocity vector, which is a nose-down torque. The price you pay for torqueing the axis of rotation is that the nose points slightly to the right as it 'traces' to follow the velocity vector. This slight nose right flight results in a lateral drift known as ‘gyroscopic drift'.

Having a left or right twist will change the direction of gyroscopic drift. Bullets fired from right twist barrels drift to the right, and vise versa by the same amount, typically 8-9 inches at 1000 yards for small arms

Okay, there is a Gyroscopic drift effect, but it is tiny for projectiles that are designed to spin on the axis of velocity. I do target shooting and hunting now but seldom even attempt a shot at 100yards, let alone 10000. I have never worried about it, 16"guns worry about it.

Accelerations due to the Coriolis Effect are caused by the fact that the earth is spinning, and are dependant on where you are on the planet, and which direction you're firing

I did have to figure this out last muzzleloading flintlock season in P.A., but I spooked the deer when I took out my slideruler and didn't get the shot.

For a smoothbore firing a RoundBall, the spin can be in any direction and the ranges are a couple hundred yards at best. These curving effects are minor compared to the "curveball // banana kick" effect of the spin acting on the air.