So the bit that attracted so much attention?
l33telboi wrote:Weakest point would be the failing to realize that force times length is the very definition of energy. Following up with a remark that's supposed to belittle the intelligence of the other debater just makes the failing that much worse.
Thanatos wrote:No, work is force times displacement (aka change in position). The gun itself only moves the total of its recoil path not its entire length.
Besides which, its utterly incorrect to use it even if it wasn't done wrong.
Now, what precisely happened?Jedi Master Spock wrote:I will say that I think most of that particular thread of discussion within that debate suffered from some misunderstandings between the two of us.
Thanatos first mentions recoil, claiming that the higher recoil force of the Conqueror means it is a more powerful gun.Thanatos #1 wrote:Modern guns are well below the level of 40K guns. The Conquerers gun had a recoil force of 190 tonnes while a modern 120mm has a recoil force of 56 tonnes. Shell effectiveness and ammunition type play a part.
Keep in mind this is the light cannon version of the Leman Russ and that's just the recoil force. Also remember that tank guns are far more powerful than arty guns.
Emphasis added. I note first that there are a "couple different ways" to measure recoil, something you fail to take note of. This will lead to future confusion.Jedi Master Spock #2 wrote:Depends on how we choose to measure recoil force. The Conqueror has a very short barrel proportionate to its diameter, meaning a light gun relative to the shell, meaning more kinetic energy applied to the recoiling barrel.
It also means the force on the bullet and the barrel itself are being applied over a shorter distance; the Conqueror barrel is 2.49m (Imperial Armour) while the Abrams barrel, a sample modern tank barrel, is 9.77m. 190T*2.49m=473T*m; 56T*9.77m=548.8T*m - that's 16% more energy.
Furthermore, the above citations make it clear that the Earthshaker operates at close to the maximum recoil of the Chimera chassis, which also constrains the force of WH40K tank guns.
Assuming the Conqueror manages to apply a peak 190 tonne force for the whole 2.49m length of its barrel, it has a muzzle energy of 4.6 megajoules. The Earthshaker, as described above, has a muzzle energy of 12.6 megajoules.
I also bring up the recoil energy of the Earthshaker.
Here Thanatos clarifies what definition of recoil force he's working with - force used to stop the gun barrel.Thanatos #2 wrote:Also incredibly wrong, its the weight of the gun not the length of the barrel that determines recoil velocity and force.
Barrel length effects the dyamics of the round and adds additional weight as a side effect, reducing recoil. While we know the total weight of the M256, we don't know the weight of the
No your quote says that
Considering that the Earthshaker weighs almost as much as the chassis its on, its not exactly surprising.
Again, wrong. Its weight not length that determines recoil force.
In this post, I clarified what the other of the "couple ways" to talk about recoil force there is: We could talk about the force between the gun and bullet (which also determines muzzle energy, and is independent of gun mass) or the force between the gun and the tank (which is dependent on gun mass).Jedi Master Spock #3 wrote:The mass of the recoiling assembly determines the recoil velocity of the assembly, which determines the energy required to stop it (force over distance).
The recoil force backwards on the recoiling assembly is the same as the forward force on the bullet, as is the total change in momentum. The muzzle energy of the gun is the force (dot) the distance traveled by the bullet.
Now, what you're talking about is the force of the gun on the tank, but these are generally proportionate, because gun mass is linearly proportionate to gun length in much the same manner.
True; however, we do know that the Earthshaker, with its massive 9m barrel, is bigger than the tank guns; thus, it will have a better ratio of recoil energy to muzzle energy, and will have less recoil force for the same shell.
So if any of the tank guns fires an equivalent shell, it will have more recoil.
Recoil restriction of the fighting compartment, meaning that if it were more powerful, it would require more recoil distance than is available or more force than the chassis can handle. Any more recoil energy would be a problem.
Length times force gives muzzle energy. I was talking about the force between the gun and bullet; you have been talking about the force between the gun and the tank. The case I described was basically the case where the entire tank is one large rigid recoiling assembly.
I also go into some details on the relationship between the two, and how it is that barrel length, recoil energy, and muzzle energy are related, and break it down into small pieces - most especially that the Earthshaker gun having recoil problems limits the momentum of other WH40k guns.
Here Thanatos says the impulse (change in momentum) of the two is the same - something I've already used in JMS #2 and JMS #3. He appears to fail to grasp the relationships I spent my time trying to explain to him - quite probably because he simply didn't grasp that I was talking about two different pairs of forces.Thanatos #3 wrote:No, the recoil impulse is the same.
No, it doesn't. The Muzzle energy is the kinetic energy of the round being fired and is calculated the exact same way you calculate any other kinetic energy.
And you run an analysis site?
In my fourth post, I made extensive use of recoil energy. My curious comment asking Thanatos if he agreed or disagreed was an attempt to resolve whether he understood that what he stated as an objection was precisely what I'd been using.Jedi Master Spock #4 wrote:Clarify. Are you agreeing or disagreeing?
Yes, it does. Force (dot) distance is the work done on the round, which is the energy applied to the round, which is the final energy of the shell. Basic physics.
And you missed the point earlier that the Earthshaker is a larger gun, and therefore can be expected to have a better ratio of recoil to muzzle energy than the Conqueror, Vanqusher, or Battle Cannon.
We also know that the Earthshaker cannon is substantially more massive (1.5+ times) than the Vanquisher, and thus handles recoil better. If the Vanquisher round has two thirds of the total momentum of an Earthshaker round, meaning if anything more recoil force, and is 13 kg as you have just suggested, then it would have a muzzle velocity of 1586 m/s, and a muzzle energy of 16 megajoules, barely any more than my initial suggestion.
However, we still face the issue of momentum, and the Conqueror's rounds - and Vanquisher's rounds - still should have substantially less momentum than the Earthshaker, whose muzzle velocity is established and repeated in a very consistent fashion from 2003 onward in IA books, and will probably continue to be repeated in similar fashion as long Warwick Kinrade and/or Tony Cottrell continue to write for Games Workshop.
If the Vanquisher has the same recoil energy as the Earthshaker, is (6.5/9.0)^3 = 38% of the mass of the much larger gun based on barrel length ratios, and fires a subcaliber sabot ten times as fast as the Earthshaker round (> mach 20 - very high velocity), we're talking 2.3 kg exiting the barrel.
Here Thanatos looks very bad, because he makes it crystal clear he never took note of my caution in JMS#2: "Depends on how we choose to measure recoil force."Thanatos #4 wrote:You don't know what impulse is?
*facepalms*
Its always funny when someone utterly flubs something and tells you how basic it is.
At this point it just becomes badgering.Jedi Master Spock wrote:I do. So make up your mind whether you're trying to agree or disagree with me on this point. Your statement was ambiguous on that count.
Thanatos, I've not flubbed a thing. If you don't care to take my word for the fact that force dot distance gives the work done on an object, you might try Hyperphysics,, Wikipedia, Yahoo Answers, various other instructional websites, or you could go ask on the physics forums.
What I'm describing is a basic law of kinematics, taught in just about every introductory physics course.
Unsurprisingly, Thanatos had nothing worthwhile to say on the topic in his final post.Thanatos #5 wrote:Actually, your "word" was that it was force times length of barrel rather than force times displacement. You tried to use barrel length as the displacement, when the recoil distance is what you would use if you were stupid enough to think you used Work to determine recoil.
Sadly, you utterly fucked it up. The question is whether it was honest stupidity, or an attempt at dishonesty. More likely the latter given what we have seen.
There's nothing to suggest that at all. So we can safely ignore this.
Especially since you don't know how recoil works.
So - is it now clear what happened in that argument? I think miscommunication did happen. Whether you blame me for not sufficiently emphasizing that there are a couple different things to talk about regarding recoil, or Thanatos for not understanding that I was discussing both force between the gun and tank and force between the gun and bullet when I spoke of recoil, is up to you.