73 replies to this topic

[Tuonela]

Aside from cockpit shake from being hit by enemy fire, does anyone think it would be a good idea if for some of the bigger guns like PPCs or Gauss you'd get some kickback? The idea is that if you're firing a big gun your aim would get thrown off a little and you'd have to re-aim, especially for long range engagements. It would put a little more skill into hitting the targets consistently and would add some realism for the energy launched out of the mech. It'd also be a nice effect for missiles and make it feel like you're really firing something powerful.

[Threat Doc]

Well, you already have it, if I'm not mistaken. It's been shown that weapons do cause some kick-back in the videos from GDC and the recent extravaganza from... oh, crap, I've forgotten their name... how inconvenient... my memory and I must really have a chat and get some things straight.

[Ravager AI]

I could see an Autocannon having some measure of recoil on smaller 'mechs. But you have to remember that a gauss uses electromagnetism to propel its shot, making it (Of what I remember from physics class) almost recoilless if not entirely so.

[Eximar]

Ravager AI, on 11 May 2012 - 12:38 PM, said:

I could see an Autocannon having some measure of recoil on smaller 'mechs. But you have to remember that a gauss uses electromagnetism to propel its shot, making it (Of what I remember from physics class) almost recoilless if not entirely so.

Nope

[Ravager AI]

Eximar, on 11 May 2012 - 12:42 PM, said:

Nope

Please, I would like a bit more of an argument against my statement then a simple and somewhat non-constructive 'Nope'.

I remember now that the munition exerts a counter force to the armament. But would not the sheer mass of the armament negate this?

[osito]

I believe one of the devs said in his post that while firing his ppc's there was a kick to it. Also in the videos we see one hunchback tilt after firing his torso mounted ac20.

[Banditman]

In this futuristic world, if they've figured out how to minimize the recoil from a 60 ton robot walking at a speed of up to 70 kph, I'm pretty sure they've come up with a way to completely eliminate the recoil from it firing a ballistic slug weighing only a hundred pounds or so.

On the other hand, I can understand why an external influence, such as being shot by an enemy would cause recoil, as that's an external factor that onboard systems cannot know is coming and therefore account for.

In other news, what "fun" does it add? I just don't see it adding any "fun factor" and certainly no real value.

[Malkenson]

What about location?

If a weapon with heavy recoil is placed in an arm, should that have more recoil effect than the same weapon in a Torso?

[Claw55]

Giant, multi ton mechs should definitely have some way to conter recoil from thier own weapons.

Edited by Claw55, 11 May 2012 - 01:05 PM.

[Shirefolk]

Ravager AI, on 11 May 2012 - 12:38 PM, said:

I could see an Autocannon having some measure of recoil on smaller 'mechs. But you have to remember that a gauss uses electromagnetism to propel its shot, making it (Of what I remember from physics class) almost recoilless if not entirely so.

For every action, there is an equal and opposite reaction.

You cannot ignore that rule.When a GR fires, the electromagnetic force is what propels the round in one direction instead of combustibles. However, JUST like combustibles, it must push something else back for an equvalent amount of force. To do this, it pushes against the coils used to generate the EM force. This pushes against the housings, supports, etc. This pushes against the arm, and consequently the mech.

An example that people never think about is gravity. The world pulls you down for (say) 200 pounds of force. However, an equally valid stance, is that you pull the world UP for 200 pounds of force. You REALLY DO. You have very little mass, but the gravity you exert is exerted on ALL of the mass of the Earth, which is a whole heck of a lot. This is also one of the ways that exoplanets are detected. The planet's orbit causes a star to wobble, thus we see the wobble and infer the planet.

Edited by Shirefolk, 11 May 2012 - 01:09 PM.

[Cold3y3s]

Shirefolk, on 11 May 2012 - 01:07 PM, said:

For every action, there is an equal and opposite reaction.

You cannot ignore that rule.When a GR fires, the electromagnetic force is what propels the round in one direction instead of combustibles. However, JUST like combustibles, it must push something else back for an equvalent amount of force. To do this, it pushes against the coils used to generate the EM force. This pushes against the housings, supports, etc. This pushes against the arm, and consequently the mech.

An example that people never think about is gravity. The world pulls you down for (say) 200 pounds of force. However, an equally valid stance, is that you pull the world UP for 200 pounds of force. You REALLY DO. You have very little mass, but the gravity you exert is exerted on ALL of the mass of the Earth, which is a whole heck of a lot. This is also one of the ways that exoplanets are detected. The planet's orbit causes a star to wobble, thus we see the wobble and infer the planet.

physics is good, physics knows all.

[Eximar]

Ravager AI, on 11 May 2012 - 12:48 PM, said:

Please, I would like a bit more of an argument against my statement then a simple and somewhat non-constructive 'Nope'.

I remember now that the munition exerts a counter force to the armament. But would not the sheer mass of the armament negate this?

Newton's law applies. f=m*a and regardless of the Lorentz force hitting the sidewall magnets, it still generates the majority of the force to the rear.

[Crimson Knight]

Now see I would think the engineers who designed the mech would account for this and design the mech to reduce the kick back to a minimum.  Especially when you consider that would be the one thing that all mech pilots would complaint about.

[Shirefolk]

Eximar, on 11 May 2012 - 01:10 PM, said:

Newton's law applies. f=m*a and regardless of the Lorentz force hitting the sidewall magnets, it still generates the majority of the force to the rear.

Assuming immpossible materials, it could generate infinet radial forces. Those are counter by force from the other side of the GR housing. However, the force in the opposite direction of the slug is ALWAYS the same as the force on the slug. The proportion of radial to longitudinal forces just depends on the efficiency of the mechanical design.

Edited by Shirefolk, 11 May 2012 - 01:16 PM.

[Shirefolk]

Crimson Knight, on 11 May 2012 - 01:12 PM, said:

Now see I would think the engineers who designed the mech would account for this and design the mech to reduce the kick back to a minimum. Especially when you consider that would be the one thing that all mech pilots would complaint about.

Possibly. However, the more kickback being neutralized, the more work is going to be needed on the machine. I am guessing (not my expertise) that this would mean more parts, expense, and weight. This reduces firepower, increases complexity, and leaves more things to go wrong. A better way to counter this is to just not fire everything at once. You are a 20-100 ton mech. If you fire a few weapons at a time and cycle them, your balance will correct most of the kickback. Just like firing a human sized gun. If you fired 10 at once, you might be knocked off balance.

Edited by Shirefolk, 11 May 2012 - 01:21 PM.

[Kasiagora]

Well if nothing else, at least the Gauss Rifle's rearward force is being built up more gradually over the course of it's travel down the barrel passing all of those electromagnets, as opposed to the much more sudden "explosion" of the propellant being burned to send the Autocannon round on its merry way.

A simile that may or may not help convey my thinking here is that it would be like modern or antique firearms. Bullets are typically designed with an ideal barrel length in mind, so that a .45 ACP that's made to fire from a handgun has a relatively short, fat cartridge resulting in more powder being burned suddenly (the explosive primer touching more of the propellant gunpowder immediately across the entire back of the cartridge) and resulting in the projectile achieving maximum velocity before it reaches the end of the barrel where unburnt powder gets wasted in the form of outward, uncontrolled force that is the muzzle flash.
A longer rifle barrel affords the time to have a slower burning powder that can build up pressure more gradually that results in a projectile moving just as fast, but with less "perceived" recoil. (What happens is that the smaller primer touches off a smaller amount of powder at the rear of a narrower cartridge, but this allows the propellant to burn its way forward while the bullet is still traveling down the barrel.)

When you shoot a carbine in a pistol cartridge, like a Beretta CX4 Storm (roughly 1,140fps), the powder from the cartridge is already expended before the bullet reaches the end of the barrel, resulting in a lower muzzle velocity than you'd achieve from a Beretta 92FS (roughly 1,280fps) shooting the same round. This is because the bullet is fighting against the friction on its sides from traveling down the barrel, but in spite of the lower velocity, it has had more time to achieve a better spin in that longer barrel, so it will fly in a more stable manner and be more accurate – its trajectory will just fall off faster and in a very controlled way. But this point is not relevant to the idea I'm trying to convey, it's just an interesting factoid.

TL;DR is that a gauss rifle will push back more gently as the projectile travels down its length, like an old black powder .50 cal. Whereas an AC/20 would have a more sudden felt recoil from the initial explosion, like a S&W 500 .50 revolver. Both might move the mech's torso 5°, but one may do it in .08 seconds and the other in .8 seconds. This may not seem like a big difference, but in terms of recovery or tracking a target, it's huge.

P.S. I thought the Gauss Rifle was supposed to be without recoil too. That's how the fluff makes it out to be and I don't know that much about general physics. I just know a lot about guns and the pressure physics that apply directly to them.

Edited by Kasiagora, 11 May 2012 - 01:52 PM.

[Monky]

Kick back is in already.

Even a modern Abrams tank experiences shake when firing its main cannon, and it is heavier than a Hunchback by a good 17 tons, while being comparably engineered around a single main weapon system that fires a heavy round out of a cannon with a propellant charge.

I would like the Mechs to feel like a real vehicle rather than a flawless fantasy machine, so I am happy with a little kickback.

Edited by monky, 11 May 2012 - 02:06 PM.

[Saren21]

i don't know about you guys, but i kinda get a warm fuzz when your fireing an AC20 or a Gauss Rifle and theres some kick back. You see your tracer round fly down range and hit its target..its like Muahah Got ya.

[Suicidal Idiot]

monky, on 11 May 2012 - 02:05 PM, said:

Kick back is in already.

Even a modern Abrams tank experiences shake when firing its main cannon, and it is heavier than a Hunchback by a good 17 tons, while being comparably engineered around a single main weapon system that fires a heavy round out of a cannon with a propellant charge.

I would like the Mechs to feel like a real vehicle rather than a flawless fantasy machine, so I am happy with a little kickback.

Also consider that the Abrams was designed around that gun, and the designers would certainly have done thier best to transmit the recoil force directly above the center of mass to eliminate twist.

It wouldn't be practical to mount it low enough to vertically align with the center of mass, so it's above, and you're going to rotate (tip, or rock backwards), but at least you wont be turning the tank.

I very much doubt that torque twisting based on lever arm length to cente of mass will be taken into account in the game physics engine, though. They probably could add the complexity if they cared, but it trades for speed and reliability.

[Suicidal Idiot]

Also remember, given the size of projectiles and ranges, recoil from absorbing impacts will be negligibly close to equaling the kick of the original shot.

I doubt the lasers would be powerful enough to have detectable recoil, but an AC20 certainly should.

Explosive shells would add yet more recoil, as the explosives would give you a kick from thrust. Missiles would do the same.

Interesting bit of trivia: The A-10 Warthog's magical nose canon has more recoil than the engines at 100% thrust. The plane slows noticably when firing

Edited by Suicidal Idiot, 11 May 2012 - 03:15 PM.