110 replies to this topic

[Tarman]

Battletech IS a major physics error.

[LauLiao]

Yes! PGI Please make our giant stompy laser shootin' space robots more realistic!

[Ashnod]

TheJackofAss, on 17 February 2013 - 05:23 PM, said:

I just noticed a major error with the physics in this game.

If you have a Catapult A1 with a XL 300 engine with the total weight being 65 tons your top speed is 74.8 kph

If you have a Catapult A1 with a XL 300 engine with the total weight being 35 tons your top speed is still 74.8 kph


Why is it that by reducing weight in a Mech the top speed is not being increased? The same amount of power in the engine, everything else equal as well (aerodynamics) except less mass to be carried but the top speed and acceleration stay the same??

Perhaps that is the top speed of the design for the mech to retain its structural integrity and not rip myomer bundles, in the novels for example on moons and planets with low gravity mechs are able to run a lot faster and they reference that its dangerous due to the fact the mechs legs can rip off or snap from the stress (Aidan prydes summoner had its leg ripped off in said fashion during his trial for his blood name)

Edited by Ashnod, 18 February 2013 - 01:44 PM.

[LauLiao]

Whenever you notice something like that, just tell yourself, "A wizard did it"

[liku]

Homeless Bill, on 17 February 2013 - 05:27 PM, said:

The fact that you liked your own post invalidates anything you have to say. If you're buying big 'mechs and leaving them with tons of spare tonnage, you're doing it all kinds of wrong.

According to your reasoning. .right now i should be dividing by zero

[Henchman 24]

These are internal structure limitations...not engine ones.

The mech itself can only go as fast as its structure is designed to, slower than that is fine, and variable with engine size, but it doesn't go in the other direction endlessly....you'd rip legs off otherwise.

[Deamhan]

Vlad Ward, on 18 February 2013 - 10:15 AM, said:

.... Did you really just say that? Basic Newtonian mechanics, of the sort you're trying to incorrectly apply to this situation, is all about particles and systems of particles. You're sitting here calling me a forum warrior when you've clearly never taken a single physics class (outside of youtube) in your life.

Comparing cars to bipedal walking machines was bullcrap when it was tried pages ago. You're right, simple is better. That's why bipedal walking machines are an awful idea that would never be implemented in the real world. They're complicated. You know what's not complicated? A tank with treads. But this isn't real life. This is Battletech, and the powers that be decided walking tanks were cool, so guess what: It's complicated.

It is known that Newtonian physics falls apart on the quantum scale. It also falls apart when talking about relavistic speeds. The equation isn't actually F=ma, I can't remember off hand the "improved" equation and I'm not gonna waste my time looking it up but what I do remember is there is a second part that relates velocity to the speed of light so that, the amount of force to maintain the same rate of acceleration approches infinity the closer to the speed of light the object gets.

I've heard two arguments come from this;

1. It would require a limitless supply of energy to produce the limitless amount of force required reach the speed of light. Which basically means you need the impossible.

2. The engine will only be capable of providing a limited amount of force and the only thing having a limitless amount of energy (fuel) will do is allow the engine to maintain that constant force indefinitely.

I believe 2 to be the way of it.

Regardless, it doesn't matter if it's a rocket engine, turbo prop, piston engine + wheels, or whatever + legs, the basic principle is indeed the same and that principle is that the top speed is limited by the amount of force the engine is able to provide regardless of the mass being moved. The only difference that reducing the weight (mass) will have is make the machine more responsive. Quicker acceleration and quicker deceleration.


However, if you think it's more complex than that......

It is artificial muscles that move these machines. The mech's movement will therefore be restricted by the max speed at which these muscles can contract. The top speed at which they contract depends on the amount of current passed through them. The max current capable of being put through them is limited by what the engine is capable of generating. Thus to go faster, you need a higher rated engine to put out more power to make those muscles contract at a faster top speed.

But....

If the mass being moved is lighter, those same muscles, although restricted to a top speed based on the amount of power from the engine, will be able to get up to speed at a faster rate which means the mech will accelerate at a faster rate. So, yes, even with these mechs, the top speed falls squarely on the amount of power the engine puts out while the rate of acceleration can be increased by both upping the engines power or decreasing the mech's mass.

[Haitchpeasauce]

Guys, guys.

A bigger engine makes the mech go faster. Therefore the mech is not solely limited by its chassis or mechanical properties.

If you put on a heavy backpack or a weight vest, you'll notice it's harder to run. Therefore, correspondingly lightening the payload on a mech could have at least SOME improvement to acceleration and top speed.

I only make the point that it is within reason to say this idea is possible!

This has never been implemented in a mechwarrior game (to my knowledge) because it affects the game balance, and it is harder to design the right constraints to keep it balanced.

Game dynamics > realism.

[MacKerris]

Come on gang. Let's just make this simple and stop trying to reinvent the "battle tech reason" or excuse and face some simple facts.

1. The TT rule say

2. The devs did #1 and adjusted for their taste.

3. The devs with all the other issues in the game. Just don't have the time to work in variable weight calculations for top speed and acceleration.

4. If they did make things this way, what would they have to do to get you to buy the next engine bigger?

[JPsi]

Deamhan, on 18 February 2013 - 02:39 PM, said:

It is known that Newtonian physics falls apart on the quantum scale. It also falls apart when talking about relavistic speeds. The equation isn't actually F=ma, I can't remember off hand the "improved" equation and I'm not gonna waste my time looking it up but what I do remember is there is a second part that relates velocity to the speed of light so that, the amount of force to maintain the same rate of acceleration approches infinity the closer to the speed of light the object gets.

Ok so, these mechs also aren't operating at a quantum scale. There really isn't any need to bring that in.
The max speed of 150Km/H isn't enough to worry about relativistic effects. There wasn't much point in bringing that up either.
Newtonian physics is fine for it.

As to the rest of it, no its not exactly simple. However I'll add in this, the damn air resistance matters a hell of a lot more than most of the other factors quoted here, you want to discuss physics errors. Start discussing why these mechs have the same top speed regardless of planet/atmosphere.

Alternatively, just realise that these are big stompy robots, hey immersion is nice but hanging up on tiny details can sometimes get rediculous.

Edited by JPsi, 18 February 2013 - 07:30 PM.

[Vlad Ward]

Deamhan, on 18 February 2013 - 02:39 PM, said:

It is known that Newtonian physics falls apart on the quantum scale. It also falls apart when talking about relavistic speeds. The equation isn't actually F=ma, I can't remember off hand the "improved" equation and I'm not gonna waste my time looking it up but what I do remember is there is a second part that relates velocity to the speed of light so that, the amount of force to maintain the same rate of acceleration approches infinity the closer to the speed of light the object gets.

I've heard two arguments come from this;

1. It would require a limitless supply of energy to produce the limitless amount of force required reach the speed of light. Which basically means you need the impossible.

2. The engine will only be capable of providing a limited amount of force and the only thing having a limitless amount of energy (fuel) will do is allow the engine to maintain that constant force indefinitely.

I believe 2 to be the way of it.

Regardless, it doesn't matter if it's a rocket engine, turbo prop, piston engine + wheels, or whatever + legs, the basic principle is indeed the same and that principle is that the top speed is limited by the amount of force the engine is able to provide regardless of the mass being moved. The only difference that reducing the weight (mass) will have is make the machine more responsive. Quicker acceleration and quicker deceleration.


However, if you think it's more complex than that......

It is artificial muscles that move these machines. The mech's movement will therefore be restricted by the max speed at which these muscles can contract. The top speed at which they contract depends on the amount of current passed through them. The max current capable of being put through them is limited by what the engine is capable of generating. Thus to go faster, you need a higher rated engine to put out more power to make those muscles contract at a faster top speed.

But....

If the mass being moved is lighter, those same muscles, although restricted to a top speed based on the amount of power from the engine, will be able to get up to speed at a faster rate which means the mech will accelerate at a faster rate. So, yes, even with these mechs, the top speed falls squarely on the amount of power the engine puts out while the rate of acceleration can be increased by both upping the engines power or decreasing the mech's mass.

Augh. I feel like it's the definition of "Particle" is what's throwing you off here. I'm not talking about leptons, friend. I'm not talking about quantum mechanics. I'm talking about Newtonian Mechanics and how they treat large objects as either single particles or systems of particles.

When you push a box along the floor and apply some fancy schmancy Newtonian mechanics (F=MA) to it, you're treating it as a point particle whose mass is all at com. That's fine and dandy when you're pushing a box along the floor or hanging a crate off a pulley or whatever the crap people do in Newtonian mechanics, but you can't just say "More force = more acceleration" with a complex mechanical system. Where is the force going? Where is it coming from? Where is it being lost? How much electric potential can be transferred to kinetic energy with those myomer muscles? What are the limiting factors for Mech speed?

The Engine is not some invisible force that pushes the Mech along the ground from behind. It is not a 1-force 1-particle system. What in the bloody blue blazes made you think that relativistic physics was even remotely relevant in this situation? I am at a loss here.

Edited by Vlad Ward, 18 February 2013 - 07:29 PM.