Why are big spaceships assumed to be slow?

[Iv121]

You think I didn’t try ? OFC I did, Im telling you the results of a pure experiment, it just doesn't work when you both move parallel because in order to turn around someone you need not only change direction of heading but also actually move in that direction, if you are both at 150 m/s your turn is meaningless and perhaps even results in you falling behind which allows the enemy to take a clear shot.

[Saravanth]

And this is why we wouldn't want Starmade.

[Ivan2006]

I will now use mathematic formulae to explain why scaled-up ships won't have the same performance.

If x is the multiplier for scale in lenght, then
m(x)=m(0)*x³
(where m(x) is the mass of a ship with the mass m(0) scaled up by a 1-dimensional multiplier of x)
any surface areas or crosssections would be
A(x)=A(0)*x²
and since thrust is
F=(m/t)*I(sp)
where in this case m/t is the rate of expelled mass and I(sp) is the speed at which said mass is expelled.
however,
F=m*a
is the force required to accellerate a mass, so for our scaled-up ship using m(x) we get
F(x)=m(0)*x³*a
because we can't change a, as the goal would be to keep that constant.
now F(x)=F(0)*x³
as seen previously, F has two components:
m/t and I(sp)
now, the first thing that comes to mind would be increasing (m/t)
however, you are trying to push an increase in m/t of x³ through an opening that has only widened by x², which poses a problem, not neccessarily because your exhausts are smaller, but because the same reduction in crosssection also effects all pipes and fuel lines that feed the engine, so feeding enough fuel would be impossible. Transfering the missing x to I(sp) is also not a viable option, since I(sp) is the efficiency of an engine and increasing the efficiency would be equivalent to more advanced technology and also influence fuel consumption, which is a part of performance.

As a conclusion, scaling up a ship without changing performance would be impossible.
Except if you find a way of getting fuel to flow through your pipes faster.
Have fun with the explosions from fuel overpressure tho.

[Iv121]

Ill tell you a secret Ivan, nobody is gonna bother with real calculus for that matter, just do what is best for gameplay, and unless someone is going to argue with me that the system in Starmade is good I suggest to limit speed by the engine strength / mass. Also your formulas are flawed at the core , in fact they describe constants: You say that mass formula is M(n) where n stands for scaled up version, however the M(n) formula has no N in it, in other words its not N dependent and it stays constant. In fact the overall usage of the formulas in your theory is completely wrong, for example why not say that M(n) = M(1) * n where n is the scale by which M(n) is bigger than n ? Why does thrust power dependent on velocity ? Is it resistance force ? No, in fact its the cause of speed and it is not dependent on it, from here on all the calculations you make are meaningless.

[Error]

Larger ship = more inertia = slower acceleration and safe speed = bigger ship go slower.

That work for everyone?

[Ivan2006]

Ill tell you a secret Ivan, nobody is gonna bother with real calculus for that matter, just do what is best for gameplay, and unless someone is going to argue with me that the system in Starmade is good I suggest to limit speed by the engine strength / mass. Also your formulas are flawed at the core , in fact they describe constants: You say that mass formula is M(n) where n stands for scaled up version, however the M(n) formula has no N in it, in other words its not N dependent and it stays constant. In fact the overall usage of the formulas in your theory is completely wrong, for example why not say that M(n) = M(1) * n where n is the scale by which M(n) is bigger than n ? Why does thrust power dependent on velocity ? Is it resistance force ? No, in fact its the cause of speed and it is not dependent on it, from here on all the calculations you make are meaningless.

1) according to what I've read in this thread so far, no one is talking about anything 'gameplay', otherwise it would be either in the RP or the development section. This was a physics thread all along.

2) you may be missing that n is not a variable at any point nor was it ever implied. Maybe you mistook my (o) for a (0), which would have made it seem so, but in fact, both o and n are simply markers for non-scaled and scaled. Instead of your missing variable n I have my x. However, the x is the scale in lenght, to avoid using rational exponents when comparing the thrust to the crosssection

3) in this case, the velocity is the speed at which the exhaust leaves the engine, also known as specific impulse. You may very well ask any astrophysicist, aerospace engineer ot even anyone who ever played KSPand they will all tell you that isp is very important for knowing how much accelleration you can get out of a specific ammount of fuel.

your argument is invalid, tho I will make some edits to my post to make it more clear.

[Archduke Daynel, PhD]

Big ship = more mass = needs more powah.
Should be idiot proof.

[Iv121]

@ Ivan:

You will fail your physics exam, you know why ? You overcomplicate things, you may as well use Global Gravitation to define the effects of gravity between molecules that leave the exhaust, those are all good and nice but irrelevant to the discussion. In fact you can cut off the whole exhaust calc out, we jsut want to prove that engine force is linearly proportional to mass.

By using actual size as your point of reference you first of all start to work off a linear function , you will thank me later for that, second your ships must be strict squares or you introduce a system of 3 variables, 3rd you don't mark a function M(n) if its not dependent on n, in your case it would be M(x) and no I don't confuse anything, I read your formuals as is.

Now let me show you how its done right:

m(n) = m(1) * n

F = ma

let us say we want to reach the same a so it remains constant (at all tiems only one variable is dependent and one is independent, in our case F and n respectively)

F = m(1) * n * a

n raises linearly and so will F as a result, end of such a difficult calculus. Want to add random stuff like fuel distance into it ? Then unfortunately you lack info, if you are troubled by the distance fuel passes it only effects the time between command and ignition, eventual result matches in any case. Now what else did you want to take into account , too small engines that don't get enough power ? Id like to remind you that F is your dependent variable, you can’t change it directly, in RL it would represent the engine size you will NEED to power that thing, it raises linearly to the object size.

[Ivan2006]

okay, I have solved the problem about the things in brackets, tho I might add that I would have put the n in subscript, but used brackets instead because subscript is not supported by bbcode, at least we don't have a custom one for that, if that helps you.

Also, yes, I agree that F raises linear to the mass. However, my x is applied to LENGHT which means it has to be cubed in order to apply for volume, making it translate as cubed into mass and further into anythign that is deprived from mass, which means that, using the variable form your formulae, n=x³, so in effect, there is no difference between our formulae at this point.

[Iv121]

Well if you realize that why do you say that it doesn't raise proportionally to the size ?

[Ivan2006]

I kinda had size=lenght while you had size=volume, which may have been what caused the confusion.

[Shadowcatbot]

Warning spoilers to life:

Spoiler:

[Tau]

Warning spoilers to life:

Spoiler:

Your image is broken, mate.

[Prototype]

None of you appear to have a fucking clue what calculus is.

[cats]

P=eN(is)