Engine stats and effects

[Daft Loon]

I've been trying to calculate speed and acceleration for various combinations of tool use, engine damage etc. I've been assuming its implemented according to basic real world physics but some of the information available seems to contradict that and itself.

In theory
Acceleration = Thrust / Mass

Max Speed = Square root(Thrust * Constant / Drag)

The wiki and many players in game state that moonshine has bonus acceleration while kerosene and phoenix claw don't which doesn't fit with moonshine and phoenix claw having both thrust and reduced drag while kerosene has only thrust.

Calculated as above
Moonshine:
300% thrust
50% drag
Acceleration = 300%
Top Speed = 245%

If its simply linear and thrust, drag or both affect top speed we get 300%,200% or 600% top speed respectively. I'm fairly sure moonshine doesn't provide 600% speed and that going backwards at 50% thrust is not as bad as 50% speed (70% by my calculations).

How is it actually calculated in game? or are the stats essentially just flavor text?

[Extirminator]

I am not near any of my data, but as far as i remember it is all real life physics stuff, you are right with your acceleration formula, but the top speed formula should be
topspeed = sqrt( drag/dragcoefficient )
While the drag coefficient is calculated like so-
Dragcoefficient = acc/(topspeed)^2

The drag coefficient is a constant so you take the known base values and use them to calculate it.
E.g. squid- base top speed of 47ms and base acc of 6.66ms2.
squid drag coe=6.66/(47^2)=0.00301493
This will always be a constant in the formula and the variable is the drag, drag in that formula is the acc you calculated using mass and thrust, and is also modified by the drag modifier. But it is modified in an opposite way that might be counterintuitive. You see, as drag is reduced you are able to reach a higher speed because you get less resistance, less resistance means more speed which in turn will hit the particles of air harder in this case. This will eventually generate more resistance which eventually evens out to be the same as your acc and opposite to it - so you reach top speed. By decreasing your drag you make it so at the moment of top speed you will need more resistance to stop you from movingfaster.
What i am trying to say in a very clumsy and long paragraph is that by saying drag is decreased in the formula it is actually increased. Minus 50% actually eventually mean plus 50% for the formula.

So
top speed=sqrt((thrust*thrustmodifier/mass)*dragmodifier/(baseacc/(basetopspeed)^2))
Or for squid using moonshine, not taking into account engine damage-
Sqrt((632500*3/95000)*1.5/(6.66/(47)^2))
Which is equal to around 100ms but because engine hp is a factor it will be averaged at quite a bit less.


Wrote this on my phone in a hurry so there could be typos.

[Daft Loon]

Good to know thanks.

I think the equation can be simplified a bit though since you have thrust/mass divided by acceleration (thrust/mass) leaving:
topspeed = Sqrt(thrustmodifier *dragmodifier * basespeed ^2)
= Sqrt(thrustmodifier * dragmodifier) * basespeed

[Extirminator]

Yeah, I just wanted to give you the full one so you can make sense of how and why each number is there.

That only applies to horizontal and longitudinal movement BTW, angular movement and the introduction of uneven thrust and torque will make the equation quite a bit more complicated and will require access to the code to actually complete for each airship because you will need inertial bounds and stuff like that...

[nhbearit]

So sorry I didn't find this thread earlier, but ya.. Muse basically just pulls the stats for ships (and their engines) out of thin air. First, Most ships have a single heavy engine, and two light engines. Every ship that has this configuration should have the same amount of thrust, which is not the case. From there, using any drag coefficient is going to be iffy at best (and harmful at worst) unless you are able to model how air would flow around and through these ships. (I can't do that with the time and resources I have, but if you can pls let me know. I'd love to look at those numbers.) Oh, and a table for you to look at:

Ship      Thrust      Mass      Top Speed       N/tonne

Junker       537500N      125tonnes     26.01m/s    4300.0
Goldfish    525000N      150tonnes   40.11m/s    3500.0
Squid    632500N      95tonnes     47.00m/s       6657.9
Galleon    672001N      320tonnes   30.02m/s       2109.4
Spire       675000N      150tonnes   28.01m/s       4500.0
Pyramidion    450000N      200tonnes   30.35m/s       2250.0
Mobula    510000N      120tonnes     28.00m/s       4250.0

And while you could use these numbers to figure out what kind of drag is applied to these ships... honestly I don't feel it's worth anyone's time. This is a game where MUSE gives projectiles lift, just so they have different gun arcs.. Take any number MUSE gives you with quite a few grains of salt..

Apologies for the formatting issues with the table, I copy+pasted it from a doc I wrote up

[BlackenedPies]

How would you calculate the effect of a -25% change in drag on top speed and acceleration?

[nhbearit]

Funnily enough that would depend on how MUSE does their math.. usually you would just run a top speed calculation then take whatever percentage off of the drag coefficient when you go to plug it in. Same basic idea to calculate acceleration.

[Daft Loon]

Whatever they do for the calculations is enough to make testing the Minotaur rather annoying in practice mode. Shooting a target dummy with it makes the balloon act like a sail of sorts and it flies off to the side rapidly.

[Extirminator]

The drag coefficient never changes in reduced drag instances. I already gave exactly how everything is calculated in a previous post in this thread.

[BlackenedPies]

This will always be a constant in the formula and the variable is the drag, drag in that formula is the acc you calculated using mass and thrust, and is also modified by the drag modifier. But it is modified in an opposite way that might be counterintuitive.

Does this mean -25% drag is +25% acceleration?

[Extirminator]

The variable named acceleration in that formula is kinda misleading. It refers to the "de-acceleration" that is produced by the drag, that counters acceleration until they become equal and thus you reach top speed because the sum of all forces working on the ship(acceleration from engines and acceleration in the opposite direction from the drag) is zero --> 0m/s^2 --> top speed reached.

if drag is REDUCED by 25%, the more force from drag you'll need to stop the ship, and so the acceleration variable in that formula will INCREASE by 25% to counteract it - again, reaching top speed with the sum of forces reaching 0.

Also, yes, a decrease in drag will increase acceleration and the opposite.

[Extirminator]

I did some more math and research on it in the last few days to bring a more accurate response to this. It is a bit more complex than just a straight up increase, and I made some graphs and points about it in a new article I wrote for the wiki - http://gunsoficarusonline.wikia.com/wiki/Airship_Movement
I think this should help with most if not all of your questions.

Also have to thank lu for some formatting help.

[Daft Loon]

That is one quality article.

I didn't know the balloon damage was that significant a speed boost, i shall have to try it to alleviate some of the tedium of crazy king long haul travel.

[Extirminator]

Keep in mind that's an exponential relationship though, it only starts making a big speed difference when balloon starts dropping to below third HP or so. But yeah, it should still make a difference on long range travels though.