23 replies to this topic

[One Medic Army]

Hey, I was bored, so I compiled an excel spreadsheet that listed the speed versus free weight for both XL and Std engines across all possible mech weights.
I've got different charts for standard structure and endosteel.

I find them useful for figuring out at a given speed what weight of chassis has the most free tonnage, or for figuring out for a given weight of armor+ammo+HS+weapons how fast I could go and in what mech.

I do need to update the charts to account for engines above 360, and it only goes up to 140kph (pre-speed-tweak).
X-axis is speed, Y-axis is free weight.

Standard:


Endosteel:


[edit] Free weight is weight left over after frame, engine, and any mandatory heatsinks, meaning all numbers are for 10heatsinks.

Edited by One Medic Army, 13 November 2012 - 11:12 PM.

[CannonFodder86]

Cool. very interesting. looks like most the heavier mechs start paying a major premium if they want to get some decent speed. looks like i won't be buy any assaults anytime soon lol

[One Medic Army]

Strangely enough, the heavier mechs that can actually get up to a decent speed do gain more free tonnage, so long as they use an XL engine.
That has it's own issues though.

[Tuhalu]

I'd like to see a graph chart that shows the ratio of free weight to speed for each mech. X axis would show speed. Y axis would show free weight/speed.

Assuming that there is a single point for each mech where the line reaches a peak value, you could then make a graph showing mech tonnage (x axis) vs engine rating (y axis) for those values. That graph should show the "perfect" engine rating for each mech tonnage where you get the peak balance between free weight and speed.

This is not to say there aren't reasons to make mechs faster (scout power!) or slower (fire power!), but then you could make an informed decision on what trade-off you were making.

[One Medic Army]

Well, here's what speed vs free weight/speed looks like for an Atlas.

Here's for a Cicada

Not really a maximum per se, since the slope is downwards at all times.

If you graph speed/used weight vs engine size you get something more like this though:

Which tells you a 195XL or 170Std is the most efficient engine to run in a 40ton mech.
However for the same free tonnage you could go faster in larger mechs, so the chart isn't telling you the whole story.

Edited by One Medic Army, 14 November 2012 - 10:27 AM.

[Tuhalu]

Seems like I was asking for the wrong thing. On the positive side, it made me learn myself some Google Spreadsheets.

Turns out what I really wanted was Tonnage vs Free Weight * Speed. Note that free Weight in this instance is defined as Weight left over after the XL Engine, any required heat sinks, Endo-Steel Internal Structure and full Armor is payed for. This gives a nice curve with a broad peak value in the middle for each tonnage. I then picked out the Engine Ratings for the maximum value of Free Weight*Speed and the min and max Engine Ratings that gave a Free Weight*Speed value within 95% of that maximum value. This gave the following chart.


As you can see, there is a fairly broad swath where-in you can choose to up your engine rating to gain speed or downgrade it to gain free weight and still have a really good balance of the two.

Some qualifiers:

• The max of 95% line is suppressed for mechs up to 30 tonnes due to the 8.6x tonnage engine limit.
  
• On the other hand, there are plenty of Mechs that cannot achieve the max of 95% line due to the stock engine rating * class modifier limit.

Of most interest to me was confirmation of my assumption that very few mechs should ever take an engine bigger than a 300XL. And the bulk of those are Assault Mechs.


And here is the chart with Tonnage vs Free Weight...

The lines are pretty straight, but you can see a few cases where anomalies occur. For instance, 65 ton mechs (I'm looking at you Catapult!) are dirty rotten sods that seem to get more free weight than 70 or 75 tonners with the max of 95% engine installed.... But what about their speed?


Woops. Turns out the 65 tonners move faster than the 70 and 75 tonners too! At least those guys get more armor ^^;;

Note that I've calculated speed with the Speed Tweak bonus of 7.5% extra speed.

Also worth noting is that the first of the Assault mechs, the 80 tonner has their peak free weight * speed skewed towards slower with more free weight. Coincidence? I think not!

And way back down in the light mechs, the 30 tonner is the best mech around if you want to go super super fast and still pack a wallop. Ain't it strange that we've got the 30 ton Spider coming with a massive engine and Jump Jets?

[One Medic Army]

Interesting stuff, going through the math on all this stuff made me realize how much of a balancing act making a mech really is, there's so many different ways to even view "optimal".

[CannonFodder86]

thats just balancing the speed. imagine trying to optimize everything. from weight, speed, crit space, damage and armor....


....and i just realize i'm having a "you know you're an engineer" moment...

[CannonFodder86]

btw i'm curious, where are you guys getting the numbers for these?

[One Medic Army]

I'm pulling the engine weights directly from the game, and the speeds from the formula the game uses (Engine/Tonnage)x16.2
Frame weights are included at 10% of mech tonnage, and endosteel removed half of frame weight.

[Tuhalu]

What One Medic Army said. It's part reading the values straight out of the game, part knowing the Battletech construction rules and part knowing the small differences in MWO.

In case anyone is interested, here is the base Engine Rating vs Free Weight * Speed chart. It's beautiful like a rainbow.


I suspect that if I could source the average area of the profile/shape/outline of each mech, I could do free weight * speed / sqrt(area of profile) and get an even nicer chart.

Edited by Tuhalu, 15 November 2012 - 03:08 AM.

[CannonFodder86]

nice, thanks. gonna have to play around with it myself to get a better feel of the numbers.

[Tuhalu]

Well, merely removing Endo-Steel from the charts didn't make much of a difference. Removing both that and XL makes a huge difference though.

The base chart...


Tonnage vs Engine Rating, no XL, no ES.


Tonnage vs Free Weight, no XL, no ES.

Tonnage vs Speed, no XL, no ES.

Edited by Tuhalu, 15 November 2012 - 04:31 AM.

[One Medic Army]

That makes sense, the more weight savings you use the less tonnage becomes the limiting factor and the more crit space becomes the limiting factor.

Hey Tuhalu, if you want the excel sheet I used, here's a link to it in google docs: https://docs.google....M2Q3QVVuczk4WFE

Edited by One Medic Army, 15 November 2012 - 05:35 PM.

[Tuhalu]

One Medic Army, on 15 November 2012 - 05:30 PM, said:

That makes sense, the more weight savings you use the less tonnage becomes the limiting factor and the more crit space becomes the limiting factor.

Hey Tuhalu, if you want the excel sheet I used, here's a link to it in google docs: https://docs.google....M2Q3QVVuczk4WFE

Indeed. BTW, I remembered something that should have probably been included in both our spreadsheets. Minimum engine rating is Tonnage * 2. I haven't played anything bigger than 40 ton in a few months, so I'd forgotten it. That makes the minimum speed of any mech 32.4 kph of course.

My spreadsheet is at https://docs.google....ZuclBlT3c#gid=0

The charts should have adjustment for the minimum engine ratings now, but everything is set to No XL, no ES... Somewhat lazy spreadsheet >.>

[One Medic Army]

You need to make the sheet shared

[Tuhalu]

One Medic Army, on 16 November 2012 - 01:09 AM, said:

You need to make the sheet shared

OK then! Thought I had it shared already. My bad.

[Mel Mad Dog Winters]

I had started a topic
(http://mwomercs.com/...17#entry1482617)
pretty much asking if anyone had noticed in MWO what you guys have been discussing here. Nice to stumble across this thread...

Years and years ago (talking mid-90s here), in a moment of curiosity and a weekend where surprisingly I had enough free time, I did a similar thing with the original board game, Battletech. The current form of that doc is here:
https://docs.google....QVE&pli=1#gid=7

Again, this is all from the board game and probably doesn't match up well with MWO.


I did notice two things though:
(1) There was an optimum tonnage range for certain speeds that formed a bell-curve of results.
(2) Adding XL engines and Endo Steel (in theory at least—on a pure tonnage level) moved the optimum-tonnage ranges for speeds to somewhat heavier mechs.


For example, again just with the board game and not necessarily with MWO, I found that if you wanted to walk 7 hexes, run 11 hexes and jump 7 hexes, a 40-ton mech was at the top of the bell curve. The Assassin could serve as an example of 3025 tech in this category. It would have 14 tons left over for weapons, armor, and other equipment (after you factored in the engine, gyro, cockpit, internal structure, jump jets, etc). It's not a lot, but it would be more than any other tonnage of mech in the game attempting to move at those speeds with that level of tech. Once you throw in both XL and Endo Steel, the bell curve changed to where a 50-ton mech was at the top of the curve with 25.5 tons left over for armor, weapons, and other equipment.


There are many other things that can make a mech awesome (or not) other than this 'bang-for-your-buck' tonnage comparrison. However, it is worth noting the diminishing returns you can get for choosing an engine rating that doesn't deliver as much for your mech's weight class.

[Ahma]

So, if one leaves free tonnage from the build (like all the slots are full), will the mech gain more speed from less tonnage?

[One Medic Army]

Ahma, on 25 August 2013 - 05:26 AM, said:

So, if one leaves free tonnage from the build (like all the slots are full), will the mech gain more speed from less tonnage?

No, speed is completely based on engine and maximum tonnage, there is no benefit for running light.