Calculating right engine for truck

[Imhotep]

My truck model is described as being underpowered and so it doesn't move that fast.

If I were to design a new model, how would I calculate the best engine to use?

Here are what I think are the relevant stats.

Hauler Truck

Weight: 12 (c10)
Carry: 5

...and currently using a Light Diesel Engine

Engine Power: 200
Weight: 45

Grunt IV infantry unit

Weight: 12 (c5)

[FourGreenFields]

I do not believe the infantry's stats play into that.

And you forgot to list the engine design stat of your truck - though that may, of course, change (but never decrease) when you redesign it.

[Imhotep]

Originally posted by FourGreenFields:

I do not believe the infantry's stats play into that.

And you forgot to list the engine design stat of your truck - though that may, of course, change (but never decrease) when you redesign it.

Do you mean these values?

Original Base Design: 75
Structural Design: 78 (out of 70 - 130)

So it has a bad number.

[Hasefrexx]

The blueprint screen is the closer it gets. It assumes design rolls equal to 100, which will probably differ to your engine roll. What is carried does not matter indeed, although carrying artillery or AT gun will come with increasing penalties for the caliber size.

[Hasefrexx]

Structural design impacts all the design rolls and is fixed for a given model.

Base design will get to improve with field training every time you design upon the same model and also affects the design rolls.

You can check the engine roll in mng/model dcreen, one of the tabs will show all the rolls, although trucks don't have armour and weapon rolls so it's a lot less relevant.

[FourGreenFields]

Originally posted by Imhotep:

Do you mean these values?

Original Base Design: 75
Structural Design: 78 (out of 70 - 130)

So it has a bad number.

Engine deisgn, not base and structural.

But boy, that structural design is bad. Base design is low, but acceptable (just send some trucks to get hit and then redesign the model to make use of the field testing... or redesign as-is, it'll still reroll and take the higher base design), but I'd probably try and get a new design-line for trucks going. Even 90 would be low (with a non-horrible model design director you'll get to keep the highest of several rolls).

[Imhotep]

Originally posted by Hasefrexx:

The blueprint screen is the closer it gets. It assumes design rolls equal to 100, which will probably differ to your engine roll. What is carried does not matter indeed, although carrying artillery or AT gun will come with increasing penalties for the caliber size.

I've not examined the blueprint screen before. It shows that any engine more powerful than the original Light Diesel Engine will result in a movement penalty due to increased weight.

Originally posted by FourGreenFields:

But boy, that structural design is bad.

It's the truck I started the game with.

So how do I tell how much the truck can carry? What about if I were to build some very heavy artillery? How would I know what engine its transport would need?

[FourGreenFields]

Originally posted by Imhotep:

So how do I tell how much the truck can carry?

It can carry one infantry or gun subunit.

Originally posted by Imhotep:

What about if I were to build some very heavy artillery? How would I know what engine its transport would need?

The speed modifiers of the truck/APC and of the carried subunit add up, afaIk. So if you have a +10% AP cost truck and a +40% AP cost subunit, the truck will move at a +50% AP cost. A -10% AP cost truck would move at +30% AP cost.

Originally posted by Imhotep:

I've not examined the blueprint screen before. It shows that any engine more powerful than the original Light Diesel Engine will result in a movement penalty due to increased weight.

This sounds like you're misreading something. It lists the AP cost; -10% AP cost means moving faster (moving into a hex that would cost 10 AP now costs just 9).

[Imhotep]

Originally posted by FourGreenFields:

This sounds like you're misreading something.

Yes, I was.

I think I've got it now.

So the best engine for the truck gives -30% AP cost and the heaviest artillery has a +71% AP cost, meaning that, overall, it would have +41% AP cost and be slower.

However, if the structural design was below 100, it could potentially go even slower?

A unit at -30% AP, without carrying anything, would make it go at 130% speed, or is speed capped at 100%? Similarly, if a unit got lucky and got structural design of 130, it would go 30% faster?

[Imhotep]

Or have I got this all wrong and the heaviest artillery having a +71% AP cost is affecting its own movement and is not a factor for a unit that's transporting it?

[FourGreenFields]

Originally posted by Imhotep:

However, if the structural design was below 100, it could potentially go even slower?

Structural (and base) design does not affect a model's performance directly. It influences the engine, weapons, and armour design scores, and those influence performance (except engine design on aircraft, that appears to do nothing).

Originally posted by Imhotep:

Or have I got this all wrong and the heaviest artillery having a +71% AP cost is affecting its own movement and is not a factor for a unit that's transporting it?

Upon checking up on things, it's possible it's currently just a cluster[Steam's lovely hearts].

Originally posted by Open Beta Patchnotes:

-Expanded rather limited implementation of moveRedux effects of artillery on transporter (truck/apc) speed. Used to be only applied if the trucks had an AP cost decrease (fast trucks), now also for all others (normal and slower than normal)

From here[www.matrixgames.com].

But at least it should be affecting truck movement, even if it currently sometimes does not.

Originally posted by Imhotep:

A unit at -30% AP, without carrying anything, would make it go at 130% speed, or is speed capped at 100%?

-30% AP would lead to a movement range of more than 130%. As far as I can tell it would be 1/0.7 -> 142.9% movement range.

For instance, with 100 AP and a movement cost of 10 per hex you could move 10 hexes. But with a movement cost of 7 per hex you could move 14 hexes (and have 2 AP left). A 40% increase.

Originally posted by Imhotep:

Similarly, if a unit got lucky and got structural design of 130, it would go 30% faster?

Engine design (as noted above, not structural design) affects the effective engine power. The effects of the engine-power:weight ratio have breakpoints. I also am unsure if it's linear-ish (as linear as it gets with breakpoints), especially considering there are also size modifiers (large models, like heavy tanks, move more slowly).

[Slippy]

If it helps (engine stuff confuses the heck out of me in this game) - engine power vs weight is what determines the +/- AP cost. Engine power is modified as a % of the engine design (100 engine design = 100%, 70 engine design = 70% etc).

I thought the 'weight' from transport was already considered in the design and doesnt change based on what you are actually carrying. Basically it assumes its always carrying something. Could be completely wrong on that.

The relationship is NOT linear between engine power vs weight. The table in the manual is the old table I believe (unless its been updated and ive missed it). Ive tried to calculate what the actual values are before but I couldnt figure it out

This is why most of your starting truck designs will be have large bad AP mods.

Whats strange is that militia trucks don't abide by any of these rules, they never have a AP mod. The 'rubbish' militia trucks will be more reliable than the trucks you can push out early game.

[FourGreenFields]

Originally posted by Slippy:

I thought the 'weight' from transport was already considered in the design and doesnt change based on what you are actually carrying. Basically it assumes its always carrying something. Could be completely wrong on that.

That is apparently a thing on top of (sometimes...) adding the modifier from the carried model. Shadow Empire just can't do anything the easy way.

See post in this thread:[www.matrixgames.com]

Originally posted by Vic:

Truck +140 simulated weight, APC +70 simulated weight in the weight:engine ratio calculations.

[Imhotep]

I did some testing comparing the movement rate along a dirt road of worst engine truck and best engine truck carrying two different types of artillery. (Note: truck has Structural Design 78)

Light Diesel Engine truck (worst)

105mm Arty: 5 hexes
300mm Arty: 3 hexes

Triple Diesel Engine truck (best)

105mm Arty: 12 hexes
300mm Arty: 7 hexes

[Slippy]

Originally posted by FourGreenFields:

Originally posted by Slippy:

I thought the 'weight' from transport was already considered in the design and doesnt change based on what you are actually carrying. Basically it assumes its always carrying something. Could be completely wrong on that.

That is apparently a thing on top of (sometimes...) adding the modifier from the carried model. Shadow Empire just can't do anything the easy way.

See post in this thread:[www.matrixgames.com]

Originally posted by Vic:

Truck +140 simulated weight, APC +70 simulated weight in the weight:engine ratio calculations.

Whoopsy, that’s my thread there and I clearly forgot Vic had told me that.

[ЧPOG]

ENG POWER directly translates into AP% bonus (or penalty). So, bigger = better.
Also, anything that decreases weight also improves AP% bonus (such as weight of ammo or armor).
I haven't found any reason for not taking the biggest engine possible yet.
(Also, field commander's skillroll MAY improve AP% of all units under his or her command)