TL;DR: You want Drag Drives unless you are using Enhanced Performance Thrusters and your ship's mass falls within a certain range.
[size=+1]Overview[/size]
Under the new engineering rules we can now choose experimental effects for thruster engineering. For most people wanting to go fast the interesting choices are going to be Drag Drives (+4% to multipliers) or Drive Distributors (+10% to masses). People who don't care about going fast but who want jump range might conceivably choose Stripped Down to get a mass reduction on the module itself.
All of these would be applied to Dirty Drive Tuning, naturally.
[size=+1]The UI[/size]
If you've seen the new system in action you are probably wondering where I got +4% from for Drag Drives, as the value displayed in the UI varies but will almost never show 4%.
Suppose we apply a grade 1 Dirty Drive Tuning modification to a set of standard thrusters. The UI will tell us that we gained +12% and our new multiplier is 112. This can be confirmed by consulting the journal file and looking for an EngineerCraft event.
Several other values are omitted for clarity.
Now suppose we buy a Drag Drives experimental effect.
The multiplier was 112.000015 after applying Dirty Drive Tuning, then 116.479996 after applying Drag Drives.
The UI shows a bonus of 4.48% because 112 + 4.48 is 116.48 but actually 112.000015 * 1.04 is 116.479996 ie a 4% bonus to the original roll.
Similarly with grade 5 multiplier of 138.960022, Drag Drives results an effective multiplier of 138.960022 * 1.04 = 144.518417 which shows in the UI as an increase of 5.56% because 144.52 - 138.96 is 5.56.
In the case of Drive Distributors the +10% benefit is easy to see. Each grade of modification has a flat penalty to optimal mass. For example at grade 5 the penalty is 12.5%. Subtracting 12.5% from a value is the same as multiplying it by 0.875 and applying a 10% benefit to that factor gives a result of 0.875 * 1.1 = 0.9625 or an effective penalty of 3.75%. These numbers can be seen in the UI and are therefore much less confusing.
[size=+1]Analysis[/size]
The formula for effective multiplier is well known. For simplicity let's write it as f(mass, min_mul, opt_mul, max_mul, min_mass, opt_mass, max_mass) where mass is the ship's fully laden mass and min/opt/max mul and mass refer to the thruster's parameters.
The effective multiplier for a thruster with Drag Drives would therefore be f(mass, min_mul * 1.04, opt_mul * 1.04, max_mul * 1.04, min_mass, opt_mass, max_mass) and with Drive Distributors f(mass, min_mul, opt_mul, max_mul, min_mass * 1.1, opt_mass * 1.1, max_mass * 1.1).
We also know that all regular thrusters of the same rating have the same set of multipliers regardless of class. So let's look at regular A-rated thrusters - I used 6A because I was in a Chieftain - and class 3 Enhanced Performance thrusters.
The minimal and maximal mass values for 6A thrusters with the Dirty Drive Tuning grade 5 penalty of 12.5% are 630T and 1890T. Here is a graph of effective multiplier for various masses within that range.
Drag Drives are superior across the board.
One noteworthy feature of the graph, which people familiar with the underlying formula will probably have predicted, is that at low mass values the benefit of Drive Distributors is lost. Once the ship is at the minimal mass its multiplier is capped at the maximum multiplier value. By increasing the minimal, optimal and maximal masses, Drive Distributors makes it possible the hit the cap at a higher mass.
To reiterate the earlier point, all regular thrusters of the same rating have the same multipliers and their mass ranges scale in proportion to their class, so Drag Drives will always be better.
As usual Enhanced Performance Thrusters behave differently. For those, the class 3 minimal and maximal masses are 61.25T and 175T after applying the 12.5% penalty. The graph is more interesting.
Again low mass values hit the cap for Drive Distributors. However at masses between 64T and 120T it outperforms Drag Drives. For class 2 Enhanced Performance Thrusters the range in which Drive Distributors are superior is 45T to 76T.
The numbers were derived through brute force. Someone smarter than me might be able to solve where the two curves intersect given arbitrary mass values.
The sweet spot will be slightly different for lower grades or Clean Drive Tuning because the optimal mass penalty won't be 12.5% and the curve will be skewed. Not by much, though.
[size=+1]Conclusion[/size]
If you have Enhanced Performance Thrusters and your laden mass is between 64T and 120T (for class 3) or 45T and 76T (for class 2) then you should get Drive Distributors. In all other cases you should get Drag Drives.
If your goal is to build the fastest possible racing ship you are safe to use Drag Drives as you will be able to engineer other modules for low mass enough to hit minimal mass.
[size=+1]Overview[/size]
Under the new engineering rules we can now choose experimental effects for thruster engineering. For most people wanting to go fast the interesting choices are going to be Drag Drives (+4% to multipliers) or Drive Distributors (+10% to masses). People who don't care about going fast but who want jump range might conceivably choose Stripped Down to get a mass reduction on the module itself.
All of these would be applied to Dirty Drive Tuning, naturally.
[size=+1]The UI[/size]
If you've seen the new system in action you are probably wondering where I got +4% from for Drag Drives, as the value displayed in the UI varies but will almost never show 4%.
Suppose we apply a grade 1 Dirty Drive Tuning modification to a set of standard thrusters. The UI will tell us that we gained +12% and our new multiplier is 112. This can be confirmed by consulting the journal file and looking for an EngineerCraft event.
Code:
{
"event":"EngineerCraft",
"Slot":"MainEngines",
"BlueprintName":"Engine_Dirty",
"Level":1,
"Modifiers":[
{ "Label":"EngineOptPerformance", "Value":112.000015, "OriginalValue":100.000000, "LessIsGood":0 }
]
}
Code:
{
"event":"EngineerCraft",
"Slot":"MainEngines",
"BlueprintName":"Engine_Dirty",
"ExperimentalEffect":"special_engine_overloaded",
"ExperimentalEffect_Localised":"Drag Drives",
"Modifiers":[
{ "Label":"EngineOptPerformance", "Value":116.479996, "OriginalValue":100.000000, "LessIsGood":0 }
]
}The UI shows a bonus of 4.48% because 112 + 4.48 is 116.48 but actually 112.000015 * 1.04 is 116.479996 ie a 4% bonus to the original roll.
Similarly with grade 5 multiplier of 138.960022, Drag Drives results an effective multiplier of 138.960022 * 1.04 = 144.518417 which shows in the UI as an increase of 5.56% because 144.52 - 138.96 is 5.56.
In the case of Drive Distributors the +10% benefit is easy to see. Each grade of modification has a flat penalty to optimal mass. For example at grade 5 the penalty is 12.5%. Subtracting 12.5% from a value is the same as multiplying it by 0.875 and applying a 10% benefit to that factor gives a result of 0.875 * 1.1 = 0.9625 or an effective penalty of 3.75%. These numbers can be seen in the UI and are therefore much less confusing.
[size=+1]Analysis[/size]
The formula for effective multiplier is well known. For simplicity let's write it as f(mass, min_mul, opt_mul, max_mul, min_mass, opt_mass, max_mass) where mass is the ship's fully laden mass and min/opt/max mul and mass refer to the thruster's parameters.
The effective multiplier for a thruster with Drag Drives would therefore be f(mass, min_mul * 1.04, opt_mul * 1.04, max_mul * 1.04, min_mass, opt_mass, max_mass) and with Drive Distributors f(mass, min_mul, opt_mul, max_mul, min_mass * 1.1, opt_mass * 1.1, max_mass * 1.1).
We also know that all regular thrusters of the same rating have the same set of multipliers regardless of class. So let's look at regular A-rated thrusters - I used 6A because I was in a Chieftain - and class 3 Enhanced Performance thrusters.
The minimal and maximal mass values for 6A thrusters with the Dirty Drive Tuning grade 5 penalty of 12.5% are 630T and 1890T. Here is a graph of effective multiplier for various masses within that range.
Drag Drives are superior across the board.
One noteworthy feature of the graph, which people familiar with the underlying formula will probably have predicted, is that at low mass values the benefit of Drive Distributors is lost. Once the ship is at the minimal mass its multiplier is capped at the maximum multiplier value. By increasing the minimal, optimal and maximal masses, Drive Distributors makes it possible the hit the cap at a higher mass.
To reiterate the earlier point, all regular thrusters of the same rating have the same multipliers and their mass ranges scale in proportion to their class, so Drag Drives will always be better.
As usual Enhanced Performance Thrusters behave differently. For those, the class 3 minimal and maximal masses are 61.25T and 175T after applying the 12.5% penalty. The graph is more interesting.
Again low mass values hit the cap for Drive Distributors. However at masses between 64T and 120T it outperforms Drag Drives. For class 2 Enhanced Performance Thrusters the range in which Drive Distributors are superior is 45T to 76T.
The numbers were derived through brute force. Someone smarter than me might be able to solve where the two curves intersect given arbitrary mass values.
The sweet spot will be slightly different for lower grades or Clean Drive Tuning because the optimal mass penalty won't be 12.5% and the curve will be skewed. Not by much, though.
[size=+1]Conclusion[/size]
If you have Enhanced Performance Thrusters and your laden mass is between 64T and 120T (for class 3) or 45T and 76T (for class 2) then you should get Drive Distributors. In all other cases you should get Drag Drives.
If your goal is to build the fastest possible racing ship you are safe to use Drag Drives as you will be able to engineer other modules for low mass enough to hit minimal mass.
Last edited:
