Effect of engine pips on agility

[Bob Lighthouse]

I just decided to mix things up and take my AspEx to a fight (for the first time).

I ended up having to run away because it was sooo different to my Vulture.

I had used Coriolis to spec it out and ensure that it wasn't too horribly compromised wrt my Vulture. So it had better DPS but somewhat weaker hull and shields. I had checked the agility figures and they were slightly worse than the Vulture but not enormously so.

However, in combat, once I diverted pips to shields and weapons... OMG the AspEx was a total pig.

I then went back to Coriolis to see if I had had some kind of brain fart while comparing the specs, and no. But when I varied the ENG pips within Coriolis, the effect on the Vulture pitch rate was negligible and the effect on the AspEx was massive.

I haven't yet drilled down into the data underneath the Coriolis calcs (but given my experience the results seem plausible) but I did a bit of Googling instead. I found a thread here (locked tho) at https://forums.frontier.co.uk/showthread.php/367675-Engine-pips which @Morbad refers to the Vulture as being affected in a "subtle" way by ENG pips while others are more extreme (e.g. Python).

Is there a comprehensive list anywhere of how ships are affected by this?

Another, slightly more exotic question: how on earth can this behaviour be "explained"? The two ships in question both have 5A Thrusters and fairly similar mass (tho fair enough, the AspEx has a lower class PD).

Asp hull is about a third more massive, w/ Vulture at 230t and the Asp 60t more.
Built similarly in combat fit, the Vulture clocks in around 450t, with the Asp about 140t more.

So just in mass it's a pretty significant difference.

 

[Krash]

Good point about heat - I'm still learning how important that is. (Among other things I'm slightly stunned that it's pretty vital to pop a heatsink after an SCB. And rail guns get hot!)

The Phantom is a ship I've not seriously looked at but will do so now. (It does have a much higher "pipSpeed" value than the Vulture though.)

PipSpeed is sensitivity of turn rate to higher pips? The vulture should be better as a small ship. Imagine a vulture with 2 extra med hard points.. and turns slower with endless boosting on 4-1-1.

 

[Bob Lighthouse]

Asp hull is about a fourth more massive, w/ Vulture at 230t and the Asp 60t more.
Built similarly in combat fit, the Vulture clocks in around 450t, with the Asp about 140t more.

So just in mass it's a pretty significant difference.

Couldn't edit the error for some reason...

 

[Neilski]

PipSpeed is sensitivity of turn rate to higher pips? The vulture should be better as a small ship. Imagine a vulture with 2 extra med hard points.. and turns slower with endless boosting on 4-1-1.

Yeah the pipSpeed thing appears to be best interpreted as the amount of speed/turn-rate that you lose for each pip you take away from the 4-pip starting point.

Example: four of the ships in the list have a rather convenient value of 0.125.

asp_scout: 0.125
cobra_mk_iii: 0.125
cobra_mk_iv: 0.125
federal_corvette: 0.125

This, despite the rather large range in ship sizes!

So let's say the Cobra has a 4-pip pitch rate of 40°/s with 4 pips. That'll mean that the 3-pip value is (1 - 0.125*1) or 7/8 of the 4-pip value, or a nice round 35°/s. The 0-pip value will be (1 - 0.125*4) or simply half of the 4-pip value -> 20°/s.

So the speed and turn rate both vary entirely linearly with the number of pips for any given ship. But the amount of variation between 0 and 4 pips is massively different when moving from a Vulture to a Type-9 Heavy (which I do on a daily basis but I always fly the T-9 with 4 pips to engines so I never noticed, LOL).

 

[Crank Larson]

I just decided to mix things up and take my AspEx to a fight (for the first time).

AspXs are built for running, not fighting. Mine's fully armed and armoured, but I'll still run away if I encounter anything bigger than a Sidewinder. Well, maybe not that bad, but the AspX is made of tin and loves exploding. Even with reactive armour.

I'd recommend the Chieftain, though. I love that ship. Small rails and everything else multicannons, and it rips even large ships to shreds.

 

[xondk]

I just decided to mix things up and take my AspEx to a fight (for the first time).

I ended up having to run away because it was sooo different to my Vulture.

I had used Coriolis to spec it out and ensure that it wasn't too horribly compromised wrt my Vulture. So it had better DPS but somewhat weaker hull and shields. I had checked the agility figures and they were slightly worse than the Vulture but not enormously so.

However, in combat, once I diverted pips to shields and weapons... OMG the AspEx was a total pig.

I then went back to Coriolis to see if I had had some kind of brain fart while comparing the specs, and no. But when I varied the ENG pips within Coriolis, the effect on the Vulture pitch rate was negligible and the effect on the AspEx was massive.

I haven't yet drilled down into the data underneath the Coriolis calcs (but given my experience the results seem plausible) but I did a bit of Googling instead. I found a thread here (locked tho) at https://forums.frontier.co.uk/showthread.php/367675-Engine-pips which @Morbad refers to the Vulture as being affected in a "subtle" way by ENG pips while others are more extreme (e.g. Python).

Is there a comprehensive list anywhere of how ships are affected by this?

Another, slightly more exotic question: how on earth can this behaviour be "explained"? The two ships in question both have 5A Thrusters and fairly similar mass (tho fair enough, the AspEx has a lower class PD).

Pools of power is the general term I use.

If you divert power to the engine pool, it can withdraw more from that pool. That pool in terms of thrusters then determines how much power you have to distribute amongst your various thrusters, so if you have a low flow from the engine pool you end up with significantly reduced agility, because you cannot divert enough thrust to the various thrusters that help manoeuvre your ship fast enough.

Kinda like if you have more pipes to drain a pool it drains faster, but if you want to drain 3 different pools, you need to decide which one would go fastest, or have them all go equal.

 

[Feros-da-Grundig]

(bizarrely?) the T10 in [...] 3rd place

Strange, but kind of makes sense. Basically allows the t-10 to tank and inflict damage well (with something like 3 0 3) while retaining much of its (already poor) maneuverability, whereas the t-9 needs to just 4 2 0 or 2 4 0 and get of dodge. A t-9 with no eng pips is basically a floating brick.

So let's say the Cobra has a 4-pip pitch rate of 40°/s with 4 pips. That'll mean that the 3-pip value is (1 - 0.125*1) or 7/8 of the 4-pip value, or a nice round 35°/s. The 0-pip value will be (1 - 0.125*4) or simply half of the 4-pip value -> 20°/s.

So the speed and turn rate both vary entirely linearly with the number of pips for any given ship.

I spot checked a bunch of ships on coriolis and this appears exactly correct. Nicely done.

 

[Feros-da-Grundig]

So just in mass it's a pretty significant difference.

Aside from small ships like courier using EPT, I think the importance of mass is slightly overstated. I slapped A rated G5 DD on an asp and made the lightest and heaviest builds I can think of (326T vs 745T). The max speed differences were 574 to 502. More than doubling the weight reduced speed by only 12%. I believe acceleration and agility follow the same curve as max speed. Granted, Asp has a particularly shallow engine curve and easily reaches the "plateau" on the light end, but it's not unique (conda, phantom are light hulled ships with shallow curves as well). If doubling the weight of a ship means you can still reverse direction with only a ~10-15% time penalty, I think that's a pretty light penalty.

https://s.orbis.zone/2au1

https://s.orbis.zone/2au2


Don't get me wrong - a small decrease in agility can make a huge difference especially in evenly matched PvP. But for my ships that don't use EPT, I question if certain often recommended weight trade offs (such as lightweight engineered lightweight alloy bulkheads versus thermal engineered reactive bulkheads) are exaggerated - at least for some ships/builds.



EDIT - for confirmation that acceleration doesn't follow typical f = ma, see

https://www.reddit.com/r/EliteDange...lite_dangerous_ship_acceleration_and_agility/

And the citations there. This (along with some lackadaisical testing of my own) is why I assume acceleration follows the very forgiving max speed curve rather than anything remotely like real world physics.

 

[Spacecat]

Definitely not true. Just go to Coriolis and compare effects of eng pips on the agility (look at "profile" tab towards bottom) of the asp, challenger and the vulture (which are examples of large effect (asp) medium effect (chally) and small effect(vulture)).

With both at 4 pips Asp is more maneuverable than Challenger. At zero pips asp is less maneuverable than Challenger. At 2 pips they are roughly equal. Meanwhile vulture loses relatively little agility from 4 to 0 pips, compared to the others.

That's why I said "mainly".

 

[Lightspeed]

OK, I reckon I just found it, rather more readily than expected.
Here's the pipSpeed setting for each ship, sorted with smallest first, in case anyone else is curious. (If this is in fact the wrong ship-data field for the pip-sensitivity effect, please lemme know and I'll wipe it! )

NB: this list uses the ship's internal name (an FD thing, not a Coriolis thing, I believe), so my AspEx is just called "asp" below.
Clearly it's at the "sensitive" end of the scale, with very few combat ships having significantly higher values. And yes indeed the Vulture is way out on its own with the FDL and (bizarrely?) the T10 in 2nd and 3rd places.
Having built myself a Python combat ship, I might now sell it off and finally try the FDL instead...

Spoiler

vulture: 0.023809523809524
fer_de_lance: 0.038461538461538
type_10_defender: 0.041666666666667
imperial_cutter: 0.05
imperial_courier: 0.053571428571429
mamba: 0.056451612903226
eagle: 0.0625
federal_assault_ship: 0.071428571428571
imperial_eagle: 0.075
orca: 0.083333333333333
alliance_chieftain: 0.08695652173913
viper_mk_iv: 0.087962962962963
alliance_challenger: 0.088709677419355
krait_phantom: 0.09
krait_mkii: 0.09375
viper: 0.09375
diamondback_scout: 0.096153846153846
python: 0.097826086956522
diamondback_explorer: 0.098214285714286
imperial_clipper: 0.1
federal_gunship: 0.10294117647059
federal_dropship: 0.11111111111111
beluga: 0.1125
asp_scout: 0.125
cobra_mk_iii: 0.125
cobra_mk_iv: 0.125
federal_corvette: 0.125
asp: 0.13
dolphin: 0.13
adder: 0.13636363636364
sidewinder: 0.13636363636364
keelback: 0.1375
anaconda: 0.13888888888889
type_6_transporter: 0.14772727272727
alliance_crusader: 0.15833333333333
hauler: 0.1625
type_7_transport: 0.16666666666667
type_9_heavy: 0.17307692307692

T10 - I knew that spoiler was important ! [woah]

 

[Morbad]

EDIT - for confirmation that acceleration doesn't follow typical f = ma, see

https://www.reddit.com/r/EliteDange...lite_dangerous_ship_acceleration_and_agility/

And the citations there. This (along with some lackadaisical testing of my own) is why I assume acceleration follows the very forgiving max speed curve rather than anything remotely like real world physics.

The end result is the same, but the conclusion that acceleration doesn't follow F=ma is probably erroneous because it's assuming that thrust is fixed. FA is never completely off, and the forces applied by the thrusters definitely vary to enforce the desired flight model (easier to do by putting in thrust slopes than redefining the underlying physics on a per-ship basis).

 

[Bob Lighthouse]

Aside from small ships like courier using EPT, I think the importance of mass is slightly overstated. I slapped A rated G5 DD on an asp and made the lightest and heaviest builds I can think of (326T vs 745T). The max speed differences were 574 to 502. More than doubling the weight reduced speed by only 12%. I believe acceleration and agility follow the same curve as max speed. Granted, Asp has a particularly shallow engine curve and easily reaches the "plateau" on the light end, but it's not unique (conda, phantom are light hulled ships with shallow curves as well). If doubling the weight of a ship means you can still reverse direction with only a ~10-15% time penalty, I think that's a pretty light penalty.

https://s.orbis.zone/2au1

https://s.orbis.zone/2au2


Don't get me wrong - a small decrease in agility can make a huge difference especially in evenly matched PvP. But for my ships that don't use EPT, I question if certain often recommended weight trade offs (such as lightweight engineered lightweight alloy bulkheads versus thermal engineered reactive bulkheads) are exaggerated - at least for some ships/builds.



EDIT - for confirmation that acceleration doesn't follow typical f = ma, see

https://www.reddit.com/r/EliteDange...lite_dangerous_ship_acceleration_and_agility/

And the citations there. This (along with some lackadaisical testing of my own) is why I assume acceleration follows the very forgiving max speed curve rather than anything remotely like real world physics.

I was mainly commenting on the claim that the mass was similar.
You weren't around for the multiple 1000s of rolls for decent dirty drives I take it.
Some of that stuff is just outdated.

 

[Feros-da-Grundig]

That's why I said "mainly".

And I completely disagree that eng pips mainly control boost frequency. Keep in mind boost is simply a multiplier. So if you boost at 0 eng pips, you will both turn and accelerate turn more slowly during the boost than you would if you boosted with 4 pips.

A reader going on your comment would get the erroneous impression "Ship maneuverability is sort of baked into the ship from the start".

There's an entire thread here showing significant eng pips effects not related to boost, and also contradicting the "baked in" part. Maneuverability is not baked into a ship, but instead is a combination of ship, pips, thrusters and weight.

What actually is baked into the ship are boost duration and multiplier, which vary from as short as ~2 seconds with a 4x multiplier to 4 seconds with a ~7x multiplier, depending solely on ship. This is pip and loadout independent. https://docs.google.com/spreadsheets/d/1UKvWx-Po1erSwAFomEpSJvB5vRbYn_A2t0T9lNhMst0

 

[TheMegaTurnip]

Yeah it was changed in the Q1 update (May have been Q2) of beyond.

To try to disuade perma boost. Why I can't fathom but eh.

Some ships, like the Vulture and DBS seem to take a significantly smaller debuff from less pips, others a very much bigger one, FDL/Viper.