Engine ISP and Weight Tweaks

[Xavven]

Alright, the game is still in alpha, so more balancing is sure to come, but I noticed some rebalancing done mostly around the 2.5m engines.

[table=width: 600, class: grid, align: left]

[tr]

[td=width: 1000]Engine[/td]

[td]Old Weight[/td]

[td]New Weight[/td]

[td]Old Isp Atm[/td]

[td]Old Isp Vac[/td]

[td]New Isp Atm[/td]

[td]New Isp Vac[/td]

[/tr]

[tr]

[td]LV-T30[/td]

[td]1.25[/td]

[td]1.25[/td]

[td]320[/td]

[td]370[/td]

[td]320[/td]

[td]370[/td]

[/tr]

[tr]

[td]LV-T45[/td]

[td]1.5[/td]

[td]1.5[/td]

[td]320[/td]

[td]370[/td]

[td]320[/td]

[td]370[/td]

[/tr]

[tr]

[td]LV-909[/td]

[td]0.5[/td]

[td]0.5[/td]

[td]300[/td]

[td]390[/td]

[td]300[/td]

[td]390[/td]

[/tr]

[tr]

[td]Aerospike[/td]

[td]1.5[/td]

[td]1.5[/td]

[td]388[/td]

[td]390[/td]

[td]388[/td]

[td]390[/td]

[/tr]

[tr]

[td]LV-N[/td]

[td]2.25[/td]

[td]2.25[/td]

[td]220[/td]

[td]800[/td]

[td]220[/td]

[td]800[/td]

[/tr]

[tr]

[td]Poodle[/td]

[td]2.5[/td]

[td]2.0[/td]

[td]270[/td]

[td]390[/td]

[td]270[/td]

[td]390[/td]

[/tr]

[tr]

[td]Skipper[/td]

[td]4[/td]

[td]3[/td]

[td]300[/td]

[td]350[/td]

[td]320[/td]

[td]370[/td]

[/tr]

[tr]

[td]Mainsail[/td]

[td]6[/td]

[td]6[/td]

[td]280[/td]

[td]330[/td]

[td]320[/td]

[td]360[/td]

[/tr]

[tr]

[td]LFB KR-1x2 (Liquid Fuel Booster)[/td]

[td]42[/td]

[td]42[/td]

[td]320[/td]

[td]360[/td]

[td]290[/td]

[td]340[/td]

[/tr]

[tr]

[td]KR-2L (Kerbodyne Advanced Engine)[/td]

[td]6.5[/td]

[td]6.5[/td]

[td]280[/td]

[td]380[/td]

[td]280[/td]

[td]380[/td]

[/tr]

[tr]

[td]S3 KS-25x4 (4x Engine Cluster)[/td]

[td]9.75[/td]

[td]9.75[/td]

[td]320[/td]

[td]360[/td]

[td]320[/td]

[td]360[/td]

[/tr]

[tr]

[td]48-7S[/td]

[td]0.1[/td]

[td]0.1[/td]

[td]300[/td]

[td]350[/td]

[td]300[/td]

[td]350[/td]

[/tr]

[tr]

[td]LV-1 and LV-1R[/td]

[td]0.03[/td]

[td]0.03[/td]

[td]220[/td]

[td]290[/td]

[td]220[/td]

[td]290[/td]

[/tr]

[/table]

My personal comments:

• Thrust was unchanged amongst all the engines.
  
• I'm most happy about the Poodle weight loss, as it's finally better than clustering four LV-909's together (aside from it fitting in a 2.5m stack well) and may actually be a good choice for mid-sized 2-man landers.
  
• I was a little surprised to see the Skipper get a boost, as I've always found use for them as transfer stages below my LV-N's, but it's a welcome change nonetheless.
  
• The Mainsail got a much needed buff to make it competitive to the Liquid Fuel Booster.
  
• The Liquid Fuel Booster got an Isp nerf. I think the LFB nerf combined with the Mainsail buff may have tipped the scales too far in the Mainsail's favor, but I'll have to do some play tests. Despite having 25% less thrust than the LFB, the Mainsail is 4 tons lighter with an Orange Tank, and has better Isp.
  
• The KR-2L Isp Atm nerf seems immaterial. [Correction: The KR-2L was unchanged this patch] Who really uses this in their lifter stages anyhow? I always used it as my heavy transfer stage.
  
• The 48-7S still seems too powerful compared to the LV-909. Personally, I'd give it a thrust nerf to encourage its use as a probe engine, leaving the LV-909 as a small lander engine.
  

Edited July 18, 2014 by Xavven

[timsfitz]

Interesting. I like the changes.

[Alshain]

Nice, that's for summarizing!

[Geschosskopf]

I used to use the RK-2L as a lifter engine quite a lot, actually. It was great for light payloads going long distances....

[Renegrade]

Alright, the game is still in alpha, so more balancing is sure to come, but I noticed some rebalancing done mostly around the 2.5m engines.

[*]The 48-7S still seems too powerful compared to the LV-909. Personally, I'd give it a thrust nerf to encourage its use as a probe engine, leaving the LV-909 as a small lander engine.

The 48-7S will still dominate for light landers with multiple engines, unless it's a crazy nerf. That being said, I think it's good that there's a class of landers for the 48, another class for the 909, and a third (possible) class for the Poodle. Diversity!

By crazy nerf, I mean like reducing it down to ant thrust levels--that wouldn't make much sense. Perhaps 15-ish kn would take it out of the Mainsail class TWR while still letting it be useful on the ultralight landers?

However, I think the radial engines are still being ignored a bit too much. The 24-77 and Mk55 could use an Isp buff (at least say, 290-330 / 300-350?)

I used to use the RK-2L as a lifter engine quite a lot, actually. It was great for light payloads going long distances....

I did as well. You get it before the KS-25x4... of course I've also used the LFB as a core engine heh..

[Specialist290]

Of course, the new economy system is going to add a new dimension for measuring efficiency. I'm wondering if there are any cases where the most fuel-efficient design for a given role might not necessarily be the most cost-efficient one...

[No one]

The KR-2L used to be my only lifter engine. I was going to stop using it in .24 anyway due to budgets, but now even more reason.

[ArcFurnace]

The O-10 monopropellant engine is now 0.09 mass, so it no longer has a ridiculous TWR (IIRC in Scott Manley's preview video it was 0.03, but that was presumably an earlier version).

[vexx32]

Moved to Development Discussion.

[Jouni]

A few notes:

• The KR-2L was 280/380 s already in 0.23.5, so it has not been changed.
  
• The Isp boost of the Skipper was a really good thing. Now it's as efficient as the 1.25 m engines for the same niches, but with a slightly higher TWR.
  
• The prices of most engines are quite balanced, but there are some inconsistencies. The KS-25x4 and the KR-2L are way too expensive, making them a lot less efficient than the baseline. The 48-7S, on the other hand, is really cheap (300), when compared to the 24-77 (480) and the LV-909 (750).
  
• Still, the 48-7S is now way too expensive for a lifter engine. For most high-TWR engines, the thrust-to-cost ratio is around 0.25, but for the 48-7S it's only 0.1.
  
• I'm not completely sure about it, but the LV-1 and the LV-1R seem to be very expensive.
  

[CaptRobau]

The KR-2L Isp Atm nerf seems immaterial. Who really uses this in their lifter stages anyhow? I always used it as my heavy transfer stage.

It was my goto second stage engine. I never use 3.75m engines outside of the atmosphere.

[Red Iron Crown]

The Poodle has become much more attractive, especially when you take cost into consideration.

[Xavven]

A few notes:

• The KR-2L was 280/380 s already in 0.23.5, so it has not been changed.
  ...
  

Thanks for the correction! I pulled the 320/380 number off of http://wiki.kerbalspaceprogram.com/wiki/Parts because I don't have an older version of the game handy. Can someone double check the correct number?

[UmbralRaptor]

I can confirm that the KR-2L wasn't nerfed. It had 280 s Isp at 1 atm in 0.23.5.

The O-10 monopropellant engine is now 0.09 mass, so it no longer has a ridiculous TWR (IIRC in Scott Manley's preview video it was 0.03, but that was presumably an earlier version).

I'd still argue that the ridiculous TWR was in fact balanced (or almost balanced) by the poor Isp and tank options. Confusingly, however, it has "PhysicsSignificance = 1" in the part.cfg...

[Jouni]

I'd still argue that the ridiculous TWR was in fact balanced (or almost balanced) by the poor Isp and tank options. Confusingly, however, it has "PhysicsSignificance = 1" in the part.cfg...

Apparently both of the new engines are physicsless. Otherwise the list of physicsless parts seems to be the same as before, including the big decoupler.

uruk:GameData jltsiren$ grep -ir physicssignificance *
Binary file MechJeb2/Plugins/MechJeb2.dll matches
NASAmission/Parts/Size3Decoupler/part.cfg://PhysicsSignificance = 1
Squad/Parts/Electrical/batteryPack/part.cfg:PhysicsSignificance = 1
Squad/Parts/Electrical/ksp_r_largeBatteryPack/part.cfg:PhysicsSignificance = 1
Squad/Parts/Electrical/solarPanels5/part.cfg:PhysicsSignificance = 1
Squad/Parts/Engine/OMSEngine/part.cfg:PhysicsSignificance = 1
Squad/Parts/Engine/vernierEngine/part.cfg:PhysicsSignificance = 1
Squad/Parts/Structural/adapterSmallMiniShort/part.cfg:PhysicsSignificance = 1
Squad/Parts/Structural/smallHardpoint/part.cfg:PhysicsSignificance = 1
Squad/Parts/Structural/strutCube/part.cfg:PhysicsSignificance = 1
Squad/Parts/Structural/strutOcto/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/commDish/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/ladder1/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/ladder1/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/LandingLeg1-2/part.cfg:PhysicsSignificance = 0
Squad/Parts/Utility/linearRCS/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/longAntenna/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/RCS block/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/sensorAccelerometer/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/sensorBarometer/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/sensorGravimeter/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/sensorThermometer/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/spotLight1/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/spotLight2/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/stackPoint1/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/telescopicLadder/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/telescopicLadder/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/telescopicLadderBay/part.cfg:PhysicsSignificance = 1
Squad/Parts/Utility/telescopicLadderBay/part.cfg:PhysicsSignificance = 1

[Red Iron Crown]

I can confirm that the KR-2L wasn't nerfed. It had 280 s Isp at 1 atm in 0.23.5.

I'd still argue that the ridiculous TWR was in fact balanced (or almost balanced) by the poor Isp and tank options. Confusingly, however, it has "PhysicsSignificance = 1" in the part.cfg...

So, instead of really high TWR it has infinite TWR?

I don't get the physicsless part thing.

[moogoob]

I like the changes - both the mainsail and skipper are now quite useful again. The LFB gets a bit of a nerf - but that's cool, it's supposed to be more brawn than brains anyways and disposed of once you no longer need all that thrust.

I've always had a soft spot for that little orange Rockomax engine. Its whole point was to have high thrust in a tiny, compact engine, to contrast with the bigger but much more efficient LV-909. If you want miniscule thrust, just use the LV-1. Nobody gives that engine any love.