Engines revamp - Thrust and performance changes discussion

[Gaarst]

2 hours ago, Tweeker said:

I'm full on board with the idea of being able to upgrade parts via the tech tree. There were some topics that floated around about the idea a few years back:

in one of them.

I aid the following, which I still stand by.

 The big challenge, from a game design standpoint  Is balancing the thrust range of single engine vs clusters, for example For example a cluster of compact LV909s  vs the Poodle. First you need to establish a paradigm for what size the full size version is vs the If you assume The compact is 1/2 the width of the full sized, (which seems to fall in line with the artwork from the first page) then the tightest you can cluster a poodle compact,1.25m  Poodle under a 2.5m stack,  is 2. otherwise you get part clipping. A compact Lv-909 on the other hand will fit 12. This suggests that the Poodle need to be bigger thrust wise, some where above 6x larger than the LV-909.

for example using the current Stats,you get the following comparison:

2X poodles, 500KN

12X 909s   720KN

This clearly illustrates the problem,

 

I suggest  a thrust of 400 KN based on current stats.This gives you:.

2X poodles, 800KN

12X 909s   720KN

Making a poodle cluster better than 909 cluster, and preserving the poodles niche.

Not knowing the starting and ending stats of both makes it hard to  throw out exact numbers. for the upgrade system. 

I think the Poodle is already powerful enough for its use as a vacuum engine. You don't need tons of TWR once in space.

Edited September 21, 2016 by Gaarst

[rkman]

Is not having large gaps in the range of thrust an unwritten design objective? 
Is there a point to having both a 650kN and a 750kN sustainer engine, but nothing between 750 and 3000kN?
Is the idea that we use clustering of engines to plug those gaps - which would mean in some circumstances we'd be forced to use less efficient (higher drag) compact versions of engines?  

Suggestion: have sea level- and vacuum versions of basically all engines except for the biggest launch engines and dedicated vacuum engines.  

Edited September 21, 2016 by rkman

[Temeter]

3 hours ago, Tweeker said:

When people discussing the Vector people often point out that it is supposed to be used to make a shuttle analog, so it make sense that the stats should reflect this.   

You aren't talking about reflecting certain charachteristics, you're asking for an engine that's inspired by the SSME to follow 100% the engines actual proportions.  Which, yeah, is unreasonable since full realism isn't the aim of any of the engines.

1 hour ago, rkman said:

Is not having large gaps in the range of thrust an unwritten design objective? 
Is there a point to having both a 650kN and a 750kN sustainer engine, but nothing between 750 and 3000kN?
Is the idea that we use clustering of engines to plug those gaps - which would mean in some circumstances we'd be forced to use less efficient (higher drag) compact versions of engines?  

Suggestion: have sea level- and vacuum versions of basically all engines except for the biggest launch engines and dedicated vacuum engines.  

Why, we got the good ol' 1500kn Mainsail booster, whose efficiency makes an ok sustainer as well, and the 1200kn Rhino upper stage engine.

And yeah, the new compact engines finally allow us to cluster weaker engines to acchieve whatever thrust level we need, so those performance gaps don't matter as much anyway.

Edited September 21, 2016 by Temeter

[regex]

26 minutes ago, Temeter said:

And yeah, the new compact engines finally allow us to cluster weaker engines to acchieve whatever thrust level we need, so those performance gaps don't matter as much anyway.

I wouldn't say "finally allow" since we've been able to do it despite tankbutts, but yeah, this exactly. Without tankbutts to force engines into specific form factors there's less of an issue with performance gaps and you can now choose engines for how they look.

[Temeter]

1 minute ago, regex said:

I wouldn't say "finally allow" since we've been able to do it despite tankbutts, but yeah, this exactly. Without tankbutts to force engines into specific form factors there's less of an issue with performance gaps and you can now choose engines for how they look.

Idk, with those buts, you could hardly ever fit more than 2 engines onto a fuel tank without obvious clipping. Or not even that when it came to 2.5m engines on a 3.75m tank. Especially compact engines like the LV-T15 or Skipper should work a lot better.

[Tweeker]

2 hours ago, KSK said:

Hang on - half the width means a quarter of the area surely? Which suggests you should be able to have a cluster of four Poodle Compacts. 

In which case the current balance looks OK to me. Even then I'm not convinced that you need to balance clusters the way you've suggested. Different tools for different jobs. 

If the engines where square, yes. But circles don't fit neatly togeher 

If you cluster 4 your parts will clip. You could slide the engines farther out, but then the mount will hang out past the edge of the tank. And that opens up a whole can of worms so best to stick with what can be fit completely under the tank. The best way to think of it is as a circle packing problem 

http://www2.stetson.edu/~efriedma/cirincir/

In our case we can just concentrate on the example where r=2 and r=4, or 1/2 & 1/4 of the diameter of the fuel tank.

 

 

 

 

[NathanKell]

16 hours ago, passinglurker said:

My god even on this topic you are full of it. Quit acting blind and lieing through your teeth.

I mentioned twice in that previous statement that the dev's said in this very thread that you shouldn't take stock in the current stats. They are essentially only place holders with no thought or testing. So your narrow scope of judgement is way off you need to look at the whole picture and start fresh to devise a balanced set of stats otherwise you are just wasting your time.

I said no such thing.

I said the current (i.e. in the game now, have been since 1.0) stats of engines were a quick rebalance in 1.0 QA that never got addressed again. I said nothing about the stats in the currently available overhaul zip, or on the overhaul document. While they are of course subject to change too, the point I was making was that people should not take the pre-existing since-1.0 stats as some hallowed uber-truth.

[regex]

35 minutes ago, NathanKell said:

While they are of course subject to change too, the point I was making was that people should not take the pre-existing since-1.0 stats as some hallowed uber-truth.

I, for one, hope for engine stats that allow a greater diversity in usage, where the choice of engine is not immediately clear and many different solutions can work. Some people may not like more homogenized choices but I think it'll result in a greater variety of craft.

The compact engines are a great move towards that.

Edited September 21, 2016 by regex

[Tweeker]

1 hour ago, regex said:

I, for one, hope for engine stats that allow a greater diversity in usage, where the choice of engine is not immediately clear and many different solutions can work. Some people may not like more homogenized choices but I think it'll result in a greater variety of craft.

The compact engines are a great move towards that.

I can agree with that.

 

[Tweeker]

There are 2 things I see right now with the compact engines,

1) The compact engines need to generate a fairing above them , kind of and egg shape that will meld into whatever they are under. This is because when they are clustered under a tank, they will hang out, and we all know how crazy that drives some people.

2) There needs to be an inter-stage, because if you cluster without an engine in the center it becomes hard to stack under this, for example in the case of the clustered upperstages. an inter-stage  would make this cleaner and easier.

I had a chance to mess around a little, and I came up with this,    

I knew that in circle packing if you are at a ratio of 1/2 the most you can pack is 2. I didn't know how to figure it for asymmetric iterations, So I did it practically, using 909s for Poodles, and Sparks for 909s. This is only slightly better than the cluster of 12. But it is interesting, It changes my thinking somewhat.

If the poodle is buffed to 300, or 310 thrust, (with weight change to match so TWR is the same) Then the situation becomes:

2 poodles = 600Kn,

12 9029s = 720 Kn

and a 2-4 cluster such as above becomes 840Kn

Interesting.

and if you consider the poodle vs 909s on 1.25 m tanks you find that you can still out perform the poodle, but now you have to cluster more than 5 909s and to accomplish this, and you are noticeably over hanging the edges.  So now I think maybe 300 to 310 isp.

10 hours ago, Gaarst said:

I think the Poodle is already powerful enough for its use as a vacuum engine. You don't need tons of TWR once in space.

On the whole I would agree with you once your in space it doesn't matter what you use for transfers, so use the lightest thing you can, The problem is the poodle is basically  a 4X 909. It has a slight thrust and TWR advantage but not enough to really make it distinct. I have always said that it need more thrust to accomplish this,  I still think that, but now I really think 300 - 310  Isp would be a really interesting place for the poodle to be.

 

 

[EpicSpaceTroll139]

I feel like nerfing the Vector in that way (reducing thrust AND increasing its diameter to size 2) would pretty much negate its point in the first place: EG: be able to stick 3 of them on the back of a mk3 fuselage for use as shuttle engines.

[Tweeker]

10 hours ago, EpicSpaceTroll139 said:

I feel like nerfing the Vector in that way (reducing thrust AND increasing its diameter to size 2) would pretty much negate its point in the first place: EG: be able to stick 3 of them on the back of a mk3 fuselage for use as shuttle engines.

Not at all. the vector could have it's thrust nerfed to 400-450KN and still be useable as a shuttle engine.

Changing it so it attaches in the same way as all other rocket engine is a good and needed change as well. And once again it would not keep you from using it as a shuttle engine>

If you make these 2 changes it in no way detract rom you ability to builda shuttle in KSP, and as a bonus:

1)  since now all the engines mount the same you can use other engine in the shuttle as well.

and

2)  You get a Bigger, Better SRB.

I see no down side.

[TheEpicSquared]

I'm assuming that the 2.5m parts have not been revamped yet, as they don't show up in the mod?

[passinglurker]

4 hours ago, Tweeker said:

Not at all. the vector could have it's thrust nerfed to 400-450KN and still be useable as a shuttle engine.

Changing it so it attaches in the same way as all other rocket engine is a good and needed change as well. And once again it would not keep you from using it as a shuttle engine>

If you make these 2 changes it in no way detract rom you ability to builda shuttle in KSP, and as a bonus:

1)  since now all the engines mount the same you can use other engine in the shuttle as well.

and

2)  You get a Bigger, Better SRB.

I see no down side.

You break saves, you ruin the mount part, and the builds don't look like shuttles anymore.

[Tweeker]

1 hour ago, passinglurker said:

You break saves, you ruin the mount part, and the builds don't look like shuttles anymore.

The vector is already being changed as part of the engine re-vamp, it's getting a thrust nerf, and it is getting a power-head, instead of being a magic nozzle. So it  is just a matter of how much thrust change, and how much taller the engine will be.

 

Unless you are objecting to Squad re-vampire the engine.

 

[regex]

17 hours ago, EpicSpaceTroll139 said:

I feel like nerfing the Vector in that way (reducing thrust AND increasing its diameter to size 2) would pretty much negate its point in the first place: EG: be able to stick 3 of them on the back of a mk3 fuselage for use as shuttle engines.

Remember that these thrust values may be the base values before tech tree upgrades, check my earlier post on this, the released parts will upgrade as you progress. The compact engine variant enables you to cluster them effectively. In fact, that's one of the main reasons to have compact engines, to allow you to slap a Rhino under a 2.5m stack, for instance.

E: Regarding upgrades, in the released pack of engines the LV-T30 goes from 275 to 350kN of thrust by the time it has been fully upgraded. I think you'll see similar increases in the thrust of other engines shown.

Edited September 22, 2016 by regex

[passinglurker]

58 minutes ago, Tweeker said:

The vector is already being changed as part of the engine re-vamp, it's getting a thrust nerf, and it is getting a power-head, instead of being a magic nozzle. So it  is just a matter of how much thrust change, and how much taller the engine will be.

 

Unless you are objecting to Squad re-vampire the engine.

 

the "thrust nerf" is irrelevant since the presented stats are subject to change and the payload masses could change to compensate if it becomes a problem.

The powerhead can and will be simply a ghost mesh in order to keep at least one of the versions in the same dimensions and reasonably preserve existing save integrity and capability.

Setting the attachment node at the throat does not make it a magic nozzle the power head is still present just hidden from view and aerodynamic forces when attached.

[Tweeker]

4 hours ago, regex said:

Remember that these thrust values may be the base values before tech tree upgrades, check my earlier post on this, the released parts will upgrade as you progress. The compact engine variant enables you to cluster them effectively. In fact, that's one of the main reasons to have compact engines, to allow you to slap a Rhino under a 2.5m stack, for instance.

E: Regarding upgrades, in the released pack of engines the LV-T30 goes from 275 to 350kN of thrust by the time it has been fully upgraded. I think you'll see similar increases in the thrust of other engines shown.

I think the values are based on "stock values, as they mostly match the current stats,  So I think it is safe  to assume that Vector is getting a nerf. And that the 909 is getting a buff. (which really messes with it balance vs the poodle.

I also note that the LV-series are really over represented, If the upgrades are based on series or family it would be best to put to make the lv-t303 and the lv-t15 in a different family.

I can't tell for sure if the buffs are based on a number, or a percent, but I think that percentage is the way to go, that way smaller engine don't receive a bigger boost, this is reall important when considering clustering,  For example the 303 looks like it goes from 25 to 40 in Thrust or about a 40% swing, the Swivel  on the other hand only appears to have a 20% swing in thrust   I also think I is better to have a sytem where each engine has an early  nerfed, then a "stock" version,  then an advanced "buffed"version. That way the max stats change less vs the current ones.

Also,  I notice  there is nothing for SRBs 

4 hours ago, passinglurker said:

the "thrust nerf" is irrelevant since the presented stats are subject to change and the payload masses could change to compensate if it becomes a problem.

The powerhead can and will be simply a ghost mesh in order to keep at least one of the versions in the same dimensions and reasonably preserve existing save integrity and capability.

Setting the attachment node at the throat does not make it a magic nozzle the power head is still present just hidden from view and aerodynamic forces when attached.

Making the power head a ghost mesh, and mounting the Vector by the throat makes no sense, when all he rest of the engines mount above the powerhead. . The vector should not be a special case engine. Changing the mounting plane of the engine mount makes more sense as it open up more engine options for the shuttle.   

[passinglurker]

10 minutes ago, Tweeker said:

I think the values are based on "stock values, as they mostly match the current stats,  So I think it is safe  to assume that Vector is getting a nerf. And that the 909 is getting a buff. (which really messes with it balance vs the poodle.

I also note that the LV-series are really over represented, If the upgrades are based on series or family it would be best to put to make the lv-t303 and the lv-t15 in a different family.

I can't tell for sure if the buffs are based on a number, or a percent, but I think that percentage is the way to go, that way smaller engine don't receive a bigger boost, this is reall important when considering clustering,  For example the 303 looks like it goes from 25 to 40 in Thrust or about a 40% swing, the Swivel  on the other hand only appears to have a 20% swing in thrust   I also think I is better to have a sytem where each engine has an early  nerfed, then a "stock" version,  then an advanced "buffed"version. That way the max stats change less vs the current ones.

Also,  I notice  there is nothing for SRBs 

Making the power head a ghost mesh, and mounting the Vector by the throat makes no sense, when all he rest of the engines mount above the powerhead. . The vector should not be a special case engine. Changing the mounting plane of the engine mount makes more sense as it open up more engine options for the shuttle.   

Most other lifter and sustainer engines of a small enough diameter to be clustered in groups of 3 or more are small enough to fit on the vectors bell. The vector is the bleeding edge and so it's treated different. Though we can go the other way and mount all the compacts at the throat 

[regex]

7 minutes ago, Tweeker said:

I think the values are based on "stock values, as they mostly match the current stats,  So I think it is safe  to assume that Vector is getting a nerf. And that the 909 is getting a buff. (which really messes with it balance vs the poodle.

Perhaps, but that doesn't mean we won't see changes elsewhere, especially since @NathanKell has mentioned that the current values are not entirely "balanced".

7 minutes ago, Tweeker said:

I also note that the LV-series are really over represented, If the upgrades are based on series or family it would be best to put to make the lv-t303 and the lv-t15 in a different family.

There is nothing to say that each engine won't receive it's own upgrade path, or that the LV series won't be broken out into smaller categories. What was released is what was available at the time, it may have been created as an internal "proof of concept".

7 minutes ago, Tweeker said:

Also,  I notice  there is nothing for SRBs 

Probably not implemented yet, or considered part of a tank art pass. They're pretty simple compared to engines, though.

[Tweeker]

45 minutes ago, regex said:

Perhaps, but that doesn't mean we won't see changes elsewhere, especially since @NathanKell has mentioned that the current values are not entirely "balanced".

There is nothing to say that each engine won't receive it's own upgrade path, or that the LV series won't be broken out into smaller categories. What was released is what was available at the time, it may have been created as an internal "proof of concept".

Probably not implemented yet, or considered part of a tank art pass. They're pretty simple compared to engines, though.

   I'm not taking this a gospel, ,but it is as good a place as any to start, I mean isn't it better to provide constructive commentary now than to wait and see what we get and then poodle about it.? .  (not poodle--apparently there is an auto correct for b!tch)

Edited September 22, 2016 by Tweeker

[Red Iron Crown]

1 hour ago, Tweeker said:

Making the power head a ghost mesh, and mounting the Vector by the throat makes no sense, when all he rest of the engines mount above the powerhead. . The vector should not be a special case engine. Changing the mounting plane of the engine mount makes more sense as it open up more engine options for the shuttle.   

I think they should leave the mounting block alone, and make the new Vector's attachment point above the pump and associated machinery like the other engines. If players want to hide the Vector's (or any other engine's) mechanicals they can use the offset tool.

[Tweeker]

50 minutes ago, passinglurker said:

Most other lifter and sustainer engines of a small enough diameter to be clustered in groups of 3 or more are small enough to fit on the vectors bell. The vector is the bleeding edge and so it's treated different. Though we can go the other way and mount all the compacts at the throat 

The vector is different because it was a band- aid, not because it is some special high tech wonder engine.  Changing all the other engines to justify this isn't the answer.

Changing the vector to align with the way all the rest of the rocket engine function is the better choice. 

There are a few obvious substitutes, for example people used to use the skipper as a shuttle engine before the vector was rolled out. the only complaint was the thrust structure clipping thru the sides, now with the compact version that is not a issue.  

  

[regex]

12 minutes ago, Tweeker said:

   I'm not taking this a gospel, ,but it is as good a place as any to start, I mean isn't it better to provide constructive commentary now than to wait and see what we get and then poodle about it.? . 

vOv

Personally I'd just start over and totally homogenize the engines based on their intended usage so that no engine is any better than another in isp, they'd just differ in thrust and that would determine the mass. Though I guess balancing based on gimbaling would be a thing...

12 minutes ago, Tweeker said:

(not poodle--apparently there is an auto correct for b!tch)

There's a reason for that and trying to subvert it is against the rules around here.

[passinglurker]

3 minutes ago, Tweeker said:

The vector is different because it was a band- aid, not because it is some special high tech wonder engine.  Changing all the other engines to justify this isn't the answer.

Changing the vector to align with the way all the rest of the rocket engine function is the better choice. 

There are a few obvious substitutes, for example people used to use the skipper as a shuttle engine before the vector was rolled out. the only complaint was the thrust structure clipping thru the sides, now with the compact version that is not a issue.  

  

The vector was different because it was and still is a rocket made for a space plane and so it needs to be sleek exposing the powerhead and breaking saves over a users fit of ocd is the worst decision.