Engines revamp - Thrust and performance changes discussion

[Jonfliesgoats]

Ramjets don't have moving parts.  They rely on the movement of the aircraft through the atmosphere to provide compression that axial and centrifugal compressors on other engines provide.  The problem with ramjets is that you have be doing about 300 knots EAS for them to really become feasible.  So you have to be fast to get your engine to work so you can go faster.  They were really popular with some high speed cruise missile ideas in the Cold War.

The SR-71 was powered by turbojets that used many, many stages of axial compressors and some really cool shock-cone intakes.  There's a whole art to controlling the intakes to manage the shockwave on the intakes and prevent a compressor stall/engine surge on those motors!  It's soo cool!  I'd drink coffee and blather about it all day long.  Anyway, here's a link to a ramjet wiki.  There are also some cool pictures available of 1950s ramjet tests.

https://en.m.wikipedia.org/wiki/Ramjet

 

[Signo]

Wasn't the "twin boar" supposed to be nerfed? It is already the best engine in the game...

[Aegolius13]

55 minutes ago, Jonfliesgoats said:

Ramjets don't have moving parts.  They rely on the movement of the aircraft through the atmosphere to provide compression that axial and centrifugal compressors on other engines provide.  The problem with ramjets is that you have be doing about 300 knots EAS for them to really become feasible.  So you have to be fast to get your engine to work so you can go faster.  They were really popular with some high speed cruise missile ideas in the Cold War.

Right, but does KSP really have any true ramjets?  Who really knows, but I was under the impression that the Whiplash was a turboramjet like the SR-71.  So not sure which engine would realistically fail to work at standstill.  

[Jonfliesgoats]

I gotcha!  My dumb is strong!  

You know, I am not really sure if we have any true ramjets in KSP.  I always thought they would be fun to play with because of their advantages and challenges, though.  I gush over all kinds of experimental propulsion to play with.  I am sure there are mods for most of this stuff.

Still, while we are talking new motors, I wanted to get in some mention of ramjets and also pulse detonation engines,

[ChickenNugger429]

For a very long time I've been anticipating revamped rocket parts, so seeing these ones leak through makes me giddy with excitement, and I hope we'll get to see them implemented into an official release not too long after 1.2 officially makes it through. 
As far as performance tweaks go, I'd genuinely like the LV-T30 to have some degree of thrust vectoring. I understand that relative to career mode it's an early game component and so it's not expected to be the most fantastic engine, but it's still designed to serve as a first stage engine nonetheless, and control is most crucial during launch through the atmosphere (barring a situation where you intend to do a landing manoeuvre on a tricky body that is, but even so, getting to such a point still requires you to leave Kerbin first ). Of course I could be wrongly concerned here, as I'm also aware that part upgrades (at least for engines) are also in the works, so for all I know in a career mode save you might start off with an LV-T30 lacking thrust vectoring but after a certain point of progression through the R&D Tech-tree you could unlock a gimble upgrade. 

[sdj64]

Lots of exciting new stuff here, some good and some questionable new stats.  Loving all the new models.

 

I have to say, the T30 and T45 need an ISP buff, not a nerf.  But those values were designed to be upgraded later on.  Good final stats for them would be, T30 = 290-300ISP, 300kN thrust.  T45 = 250-320ISP, 200kN thrust.

The terrier got a sidegrade - its thrust was increased and its mass decreased, but ISP decreased.  It should be better for most landers, even without upgrading.  For upper stages, particularly for interplanetary probes, the new terrier might be worse.

The new Pug engine would be interesting for small landers.  It's got an ISP better than anything that small, and holds fuel.

The Valiant fills a good gap in existing engines, but with those ISP values I'd expect it to run on Monopropellent.  Good final stats would be, 250-310 ISP, 120kN thrust.

The Boar and the 2.5m Vector fill the same role, so there should be a better way of giving them defined roles.  Up the Boar to 1100 kN, and it makes sense with the Twin Boar (and is more clearly different from the now lower thrust, higher ISP Vector).  The Mainsail might benefit from a thrust increase too (1800 or so).

To go along with the Vector/Mammoth nerf, we need 2.5m SRBs, so that they can pick up some lifting slack for SLS and Shuttle designs.  The Mammoth should get an internal fuel tank since that now seems to be popular.  We also don't have a 3.75m Booster engine. (5xBoar for a Saturn 5 inspired engine, or 4xMainsail for a Russian-type one would be good)

Edited September 15, 2016 by sdj64

[Gaarst]

5 minutes ago, sdj64 said:

To go along with the Vector/Mammoth nerf, we need 2.5m SRBs, so that they can pick up some lifting slack for SLS and Shuttle designs.  The Mammoth should get an internal fuel tank since that now seems to be popular.  We also don't have a 3.75m Booster engine. (5xBoar for a Saturn 5 inspired engine, or 4xMainsail for a Russian-type one would be good)

My thoughts exactly. The Mammoth being classified as a sustainer engine means we don't have any lifter engine for large first stages. We can use liquid boosters with clustered engines, but having the choice beteween LF boosters and 2.5m SRBs would be nice, we need them more than ever if we are to follow this classification.

[Guest]

18 hours ago, Jonfliesgoats said:

Porkjet does amazing work!

Are we still giving ramjet engines thrust at 0m/s?  It would be nice they smoked and sputtered worthlessly until .5 Mach or so.  

 

The Whiplash is a turbo-ramjet. Those do have thrust at 0 m/s.

[Tweeker]

On ‎9‎/‎14‎/‎2016 at 3:42 PM, regex said:

No, not at all. Those compact designs will be incredible for clustering without ugly tankbuttes. Throw four LVT-30s and four LVT-45s under a 3.5m tank (or an adaptor with some 1.5 tanks in their own cluster) and you've got yourself a Saturn Ib. And then you can slap two Skippers under a 2.5m tank and have a Titan II. The possibilities just opened up.

 

The problem with the compact design is it turns rockets into "magic nozzels" by omitting the turbo machinery and the support structure that hides under the boat-tail. The vector is a prime example of this.  

[regex]

11 minutes ago, Tweeker said:

The problem with the compact design is it turns rockets into "magic nozzels" by omitting the turbo machinery and the support structure that hides under the boat-tail. The vector is a prime example of this. 

Have you looked at the proposal image? All the machinery is there it's just that the "compact" versions reduce the thrust structure to something reasonable, as opposed to KSP's default (and terrible) tankbutte, or an equally-as-wide thrust structure.

Seriously, have a good look at it.

While you're at it, notice how the Vector is changed to include the machinery.

Edited September 15, 2016 by regex

[Tweeker]

1 hour ago, regex said:

Have you looked at the proposal image? All the machinery is there it's just that the "compact" versions reduce the thrust structure to something reasonable, as opposed to KSP's default (and terrible) tankbutte, or an equally-as-wide thrust structure.

Seriously, have a good look at it.

While you're at it, notice how the Vector is changed to include the machinery.

The vector OMITS a lot of the machinery,

 

 

Edited September 15, 2016 by Tweeker

[regex]

3 minutes ago, Tweeker said:

The vector OMITS a lot of the machinery,

The Vector redesign ADDS a lot of the machinery, did you even look at the link I posted? The Vector as it is right now is a nozzle, like most of the KSP engines. The redesign mock-up looks so much better.

E: Or is your objection to the compact Vector engine having the same ring as before with the machinery behind it? That makes it easier to replicate the STS look.

Edited September 15, 2016 by regex

[Tweeker]

I looked at it before I posted my statement, and again after.

The vector is a SSME analogue, hard to argue agaist that,

But the compact version omit much of the machinery

 

The compact version has only about 1/2 of the pumps ect, and none of the mounting strurcture

[regex]

4 minutes ago, Tweeker said:

The vector is a SSME analogue, hard to argue agaist that,

That's why the compact version looks like it does, so people can have their STS "replicas". No machinery visible here:

[Aegolius13]

I guess it makes sense that the extra machinery is assumed to be nestled within whatever the engine is attached to.  On the other hand, similar to manual clipping, that's kind of cheating (I.e, if the fuel tank can still be filled to capacity, you have two things occupying the same space).

[Tweeker]

Believe me Regex, I've been down this road before. But for the benefit of others who may not have I'll go down it again,

Having a shuttle analog in laudable, but There are several problem with the vector as a SSME

1) it is vastly OP for that purpose, It has to be to compensate for the underpowered SRBs, IRL the SSME has 1,850 Kn to the SRBs 12,000 Kn

   so the shuttles provides about 5500 KN of thrust to the 24,000 for the boosters, or about 1:6 In KSP the SRBs provide about 1200KNn at launch vs the shuttle's 2900KN

or about 2.5:1

2) on the shuttle the machinery is recessed in the shuttle's rear, It would be better to have an engine with all the pumps ect, and a adapter that served as a shroud. Sure it looks right when it is put on the shuttle, but on anything else it is just wrong,

18 minutes ago, Aegolius13 said:

  On the other hand, similar to manual clipping, that's kind of cheating (I.e, if the fuel tank can still be filled to capacity, you have two things occupying the same space).

And that's really the issue

[regex]

20 minutes ago, Tweeker said:

1) it is vastly OP for that purpose

You can tweak the thrust down if you must have three engines, the controls are all there. I prefer using two since I'm not into building "replicas" in a game with a glaring realism problem.

20 minutes ago, Tweeker said:

2) on the shuttle the machinery is recessed in the shuttle's rear, It would be better to have an engine with all the pumps ect, and a adapter that served as a shroud.

Then you should use the "bare" version with the large mount which has all the machinery.

[Temeter]

6 minutes ago, regex said:

Then you should use the "bare" version with the large mount which has all the machinery.

Wait... So you're saying he's supposed to rely on choice? D:

[Tweeker]

3 minutes ago, regex said:

You can tweak the thrust down if you must have three engines, the controls are all there. I prefer using two since I'm not into building "replicas" in a game with a glaring realism problem.

Then you should use the "bare" version with the large mount which has all the machinery.

The problem is in how the base vector relates to all the other engines, it is OP vs the whole of the 1.25m line, and OP in it's intended application. A better solution would have been to introduce a 2.5m SRB with ~2500kn thrust,  and a vector in the 450 KN range. Then the vector is not so crazy OP vs the rest of the 1.25m engine, and  large launches are not so reliant on the more expensive liquid fuel rockets, or large clusters of  1.25m SRBs 

[Temeter]

1 minute ago, Tweeker said:

The problem is in how the base vector relates to all the other engines, it is OP vs the whole of the 1.25m line, and OP in it's intended application. A better solution would have been to introduce a 2.5m SRB with ~2500kn thrust,  and a vector in the 450 KN range. Then the vector is not so crazy OP vs the rest of the 1.25m engine, and  large launches are not so reliant on the more expensive liquid fuel rockets, or large clusters of  1.25m SRBs 

Comparing the vector to 1.25m engines is stupid. Not really a nicer way to say it. If it's more powerfull and heavier than a skipper, then it's probably not a challenger for the 909. Also, next update you can put compact Rhinos onto 1.25m stacks. Compare them to size 1 engines

As for the next update, the vectors thrust will most likely be nerfed, which is what was discussed here.

 

[regex]

4 minutes ago, Tweeker said:

The problem is in how the base vector relates to all the other engines, it is OP vs the whole of the 1.25m line, and OP in it's intended application. A better solution would have been to introduce a 2.5m SRB with ~2500kn thrust,  and a vector in the 450 KN range. Then the vector is not so crazy OP vs the rest of the 1.25m engine, and  large launches are not so reliant on the more expensive liquid fuel rockets, or large clusters of  1.25m SRBs 

Oh, I thought we were talking about the art, not the stats. Well, that's pretty subjective, just like the art, I have no issues with it and it's balanced in career mode through a high cost.

Plus, I'm not hung up on the concept of engines belonging to a particular form factor of parts, especially since we'll hopefully get a bunch of compact bases that'll put that silly notion to rest.

Edited September 15, 2016 by regex

[Hydrothermalventclam]

I think that the mesh switching aspect of this upgrade looks really nice, and I am super excited to see it in the game whenever it happens. There are a lot of times when I wish to use an engine with a tank of a different size, and this will make that look SO much better.

[Tweeker]

23 minutes ago, regex said:

Oh, I thought we were talking about the art, not the stats. Well, that's pretty subjective, just like the art, I have no issues with it and it's balanced in career mode through a high cost.

Plus, I'm not hung up on the concept of engines belonging to a particular form factor of parts, especially since we'll hopefully get a bunch of compact bases that'll put that silly notion to rest.

 So what you have to put down a base, then a nozzle? Why split engines into 2 parts?

 

[regex]

3 minutes ago, Tweeker said:

 So what you have to put down a base, then a nozzle? Why split engines into 2 parts?

The concept art includes the idea of three models for every engine, and the released models have two (omitting the compact version). One is "bare" with a base, one has a boat tail covering with a "magic nozzle" sticking out of it, and one is "bare" with a compact base. In the Vector's case the compact version has a covering over the machinery to better fit its role as an SSME. Each of those is a different mesh for the exact same part.

Edited September 15, 2016 by regex
stupid phone

[Tweeker]

Just now, regex said:

The concept art includes three models for every engine. One if "bare" with a base, one has a boat tail covering with a "magic nozzle" sticking out of it, and one is "bare" with a compact base. In the Vector's case the compact version has a covering over the machinery to better fit its role as an SSME. Each of those is a different mesh for the exact same part.

The boat tail version is the closest to what we have now, the machinery is there, but hidden under a shroud, that also likely hides the supports that attach the engine to the tank.  There is no magic nozzle in this case.

   The "compact" version often results in a magic nozzle, the vector is a prime example of this. Judging by the design sheet, the Rhino in compact form will become another magic nozzle.

  The vector in compact version does not cover machinery, it removes it.

Even the new compact concept omits about 1/2 of the machinery, Hence it is a magic nozzle