Snark

[1.7.x] Vector Repurposed: tweak Vector to be a rocket (not spaceplane) engine

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1 hour ago, Phelan said:

So, in terms of realism, the Vector is rather weak

And in terms of realism, none of KSP's engines make any sense because they're balanced for a planet a tenth the diameter of Earth with an atmosphere only 70 km tall.  So, molest me not with this "realism" stuff.  Not relevant, couldn't care less.  If you want to talk realism and SpaceX engines or whatever, go play RO / RSS and talk in their threads... then it's relevant.  :wink:

What I do care about is that the Vector's hopelessly out of whack with all the other stock KSP engines in terms of thrust per area-- I mean, seriously off the charts-- thus this mod.  If someone likes the Vector how it is, then don't use the mod, simple enough.

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I'm not sure why the Vector is supposedly such a great "spaceplane engine".   

In my opinion, spaceplanes don't need stonking thrust levels because they have wings to counteract gravity.  A rocket needs more thrust than weight or it will not even lift off the pad.   Wings provide lift to counteract gravity, at the expense of increased drag.   The L/D ratio remains above 2.5 even under the worst circumstances, which lowers the bar for flight.

More typically you see 6-10:1 during the subsonic initial climb.  The supersonic / speedrun phase is inefficient, at 2.5 to 1 or less, but who cares when you're airbreathing at 3800 ISP or better, and your engines are getting a ram air effect for 5x their static thrust?   And once you get above airbreathing altitude, the 2.5 to 1 L/D ratio is not as bad as it sounds because by then you're going so fast, orbital free fall effect is supporting half or more of the craft's weight.  Less lift needed, hence less drag.

TL;DR - most of my spaceplanes have static TWR of 0.4 to 0.6 to 1 , according to RCS build aid.

Most spaceplanes need one thing and one thing alone from their rocket engine - the highest possible vacuum ISP to offset the dry mass penalty of all those jet engines, wings etc.  Atmo ISP is irrelevant, you'll be on jet power down low.  TWR for the reasons just given (and because the rocket engine makes up a lower fraction of a spaceplane's dry mass than of a typical upper stage, so it's own TWR is less important).

Back to that unique case - the Space Shuttle.

The real SSME weren't that impressive from a thrust standpoint.  Good for a  liquid hydrogen motor, but not compared with some of the RP1 first stages out there.    What really sets it apart is the ISP - best there is bar none at sea level, beaten marginally by a couple of dedicated upper stage engines with extending nozzles.

For me, the absurd density of this engine is a disadvantage when trying to create a KSP shuttle replica.  All of that weight right at the rear of the craft renders it unflyable once the payload and ET are gone.   And realistically you just don't need THAT much power on the orbiters engines.    Wasn't it 80% of the launch thrust coming from the SRBs in real life?

For weight and balance reasons, my shuttle ended up with 3 Terriers instead of 3 Vectors

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@Snark Just wanted to offer my opinion on balance for this. I think you nerfed the gimbal too much. For a few reasons, in no particular order:

-It is an engine themed around having a large gimbal range (for spaceplanes), and should at least have a gimbal larger then the LV-T45

-The mk55 has a range of 8 degrees

-Most top tier engines offer something in addition to larger thrust, such as using xenon, being a booster that uses liquid fuel, nukes, etc. I feel like this engine should retain something that gives you more reason to want to unlock it in the tech tree

I suggest a gimbal range of 9 degrees, reducing the range from the original 10.5 a little bit. That way it is still relevant for shuttles, without being OP in thrust. Infact the reason I have not been using the vector for my shuttles (and have been using the mk55 instead) is because it has way more thrust then I need (mk2 cross section shuttles).

Anyway, just my two cents. I agree with everything else you did to balance it. It might be a touch on the cheap side now too, but that's more of a personal taste thing. The gimbal is what actually makes this an interesting engine. If you don't need it for rockets, there's always gimbal range limiters. 

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20 hours ago, Errol said:

Just wanted to offer my opinion on balance for this. I think you nerfed the gimbal too much.

*shrug*  Then feel free to edit the .cfg to make it what you like when you play.  :)

As far as I'm concerned, I nerfed it exactly the right amount.  I nerfed it that way because I don't like rocket engines with huge gimbals; I consider that to be overpowered, I just don't like it.  That's what I did here.  I'm not trying to make any assertion that this is "right" or that anyone else should play that way, I just prefer it thus.

20 hours ago, Errol said:

It is an engine themed around having a large gimbal range (for spaceplanes)

Right.  Which I hate.  As I mention in the OP for this thread, I'm a rocket guy, I'm not a spaceplane guy.  I want a rocket engine, thus this mod.

20 hours ago, Errol said:

The mk55 has a range of 8 degrees

Yup.  Which I also consider to be overpowered, and don't like.  Didn't bother to mod it, because I have no use for the Mk-55 and never use it anyway, so it's no skin off my nose.

20 hours ago, Errol said:

Most top tier engines offer something in addition to larger thrust, such as using xenon, being a booster that uses liquid fuel, nukes, etc. I feel like this engine should retain something that gives you more reason to want to unlock it in the tech tree

Yup, which is why I feel that this fits like a glove.  Top tier engines give you an extra feature.  The feature here is "higher thrust".  It's a mini-Mammoth.  In any case, discussion here is irrelevant because this is how I like it, so that's what the mod does.  :)  Folks who don't like it can certainly use some other mod, or no mod at all and use the stock Vector.  Or just open a text editor and change the numbers to whatever they like.

20 hours ago, Errol said:

The gimbal is what actually makes this an interesting engine.

For others, perhaps, not for me.

20 hours ago, Errol said:

If you don't need it for rockets, there's always gimbal range limiters. 

Which doesn't (for me) deal with the fact that the gimbal is overpowered.  After all, when I say "this engine is way too overpowered with 1000 kN thrust", someone could say "well if you don't like it, you don't need a mod, just use the thrust limiter."  That's not the point.  The point is that I don't want it to have the capability.

Again:  Not making any assertions whatsoever about "rightness"; that's entirely subjective, it's not possible to make assertions about it, really.  Just, "I've tweaked this engine to make it the way I, personally, happen to like it.  Here's the config in case anyone else cares to do the same thing."

Thanks for the detailed and thoughtful feedback, though.  You make perfectly reasonable points, and it's not your fault that I'm mulishly stubborn.  :)

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Snark, I made an alternate config built off of yours to clone the SSME instead of replace it, putting the Viktor as the KS-15 in Heavier Rocketry and leaving the Vector with some flavor text about it being an expensive improvement on the Viktor in Very Heavy Rocketry. Would you like that at all?

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1 hour ago, theonegalen said:

Snark, I made an alternate config built off of yours to clone the SSME instead of replace it, putting the Viktor as the KS-15 in Heavier Rocketry and leaving the Vector with some flavor text about it being an expensive improvement on the Viktor in Very Heavy Rocketry. Would you like that at all?

Check the previous page. He talked about this before, and he even provided such a +SSME config for someone that wanted it even though he didn't feel like adding it to his own mod.

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Minor necro here:

@Snark, would you like me to update CKAN for this?  Right now it stops at 1.4.4

Also, a question about it's position in the tech tree.  Since this is changing and reducing the stats, would it make sense to move it up one level in the tech tree?

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13 hours ago, linuxgurugamer said:

would you like me to update CKAN for this?  Right now it stops at 1.4.4

Thanks for noticing!  My guess would be that it's because all my mods' CKAN integration is currently handled through SpaceDock (at least, until I get around to adding AVC files).  SpaceDock has a function for marking "what version of KSP does your mod work with".  I've always assumed that updating that value causes SpaceDock to go and tweak something in CKAN accordingly.  I've never really paid close attention to it because I never use CKAN or any sort of automated mod-management tools myself, so it's only one of those vague things in the background of my peripheral awareness.

Anyway, whenever a new KSP version releases, SpaceDock is often a bit slow to add the new KSP version to the drop-down list of selectable KSP versions.  For example, it hasn't yet added 1.4.5, so it's not physically possible right now for me to mark the mods as 1.4.5.  Once SpaceDock adds that, I'll go through and update and my guess is that CKAN will then update automatically?  Maybe?  Not clear on how all the gears work.  :)

Anyway, I certainly have no objection to it if you'd like to go ahead and update it now-- as far as I can tell, all of my mods work just fine in 1.4.5.  Thank you for the offer.

13 hours ago, linuxgurugamer said:

Also, a question about it's position in the tech tree.  Since this is changing and reducing the stats, would it make sense to move it up one level in the tech tree?

Well, if anything, I would have thought that reducing the stats would have suggested moving it down in the tech tree, rather than up.

In any case, though-- actually, I'm pretty happy with where it is.  Even with the reduced stats from this mod, I still consider it to be an "advanced engine" and prefer to leave it until late game.  For me, the prior, unmodded stats of the Vector were just "broken" for any tech level, and I think it fits in nicely at the current position with the modded stats.

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2 minutes ago, Snark said:

Well, if anything, I would have thought that reducing the stats would have suggested moving it down in the tech tree, rather than up.

In any case, though-- actually, I'm pretty happy with where it is.  Even with the reduced stats from this mod, I still consider it to be an "advanced engine" and prefer to leave it until late game.  For me, the prior, unmodded stats of the Vector were just "broken" for any tech level, and I think it fits in nicely at the current position with the modded stats.

When I said up, I meant up the tree to the top :D

I really think it belongs between heavierRocketry and advancedrocketry, given the adjusted stats.  I may make a patch for that (yet another node in the tech tree :D   )

 

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So, hoping you don't mind discussing this

Your Viktor, compared to the Bobcat, is superior in every statistic:

 

  Mass) Thrust (ASL) Thrust (Vac) ISP (ASL) ISP (Vac)
Bobcat 2.0 374.194 400.0 290 310
Viktor 1.8 421.429 450.0 295 315

I'm trying to come up with a use case for the Bobcat, but can't, given the current stats.  Was wondering what your thoughts on this would be

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3 hours ago, linuxgurugamer said:

When I said up, I meant up the tree to the top :D

Yes, but it's already up at the top of the tree, thus my confusion.  There's literally nowhere higher for it to go.

Anyway, I think of it as a high-tech engine, not a low-tech one.  It's a lot better than other small engines, thus its position way up at the top of the tree.

57 minutes ago, linuxgurugamer said:

Your Viktor, compared to the Bobcat, is superior in every statistic:

 

  Mass) Thrust (ASL) Thrust (Vac) ISP (ASL) ISP (Vac)
Bobcat 2.0 374.194 400.0 290 310
Viktor 1.8 421.429 450.0 295 315 

I'm trying to come up with a use case for the Bobcat, but can't, given the current stats.  Was wondering what your thoughts on this would be

Well, not in every statistic.  The Bobcat is way cheaper (less than half the cost), and also significantly lower on the tech tree (it's down in the 160 tier, whereas the the Viktor's up in the 550 tier).  Notably, it's under 300, meaning that it's available after just one R&D upgrade.  I use the Bobcat a lot, simply because it's the highest-thrust 1.875m engine available.

That said, I've never been thrilled with the Bobcat's balance.  It feels kind of anemic to me, especially given that it's way up in the same tier as the Mainsail.  It's just barely over double the Swivel's thrust, despite being 2.25x the cross-sectional area.  I've always thought that the Bobcat ought to have about 10-15% more thrust than it does.  (And that the Wolfhound should be nerfed to about 80% its current thrust, and its Isp lowered to something that's slightly better than the Poodle but waaaaaay up at 412.  But I digress, and let's not open that can of worms here.)

Anyway, I'm fine with the Viktor as it is, given that it's considerably higher in the tech tree and is also way more expensive.  My main litmus test for "is the balance out of whack" is, "does it cause me not to use other things".  For example, I routinely find myself using the Bobcat engine, even with VectorRepurposed installed, so that tells me that (at least for my purposes) there's not too much of a "balance gap".

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Amazing mod! I for one would love it to make a copy of the Vector (can easily be done using a simple MM patch), because I use the stock Vector all the time.
 

I am not a spaceplane person (only rockets for me!), but love the super high thrust. I only ever play in Sandbox, so price is irrelevant. I wrote a MM patch that allows anything to be surface attached, so I find the surface attachment node to be actually quite useful. And lastly, the high thrust allows people to make very heavy payloads without needing to have a large cross-section.

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2 hours ago, IMLL1 said:

Amazing mod! I for one would love it to make a copy of the Vector (can easily be done using a simple MM patch), because I use the stock Vector all the time.

That would be me too...  I love the idea of Viktor for 1.2 and 1.8 stacks, but I use clustered Vectors on 2.5 and larger all the time.

Edited by DerekL1963

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16 hours ago, IMLL1 said:

I for one would love it to make a copy of the Vector (can easily be done using a simple MM patch), because I use the stock Vector all the time.

14 hours ago, DerekL1963 said:

That would be me too...  I love the idea of Viktor for 1.2 and 1.8 stacks, but I use clustered Vectors on 2.5 and larger all the time.

Yep, different people like different things.  The reason I have this change the Vector, rather than copying it, is that I specifically want to get rid of the Vector because its stats offend me and I don't want it in my game-- I consider it overpowered.  Not making any judgment about what other people like to do-- if other people like the Vector and don't consider it overpowered, great!  Good for them.  :)

But I don't need it, and making this mod copy the Vector instead of replacing it would mean that this mod wouldn't be doing what I want.  So it won't do that, 'coz it's my mod.  ;)

If someone wants a copy rather than a replacement, it's easy enough to just go in and edit a line or two of the MM config to make it do that.  But I won't be doing that in the version of this mod that I release, myself.

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On 8/5/2018 at 12:12 PM, Snark said:

That said, I've never been thrilled with the Bobcat's balance.  It feels kind of anemic to me, especially given that it's way up in the same tier as the Mainsail.  It's just barely over double the Swivel's thrust, despite being 2.25x the cross-sectional area.  I've always thought that the Bobcat ought to have about 10-15% more thrust than it does.  (And that the Wolfhound should be nerfed to about 80% its current thrust, and its Isp lowered to something that's slightly better than the Poodle but waaaaaay up at 412.  But I digress, and let's not open that can of worms here.)

You may want to take a look at Engine Tweaks. It tackles both of these problems in (I hope) a balanced way:

 

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2 hours ago, Snark said:

Yep, different people like different things.  The reason I have this change the Vector, rather than copying it, is that I specifically want to get rid of the Vector because its stats offend me and I don't want it in my game-- I consider it overpowered.  Not making any judgment about what other people like to do-- if other people like the Vector and don't consider it overpowered, great!  Good for them.  :)

But I don't need it, and making this mod copy the Vector instead of replacing it would mean that this mod wouldn't be doing what I want.  So it won't do that, 'coz it's my mod.  ;)

If someone wants a copy rather than a replacement, it's easy enough to just go in and edit a line or two of the MM config to make it do that.  But I won't be doing that in the version of this mod that I release, myself.

OK. That's fair ;)

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