On the vector and reliant engines, their issues and suggested solutions

[Strawberry]

1 minute ago, Bej Kerman said:

Yes, and the difference is more than made up by the additional ISP. Your dV will go up even with the added power production.

Probably not a problem for colonies that are millions of kilometers, if not light years, from the nearest bank or political border that has an associated currency.

Im talking about colonies here, money doesnt matter, but energy production and resources very much do as those things have high opportunity costs.. If you wish to do large amounts of trade in an efficient matter, you need to do it cheaply, and chemical engines fill that role (at least for getting into orbit). Chemical engines in majority of cases will work for getting things to orbit, and the materials to make them are decently common, so you'll likely end up using them a bunch for colonies.

[Bej Kerman]

5 minutes ago, Strawberry said:

If you wish to do large amounts of trade in an efficient matter, you need to do it cheaply, and chemical engines fill that role (at least for getting into orbit)

They literally don't. You're getting to orbit using fireworks. You want to use something more efficient if you want to be sustainable.

[jimmymcgoochie]

I don't remember the last time I used a Reliant on a rocket and the only time I've used one at all that I can remember is on an SSTO spaceplane, where I eventually replaced them with Swivels or aerospikes as I modified the original design. For dumb boosters, solid rockets are cheaper and fewer parts which both count against the Reliant in career mode, while the lack of gimballing makes it less suitable for core stages. If it was a bit more powerful or unlocked earlier in the tech tree (or the Swivel a bit later) then it might get a bit more use, but the small advantages in thrust, sea level ISP and weight over the Swivel don't outweigh the inferior vacuum ISP and the lack of gimbal in most cases- at least in my experience.

Were the Reliant able to produce 300kN and the Swivel only 150 in KSP2, it would be a different story...

[Strawberry]

1 hour ago, Bej Kerman said:

They literally don't. You're getting to orbit using fireworks. You want to use something more efficient if you want to be sustainable.

What fireworks are you using that are methane powered?

[Bej Kerman]

54 minutes ago, Strawberry said:

2 hours ago, Bej Kerman said:

They literally don't. You're getting to orbit using fireworks. You want to use something more efficient if you want to be sustainable.

What fireworks are you using that are methane powered?

It's an analogy.

[magnemoe]

On 2/5/2023 at 11:06 PM, jimmymcgoochie said:

I don't remember the last time I used a Reliant on a rocket and the only time I've used one at all that I can remember is on an SSTO spaceplane, where I eventually replaced them with Swivels or aerospikes as I modified the original design. For dumb boosters, solid rockets are cheaper and fewer parts which both count against the Reliant in career mode, while the lack of gimballing makes it less suitable for core stages. If it was a bit more powerful or unlocked earlier in the tech tree (or the Swivel a bit later) then it might get a bit more use, but the small advantages in thrust, sea level ISP and weight over the Swivel don't outweigh the inferior vacuum ISP and the lack of gimbal in most cases- at least in my experience.

Were the Reliant able to produce 300kN and the Swivel only 150 in KSP2, it would be a different story...

Agree, I have used Reliant a only a few times, one typical use is on early Mun landing missions where I tend to use liquid fuel side boosters since I have weight constrains and not unlocked larger SRB. 
Think I used them as landing engines on an Laythe base, it did not need gimbal as it had parachutes and the engines only needed to reduce landing speed. 
And most fitting as outer engines on a starship replica for the dart mission, I went a bit bigger than expected with that one  
One thing in KSP is that we mostly use stack size for engine size so 2.5 meter engines for 2.5 meter rockets, and we has tree 2.5 first stage engines in stock who fit most uses. 
 

[tstein]

On 2/5/2023 at 5:42 PM, Bej Kerman said:

Probably not a problem for colonies that are millions of kilometers, if not light years, from the nearest bank or political border that has an associated currency.

 

Cost is not an abstraction created out of thin air. Cost is always a product of demmand and offer. Sine the demand for rockets  is always.. low.. the problem is  they have low offer. Exquisite  tech by logic will be even HARDER to keep hold on  at a colony than in kerbin. As an analog...  a ferrari suddenly is  cheap when you are stranded in the south pole? no.. it does not. In fact it is even harder to find a ferrari there than in Italy.

[Bej Kerman]

Just now, tstein said:

In fact it is even harder to find a ferrari there than in Italy.

Even if said south pole colony has a wing dedicated to manufacturing cars of the sort?

[t_v]

1 hour ago, Bej Kerman said:

Even if said south pole colony has a wing dedicated to manufacturing cars of the sort?

I think that’s their point, you won’t have access to the materials required to build or fuel these engines, and so you will need to use methalox. If you are wondering why you wouldn’t have the resources, it is because not every resource will be abundant everywhere. 

[tstein]

1 hour ago, Bej Kerman said:

Even if said south pole colony has a wing dedicated to manufacturing cars of the sort?

Yes.. very likely as those facilities will have far less access to supplies and will be much smaller than in Maranello.  Think on real world colonies.. it took a VERY long time until high end products were cheaper in USA than in UK.

[Tapeta]

I am using Reliant engines as boosters for my Mun missions in my current Carrier play through (1 Bobcat engine and 4 Reliants in asparagus staging can lift my Mun lander). The main plus for reliant is that it is cheap, it cost only 1100 kerb bucks. Bobcat cost just 2000.  And Vector that thing cost freaking 18000! That thing must be recovered and reused, otherwise I will bankrupt myself. 

[tstein]

8 minutes ago, Tapeta said:

I am using Reliant engines as boosters for my Mun missions in my current Carrier play through (1 Bobcat engine and 4 Reliants in asparagus staging can lift my Mun lander). The main plus for reliant is that it is cheap, it cost only 1100 kerb bucks. Bobcat cost just 2000.  And Vector that thing cost freaking 18000! That thing must be recovered and reused, otherwise I will bankrupt myself. 

The soviet styled 4 nozzled one (forgot the name) is simply superior to the reliant in every way

[Tapeta]

5 minutes ago, tstein said:

The soviet styled 4 nozzled one (forgot the name) is simply superior to the reliant in every way

You mean RK-7 Kodiak.

Yes but I got to the Mun before I unlocked Kodiak.
The newest iteration of this rocket which I use for Minmus mission is: 2 Kodiaks (1st stage), 2 Reliants (2nd stage) and Bobcat (last stage(core)) {Kodiak have lower vacuum Isp 300 compared to Reliant 310}

[Bej Kerman]

1 hour ago, t_v said:

I think that’s their point, you won’t have access to the materials required to build or fuel these engines, and so you will need to use methalox. If you are wondering why you wouldn’t have the resources, it is because not every resource will be abundant everywhere. 

Sometimes resources aren't abundant... That doesn't give your space program an excuse to start using fireworks and srone wheels again.

[t_v]

1 hour ago, Bej Kerman said:

Sometimes resources aren't abundant... That doesn't give your space program an excuse to start using fireworks and srone wheels again.

It does if wood, rubber and metal simply aren’t there. There will absolutely be situations were colonies cannot manufacture metallic hydrogen and don’t have any uranium for nuclear engines. 

[Bej Kerman]

4 minutes ago, t_v said:

It does if wood, rubber and metal simply aren’t there. There will absolutely be situations were colonies cannot manufacture metallic hydrogen and don’t have any uranium for nuclear engines. 

Being absolutely incapable of retrieving either of those resources sounds exceedingly unlikely to me.

[t_v]

7 minutes ago, Bej Kerman said:

Being absolutely incapable of retrieving either of those resources sounds exceedingly unlikely to me.

Oh sure you can retrieve them, there’ll probably be good deposits to build up production on a nearby celestial body. Now you just need rockets to ferry the cargo, and enough fuel to supply the new supply route…

[Bej Kerman]

Just now, t_v said:

Oh sure you can retrieve them, there’ll probably be good deposits to build up production on a nearby celestial body. Now you just need rockets to ferry the cargo, and enough fuel to supply the new supply route…

And there will probably be yet another fuel type you can use for those rockets. If you've got rockets efficient enough to start colonies, just resorting to something like NERV isn't that big of an ask and is 100% preferable to methalox.

In real life though, the solution would be to... just not build colonies that are in the middle of nowhere and miles away from the nearest resource hotspot?

[t_v]

For the question of “why not use the advanced engines we brought?”  it is for the same reason that we don’t use space-grade (higher efficiency, even accounting for atmosphere) solar arrays for solar power plants on the ground. Less efficient or powerful technology can be easier to produce at scale, and when that colony needs capacity to lift 1000 tons to orbit, there might simply not be enough metallic hydrogen production or nuclear engines to fuel the first stage tanks. 

[SolarAdmiral]

2 minutes ago, t_v said:

For the question of “why not use the advanced engines we brought?”  it is for the same reason that we don’t use space-grade (higher efficiency, even accounting for atmosphere) solar arrays for solar power plants on the ground. Less efficient or powerful technology can be easier to produce at scale, and when that colony needs capacity to lift 1000 tons to orbit, there might simply not be enough metallic hydrogen production or nuclear engines to fuel the first stage tanks. 

I imagine the liquid rockets will remain relevant even in the late game in some places just due to it being good enough and easy to make. For anything smaller than Moho, it doesn't take that much liquid fuel to get to orbit and back. If you're just lifting payloads to orbit or a nearby station or landing stuff brought in by a ship, why waste all your better advanced fuel. When it could be saved for interplanetary/interstellar, or landing on more dv demanding worlds like Tylo and Eve.

Asking why use liquid when the fancier fuels are around is like asking why use a spark when you have the wolfhound. Sometimes the new stuff will make sense, sometimes the old stuff will make sense.

[Bej Kerman]

40 minutes ago, SolarAdmiral said:

I imagine the liquid rockets will remain relevant even in the late game in some places just due to it being good enough and easy to make

They are the bare minimum you need to get to orbit. Their obsolescence will happen very quickly.

41 minutes ago, SolarAdmiral said:

Asking why use liquid when the fancier fuels are around is like asking why use a spark when you have the wolfhound. Sometimes the new stuff will make sense, sometimes the old stuff will make sense.

Spark and wolfhound aren't far apart in terms of efficiency, compared to other engine types.

[SolarAdmiral]

1 hour ago, Bej Kerman said:

They are the bare minimum you need to get to orbit. Their obsolescence will happen very quickly.

Spark and wolfhound aren't far apart in terms of efficiency, compared to other engine types.

I mean, yes they'll become obsolete if you just insist on always using the best available no matter the cost. But if you have a cheap liquid fueled lander already laying around that works and you've got a bunch of tanks full of liquid fuel ready, why not use it? A Moho lander already needs less fuel than payload for a round trip. It's an even smaller fraction on the Mun or Bop and Pol. I'm going to guess there's more involved with making and storing large quantities of metallic hydrogen than regular old liquid fuel, so it will have a larger material cost for fueling up. You could insist on always using the newest and best if you like. Or you could upgrade where needed and keep using cheaper older established engines where they still work just fine. If it's balanced right, all routes will be possible, but optimizing for resource use will encourage a lot of different paths.

The simple fact is they are going to be obsolete, just by definition. We're going into future engine techs, all the old engines will be older, less capable. But just because the jet engine was invented doesn't mean we don't still build turboprop planes.

One of the things I'm looking forward to is watching all the engines fall into their niches and watching those niches change as new stuff becomes available. I'm picturing a once state of the art interstellar vessel being replaced with new engines, and being used instead to run slow cargo between planets in system or from orbit to a moon.

The spark and the wolfhound are similar. But obviously there are times where one or the other is more appropriate despite the wolfhound being far better on paper for vacuum burns.

[Bej Kerman]

5 minutes ago, SolarAdmiral said:

I mean, yes they'll become obsolete if you just insist on always using the best available no matter the cost. But if you have a cheap liquid fueled lander already laying around that works and you've got a bunch of tanks full of liquid fuel ready, why not use it?

Because if you've got bottle rockets laying around, why not use them instead of fireworks?

5 minutes ago, SolarAdmiral said:

The simple fact is they are going to be obsolete, just by definition. We're going into future engine techs, all the old engines will be older, less capable. But just because the jet engine was invented doesn't mean we don't still build turboprop planes.

We still build turboprop engines, that doesn't mean they aren't obsolete.

[SolarAdmiral]

15 minutes ago, Bej Kerman said:

Because if you've got bottle rockets laying around, why not use them instead of fireworks?

We still build turboprop engines, that doesn't mean they aren't obsolete.

If the bottle rocket does the job and is cheaper, easier, yeh, why not? So, did you just not get the point? Turboprops are "obsolete" but they still have their use. Otherwise all planes would be jets. Internal combustion is "obsolete" but not everyone drives electric yet. Steam power is "obsolete", but I work building brand new power plants and they all still use steam, including nuclear plants. x86 and x64 processors have been obsolete for 10 years, and yet they'll be the only way to play KSP2 day one, until there's support for Mac silicon. There's nothing stopping us from using liquid engines plenty even once new stuff comes along, especially if there's still niches where they work just as well while saving us resources. Just because something is obsolete, doesn't mean it isn't useful. Doesn't even mean it isn't the best solution for certain cases.

So like, what are you even arguing anymore? Do you just not want engines to be any better than what is in KSP1 now, or are you just determined to never use liquid engines once new ones become available? 

 

 

[Bej Kerman]

5 hours ago, SolarAdmiral said:

If the bottle rocket does the job and is cheaper, easier, yeh, why not? So, did you just not get the point? Turboprops are "obsolete" but they still have their use. Otherwise all planes would be jets. Internal combustion is "obsolete" but not everyone drives electric yet. Steam power is "obsolete", but I work building brand new power plants and they all still use steam, including nuclear plants. x86 and x64 processors have been obsolete for 10 years, and yet they'll be the only way to play KSP2 day one, until there's support for Mac silicon. There's nothing stopping us from using liquid engines plenty even once new stuff comes along, especially if there's still niches where they work just as well while saving us resources. Just because something is obsolete, doesn't mean it isn't useful. Doesn't even mean it isn't the best solution for certain cases.

So like, what are you even arguing anymore? Do you just not want engines to be any better than what is in KSP1 now, or are you just determined to never use liquid engines once new ones become available? 

Get anything useful to low Kerbin orbit using a bottle of water then we can talk about using methalox rockets and their horrible atrocious ISP during the part of the game you've got torch drives. Unless you want to argue that the Puff engine has been of any use to you just because you want to justify using engines that are obviously outranked by everything else, even if they are a tad lighter.

Edited February 8, 2023 by Bej Kerman