Monoprop RCS, why bother since vernors are out?

[panzer1b]

As the title says, while ive always used teh little 1 port or 4 port RCS thingies, whats the point of them where now we get vernors, that are 12 times as powerful, and use regular fuel, allowing a single fuel tank to service all engines and docking. Aside from the fact that crew pods have some monoprop (which i myself drain as nothing uses it on most of my craft), is there any good reason not to use a vernor thruster? It doesnt even weigh much more (.08 vs .05, not that being massless matters at all), provides much more utility, and can be used as a backup engine when you have had your main engines shot apart by enemy ships.

Now for very very small craft i guess they make some sense, but above 10t i fail to see why anyone would use the smaller rcs. Had they been more fuel efficient perhaps, but both have the exact same isp (vernors are better near the ground, not that youd use rcs on ground).

So, since i clearly dont get it, what are the advantages of the old monoprop RCS thrusters above the new vernors, which at least for me have more or less replaced the old rcs, as now i only need 6 at most for 90% of my craft, just 1 per direction, with reaction wheels for rotation (im not going to use fuel to rotate a ship if reaction wheels exist), whereas some larger craft such as capital ships before needed many smaller rcs engines, the 100-300t ships needing 100s of em just to rotate the thing.

Edited March 8, 2015 by panzer1b

[Flixxbeatz]

well if you're someone who prefers running refuel missions, monoprop rcs is preferred (at least for me) so that the fuel payload is still full by the time you arrive on the ship to be refueled.

monoprop RCS are still useful for 2m crafts and small 3m stuff, but for massive ones, vernors are to go.

[Foxster]

Agreed. I just don't drag RCS tanks around anymore. They always ended up at best half empty and so were wasted mass to haul into space.

I only ever use RCS for docking and on little ships the vernors are a bit rough but nothing that can't be managed with a little care.

You have to think a little more about placement as they are uni-directional, but that's like 20 secs of planning.

[Captain Vlad]

The only think I've used a vernor thruster for so far is getting the nose of some spaceplanes off the ground quicker. I find monoprop RCS to be more useful for fine adjustments than the vernors, and since fine adjustments are what I need the things for anyway....

[breakthrough]

Cost in funds, part count, and having a separate dedicated fuel supply so I don't inadvertently blow 2km/s of LVN delta-v doing 10m/s of maneuvers with 260Isp thrusters.

[panzer1b]

Cost in funds, part count, and having a separate dedicated fuel supply so I don't inadvertently blow 2km/s of LVN delta-v doing 10m/s of maneuvers with 260Isp thrusters.

I guess that is true, but given i dont play career (i learned the game in sandbox, and while careers great and all, i tend to build for fun/aesthetics/combat, none of that is reaklly doable in career as you build for efficiency or mission acomplishment there, something i never cared for as almost all 100% efficient design look like crap, or at least i dont dig the efficiency look). I like the freedom to do my own missions and do whatever im in the mood for, making career not really that fun for me.

The extra fuel inadventently being burned isnt that big a deal, as 90% of teh time if im docking its to refuel, so if i do waste a hair more fuel, so be it. If you dont have any monoprop, that means that mass = more lfo, which means even more total dV, or docking, whereas monoprop is worthless for moving yourself unless its like 10-20m/s or something of the sort.

The only think I've used a vernor thruster for so far is getting the nose of some spaceplanes off the ground quicker. I find monoprop RCS to be more useful for fine adjustments than the vernors, and since fine adjustments are what I need the things for anyway....

Im used to more of a kick from rcs (after being used to EVA kerbals). I also tend to build very few craft that are light enough that the monoprop engines end up underpowered for most of my deisgns anyways.

i guess monoprop stil has its uses, but i guess for anythign but very lightweights, vernors are both less parts total (heavies need multiple monos per direction at a minimum), and dont require me to use rcs fuel, making my ships have one unified fuel system for everything from main engines, to maneuvering, to firing the mass driver cannons.

Edited March 8, 2015 by panzer1b

[Rusty6899]

You missed "Monopropellant is extortionatley expensive compared to monopropellant liquid fuel." (although Vernors are significantly more expensive than monopropellant powered RCS ports).

I would have thought that the "4 port RCS thingies" are better for docking as they give omnidirectional thrust. Also, having 2 different types of fuel may be beneficial in a situation where you are landing on a body while leaving a mother ship in orbit, as you will not have to worry about leaving enough RCS fuel to rendezvous and dock with the mothership on your ascent. The low thrust isn't always a bad thing either, as you generally will want a very precise control of your velocity when docking or when making minor adjustments to an orbit. The multi-port RCS are also better for making adjustments to orbits as you will always be able to thrust in the prograde/retrograde directions if you place your ports sensibly, whereas the vernors would be difficult to line up in that way, as their thrust vector would not necessarily be moving through the centre of mass of the ship.

If you like the Vernors, you're probably best off using them, but the old ports do have some advantages. There are rarely set rules dictating that "Part X is better than Part Y". It's more common to find that some parts are better than others in a specific situation.

[panzer1b]

You missed "Monopropellant is extortionatley expensive compared to monopropellant liquid fuel." (although Vernors are significantly more expensive than monopropellant powered RCS ports).

I would have thought that the "4 port RCS thingies" are better for docking as they give omnidirectional thrust. Also, having 2 different types of fuel may be beneficial in a situation where you are landing on a body while leaving a mother ship in orbit, as you will not have to worry about leaving enough RCS fuel to rendezvous and dock with the mothership on your ascent. The low thrust isn't always a bad thing either, as you generally will want a very precise control of your velocity when docking or when making minor adjustments to an orbit. The multi-port RCS are also better for making adjustments to orbits as you will always be able to thrust in the prograde/retrograde directions if you place your ports sensibly, whereas the vernors would be difficult to line up in that way, as their thrust vector would not necessarily be moving through the centre of mass of the ship.

If you like the Vernors, you're probably best off using them, but the old ports do have some advantages. There are rarely set rules dictating that "Part X is better than Part Y". It's more common to find that some parts are better than others in a specific situation.

True, i guess that the 4 directionals have the advantage of a single thruster being able to function as complete 2 axis controls. Then youd technically only need 1 more to get the last axis, making 2 parts to control an extremely lightweight craft. Still, vernors are 5 parts to control any ship up to the 200t levels. 1 backwards, and 4 to each side (forwards can be achieved via main engines). Also, the 4 directionals dont give thrust in any direction, just in 4 directions. From a part count perspective this can be good or bad, depending on what else you need to bring along (monoprop needs dedicated fuel tanks, whcih can be extra part count if you need enough of em).

The center of mass in my designs isnt usually an issue, as many of my craft have offcenter thrust to begin with, forcing em to use at least 2-3 reaction wheels to keep it going where i want to. So at least for my construction style, making 100% sure i have a thruster in like with cog isnt really important as odds are, the entire craft is already going to have some offcenter issues in teh 1st place.

[Jouni]

Two words: fuel flow.

I don't think I've ever used the Vernor Engines for anything. Monopropellant RCS is much easier to use, especially in big ships with complex fuel flows.

[Wanderfound]

Vernors = stability during flight, budget low-grav VTOL.

RCS = docking.

Vernor thrusters are much too powerful for docking use.

[Gerandar]

Monoprop RCS all the way, i dont want to waste my LFO on such things.

[panzer1b]

Monoprop RCS all the way, i dont want to waste my LFO on such things.

yeah, but mass is mass, and vernon ISP is equal to mono ISP. Point is, if you want to dock, be it LFO or monoprop, you will have to drag mass up there, i find it easier to just stick to lfo, and bring an extra tank for docking atop the usual amount id need (bring equal mass of LFO as i wouldve had of monoprop, lets me do teh exact same docking).

Perhaps they should give them thrusters actual mass, until they remain massless there is not a single reason to not use them unless your craft is so light that 12N of thrust (3 times that of a ant motor) is overkill and will make it undockable.

[FlyingPete]

See I've taken the opposite approach with a few types of craft, such as 1-man SSTOs. Since the jet engine can get you mostly into orbit on its own, I just added a couple of monoprop engines to the back for the circularisation burn. Then there's a single fuel for both rendezvous and docking.

[GoSlash27]

All the craft I build are too small to justify Vernors. I can easily see how they would be preferred for larger craft, though.

Best,

-Slashy

[sdj64]

yeah, but mass is mass, and vernon ISP is equal to mono ISP. Point is, if you want to dock, be it LFO or monoprop, you will have to drag mass up there, i find it easier to just stick to lfo, and bring an extra tank for docking atop the usual amount id need (bring equal mass of LFO as i wouldve had of monoprop, lets me do teh exact same docking).

Perhaps they should give them thrusters actual mass, until they remain massless there is not a single reason to not use them unless your craft is so light that 12N of thrust (3 times that of a ant motor) is overkill and will make it undockable.

Almost every craft that gets docked should be so light that vernors are overkill. Except for station fuel pods and some station modules and interplanetary ship modules, but these are usually docked once and left there. If your reusable lander for anywhere but Tylo is over 15 tons, you're doing something wrong. Plus for a reasonably sized lander the amount of monoprop in the pod is enough to dock it, you don't have to put extra tanks on. Also, many landers don't have good surfaces to mount forwards/backwards vernors on, while the 4 way RCS ports work perfectly for the job.

Of course that will change once resources are introduced, you'll actually have a use for very large ships that are docked and undocked repeatedly over their lifespan (mining landers).

[Greenfire32]

RCS allows for finer movements. RCS doesn't gobble up your fuel supply. RCS is more than strong enough for most crafts.

Verneers are for the huge crafts that need it. Not the small crafts that want it.

[monstah]

Besides, RCS is fine control enough to setup a KSO or a synchronized constellation which will stay in synch for months of timewarp, just by eyeballing orbital period on KER readouts.

[panzer1b]

Almost every craft that gets docked should be so light that vernors are overkill. Except for station fuel pods and some station modules and interplanetary ship modules, but these are usually docked once and left there. If your reusable lander for anywhere but Tylo is over 15 tons, you're doing something wrong. Plus for a reasonably sized lander the amount of monoprop in the pod is enough to dock it, you don't have to put extra tanks on. Also, many landers don't have good surfaces to mount forwards/backwards vernors on, while the 4 way RCS ports work perfectly for the job.

Of course that will change once resources are introduced, you'll actually have a use for very large ships that are docked and undocked repeatedly over their lifespan (mining landers).

I think the whole "every ship that needs to dock should be lightweight" isnt seeing the big picture. I rarely if ever touch a craft below 20t (even my lightweight fighters are 10t at a minimum to give em the dV i want), so i guess for that weight i just cant justify the monoprop rcs. I have plenty of need to dock massive ships together (refuel a capital ship fro another, ammo transfers, ect), so i guess im not in your boat about teh whole super light stuff. Youd also be rather surprised if you saw what i use to land on planets/whatever (massive 20-30t VTOL dropships, sci-fi style, never bothered making 100% realistic stuff, also, if your mothership is 500t with over half of that fuel, who cares about efficiency at that point).

I guess its maybee its my playstyle that makes me see no benefit to them, and usually for super light craft (say ion drone interceptors) i dont have any rcs and dock using main engine as they are so light that i can spin around almost instantly, and gettinhg remotely near docking port = instant attach as its so light.

Although from this thread, i have concluded they have their uses, but my original opinion that vernors are better in 90% of situations still stands (at least hen i look at how i play KSP and what i use RCS for in the 1st place).

Also, has anyone noticed that they make great landing engines for lightweight armored cars (i was bored and made a working mako replica that could deorbit itself on just those alone in duna or atmospheric situations, and on low gravity as well as it has like 500dV with the vernors).

Edited March 8, 2015 by panzer1b

[Red Iron Crown]

Almost every pod has some monoprop capacity, usually enough for docking if you're halfways careful with it. Why not put that "free" tankage to use for powering the smaller RCS thrusters?

I use the Vernors far less, generally for really big vessels like propellant depots or interplanetary motherships.

[cantab]

More Vernors are required. For translation three 4-way RCS thrusters suffice (though four is preferable), vs six Vernors. For rotation and translation six 4-way RCS thrusters suffices (8 preferable), whereas I think you need twelve Vernors.

Vernors deliver more thrust. When it comes to making the kind of fine movements you want RCS thrust for, too much thrust can be a bad thing.

Vernors use liquid fuel and oxidizer, which means you need to worry about fuel flow for them. For example suppose your ship has a command module without fuel and a service module with the fuel, separated by a decoupler; Vernors won't work on the command module without additional workarounds. RCS thrusters use monopropellant so you can add them anywhere.

[FleshJeb]

Mono storage is much smaller per unit fuel. Being able to build a more compact craft can be a huge benefit.

[zarakon]

I've never used vernors because they seem too awkward to place correctly on most of my craft. 4-way RCS thrusters are much easier to work with

[Red Iron Crown]

Vernors use liquid fuel and oxidizer, which means you need to worry about fuel flow for them. For example suppose your ship has a command module without fuel and a service module with the fuel, separated by a decoupler; Vernors won't work on the command module without additional workarounds. RCS thrusters use monopropellant so you can add them anywhere.

I don't think that's so about the Vernors. The regular LFO fuel flow rules are overridden for them and they draw LFO in the same manner that monoprop RCS thrusters draw fuel.

[GoSlash27]

I think the whole "every ship that needs to dock should be lightweight" isnt seeing the big picture. I rarely if ever touch a craft below 20t (even my lightweight fighters are 10t at a minimum to give em the dV i want), so i guess for that weight i just cant justify the monoprop rcs.

I don't know about the "big" picture, but clearly RCS doesn't fit your needs.

I build all my stuff to be as light and efficient as I can. Since I can do pretty much everything required in this game with tiny vehicles, vernors are unsuitable for my needs. Your mileage may (and clearly does) vary.

Best,

-Slashy

[vixr]

I use RCS thrusters for precision docking... crooked solar panels drive me nuts. Rarely use vernors...They are handy for killing velocity while docking, if placed on the bow, instead of rotating 180 while docking.

Edited March 9, 2015 by vixr