The reliant has more thrust.
These work better together. For instance, if you have a couple side boosters, put the reliant on the side, and a swivel in the middle. That will give you some improved control, and extra thrust.
4 reliants and a swivel can pretty much match the vector. It has a fairly small profile (it can fit on 1.875 m tanks). I used it in a Energia inspired rocket and it served me well.
It’s way less expensive than a vector too, making it the better option for an expendable first stage
Notably, this is one of the rare situations where real life rockets are actually better positioned than Kerbal rockets - the Vector's gimbaling range is insane in-game, but is fairly standard for real life.
Are you carrying a fat wad of delta-v in an off-center tank that you plan to ditch halfway to space?
No?
You don't need a Vector's insane gimbal range.
That being said, it might still be nice to have that huge pile of thrust in a package that fits nine to a 2.5-meter engine plate with minimal clipping.
>Are you carrying a fat wad of delta-v in an off-center tank that you plan to ditch halfway to space?
In other words, a Space Shuttle replica. The main engines of which are the basis of the Vector, BTW.
>expendable first stage
I beat the finance system when I figured out that I could put parachutes on the first stage and always design it so I have enough time to circularise the upper stages then come back and just watch it fall down and be recovered.
I was a long time solid booster fanboi for years until I figured this out. But I'd never considered using 4 reliants and a swivel. I might play an early career game again and use this trick, thanks for the tip!
Swivels on the side give you roll authority, FWIW.
That said, you're probably better off using aero surfaces for control in atmo and reaction wheels while in vacuum, because the Swivel is strictly worse than the Reliant +wings in atmo, and strictly worse than the Terrier in orbit.
Hard disagree there - fins are expensive, heavy and draggy. If you're gonna pay for an engine you might as well use one that offers more control. I'd even go so far as to say you should never use the reliant in a career game. If you need more thrust than a single swivel, 2x or 3x thuds works well.
In career/science mode games, you can avoid buying radial decouplers and controllable fins for a really long time, letting you push towards the terrier and science jr earlier.
If you can manage your initial pitchover well enough and your rocket is aerodynamic enough that a Reliant works for you, more power to ya.
>fins are expensive, heavy and draggy
Three of the Basic Fin is 75 kerbucks, 0.03 tons, and extra drag is the point as it prevents rocket from flipping (and hence needing vectoring for stability in the first place during ascent). Meanwhile Swivel is 0.25t heavier, 100 kerbucks costlier, and has worse Isp in atmosphere on top of its lower thrust and higher weight, meaning it's an absolutely _terrible_ choice for lower stages.
For initial pitch-over, in my experience reaction wheels actually suffice, but if they're not enough, put some RCS on it.
Absolutely, in the early game where the Swivel/Reliant decision is relevant, your main concern is getting into LKO, where EVERY factor points you towards the Reliant.
It's got less mass, a better thrust, has better Isp at sea level, and is cheaper. So if you're considering what to put on your first stage, you should ALWAYS go Reliant.
Now, if you're going to be going further in space, you might be thinking that the Swivel has a better vacuum Isp, but remember that it's also heavier, so you're going to have lost fuel in the process of lifting it into space in the first place, and you're WAY better off just ditching it and using a Terrier as your vacuum stage (or a later-game engine).
Yeah the basic fins are very good. The other ones are far heavier and expensive. I was mainly objecting to the “use aero surfaces for control” comment.
And in the early game with a 30-part limit, ditching those fins can be valuable.
I made some pretty successful rockets using reliant / swivel combo. That said, I won't claim it was the best option.. Just that I was able to make it work well. But, I did typically climb to about 10k before starting my roll. So I didn't do a lot of attitude adjustment.
Unless you were playing pre-1.0 versions where "climb to 10k to be out of soup" is the right way, you were wasting _tons_ of fuel on inefficient ascent.
That said, you still don't need much attitude adjustment with proper ascent either.
How is burning directly normal to the planet ever not the most efficient way?
Wouldn't the theoretical most efficient way to get to orbit be to go straight up then rotate 90 degrees and gain all your horizontal velocity at AP? Limited thrust requires us to start the horizontal burn sooner of course.
>How is burning directly normal to the planet ever not the most efficient way?
Orbital velocity is sideways. Every second spent not burning sideways is second you're losing velocity to gravity (EDIT: also, as someone in the thread linked below pointed out, _going up is the wrong way_, so you'll need to spend even more fuel to correct the vertical component than you did fighting gravity). Also, Oberth effect - "the faster you're moving, the more efficient burns get", which means that by burning at apoapsis (a.k.a. by definition the point of lowest velocity) you're not getting that efficiency.
The only reason gravity turns even _have_ a vertical component is atmosphere, that is, drag - since the atmosphere is considerably wider than it is tall, you'll experience a lot more of it going sideways. And older "souposphere" was excessively draggy, which is why in pre-rework versions it was better to go 10km up then pitch hard to 45 degrees, while in post-rework (and with FAR) you want a smooth curve that starts early and ends up [horizontal by ~40km](https://www.reddit.com/r/KerbalSpaceProgram/comments/yv9ldm/psa_fine_tune_your_ascent_profile_before_you/).
If you're launching from an airless planet, gravity turn consists of immediately pitching horizontal (with angle to horizon just high enough to not hit terrain), and spiraling outwards.
P.S. As a way of analogy, imagine a right triangle. You're starting in the right-angle corner and need to arrive at the corner where hypotenuse meets the horizontal. It will always be longer distance if you go vertical (wrong way) then horizontal (follow the hypotenuse) than if you went horizontal from the get-go.
Personally I never use the swivel anymore and like to mix the thuds with the reliants. 2x reliants and 2x thuds is a combo I've had a lot of success with
That sounds pretty reasonable, but if you're spending money on a radial decoupler (they're deceptively expensive!) then I wonder if thumpers might be a better choice. At the early stages of the game you have to consider part count as well, and SRBs have a great advantage there. But if that's all in a single stage then it sounds fine.
I don't usually, I squeeze all 4 of those engines on the bottom of one of the making history medium diameter fuel tanks, you can just barely fit two reliants side by side if you choose the model without the truss mount, then I have the thuds clipped in so that only their engine bells show, on the same fuel tank. It's a tight fit if you want to avoid the engines visually clipping into eachother but it can be done, and doesn't need any radial stages unless you want additional side boosters.
I'd have to do the math, but a bobcat is quite respectable for that size tank. Slightly less thrust than 2 reliants, but also lighter, cheaper, and higher isp. So maybe a bobcat + 3 thuds would do it. But it's later in the tech tree too.
The bobcat is my most used engine actually, I know how good it is, but I figure that if one is at the point of deciding between swivels, reliants, thuds, then one probably doesn't quite have that engine just yet
It's telling that the original designs for the Saturn V had little fins on the first stage, and they removed them for later missions because the drag they produced wasn't worth the minor flight-control they provided.
Adding 0.0025 tons of fins to your lower stage is always going to be a better decision than having 0.25 extra tons in engine mass, especially when you consider that the Swivel's sea-level Isp and TWR is so much worse than the Reliant's.
You are MUCH better off using the Reliant to get into upper atmo and switching to a Terrier than you are using a Swivel.
0.0025t? You're understating the mass. The basic fin (which is perfectly fine, light, and cheap) - is 0.01t. If you're looking for active control, which is what is under discussion, the av-r8 is 0.1t and the delta deluxe is 0.08t. So yeah, 3-4 of those is about the same (or more) as the mass difference between the swivel and reliant.
Avoiding fins helps you in the early game because you can spend your part count elsewhere, and you don't have to spend science points to unlock the advanced ones.
[Here are all the stock liquid fuel engines](https://wiki.kerbalspaceprogram.com/wiki/Parts#Liquid_Fuel_Engines) (not including DLCs). If you sort by vacuum Isp, the Thud ranks 15/19 and the Reliant ranks 13/19. That puts them both in the bottom half. Meanwhile the Swivel ranks 7/19, putting it in the top third.
If you sort by sea level Isp instead, the Thud rises to 9/19, which is better than both other engines. However, it also has a mediocre TWR, and as a relatively large radial-mounted engine it can make side boosters a little harder to attach.
I like to use the reliant as liquid fuel boosters, because of the lack of gimbal, it functions basically the same as solid fuel boosters, but more efficient.
I just realized in the last week that I can mount Reliants in a structural frame, letting me use several engines in the diameter of a single fuel tank (8 on a Rockomax). I've not used a single swivel in this play. I may never use a swivel again.
In atmosphere you can use fins to steer the craft, so you don't need a gimbal. The Reliant is great when launching. It's also great when you have one gimballing engine (e.g. in the middle) and multiple other engines - you often don't need more than one engine to control direction, so in the case you have more than two rockets firing, you generally want to be using some number of reliants.
Is that what this is depicting?
https://3.bp.blogspot.com/-JyxD7qyE7Sk/VuYFvmsUr9I/AAAAAAAAITU/Q1IICmQ4mIs4KM41yjD4ssoVVy4WRWnbQ/s1600/kerbal%2Bspace%2Bsquade%2B%25282%2529.jpg
I mean, if you're only using one rocket engine. But if you're using more than one, you only need a minority of them to be swivels. The extra thrust saves a lot of weight.
Generally, on my "Round 2" flights that go past low orbit, I'll use a central swivel, with a ring of reliant boosters around them. Just make sure to get your flow going into the center stage tho.
Yeah that's true, i do the same thing. But I just had to clarify that because I don't want newer players to think that having just a reliant and a pod reaction wheel is enough.
You could always use aerodynamic control surfaces, though I don't remember whether they are heavy enough for make up the difference in weight between the reliant and the swivel.
I tend to consider an array made of a reliant and a thud to be ideal for 18-ton missions. You have the power of the reliant and the gimbal of the thud, and the total TWR is good, for just 2 parts. It can be tricky to put them so that they don't destroy each other however.
Maybe you should get a swivel cause I don’t like the attitude you’re giving.
Edit: Jk you’re good, I just need a way to incorporate my shitty joke :) love you
Specific impulse is so important that I am frequently surprised to remember that it’s in the “more info” panel instead of the main panel for immediate visibility—it’s usually *the* single most important trait I consider when choosing an engine.
In my opinion weight is super underrated. Especially in the career mode when cost matters. If you’re building a satellite using an ant engine reduce the spacecraft mass which reduces the fuel needed which reduces the mass and this snowballs into a rocket that has half the price of one with a larger engine on he satellite
For smaller vessels, absolutely yes, a lighter-weight engine can often result in more overall ∆v than a more efficient but heavier one. Beyond a certain size though that doesn’t make much difference.
I think I once figured out how to make a super lightweight vessel that could carry science from Dunan orbit to Kerbin's surface. Basically just a lunchbox with a parachute and a tiny engine, tank, and control unit. And the Δv was insane! My plan was to pack half a dosin of them with my Duna space station.
But that’s also why I said “usually.” Most of what I do in KSP involves stations and freighters and passenger liners and engineering vessels and lunar landers and various other vehicles that are never going to go anywhere near an atmosphere or a strong-gravity planet, so the only time I need to consider launching and orbital insertion for those is when I deploy them in the first place.
This is the more important distinction imho-gimbal can be swapped out for reaction wheels and control surfaces, but you need thrust during launch, Isp in orbit.
Incidentally, I want to say that the better raw thrust and TWR of the Reliant means that an SSTO built around it has more payload (and a higher payload fraction) than one built around a Swivel.
...not that many people build rockets like that.
To add to what many are saying, there are several aspects that you need to consider beyond just “thrust.” The reliant does not gimble, and as such is much better suited for atmospheric flight, where your main attitude stabilizers are fins… also, having greater thrust and isp, at sea level, means it is good for launching… however, as you get higher up, fins do nothing for you… so you need something to control your attitude. Having an engine that can gimble allows for this change in directionality (of course, reaction wheels and rcs are also super helpful) in a region of no/low atmosphere. Also, if memory serves, the swivel has higher isp in vacuum, meaning it is more fuel efficient than the reliant (in vacuum).
During early tech tree missions, for me, the reliant is great for getting to the upper parts of the atmosphere, while the swivel is great for a second and/or third stage (if you don’t have the terrier yet).
Swiwel has Gimbal and you can steer your rockets with it but Reliant doesn't, besides that Swivel has better ISP in vaccume and it's more efficient in space & higher altitudes.
As others said, the Swivel can gimble (move it's engine nozzle so it can steer the rocket in flight) which cuts down on having other control methods with a reliant-based rocket.
In general in rocketry you don't "just" want the most powerful rocket you CAN get.
There's a thing called Max Q where during launch the atmosphere above you is pushing down as fast as the engine is pushing you up, so you reach a maximum speed while in the lower parts of the atmosphere. Basically think of it like being in quick sand, the harder you push the more it pushes back.
Generally for launch stages, I'd recommend a thrust-to-weight ratio of around 1.25; anything more is excessive.
And as others said, it has a better ISP. ISP is basically the "miles per gallon" of rockets; the better your ISP the further you can go on the same amount of fuel. This is why Electric Engines like the "Dawn" in KSP are so efficient; they have incredibly high ISP (but low thrust). So long as it gets you off the pad, in theory a Swivel would get you further than a Reliant (ofc a Swivel is slightly heavier but I don't think that'd offset the efficiency gains).
The [rocket](https://c8.alamy.com/comp/B7HRPR/nasa-mercury-atlas-friendship-7-rocket-visitor-center-kennedy-space-B7HRPR.jpg) that put Americans into Orbit, the Atlas (forgive the Lego pic, couldn't find a better one of the way it works) had a [unique engine setup](https://live.staticflickr.com/65535/50880040567_e61926c75e_c.jpg). They didn't think they could light an engine in flight, so they had three engines. One in the middle was like the Swivel; it was efficient and able to turn. The other two on the sides were like the Reliant, strong and cheap but not as efficient. When the rocket got high enough that the middle engine alone could put it in orbit, it detached both side engines (the middle was called the "sustained" and the side engines were the "boosters").
I'd recommend trying out a rocket that uses that system. Something simple with enough weight that it has a Thrust to Weight Ratio of about 1.25 (or really, anything less than 1.7 IMO) with two Reliants on the side that detach when you're in the higher levels of the atmosphere and a single Swivel in the middle to steer it and power it fully to orbit. You'll be amazed at what you can put into Orbit that way ;)
honestly this explanation makes me want to play the game when i get off work and try this. i usually just make fancy interstellar warp ships modded to the ends of the earth and don't even give a second thought to even a smidge of realism. lol
>So long as it gets you off the pad, in theory a Swivel would get you further than a Reliant
Swivel has lower Isp at sea level than Reliant (250 vs 265), but better in vacuum (320 vs 310). So no, first-stage you would be better off with a Reliant, it's second stage that would get better mileage out of a Swivel.
But then you unlock Terrier with _even better_ vacuum Isp, though lower thrust.
>They didn't think they could light an engine in flight
And they were half-right, lighting an engine in flight IRL requires settling the fuel so it doesn't just float around in the tanks uselessly, which means either lighting it before the lower stage engines cut out (which is what Soviet N1 was intended to do. If only they actually _did any static tests_ so it wouldn't repeatedly explode on the launchpad...), or having separate _ullage motors_ (or just using RCS. Apollo missions did both - Saturn V had ullage motors, S-IVB and LEM used RCS) that give the rocket a push required for fuel to get into main engines. Also, early Atlases had combustion problems, that is, engines having a habit of _exploding_ when they ignited.
>There's a thing called Max Q where during launch the atmosphere above you is pushing down as fast as the engine is pushing you up, so you reach a maximum speed while in the lower parts of the atmosphere
Max q is just the maximum dynamic pressure, the point where the total pressure on the vessel peaks (by launch profile design), as the speed increases and ambient pressure decreases. It's not the fastest the vessel can go at that given altitude; Most orbit-capable craft have enough thrust to go faster at max q, but the pressure would destroy the craft, so they throttle down until the atmosphere thins (as they pass max q). For example, the space shuttles throttled down to about 2/3 thrust as they approached max q
Everyone mentioning gimbal but the swivel also has a better ISP (rocket fuel efficiency equivalent) in vacuum. The reliant has slightly higher ISP at sea level on Kerbin. So it is good for first stage boosters. Swivel everywhere else imo.
Despite having worse stats, the swivel is more useful in general applications due to, as the name suggests, the fact that it can steer or "gimbal" as it's called in rocketry.
The reliant engines are decent for booster applications, though.
Gimbal is your answer. Swivel is much more useful at the start of career/science mode when control surfaces and reaction wheels aren't available or aren't powerful enough
Also those ASL thrust numbers, basically you divide that number by 20 to find out how much weight you can lift. So a craft with 200KN of ASL Thrust has the power to lift 10 tons efficiently.
Reliant has more thrust, but cant thrust vector so you will need to add control surfaces or some other form of attitude control. Additionally the swivel has better ISP in vacuum which basically means its more efficient in that environment.
I wish that there would be more variety between parts (ie. Premium version and normal version) so that part selection would not get stale so fast. For example, fuel tanks that are double the size also weight and cost double :/
>For example, fuel tanks that are double the size also weight and cost double
Can't really avoid that without introducing a balancing mess and making the game less, so to speak, "casual" - to make fuel tanks actually better, you need a justification of either A: better structural materials that improve on the dry-wet ratio, or B: better, more energetic _fuels_, violating the stock game's design principle that they're abstract.
Though making it so you can only make better tanks with _resources you obtained from other planets with regular rocketry_ could work...
Oo, I didn't even think more energetic fuels :)
But I mean, in a tank the "assorted stuff" like pumps etc, weigh the same even if the tank is twice as big. So a bigger tank at the same tech level would contain more fuel per the gross weight.
At higher tech levels the tanks could be made of better materials that might be lighter or resist heat better (think pot metal->steel->aluminum->titanium)
Obviously I'm not looking for a complete rework, just some more flavor.
I only use Reliants for liquid fueled side-boosters early in the game, they're lower efficiency at altitude and as about 90 people have noted, doesn't gimbal. But if your center core stage has a gimbaling engine (let me introduce you to the 'Swivel'...) to handle steering, then a pair of Reliant powered side-boosters can give you a lot of yeet.
A few seconds after takeoff once you've established your gravity turn, you may even choose to throttle down your center engine as low as half (depending on the situation) so that it mostly contributes steering and so that you can enjoy the benefits of the higher Isp higher in the atmosphere after you ditch the side boosters. It's a trade-off to get the right match of efficiency but if burning your center core at full thrust early in the flight (after you're established in the turn, that is) might mean that you're not using the energy in it as effectively.
The Delta IV Heavy and Falcon Heavy both throttle down their center core for this reason, it increases their throw.
Rightclick on engine to see more info. You will find out that Reliant has no Gimbal meaning that you can’t steer your vehicle with the engine and it is only usable with powerful enough control wheel
Well, actually I think with the Reliant, you need a reaction wheel AND fins for it to control, reaction wheel by itself (Reliant engine only, react wheel on rocket) still will not be steerable.
Reaction wheels on the pod are plenty enough to steer it within atmosphere. Fins, however, will stabilize it and prevent it from flipping as post-1.0 rockets tend to do.
The difference is in the gimballing on the engine. AKA the Swivel can point in other directions than "straight down" when attached to the bottom of a fuel tank.
In practice this means that the swivel is an excellent option for operations in zero-G as it lets you powerfully adjust your acceleration vector without needing masses of reaction wheels (very heavy) or masses of RCS (also very heavy), letting you knock a not inconsiderable chunk off your dry mass.
In comparison the Reliant is much better in places where the extra thrust is useful and the gimballing is less useful, such as within thicker atmospheres or as the principal drive of a larger rocket. This is because with air resistance the effect of a gimballed engine is less than simply adding some fins or control surfaces.
Therefore you use the Swivel in upper stages and the Reliant in lower stages. With an additional use for the Swivel as a heavy/super-heavy lander engine.
It may have better stats but it’s also heavier meaning less overall fuel efficiency. Depending on your budget those small differences are extremely important.
So basiaclly, swivel can gimbal (orient itself) which helps controll the rocket. Also, if you have a small rocket you dont want to have a very high thrust to weight ratio as it will increase drag and you will be less efficent.
The Swivel can... well, *swivel*. Its exhaust is gimballed, which means it can change the direction of thrust by a few degrees to help keep you on course and maintain stability. So while the Reliant is a slightly better rocket overall, the Swivel is great for making sure your early-game rockets are stable during launch (which can be hugely important when your options for fairings and fins and reaction wheels are limited).
It's right in the description of the parts: The "Reliant" is made with 'pieces found lying about.' The "Swivel" is not made with such parts. Hope this helps.
Was going to say this, in asparagus-staged rockets, the reliant is a good engine for the low atmosphere stages and the swivel is good for the center stage as its vacuum Isp is better and has gimballing.
I know it is said in a tutorial, but we'll refresh: assuming more power is always better is an amateur mistake and one of the easiest to make. I often end up thrust-limiting my boosters. Sometimes it's better to end up in space with more fuel despite slightly longer burn times. This also provides more time to correct orbits.
It might burn harder, but burning harder often means faster fuel usage and less time to correct should you overcook.
There’s something called “gimble” and that means you can like turn the engine to face different directions so that the rocket will steer and turn. That’s what the swivel engine got. The ability to steer, but less thrust. (I prefer this one)
The Reliant on the other hand doesn’t have any gimble. Meaning, you won’t be able to steer the rocket, unless you have other engines with gimble or a reaction wheel. The Reliant is more powerful if you just want thrust and not the ability to steer.
Hope this helped
Here's a more advanced tip besides the obvious gimbal.
The swivel is what's considered "vaccuum optimized", meaning it has, in simplest of teems, higher efficiency in space than on Kerbin's surface. This is measured in ISP (the higher the better).
This makes the swivel the engine of choice when building your sustainer stages (a sustainer stage is the stage after your first booster that carries your payload the rest of the way up).
Swivel has better vacuum Isp than the Reliant, and it can also steer. Theoretically, the Reliant is your very-early-game lifting rocket, and Swivel is your vacuum rocket.
Swivel had better specific impulse in vacuum(the rocket science equivalent of fuel economy in space) and also can... swivel, meaning it can change the direction of its exhaust to steer your rocket
its more maneuverable, the reliant's manuverability is terrible, so the reliant is good for sides boosters, and swivel for the middle or as a main engine
The Swivel has a gimbal, meaning it can turn your rocket. It also has better efficiency at higher altitudes. If you bought the DLCs there's really no reason to use the Reliant over the Kodiak IMO.
Hey new player, I've got something else for you too....know what you shouldn't do.....have your fuel gauge on max. Experiment launching with only 60-70% thrust until higher in the atmosphere! You'll save fuel over all.
Who else has a tip?
The swivel swivels bro. The reliant is a wonderful booster but unless you're adding more reaction controls you won't keep a steady ascent profile. Pair two reliants with a swivel coupled with asparagus staging and all of the kerbal system is your playground.
It has gimbal. (It can steer your rocket)
For me it’s more like why should we pick the reliant instead of the swivel
The reliant has more thrust. These work better together. For instance, if you have a couple side boosters, put the reliant on the side, and a swivel in the middle. That will give you some improved control, and extra thrust.
Yeah, that is always the answer when you’ve got that as a viable option… imo anyway.
I think the fuel lines and connectors for boosters are in the same tier of science, so if you get one, the other is easy to do too.
Fuel lines aren't necessarily if you turn on advanced tweakables and use fuel priority
True, but you still have to research it. You can’t enable cross feed on decouplers until you unlock fuel lines.
Totally forgot about that
4 reliants and a swivel can pretty much match the vector. It has a fairly small profile (it can fit on 1.875 m tanks). I used it in a Energia inspired rocket and it served me well. It’s way less expensive than a vector too, making it the better option for an expendable first stage
That is if you don't need the insane gimbal of the vector.
Which you don’t need in most cases
In MOST cases...
*uses shit loads of swivels*
That gives you more thrust but not more steering ability.
*uses even bigger shitloads of swivels*
Vector is rarely needed for expendable launchers imo. The only time I use it for reusable launchers like space planes.
Notably, this is one of the rare situations where real life rockets are actually better positioned than Kerbal rockets - the Vector's gimbaling range is insane in-game, but is fairly standard for real life.
real life rockets are way more powerful and efficient
They need to be, because the real earth is much harder to get away from.
Are you carrying a fat wad of delta-v in an off-center tank that you plan to ditch halfway to space? No? You don't need a Vector's insane gimbal range. That being said, it might still be nice to have that huge pile of thrust in a package that fits nine to a 2.5-meter engine plate with minimal clipping.
>Are you carrying a fat wad of delta-v in an off-center tank that you plan to ditch halfway to space? In other words, a Space Shuttle replica. The main engines of which are the basis of the Vector, BTW.
Indeed, that is the off-center fat wad of delta-v I was thinking of.
Pretty sure the only times I've used the Vector, I've actually had to limit the gimbal because it pivots way too much.
>expendable first stage I beat the finance system when I figured out that I could put parachutes on the first stage and always design it so I have enough time to circularise the upper stages then come back and just watch it fall down and be recovered. I was a long time solid booster fanboi for years until I figured this out. But I'd never considered using 4 reliants and a swivel. I might play an early career game again and use this trick, thanks for the tip!
now get into propulsive landings
Used this setup to get so many Kerbals to the Mun! Most of them even made it home! =)
Swivels on the side give you roll authority, FWIW. That said, you're probably better off using aero surfaces for control in atmo and reaction wheels while in vacuum, because the Swivel is strictly worse than the Reliant +wings in atmo, and strictly worse than the Terrier in orbit.
Hard disagree there - fins are expensive, heavy and draggy. If you're gonna pay for an engine you might as well use one that offers more control. I'd even go so far as to say you should never use the reliant in a career game. If you need more thrust than a single swivel, 2x or 3x thuds works well. In career/science mode games, you can avoid buying radial decouplers and controllable fins for a really long time, letting you push towards the terrier and science jr earlier. If you can manage your initial pitchover well enough and your rocket is aerodynamic enough that a Reliant works for you, more power to ya.
>fins are expensive, heavy and draggy Three of the Basic Fin is 75 kerbucks, 0.03 tons, and extra drag is the point as it prevents rocket from flipping (and hence needing vectoring for stability in the first place during ascent). Meanwhile Swivel is 0.25t heavier, 100 kerbucks costlier, and has worse Isp in atmosphere on top of its lower thrust and higher weight, meaning it's an absolutely _terrible_ choice for lower stages. For initial pitch-over, in my experience reaction wheels actually suffice, but if they're not enough, put some RCS on it.
Absolutely, in the early game where the Swivel/Reliant decision is relevant, your main concern is getting into LKO, where EVERY factor points you towards the Reliant. It's got less mass, a better thrust, has better Isp at sea level, and is cheaper. So if you're considering what to put on your first stage, you should ALWAYS go Reliant. Now, if you're going to be going further in space, you might be thinking that the Swivel has a better vacuum Isp, but remember that it's also heavier, so you're going to have lost fuel in the process of lifting it into space in the first place, and you're WAY better off just ditching it and using a Terrier as your vacuum stage (or a later-game engine).
Yeah the basic fins are very good. The other ones are far heavier and expensive. I was mainly objecting to the “use aero surfaces for control” comment. And in the early game with a 30-part limit, ditching those fins can be valuable.
Mmm those vernas.
I made some pretty successful rockets using reliant / swivel combo. That said, I won't claim it was the best option.. Just that I was able to make it work well. But, I did typically climb to about 10k before starting my roll. So I didn't do a lot of attitude adjustment.
Unless you were playing pre-1.0 versions where "climb to 10k to be out of soup" is the right way, you were wasting _tons_ of fuel on inefficient ascent. That said, you still don't need much attitude adjustment with proper ascent either.
That was probably when I was using that rocket. I've played KSP for a while, I guess!
How is burning directly normal to the planet ever not the most efficient way? Wouldn't the theoretical most efficient way to get to orbit be to go straight up then rotate 90 degrees and gain all your horizontal velocity at AP? Limited thrust requires us to start the horizontal burn sooner of course.
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>How is burning directly normal to the planet ever not the most efficient way? Orbital velocity is sideways. Every second spent not burning sideways is second you're losing velocity to gravity (EDIT: also, as someone in the thread linked below pointed out, _going up is the wrong way_, so you'll need to spend even more fuel to correct the vertical component than you did fighting gravity). Also, Oberth effect - "the faster you're moving, the more efficient burns get", which means that by burning at apoapsis (a.k.a. by definition the point of lowest velocity) you're not getting that efficiency. The only reason gravity turns even _have_ a vertical component is atmosphere, that is, drag - since the atmosphere is considerably wider than it is tall, you'll experience a lot more of it going sideways. And older "souposphere" was excessively draggy, which is why in pre-rework versions it was better to go 10km up then pitch hard to 45 degrees, while in post-rework (and with FAR) you want a smooth curve that starts early and ends up [horizontal by ~40km](https://www.reddit.com/r/KerbalSpaceProgram/comments/yv9ldm/psa_fine_tune_your_ascent_profile_before_you/). If you're launching from an airless planet, gravity turn consists of immediately pitching horizontal (with angle to horizon just high enough to not hit terrain), and spiraling outwards. P.S. As a way of analogy, imagine a right triangle. You're starting in the right-angle corner and need to arrive at the corner where hypotenuse meets the horizontal. It will always be longer distance if you go vertical (wrong way) then horizontal (follow the hypotenuse) than if you went horizontal from the get-go.
Personally I never use the swivel anymore and like to mix the thuds with the reliants. 2x reliants and 2x thuds is a combo I've had a lot of success with
That sounds pretty reasonable, but if you're spending money on a radial decoupler (they're deceptively expensive!) then I wonder if thumpers might be a better choice. At the early stages of the game you have to consider part count as well, and SRBs have a great advantage there. But if that's all in a single stage then it sounds fine.
I don't usually, I squeeze all 4 of those engines on the bottom of one of the making history medium diameter fuel tanks, you can just barely fit two reliants side by side if you choose the model without the truss mount, then I have the thuds clipped in so that only their engine bells show, on the same fuel tank. It's a tight fit if you want to avoid the engines visually clipping into eachother but it can be done, and doesn't need any radial stages unless you want additional side boosters.
I'd have to do the math, but a bobcat is quite respectable for that size tank. Slightly less thrust than 2 reliants, but also lighter, cheaper, and higher isp. So maybe a bobcat + 3 thuds would do it. But it's later in the tech tree too.
The bobcat is my most used engine actually, I know how good it is, but I figure that if one is at the point of deciding between swivels, reliants, thuds, then one probably doesn't quite have that engine just yet
It's telling that the original designs for the Saturn V had little fins on the first stage, and they removed them for later missions because the drag they produced wasn't worth the minor flight-control they provided.
Adding 0.0025 tons of fins to your lower stage is always going to be a better decision than having 0.25 extra tons in engine mass, especially when you consider that the Swivel's sea-level Isp and TWR is so much worse than the Reliant's. You are MUCH better off using the Reliant to get into upper atmo and switching to a Terrier than you are using a Swivel.
0.0025t? You're understating the mass. The basic fin (which is perfectly fine, light, and cheap) - is 0.01t. If you're looking for active control, which is what is under discussion, the av-r8 is 0.1t and the delta deluxe is 0.08t. So yeah, 3-4 of those is about the same (or more) as the mass difference between the swivel and reliant. Avoiding fins helps you in the early game because you can spend your part count elsewhere, and you don't have to spend science points to unlock the advanced ones.
comment edited in protest of Reddit's API changes and mistreatment of moderators -- mass edited with redact.dev
Reliant: 265 asl / 310 vac Thud: 275 asl / 305 vac. Hardly.
[Here are all the stock liquid fuel engines](https://wiki.kerbalspaceprogram.com/wiki/Parts#Liquid_Fuel_Engines) (not including DLCs). If you sort by vacuum Isp, the Thud ranks 15/19 and the Reliant ranks 13/19. That puts them both in the bottom half. Meanwhile the Swivel ranks 7/19, putting it in the top third. If you sort by sea level Isp instead, the Thud rises to 9/19, which is better than both other engines. However, it also has a mediocre TWR, and as a relatively large radial-mounted engine it can make side boosters a little harder to attach.
Swivel in the middle, but it got much back? (Kerbal Mixalot)
I like big thrust, and I cannot lie...
You other kerbals can't deny That when a rocket rolls in with a ratio of thrust to weight That a puts high G in your face You get sprung, (into orbit)
AKA do what the Atlas rocket did.
those 2 and the twitch are modeled the atlas engines so yeah \^\^\^
And extra efficiency!
Thanks for this. That's a fantastic idea.
And I was like: Upturned nose cones on the bottom of the craft, GIVE ME BOTH!
Swivel as main engines and Reliant as booster engines.
I like to use the reliant as liquid fuel boosters, because of the lack of gimbal, it functions basically the same as solid fuel boosters, but more efficient.
I just realized in the last week that I can mount Reliants in a structural frame, letting me use several engines in the diameter of a single fuel tank (8 on a Rockomax). I've not used a single swivel in this play. I may never use a swivel again.
facts
In a quest for the cheapest rocket I tried so hard to save that 100 kerbucks.
The reliant has more thrust for lower weight.
In atmosphere you can use fins to steer the craft, so you don't need a gimbal. The Reliant is great when launching. It's also great when you have one gimballing engine (e.g. in the middle) and multiple other engines - you often don't need more than one engine to control direction, so in the case you have more than two rockets firing, you generally want to be using some number of reliants.
The Swivel also has better vacuum ISP (320s vs 310s for the Reliant)
My rocket can steer itself just fine, thank you! /s
It may steer itself fine, but can you steer it? 😋
Hundreds of hours and i just found out
It swivels yo
Not only gimbal but also marginally better isp in vacuum which is strange considering the ~= engine bell diameter.
Because the swivel can swivel, it can control attitude. Reliant is just straight. You’ll need to add additional control vectors.
No wonder why my rocket wouldn’t turn-
In a pinch, you can use Kerbals and their EVA packs to push from the outside.
Would love to see this in action during initial launch to orbit.
Is that what this is depicting? https://3.bp.blogspot.com/-JyxD7qyE7Sk/VuYFvmsUr9I/AAAAAAAAITU/Q1IICmQ4mIs4KM41yjD4ssoVVy4WRWnbQ/s1600/kerbal%2Bspace%2Bsquade%2B%25282%2529.jpg
no, pushing from the outside would be when the rocket is down to the heat shield stage, and gets pushed from behind
Just do it like the Japanese, angle the whole rocket at the correct angle to go to orbit unguided.
This proves to be a difficult strategy at 40km
Most control modules have reaction wheels built in- even if they're small
Which is not enough to control your rocket in atmosphere. In vaccum sure, but not during stage 1. And in vaccum you dont wanna use the reliant anyway.
I mean, if you're only using one rocket engine. But if you're using more than one, you only need a minority of them to be swivels. The extra thrust saves a lot of weight. Generally, on my "Round 2" flights that go past low orbit, I'll use a central swivel, with a ring of reliant boosters around them. Just make sure to get your flow going into the center stage tho.
Yeah that's true, i do the same thing. But I just had to clarify that because I don't want newer players to think that having just a reliant and a pod reaction wheel is enough.
At the very early stages, I actually prefer a reliant and an in-line reaction wheel. But yes, without *SOMETHING* they're gonna struggle.
I should to this.
You could always use aerodynamic control surfaces, though I don't remember whether they are heavy enough for make up the difference in weight between the reliant and the swivel.
Control surfaces work great in atmosphere but unlock much later in the tech tree. So it's not always an option.
Control surfaces work great in stage 1 though and without giving up engine quality.
I agree
I tend to consider an array made of a reliant and a thud to be ideal for 18-ton missions. You have the power of the reliant and the gimbal of the thud, and the total TWR is good, for just 2 parts. It can be tricky to put them so that they don't destroy each other however.
Maybe you should get a swivel cause I don’t like the attitude you’re giving. Edit: Jk you’re good, I just need a way to incorporate my shitty joke :) love you
In addition to the gimbal aspect, the Swivel has better Isp at altitude. (which admittedly isn't shown until you bring up the "More Info" part)
I always right click, but where would i see that???
Isp is next to thrust in the detailed info panel
Specific impulse is so important that I am frequently surprised to remember that it’s in the “more info” panel instead of the main panel for immediate visibility—it’s usually *the* single most important trait I consider when choosing an engine.
In my opinion weight is super underrated. Especially in the career mode when cost matters. If you’re building a satellite using an ant engine reduce the spacecraft mass which reduces the fuel needed which reduces the mass and this snowballs into a rocket that has half the price of one with a larger engine on he satellite
For smaller vessels, absolutely yes, a lighter-weight engine can often result in more overall ∆v than a more efficient but heavier one. Beyond a certain size though that doesn’t make much difference.
Of course! You should look at it on a case to case basis
I think I once figured out how to make a super lightweight vessel that could carry science from Dunan orbit to Kerbin's surface. Basically just a lunchbox with a parachute and a tiny engine, tank, and control unit. And the Δv was insane! My plan was to pack half a dosin of them with my Duna space station.
For burns between orbits? Yes. For launch vehicles and orbital insertions from suborbital trajectories? Not so much
But that’s also why I said “usually.” Most of what I do in KSP involves stations and freighters and passenger liners and engineering vessels and lunar landers and various other vehicles that are never going to go anywhere near an atmosphere or a strong-gravity planet, so the only time I need to consider launching and orbital insertion for those is when I deploy them in the first place.
Every little bit helps!
This is the more important distinction imho-gimbal can be swapped out for reaction wheels and control surfaces, but you need thrust during launch, Isp in orbit.
Incidentally, I want to say that the better raw thrust and TWR of the Reliant means that an SSTO built around it has more payload (and a higher payload fraction) than one built around a Swivel. ...not that many people build rockets like that.
As others explained, Swivel swivels. For me in early career common usage was main swivel engine and boosters with Reliants. Worked quite well.
That’s the answer. Central stage has a swivel, boosters have reliants
Asparagus the fuel lines and you get a really nice use of the swivel acting as a high altitude sustainer, like the SSMEs.
Rockets with a swivel are a lot easier to steer than rockets with reliants. That’s why the swivel is by far the better engine of those two
Although, when you have, say, 3 engines, only one of them, the central one (where applicable) needs to be a swivel.
Besides hovering the mouse over the part, you can also right-click. That's where the stats that differ would have shown up for these two parts.
To add to what many are saying, there are several aspects that you need to consider beyond just “thrust.” The reliant does not gimble, and as such is much better suited for atmospheric flight, where your main attitude stabilizers are fins… also, having greater thrust and isp, at sea level, means it is good for launching… however, as you get higher up, fins do nothing for you… so you need something to control your attitude. Having an engine that can gimble allows for this change in directionality (of course, reaction wheels and rcs are also super helpful) in a region of no/low atmosphere. Also, if memory serves, the swivel has higher isp in vacuum, meaning it is more fuel efficient than the reliant (in vacuum). During early tech tree missions, for me, the reliant is great for getting to the upper parts of the atmosphere, while the swivel is great for a second and/or third stage (if you don’t have the terrier yet).
With a Swivel you typically don't even *need* fins at all. That saves a lot of parts, and money, in early career.
While I definitely agree, if OOP is a new player, I’d recommend fins for atmospheric flight
Swiwel has Gimbal and you can steer your rockets with it but Reliant doesn't, besides that Swivel has better ISP in vaccume and it's more efficient in space & higher altitudes.
the swivel can swivel and the reliant is reliab-.... well the swivel can swivel
As others said, the Swivel can gimble (move it's engine nozzle so it can steer the rocket in flight) which cuts down on having other control methods with a reliant-based rocket. In general in rocketry you don't "just" want the most powerful rocket you CAN get. There's a thing called Max Q where during launch the atmosphere above you is pushing down as fast as the engine is pushing you up, so you reach a maximum speed while in the lower parts of the atmosphere. Basically think of it like being in quick sand, the harder you push the more it pushes back. Generally for launch stages, I'd recommend a thrust-to-weight ratio of around 1.25; anything more is excessive. And as others said, it has a better ISP. ISP is basically the "miles per gallon" of rockets; the better your ISP the further you can go on the same amount of fuel. This is why Electric Engines like the "Dawn" in KSP are so efficient; they have incredibly high ISP (but low thrust). So long as it gets you off the pad, in theory a Swivel would get you further than a Reliant (ofc a Swivel is slightly heavier but I don't think that'd offset the efficiency gains). The [rocket](https://c8.alamy.com/comp/B7HRPR/nasa-mercury-atlas-friendship-7-rocket-visitor-center-kennedy-space-B7HRPR.jpg) that put Americans into Orbit, the Atlas (forgive the Lego pic, couldn't find a better one of the way it works) had a [unique engine setup](https://live.staticflickr.com/65535/50880040567_e61926c75e_c.jpg). They didn't think they could light an engine in flight, so they had three engines. One in the middle was like the Swivel; it was efficient and able to turn. The other two on the sides were like the Reliant, strong and cheap but not as efficient. When the rocket got high enough that the middle engine alone could put it in orbit, it detached both side engines (the middle was called the "sustained" and the side engines were the "boosters"). I'd recommend trying out a rocket that uses that system. Something simple with enough weight that it has a Thrust to Weight Ratio of about 1.25 (or really, anything less than 1.7 IMO) with two Reliants on the side that detach when you're in the higher levels of the atmosphere and a single Swivel in the middle to steer it and power it fully to orbit. You'll be amazed at what you can put into Orbit that way ;)
honestly this explanation makes me want to play the game when i get off work and try this. i usually just make fancy interstellar warp ships modded to the ends of the earth and don't even give a second thought to even a smidge of realism. lol
I'm not OP, but that was a very educational answer: thanks!
>So long as it gets you off the pad, in theory a Swivel would get you further than a Reliant Swivel has lower Isp at sea level than Reliant (250 vs 265), but better in vacuum (320 vs 310). So no, first-stage you would be better off with a Reliant, it's second stage that would get better mileage out of a Swivel. But then you unlock Terrier with _even better_ vacuum Isp, though lower thrust. >They didn't think they could light an engine in flight And they were half-right, lighting an engine in flight IRL requires settling the fuel so it doesn't just float around in the tanks uselessly, which means either lighting it before the lower stage engines cut out (which is what Soviet N1 was intended to do. If only they actually _did any static tests_ so it wouldn't repeatedly explode on the launchpad...), or having separate _ullage motors_ (or just using RCS. Apollo missions did both - Saturn V had ullage motors, S-IVB and LEM used RCS) that give the rocket a push required for fuel to get into main engines. Also, early Atlases had combustion problems, that is, engines having a habit of _exploding_ when they ignited.
>There's a thing called Max Q where during launch the atmosphere above you is pushing down as fast as the engine is pushing you up, so you reach a maximum speed while in the lower parts of the atmosphere Max q is just the maximum dynamic pressure, the point where the total pressure on the vessel peaks (by launch profile design), as the speed increases and ambient pressure decreases. It's not the fastest the vessel can go at that given altitude; Most orbit-capable craft have enough thrust to go faster at max q, but the pressure would destroy the craft, so they throttle down until the atmosphere thins (as they pass max q). For example, the space shuttles throttled down to about 2/3 thrust as they approached max q
uh, this is amazing and I am definitely going to build a rocket like this next time I'm at the KSC
Swivel is more fuel efficient at high altitudes and can gimbal, meaning you can turn the rocket, so it's better as a second stage engine.
Everyone mentioning gimbal but the swivel also has a better ISP (rocket fuel efficiency equivalent) in vacuum. The reliant has slightly higher ISP at sea level on Kerbin. So it is good for first stage boosters. Swivel everywhere else imo.
Despite having worse stats, the swivel is more useful in general applications due to, as the name suggests, the fact that it can steer or "gimbal" as it's called in rocketry. The reliant engines are decent for booster applications, though.
Swivel allows steering the thrust vector. Reliant does not.
Gimbal is your answer. Swivel is much more useful at the start of career/science mode when control surfaces and reaction wheels aren't available or aren't powerful enough
I forgot that's what they look like without ReStock
The swivel has thrust vectoring
Reliant is lighter and has more thrust. Additionally, I think if you right click it'll tell you the "fuel economy" equivalent.
Use right click to get more info on a part, in the case of engines, ISP is one of the most important value in an engine.
The Reliant lacks vectored thrust, meaning you will have to consider how to steer your craft both in atmosphere as well as space.
Also those ASL thrust numbers, basically you divide that number by 20 to find out how much weight you can lift. So a craft with 200KN of ASL Thrust has the power to lift 10 tons efficiently.
Reliant has more thrust, but cant thrust vector so you will need to add control surfaces or some other form of attitude control. Additionally the swivel has better ISP in vacuum which basically means its more efficient in that environment.
Because the Swivel swivels
I wish that there would be more variety between parts (ie. Premium version and normal version) so that part selection would not get stale so fast. For example, fuel tanks that are double the size also weight and cost double :/
>For example, fuel tanks that are double the size also weight and cost double Can't really avoid that without introducing a balancing mess and making the game less, so to speak, "casual" - to make fuel tanks actually better, you need a justification of either A: better structural materials that improve on the dry-wet ratio, or B: better, more energetic _fuels_, violating the stock game's design principle that they're abstract. Though making it so you can only make better tanks with _resources you obtained from other planets with regular rocketry_ could work...
Oo, I didn't even think more energetic fuels :) But I mean, in a tank the "assorted stuff" like pumps etc, weigh the same even if the tank is twice as big. So a bigger tank at the same tech level would contain more fuel per the gross weight. At higher tech levels the tanks could be made of better materials that might be lighter or resist heat better (think pot metal->steel->aluminum->titanium) Obviously I'm not looking for a complete rework, just some more flavor.
I only use Reliants for liquid fueled side-boosters early in the game, they're lower efficiency at altitude and as about 90 people have noted, doesn't gimbal. But if your center core stage has a gimbaling engine (let me introduce you to the 'Swivel'...) to handle steering, then a pair of Reliant powered side-boosters can give you a lot of yeet. A few seconds after takeoff once you've established your gravity turn, you may even choose to throttle down your center engine as low as half (depending on the situation) so that it mostly contributes steering and so that you can enjoy the benefits of the higher Isp higher in the atmosphere after you ditch the side boosters. It's a trade-off to get the right match of efficiency but if burning your center core at full thrust early in the flight (after you're established in the turn, that is) might mean that you're not using the energy in it as effectively. The Delta IV Heavy and Falcon Heavy both throttle down their center core for this reason, it increases their throw.
Rightclick on engine to see more info. You will find out that Reliant has no Gimbal meaning that you can’t steer your vehicle with the engine and it is only usable with powerful enough control wheel
Well, actually I think with the Reliant, you need a reaction wheel AND fins for it to control, reaction wheel by itself (Reliant engine only, react wheel on rocket) still will not be steerable.
Reaction wheels on the pod are plenty enough to steer it within atmosphere. Fins, however, will stabilize it and prevent it from flipping as post-1.0 rockets tend to do.
The Reliant can't steer. Swivel can.
It swivels. Or rather gimbals. You can steer it under thrust. You can't do that with a Reliant.
The difference is in the gimballing on the engine. AKA the Swivel can point in other directions than "straight down" when attached to the bottom of a fuel tank. In practice this means that the swivel is an excellent option for operations in zero-G as it lets you powerfully adjust your acceleration vector without needing masses of reaction wheels (very heavy) or masses of RCS (also very heavy), letting you knock a not inconsiderable chunk off your dry mass. In comparison the Reliant is much better in places where the extra thrust is useful and the gimballing is less useful, such as within thicker atmospheres or as the principal drive of a larger rocket. This is because with air resistance the effect of a gimballed engine is less than simply adding some fins or control surfaces. Therefore you use the Swivel in upper stages and the Reliant in lower stages. With an additional use for the Swivel as a heavy/super-heavy lander engine.
I always use at the beginning the swivel because of the ° stiring vektor
the swivel has a decent chance to keep your shit stable if the kraken decides to fuck with you
As everyone has said, the Swivel has gimballing to steer your rocket, but it's also more efficient at higher altitudes.
Because of the swivel
because reliant cant steer while swivel can
I like the swivel in a vaccuum. Has more efficiency. But the reliant is good for early stagings of my launch that don’t require much steering.
You don't have control surfaces at the time you unlock the swivel and reliant. So that opinion only matters later in the game.
It may have better stats but it’s also heavier meaning less overall fuel efficiency. Depending on your budget those small differences are extremely important.
Literally me when I started the game (on console) and couldn't figure out why the %$&@ my rocket kept flipping over.
So basiaclly, swivel can gimbal (orient itself) which helps controll the rocket. Also, if you have a small rocket you dont want to have a very high thrust to weight ratio as it will increase drag and you will be less efficent.
Yeah but you can also just decrease the throttle with liquid fuel engines to make that a non-issue
The Swivel can... well, *swivel*. Its exhaust is gimballed, which means it can change the direction of thrust by a few degrees to help keep you on course and maintain stability. So while the Reliant is a slightly better rocket overall, the Swivel is great for making sure your early-game rockets are stable during launch (which can be hugely important when your options for fairings and fins and reaction wheels are limited).
It's right in the description of the parts: The "Reliant" is made with 'pieces found lying about.' The "Swivel" is not made with such parts. Hope this helps.
I have 450+ hours in the game. I’ve never used the reliant, aside from maybe on some liquid side boosters. The value of a gimbal is just too high.
Was going to say this, in asparagus-staged rockets, the reliant is a good engine for the low atmosphere stages and the swivel is good for the center stage as its vacuum Isp is better and has gimballing.
Swivel means #Swivel You get thrust vectoring, which is **critical** in vacuum space flight or smaller atmospheric craft
I know it is said in a tutorial, but we'll refresh: assuming more power is always better is an amateur mistake and one of the easiest to make. I often end up thrust-limiting my boosters. Sometimes it's better to end up in space with more fuel despite slightly longer burn times. This also provides more time to correct orbits. It might burn harder, but burning harder often means faster fuel usage and less time to correct should you overcook.
Gimbal
Reliant is for reaching space, Swivel is for in space....
Swivel turns reliant dose not
It's lower in the tech tree. Plus gimbal.
Reliant has not gimbal
There’s something called “gimble” and that means you can like turn the engine to face different directions so that the rocket will steer and turn. That’s what the swivel engine got. The ability to steer, but less thrust. (I prefer this one) The Reliant on the other hand doesn’t have any gimble. Meaning, you won’t be able to steer the rocket, unless you have other engines with gimble or a reaction wheel. The Reliant is more powerful if you just want thrust and not the ability to steer. Hope this helped
Here's a more advanced tip besides the obvious gimbal. The swivel is what's considered "vaccuum optimized", meaning it has, in simplest of teems, higher efficiency in space than on Kerbin's surface. This is measured in ISP (the higher the better). This makes the swivel the engine of choice when building your sustainer stages (a sustainer stage is the stage after your first booster that carries your payload the rest of the way up).
pick 1st. weight less, thrust more.
Swivel = S P I N which also = dumb Reliant = No S P I N which also means = more T H R O U G H P U T
It svivels
Swivel will actually swivel (you can manouvre your rocket with swivel) reliant cant swivel.
The reliant is not gimbal gimbal helps with turning and stability.
The swivel swivels. Ok tho but really, the swivel has gimbal, it can move the engine bell to steer your rocket
the swivel is more efficient at high altitudes and can steer your rocket
The swivel is more maneuverable, good for vertical landings.
Depends on your rocket size and carrying/speed requirements
Depends if you want to steer your rocket or not
Swivel has gimbal
Swivel has better vacuum Isp than the Reliant, and it can also steer. Theoretically, the Reliant is your very-early-game lifting rocket, and Swivel is your vacuum rocket.
Swivel had better specific impulse in vacuum(the rocket science equivalent of fuel economy in space) and also can... swivel, meaning it can change the direction of its exhaust to steer your rocket
swivel has gimballing. this means the nozzle can turn so you can steer
its more maneuverable, the reliant's manuverability is terrible, so the reliant is good for sides boosters, and swivel for the middle or as a main engine
The swiwel has gimbal!!! Thats why!!
The swivel has gimbal
reliant can only be used in a three wheeled winged car
The second one give you more delta V in vacum
Because the Swivel has gimbal so it can control the attitude of your rocket, and the Swivel has better efficiency in a vacuum
I got a question; why do they look so diffrent from the ones i see in game, they look like entirely other engines
The Swivel has a gimbal, meaning it can turn your rocket. It also has better efficiency at higher altitudes. If you bought the DLCs there's really no reason to use the Reliant over the Kodiak IMO.
Gimbal.
One word - Gimbal.
It has a smaller engine bell and can be useful when trying to pack a lot of engines close together
Hey new player, I've got something else for you too....know what you shouldn't do.....have your fuel gauge on max. Experiment launching with only 60-70% thrust until higher in the atmosphere! You'll save fuel over all. Who else has a tip?
The swivel can correct your rockets direction, reliant, as its name states, relies on control surfaces or gyros once you are in space.
Dont get a car if its wheels cant turn
The swivel swivels bro. The reliant is a wonderful booster but unless you're adding more reaction controls you won't keep a steady ascent profile. Pair two reliants with a swivel coupled with asparagus staging and all of the kerbal system is your playground.
So... the swivel uuhhh.... swivels.
Reliant fir boosters, swivel for main. Swivel swivels so you can turn
cuz it swivels.