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Whats your favourite engine in KSP?

POLL TIME!  

95 members have voted

  1. 1. Whats your favourite type of engine?

  2. 2. What is your No.1 engine priority?



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We have a simulair thread for real engines, but what about the KSP engines?

discuss here!

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I love the Puff Monoprop engine. If only there was an inline version of it, so you can use it like every other engine.

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2 minutes ago, Physics Student said:

I love the Puff Monoprop engine. If only there was an inline version of it, so you can use it like every other engine.

I also like the Puff, especially for my LKO only transporters. I think having an Inline version would be very nice indeed.

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2 hours ago, Physics Student said:

I love the Puff Monoprop engine. If only there was an inline version of it, so you can use it like every other engine.

You can always just rotate and offset to make it inline... but yeah I agree, a proper inline version would be pretty darn cool. I don't find myself using it overly much, mostly because it isn't really that good... but I do have a mono-propellant lander design inspired by Raptor's designs :) 

Also, the part of this question about what I look for in an engine... that very much depends on circumstances. I'm not overly fussy about individual isp, thrust, mass or cost but how they all work together to find the optimal engine for that vehicle. For example, I have a rocket which uses a single Mainsail engine on the first stage - for lighter loads I *could* get away with slapping a vector on the underside, but that makes it ridiculously expensive. On the other hand, I have a shuttle with three vectors (very expensive) because it needs the trust and gimbal ability - cost becomes a non-issue as the craft is recovered completely :)

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The Terrier is probably my MVP. Almost every ship will have them. I'm a huge fan of the Spark for return stages, though. On atmospheric worlds like Duna and Laythe, I always use the Dart for landers.  Just an all-around great engine (other than the lack of gimbal). And to get to orbit, the Kickback is my go-to guy. Cheap and powerful.

For the question itself, in this order; thrust, mass/isp equally, then cost. I never use nukes, and would use an Ion only when I have to. For instance, if there were a gun pointed at my head.

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I choose LF/O and High thrust.

The thing is, apart from some crazy LF only designs that set of options gets you everywhere, other engines do not
Ultimately, I like every engine, but I had to choose ... thus :confused:

I like nuclear engines to because they're efficient (I would love IONs more then I do now if higher physical timewarp were a thing, yeah there's that mod, ikr)
You don't use jet engines only either, unless your only building pure LF only spaceplanes. 
I also do spaceplanes. 
I rather get a heavy lifter RAPIER or for that matter LF/O spaceplane to LKO where I will jettison a mission specific payload rather then making a SSTO to everywhere. Of course many people do try to make the most capable spaceplane out there. To me it's just to finicky to overdesign a spaceplane so it can land on laythe, jettison payload and get back to Kerbin while I can jettison a payload in LKO who gets it there and back again easier and with more payload.

But that is just my style of course :) 

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My "favorite" engine is simply the one that's ideal for the circumstances :D

My design philosophy is "cheap & cheerful"

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Jet engines: Panther and Whiplash

Lf+Ox engines: vector and aerospike

No.1 engine priority: looks and sound (no, really. I love engine exhaust with cool blue glow or other exotic type of exhaust appearance. As for sounds, I love the progressional noise like the one on OPT mods (which goes from low and the high pithed noise when afterburner activates at certain airspeed))

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My #1 engine priority is how the engine works with the craft. There is no single killer consideration for me.

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Tough question.  The Spark, Terrier, NERV, Swivel, Poodle, Skipper, TwinBoar and Kickback all get pretty heavy use from me.  I also have an irrational attachment to the Rhino despite objectively knowing it's got bad stats.

If I had to pick a "favorite" (as opposed from most used or best), I guess I'd go with the Terrier.  To quote @GoSlash27 above, to me it's the epitome of "cheap and cheerful."  Simple yet effective, and great in everything from sustainer stages in small rockets, to orbital shuttles, to midsize landers.  

Edited by Aegolius13

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7 hours ago, Physics Student said:

I love the Puff Monoprop engine. If only there was an inline version of it, so you can use it like every other engine.

I just stick a linear on the bottom of things and hit H.  You can move it to the exact center with the 'move' tool with snap on.  If you felt like being fancy you could make it available as an engine under advanced tweakables.

I like the Ant.  It can do amazing things for tiny probes.  It's like a poor-man's ion drive. 

Edited by Corona688

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Probably the kicker, with a mention that I used hammers all but exclusively before beta (nearly all delta-v came from hammers).  Also a huge fan of NERV and terriers.

Having "favorites" interferes with design, although for things like terriers/poodles they have wide enough use to justify using them enough to be a "goto" use.  I suspect mamouths and twinboar for heavy lifts play a similar role, but you shouldn't pick an engine just because it is your favorite (when your second stage is a kicker you know you have an SRB problem*).

* this isn't to say that it might not be the "right" design.  But such things are so unlikely that you shouldn't have considered it or wasted the time checking.

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1 hour ago, regex said:

My #1 engine priority is how the engine works with the craft. There is no single killer consideration for me.

Yup. There is no do-all kind of engine IMHO. You pick the engine depending on your current needs.

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The panther. The ability to switch between efficent and insane makes it so useful in all of my atmospheric builds (read: all of my builds)

EDIT: 100th Post!

Edited by TheMadKraken2297
100th post!

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The Vector is my most used engine. I put a lot of strange shaped things into orbit and when drag is high, MOAR thrust is the answer. Well, not the only answer but the one I prefer.

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2 hours ago, wumpus said:

Probably the kicker, with a mention that I used hammers all but exclusively before beta (nearly all delta-v came from hammers).  Also a huge fan of NERV and terriers.

How do you use the kickback?  It gives me trouble.  Very difficult to control and super-expensive.

2 hours ago, wumpus said:

(when your second stage is a kicker you know you have an SRB problem*).

One of my favorite small-payload boosters is seven BACCS in a star.  Four fire, then three.  It's difficult for me to improve upon cost-wise.

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52 minutes ago, Corona688 said:

How do you use the kickback?  It gives me trouble.  Very difficult to control and super-expensive.

One of my favorite small-payload boosters is seven BACCS in a star.  Four fire, then three.  It's difficult for me to improve upon cost-wise.

Attach two to side couplers on either side, then keep attaching kickbacks in pairs to them (don't pay for more than one side decoupler).  Setting on the launch clamps with a tiny angle to the East goes a long way.

Control is done by attaching two AV-R8 winglets North-South (for control up and down while heading East).  Optionally a liquid rocket in the center for control (sometimes you just want a vacuum rocket in the center).  If it is an option (career mode may get in the way), you should attach liquid fuel tanks above the kickers to supply any center rocket.

I'll have to try out the 7BACCS system.  I suspect that a single kicker + BACC will do the job better (although the height may interfere with career limitations).  Part of my love for kickbacks comes from previous editions where I'm reasonably certain they wildly outperformed (for money and mass) BACCS and Hammers (if they did, it's certainly fixed now).

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1 hour ago, Corona688 said:

How do you use the kickback?  It gives me trouble.  Very difficult to control and super-expensive.

I usually use them in conjunction with an LFO core stage, such as a Skipper and orange tank combo.  Using an SRB by itself is going to result in control troubles and very steep thrust curve.  But if you want to, you could look at adding either a set of fins, or a small LFO tank, and some little engines like the Spider or Ant.  

Have to disagree that they're expensive.  The thrust they produce is comparable to a Skipper, which costs about twice as much, even before you pay for the fuel and tank (yeah, they will provide less delta-v, but at a MUCH lower cost).  Alternatively, they cost approximately the same as a booster made of a Reliant and a couple FL-T800 tanks, but supply way more thrust.  

For their main role (supplying big dumb thrust to help an underpowered LFO core stage get off the ground), I think they're great.

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Yes to Kickbacks. I can't remember the last time I launched from Kerbin with out any. Most of my launches include at least 2, I've had as many as 12 on one ship though. I would say the average launch has 4.

As far as actual engines? The Terrier, it's just a vacuum workhorse.

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3 hours ago, Corona688 said:

How do you use the kickback?  It gives me trouble.  Very difficult to control and super-expensive.

Corona688,

 The Kickback is the least- expensive booster in the game when used properly (in terms of $ per tonne of payload accelerated). The general rule of thumb is 1 Kickback per 9 tonnes upper stage, and throttle it back to about 80% so you have 1.2G off the pad. This will get you about 1,700 m/sec DV from the pad; halfway to orbit.
 Using multiples in parallel to lift large payloads helps with the runaway train acceleration that they tend to exhibit as their fuel burns off. Throttle the earlier stages to burn hotter and the later stages to burn slower, jettisoning the burned out stages as you go.
 For ultimate cheapness, attach fuel tanks to the Kickbacks and plumb them to a liquid fuel core asparagus- style. This also adds controllability. If your central core happens to be a Twin Boar, you will be running just about as cheap as it is possible to be.

qudtYyO.jpg

140 tonnes to orbit for less than $100,000.

Best,
-Slashy

 

 

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1 hour ago, GoSlash27 said:

Corona688,

 The Kickback is the least- expensive booster in the game when used properly (in terms of $ per tonne of payload accelerated). The general rule of thumb is 1 Kickback per 9 tonnes upper stage, and throttle it back to about 80% so you have 1.2G off the pad. This will get you about 1,700 m/sec DV from the pad; halfway to orbit.
 Using multiples in parallel to lift large payloads helps with the runaway train acceleration that they tend to exhibit as their fuel burns off. Throttle the earlier stages to burn hotter and the later stages to burn slower, jettisoning the burned out stages as you go.
 For ultimate cheapness, attach fuel tanks to the Kickbacks and plumb them to a liquid fuel core asparagus- style. This also adds controllability. If your central core happens to be a Twin Boar, you will be running just about as cheap as it is possible to be.

140 tonnes to orbit for less than $100,000.

Best,
-Slashy

 

 

Throttling a rocket down almost never makes that stage more efficient, but having one set at full power and another set throttled down might let you add more kickbacks (and thus more cheap thrust).  You are sacrificing efficiency of the kickback to use it instead of a more expensive twin boar (so try to have as many at full thrust so you can drop them early).  Lots of variables to consider with these things.

Also that "runaway train acceleration" sometimes comes in handy to stabilize otherwise noodly rockets (if a rocket insists on being unstable where SRBs take off: try "more boosters").  While at least one real life model rocket engine maker suggests TWR>=5 for stability, I'm not sure it works with real-sized rockets in real life.

If I had 16 kickers at 80% thrust, I would at least experiment with breaking it into groups of 14 SRBs at 92% and reserve the remaining two for a second stage (don't ignore the use of putting drop tanks on both stages of kickbacks).  This may not leave you with a remotely circular orbit, but it should be more efficient in theory.

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10 hours ago, regex said:

My #1 engine priority is how the engine works with the craft. There is no single killer consideration for me.

exactly what I said only 10x more succinct.

8 hours ago, Aegolius13 said:

TwinBoar

Really? I never use this engine, mostly because it sticks out like a sore thumb compared to the other tanks (unmodded) but I usually find that I don't need it anyway. What circumstances do you use it in? Got any build pics floating around?

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55 minutes ago, wumpus said:

Throttling a rocket down almost never makes that stage more efficient, but having one set at full power and another set throttled down might let you add more kickbacks (and thus more cheap thrust).  You are sacrificing efficiency of the kickback to use it instead of a more expensive twin boar (so try to have as many at full thrust so you can drop them early).  Lots of variables to consider with these things.

Also that "runaway train acceleration" sometimes comes in handy to stabilize otherwise noodly rockets (if a rocket insists on being unstable where SRBs take off: try "more boosters").  While at least one real life model rocket engine maker suggests TWR>=5 for stability, I'm not sure it works with real-sized rockets in real life.

If I had 16 kickers at 80% thrust, I would at least experiment with breaking it into groups of 14 SRBs at 92% and reserve the remaining two for a second stage (don't ignore the use of putting drop tanks on both stages of kickbacks).  This may not leave you with a remotely circular orbit, but it should be more efficient in theory.

wumpus,

 In the case of SRBs, you have to throttle back when staging them off gradually, else you wind up burning them all out at the same time. I'm of the same mind as you about throttling back when using LF&O boosters, but solids are a different story. Solids cannot be vectored and have a much higher disparity between their acceleration at the pad vs acceleration just before burnout. Consequently, they must be tailored in order to facilitate controllability and drag/ heating issues.
 Running full- tilt can aid you in getting to orbit with less DV than not, but it overlooks the bigger picture IMO: Having a rocket that follows a precise gravity turn without undue effort and running into excessive drag at low altitude also helps total DV. Moreover, having a rocket that doesn't explode or flip during launch saves what's *really* important: Getting your payload to orbit for less money and effort.
 A SRB is, in effect, a fixed quantity of "boom". If you use all of it at once, you wind up with a cannon that wastes a lot of it's energy fighting drag and acting like an uncontrollable monster. If you rein it in some, it becomes more controllable and efficient.

 TL/DR: Throttling back a LF&O engine isn't a waste of the engine's potential, it's just a sign that you spent more cash and mass on engines than was actually needed for the job. Your glass isn't half-full or half- empty, you just have more glass than required.
 In the case of SRBs, the ratio of engine to propellant is fixed and you can't add more propellant, so the trick lies in expending the propellant you have as efficiently as possible. To take full advantage of them, they need to be dialed back from the stock setting.

Best,
-Slashy

 

46 minutes ago, MR L A said:

Really? I never use this engine, mostly because it sticks out like a sore thumb compared to the other tanks (unmodded) but I usually find that I don't need it anyway. What circumstances do you use it in? Got any build pics floating around?

MR L A,

 Oh, the Twin-Boar is an absolutely *stellar* engine! Best thrust to weight of all the LF&O engines, cheapest LF&O in terms of $ per tonne, good Isp at sea level, good Isp in a vacuum... It makes an awesome core engine and an awesome booster.

 If you're looking to put big tonnage into orbit for cheap, this is the engine you want. To compare it properly to it's brethren, subtract the cost and mass of a fully- loaded jumbo-64 tank and re-run the numbers.

Best,
-Slashy

 

Edited by GoSlash27

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48 minutes ago, MR L A said:

Really? I never use this engine, mostly because it sticks out like a sore thumb compared to the other tanks (unmodded) but I usually find that I don't need it anyway. What circumstances do you use it in? Got any build pics floating around?

Like Slashy said, the TwinBoar is a great launch engine (especially for Career) due to its phenomenal thrust and low cost.  The stats may look bad at first, but once you back out the mass and cost of the built-in fuel tank (which is equivalent to an orange tank), it's a monster.  For example, it's cheaper than the Mainsail, has significantly more thrust, and its ISP is only a little bit lower.

For any load too big to launch with a Skipper and some SRBs, I almost exclusively use TwinBoars and Kickbacks.  They can used as a decent core stage, though this might not be ideal if you're using 3.75m parts.  But where I think they shine the most is as radial boosters, with ~2 orange tanks worth of fuel sitting above them.  Since their relative weakness is ISP, they work very well in conjunction with a more efficient core stage (e.g., Skipper, Mainsail, Vector or even Mammoth).

Their major real weakness are:

-They have no bottom node, so you cannot put other parts beneath them.  But you'd pretty much never want to do this anyway, since the TwinBoar works best as a launch engine.  If you're making an Eve lander or something, you're probably better off with a couple Vectors.  

-Since the fuel tank is built in, you get it whether you want it or not.  But you almost always want a lot of fuel on top of this thing anyway, so again it's not much of an issue.

-The base is slightly wider than a standard 2.5m part.  This can lead to decoupling issues if you have parts attached to the longer side, but it's not too much of a problem to design around.

-Their ISP is the worst of the game's heavy engines.  But ISP is comparatively less important in your early stages, so this is more than a fair trade for the other advantages. 

 

Here's an example of a TwinBoar as launch stage, with the very simple task of getting a full orange tank to orbit.  I have not tested this one, but the numbers suggest it ought to be able to get to orbit.  

TULMJ6y.png

 

Here's a space station launch rig from a career or two ago, using TwinBoars as radial boosters.  By the time these cut out, the Skipper mounted under center was able to get me close enough to orbit that the Poodle above could finish the job.

Vpcz9ri.png

 

 

 

52 minutes ago, GoSlash27 said:

To take full advantage of them, they need to be dialed back from the stock setting.

I usually prefer to tame the Kickback's... kickback by pairing them with an LFO core stage.  This means the Kickbacks comprise less of the total thrust, which means they have a small impact on TWR by the time they burn out.  If I have more TWR than I need, my preferred solution is to add more LFO and/or downsize the engine, both of which can help increase delta-v.   

Throttling down the LFO engine is also a viable option, since this conserves higher ISP fuel for later in the flight.  For example, I sometimes pair a Swivel with a couple of Thumpers, and leave the Swivel at <1/4 throttle until the SRBs burn out.  This gives me enough control authority to steer, and avoids wasting too much Swivel fuel down low where its ISP is lousy.  This concept could probably be scaled up with Kickbacks and a big LFO engine like the Rhino.  

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5 minutes ago, Aegolius13 said:

Since their relative weakness is ISP,

I should add that Isp appears much more important to the naked eye than it winds up being in the relatively short burn times of launches. Generally, higher Isp comes at the cost of additional mass and $$ for the engine, but when you run the numbers, you find out that the lower Isp engine is not only cheaper, but lighter as well. You have to run a stage out for a while before the advantages of specific impulse come into play.

The Twin-Boar is a lurking beast in the launcher regime :D

-Slashy

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