Squad Should Re-Balance the Poodle Engine

[Jouni]

Basically, there's three things coming together:

• the 38-7S is way overpowered -- in almost every use case where the 909 or Poodle should rule, the 38-7S is better. And cheaper, too.
  
• in many designs, the center spot is reserved for the docking port, while the engines are mounted radially.
  
• 220kN is an odd number. Most use cases require a lot more, or much less.
  

The first is an objective fact -- check Traverts charts.

The 48-7S used to be overpowered. With the "new" engines in 0.23.5 and the rebalancing in 0.24, it's now comparable to or slightly worse than most large engines (Skipper and up). Now it just makes the LV-909 mostly obsolete, without really affecting the other engines. Tavert's charts are a good starting point for engine comparisons, but they don't tell how significant the performance differences are, and they also don't take part counts or other design issues into account.

The other two are arguably a question of playstyle, but I'm of the opinion that the game is funneling the players' decisions towards designs where the Poodle would be out of place.

The Poodle has a very common use case as an upper stage engine for launching 10-30-tonne payloads with rockets that resemble real rockets. It's not relevant in all playstyles, but it's very important for the players who build traditional rockets. Of course, it may well be that Squad decides to solve the career mode balance mess by forcing everyone to use reusable/recoverable designs, while making traditional rockets obsolete.

[Francois424]

Not specifically for the Poodle, but for engines in general, there is a hue gap in efficiency from 380 to 800. Those "Useless/weak" engines should have better ISP to compensate, but that might make them unbalanced for the game as a whole if done (who is to stop players of mounting 10 of them and have say 550isp instantaneously ?

But yeah take those 2-3 weak engines and boost their ISP to ~500-550; they'll see much more uses than in their current iterations.

[prophet_01]

Not specifically for the Poodle, but for engines in general, there is a hue gap in efficiency from 380 to 800. Those "Useless/weak" engines should have better ISP to compensate, but that might make them unbalanced for the game as a whole if done (who is to stop players of mounting 10 of them and have say 550isp instantaneously ?

But yeah take those 2-3 weak engines and boost their ISP to ~500-550; they'll see much more uses than in their current iterations.

I am not an expert, but as far as I know there is no 500 isp engine. I've heard of a couple of engines with more than 400, but as far as I know there aren't any LfO engines with an isp of 500 or more (the lower isp in ksp is more an issue of balancing the 1/10 th size of kerbin anyway). And also I don't think that isp related changes are needed. The gap betwen the skipper and the poddle seems to offer enough room to make every engine unique. And regarding the poddles upper stage capability that were mentioned, I have to disagree. A 50 km apoapsis with the early stage(s) is arguably not the most efficient gravity turn profile (and with a more realistic atmosphere, the desired altitude for the start of the circulisation burn gets even lower). I can understand that people may do theire lifters and ascent progiles differrently. There is nothing wrong about that. But if you are saying my plsystyle isthe only reason why I have arguments for a change I could easily say the same about you.

This is not going to help. My suggestion would be to raise the thrust to about 300 snd slightly increase the weight (although I'm not sure thst is even necessary).

Since there obviously are people that have a use for the poddle, you can always argue that it's not needed. The issue that has been mentioned multiple times is the lack of an engine with something like thrust betwen 300 - 400. I see 2 solutions: a new engine or a rebalancing of the ones we have. If the poddle gets a higher thrust the gap would be mostly closed. In my opinion there is no significant new gap created by doing that. But I admit that this can be evaluated more objectively by the people that use the poddle a lot currently.

Edited November 24, 2014 by prophet_01

[Jouni]

This is not going to help. My suggestion would be to raise the thrust to about 300 snd slightly increase the weight (although I'm not sure thst is even necessary).

Since there obviously are people that have a use for the poddle, you can always argue that it's not needed. The issue that has been mentioned multiple times is the lack of an engine with something like thrust betwen 300 - 400. I see 2 solutions: a new engine or a rebalancing of the ones we have. If the poddle gets a higher thrust the gap would be mostly closed. In my opinion there is no significant new gap created by doing that. But I admit that this can be evaluated more objectively by the people that use the poddle a lot currently.

The gap below the Poodle is much larger than the gap above it:

[table]

[tr]

[td]Thrust[/td]

[td]Engine(s)[/td]

[td]Mass[/td]

[/tr]

[tr]

[td]650 kN[/td]

[td]Skipper[/td]

[td]3 tonnes[/td]

[/tr]

[tr]

[td]--[/td]

[td]--[/td]

[td]--[/td]

[/tr]

[tr]

[td]220 kN[/td]

[td]Poodle[/td]

[td]2 tonnes[/td]

[/tr]

[tr]

[td]--[/td]

[td]--[/td]

[td]--[/td]

[/tr]

[tr]

[td]80 kN[/td]

[td]4x 24-77[/td]

[td]0.36 tonnes[/td]

[/tr]

[tr]

[td]60 kN[/td]

[td]3x 24-77[/td]

[td]0.27 tonnes[/td]

[/tr]

[tr]

[td]50 kN[/td]

[td]LV-909[/td]

[td]0.5 tonnes[/td]

[/tr]

[tr]

[td]40 kN[/td]

[td]2x 24-77[/td]

[td]0.18 tonnes[/td]

[/tr]

[tr]

[td]30 kN[/td]

[td]48-7S[/td]

[td]0.1 tonnes[/td]

[/tr]

[/table]

There are several reasonable engines or engine combinations below 0.5 tonnes that can provide at most 80 kN of thrust. Above that, we either need a several times heavier engine (the Poodle), ugly hacks (using multiple inline engines or using inline engines smaller than the stack), or an unreasonable number of engines. On the other hand, if the Poodle is too weak, we only need to increase engine mass by 50% to get much more power. The gaps in engine mass matter more than the gaps in thrust, because excess thrust can always be tweaked down.

[Laie]

There are several reasonable engines or engine combinations below 0.5 tonnes that can provide at most 80 kN of thrust. Above that, we either need a several times heavier engine (the Poodle), ugly hacks (using multiple inline engines or using inline engines smaller than the stack), or an unreasonable number of engines.

"Unreasonable" is in the eye of the beholder. Or designer, which probably is the same person in most cases.

But yes, you're touching on an important point: While the LV-909 is basically a scaled-down, slightly worse variant of the Poodle, the 48-7s blows both out of the water in almost all circumstances. A cluster will deliver a Poodle's thrust at 0.7-0.8 tons rather than two. And if a mere 150kN will do, you can build a smaller cluster, while a Poddle is a Poddle. I still believe the actual problem is the 48-7S being too good; it's TWR is on par with the biggest baddest engines in the game, no other small engine comes even close. Not even the LV-T30, which isn't a small engine in my book.

It should also be noted that TWR beats ISP for most use cases. I don't think an improved ISP would increase the poodles' attractiveness.

The Poodle has a very common use case as an upper stage engine for launching 10-30-tonne payloads with rockets that resemble real rockets. It's not relevant in all playstyles, but it's very important for the players who build traditional rockets. Of course, it may well be that Squad decides to solve the career mode balance mess by forcing everyone to use reusable/recoverable designs, while making traditional rockets obsolete.

Well, that is the current state of things, isn't it? The game greatly encourages players to recover as much as possible.

[prophet_01]

if you tweak excess thrust down you are using something that's heavier with a worse isp. If the gap is closed thrust wise (with adequate mass and isp) you are getting more efficient results and get a nive amd clean staging without cliping and a dozen decouplers + structural parts (they also whoble a bit). You left out the t-30 and t-45. From my point of view those close the gap below the podle. Maybe it's just me but I never had the need for another 100-150kN engine, since most 2.5m designs require more thrust in the ascent stages and in orbit thrust doesn't matter as much. I would still prefer an additional 100kN for the podle and a slight increase in weight

[Ravenchant]

I think a part of why Poodle isn't as popular is because it's intended as a vacuum engine, yet it doesn't look the part. The word silly comes to mind- its nozzle is comically short and a bit on the small side for its rated power; also the 2.5m attachment node means you lose some space which could be used otherwise (say, with RCS tanks or batteries)

[Murph]

I think a part of why Poodle isn't as popular is because it's intended as a vacuum engine, yet it doesn't look the part. The word silly comes to mind- its nozzle is comically short and a bit on the small side for its rated power; also the 2.5m attachment node means you lose some space which could be used otherwise (say, with RCS tanks or batteries)

It's intended as a lander engine, hence why it's short, so that it works nicely with the large sized landing legs. Poodle with an 8 or 16 2.5m tank, 2.5m RCS tank, 2.5m battery, and 2.5m lander can works very nicely for things like Mun & Minimus landing. That's the intended niche for it, which it seems to fit quite nicely.

I won't claim that it's perfectly balanced as-is, since the entire game needs some balancing before release. I do think that it should be left alone, and not "fixed" to cover a multitude of other roles, like Kerbin ascent, transfers, interplanetary, etc. Let it just be a convenient small height 2.5m engine for low-gravity landers, which it is. There are other roles where it can be successfully used, but the primary role that it needs to be good for is a fairly simple 2.5m low-gravity lander. People who are not interested in using 2.5m smallish landers need to remember that others do like to use them.

If other roles need significantly different engines, then those need to be added, not at the expense of losing the 2.5m smallish lander engine. Changing it to have a ridiculous Isp makes no sense, artificially plugging the realistic large gap between LF+O and NERVA makes no sense.

If the current poodle doesn't seem to be working well for you (aiming at nobody in particular, this is the general "you"), I think that it's far more likely that the fault lies with you and not the engine. It works very well in the right circumstances, and you should change your design to use a different engine if your circumstances don't suit the poodle.

[Wanderfound]

Speaking of rebalancing...I would like to see the LF-N nerfed in some way. Not necessarily through ISP or thrust; a major price increase would probably do the job.

At the moment, there is very little reason to use the high-efficiency LFO vacuum engines outside of landers; they just can't compete with the LV-N. Keeping the ISP characteristics of the LV-N but beefing up the cost to make it a very expensive option would give some viability to Poodles and LV-909's.

[Ravenchant]

It's intended as a lander engine, hence why it's short, so that it works nicely with the large sized landing legs. Poodle with an 8 or 16 2.5m tank, 2.5m RCS tank, 2.5m battery, and 2.5m lander can works very nicely for things like Mun & Minimus landing. That's the intended niche for it, which it seems to fit quite nicely.

Its length doesn't need do be changed though For example, Ven's stock part revamp has a service engine that doesn't seem any longer than the Poodle yet looks like one would expect a vacuum upper stage/lander to look.

[rkman]

Assuming that efficiency matters, no matter how any engine is balanced it will be a good choice only within a narrow range of application. Outside of that range it's either overkill, to heavy/to low engine twr (if thrust is tweaked to a lower value), or simply results in to little thrust.

This is less of an issue for launch stages, because there is room for engine clusters (and room for boosters). But for mid- and upper stages engine clustering quickly becomes awkward, both in terms of building and in how it looks.

Imo KSP needs more options for mid- and upper stage engines and/or it needs (better) support for engine clustering.

[CaptRobau]

Assuming that efficiency matters, no matter how any engine is balanced it will be a good choice only within a narrow range of application. Outside of that range it's either overkill, to heavy/to low engine twr (if thrust is tweaked to a lower value), or simply results in to little thrust.

This is less of an issue for launch stages, because there is room for engine clusters (and room for boosters). But for mid- and upper stages engine clustering quickly becomes awkward, both in terms of building and in how it looks.

Imo KSP needs more options for mid- and upper stage engines and/or it needs (better) support for engine clustering.

A more procedural engine fairing system would be a good way to make engine clustering on upper/landing stages easier. The decoupler would decide what size the fairing would be. So if you add a LV-909 to a 2.5m tank and a 2.5m decoupler below that the engine fairing would be 2.5m as well. Procedural fairings does it a bit hacky, so I imagine that with access to the game itself Squad could make something even better/more intuitive.

[Jouni]

"Unreasonable" is in the eye of the beholder. Or designer, which probably is the same person in most cases.

If we are ready to use "unreasonable" engine combinations, the game doesn't really lack anything (except perhaps a high-thrust 3.75 m engine for rockets without boosters). We can mix LV-Ns with conventional engines to get Isp in the 500-600 s range, we can augment the Poodle with smaller engines to get 300-400 kN of thrust, and so on.

I still believe the actual problem is the 48-7S being too good; it's TWR is on par with the biggest baddest engines in the game, no other small engine comes even close.

Making it similar to the 24-77 would probably solve the problem without creating any new ones. It would still be a small high-thrust engine, but its Isp would be low enough that it wouldn't compete with the LV-909 anymore.

Well, that is the current state of things, isn't it? The game greatly encourages players to recover as much as possible.

Right now the game doesn't really encourage anything, because everything is so cheap and money is so easy to get.

if you tweak excess thrust down you are using something that's heavier with a worse isp.

The whole idea was about having a bigger engine than the current Poodle. With a small (50%) increase in mass, we get an engine that can be tweaked for up to 3x the thrust of a Poodle. The difference in Isp is around 5%, which is negligible, when we're talking about stages with much less than 3 km/s of delta-v.

If the gap is closed thrust wise (with adequate mass and isp) you are getting more efficient results and get a nive amd clean staging without cliping and a dozen decouplers + structural parts (they also whoble a bit). You left out the t-30 and t-45. From my point of view those close the gap below the podle.

The LV-T30 and the LV-T45 have awkward shapes for 2.5 m payloads. If we're willing to ignore such issues, we can use dual LV-T30s for 430 kN of thrust, with engine mass halfway between the Poodle and the Skipper. That's basically the same as the bigger Poodle you'd like to have.

Maybe it's just me but I never had the need for another 100-150kN engine, since most 2.5m designs require more thrust in the ascent stages and in orbit thrust doesn't matter as much. I would still prefer an additional 100kN for the podle and a slight increase in weight

I haven't needed a 100-150 kN engine either. What I have needed is an ~1-tonne 2.5 m engine for crew shuttles and other small 2.5 m upper stages/payloads, where the Poodle would be too heavy. Such engine might produce around 100 kN of thrust, but that's just a coincidence.

[prophet_01]

A more procedural engine fairing system would be a good way to make engine clustering on upper/landing stages easier. The decoupler would decide what size the fairing would be. So if you add a LV-909 to a 2.5m tank and a 2.5m decoupler below that the engine fairing would be 2.5m as well. Procedural fairings does it a bit hacky, so I imagine that with access to the game itself Squad could make something even better/more intuitive.

I couldn't agree more. Cluster engines could rly need a more intuitive integration. Since they already are integrated in a basic form, I don't see a reason why that aspect shouldn't be improved further. It could be a fair compromise

[dryer_lint]

it's pretty much useless for anything but landers.

So... use it for landers?

[Tweeker]

I posted about this some time ago in another thread,

http://forum.kerbalspaceprogram.com/threads/75661-The-7-Balance-Points-of-engines-in-a-Full-Career-Mode/page2

basically I think the problem is that the poodle is too small thrust wise, it needs to have it's thrust raised enough that it isn't competeing with the lv-t30/45

It seems to make a poor choice for a lander engine, as it can be replaced by clusters of lighter more efficient engine such as the lv-909, every time I've tried to use the poodle I end up swaping it out for something else that ends up working better.

I think the real key to balancing it is giving it a roll where it isn't competing with other engine. such as a 350-500 thrust engine with good efficiency.

[Jouni]

I posted about this some time ago in another thread,

http://forum.kerbalspaceprogram.com/threads/75661-The-7-Balance-Points-of-engines-in-a-Full-Career-Mode/page2

That discussion was before the engine rebalancing in 0.24, when the mass of the Poodle was reduced from 2.5 tonnes to 2 tonnes. Before the rebalancing, the Poodle had 4.4x the thrust and 5x the mass of an LV-909, while it has 4.4x the thrust and 4x the mass now.

I think the real key to balancing it is giving it a roll where it isn't competing with other engine. such as a 350-500 thrust engine with good efficiency.

The Poodle is a vacuum engine, just like the LV-909. In comparison to general-purpose engines, such as the Skipper, the LV-T30, and the LV-T45, it should have a lower TWR and a higher vacuum Isp. Additionally, because it's the smallest engine in the 2.5 m Rockomax line, it should weight less than the Skipper.

The basic restrictions are that the Poodle should weight less than 3 tonnes, and its thrust should be less than 133 kN/tonne. If we keep its current mass, the thrust can't be increased past 250 kN, without the Poodle being too close to the LV-T45 in TWR. With 2.5 tonnes of mass, the thrust can't be more than 310 kN. Increasing the mass past 2.5 tonnes doesn't seem reasonable, as the weight of the Skipper is only 3 tonnes after the rebalancing.

[Tweeker]

The Poodle is a vacuum engine, just like the LV-909. In comparison to general-purpose engines, such as the Skipper, the LV-T30, and the LV-T45, it should have a lower TWR and a higher vacuum Isp. Additionally, because it's the smallest engine in the 2.5 m Rockomax line, it should weight less than the Skipper.

All this is true, but the poodle's problem isn't it's TWR, or ISP. The update raised the poodle'sTWR, but the TWR could be 30 and it would still be hard to find a use for it. Once you are in orbit you want the lightest engine with the highest ISP. That is the LV-909, until the lv-N comes along The LV-909 is the choice for interplanetary travel. This is a good progression, and short of raising the poodle's ISP no amount of tweaking will make the Poodle a better choice for interplanetary travel.

If the ISP of the LV-909 is lowered or the Poodle raised then the Poodle might have a place as a gap filler between the LV-N and the LV-909, but this would make it a real niche engine, existing only to replace the LV-909 and then to be replace by the LV-N

As a lander engine it is ok, but it would have to be lifting a very large lander, most of the time smaller engines have plenty of lift with less weight, or more weight for fuel. Additionally using 4 radially mounted LV-909s has the added benefit of making the lander fatter radially, so the landing gear can be farther out, making the lander more stable. Again tweeking the TWR, ISP, ETC. will not compensate for this.

If the thrust of the Poodle is raised it moves out of the lv-t30, lv-t45, Aerospike thrust cluster. This is important because it giving the poodle it's own role, upper stage lifter. One reason I suggest 300-500 thrust is that in the past a single poodle proved to be too anemic to lift the last stage of a rocket into orbit. Another reason is that this moves it out of the thrust range of multiple LV-909s. If it's weight is increased to maintain it's TWR the only problem is that it gets too close to the Skipper. There is plenty of room to push the Skipper's weight and thrust up without stepping on any other engine.

[Jouni]

All this is true, but the poodle's problem isn't it's TWR, or ISP. The update raised the poodle'sTWR, but the TWR could be 30 and it would still be hard to find a use for it. Once you are in orbit you want the lightest engine with the highest ISP. That is the LV-909, until the lv-N comes along The LV-909 is the choice for interplanetary travel. This is a good progression, and short of raising the poodle's ISP no amount of tweaking will make the Poodle a better choice for interplanetary travel.

If the ISP of the LV-909 is lowered or the Poodle raised then the Poodle might have a place as a gap filler between the LV-N and the LV-909, but this would make it a real niche engine, existing only to replace the LV-909 and then to be replace by the LV-N

The Poodle is an upper stage engine. It's meant for providing the last 800-1500 m/s before reaching orbit. If you don't build rockets with upper stages like that, then you probably don't need the Poodle at all. If you do build such rockets, it's a very useful engine.

Interplanetary travel is the domain of the 48-7S before nuclear engines. It's marginally less efficient than the LV-909, but its substantially higher TWR means that you can carry more fuel and often have more delta-v for the same mass.

If the thrust of the Poodle is raised it moves out of the lv-t30, lv-t45, Aerospike thrust cluster. This is important because it giving the poodle it's own role, upper stage lifter. One reason I suggest 300-500 thrust is that in the past a single poodle proved to be too anemic to lift the last stage of a rocket into orbit. Another reason is that this moves it out of the thrust range of multiple LV-909s. If it's weight is increased to maintain it's TWR the only problem is that it gets too close to the Skipper. There is plenty of room to push the Skipper's weight and thrust up without stepping on any other engine.

It seems that you really want a fourth Rockomax engine between the Poodle and the Skipper, possibly making the Poodle a bit smaller and the Skipper a bit larger in the process.

The ideal TWR for an upper stage is around 0.7. You can live with as low TWR as 0.5, and a higher TWR will obviously work, but if the TWR is above 1, you're just carrying useless engine mass to orbit. Let's assume that the payload is 20 tonnes, which is quite typical for a medium-lift launch vehicle in stock KSP. With such payload capacity, you can launch crew shuttles, space station modules, landers, command modules of interplanetary ships, and other common payloads. Let's add a Poodle (2 tonnes), a decoupler (0.4 tonnes), a probe core for deorbiting the upper stage (0.5 tonnes), and an X200-16 fuel tank (9 tonnes). The total mass of the upper stage and the payload is 31.9 tonnes, and the upper stage provides around 1100 m/s of delta-v. Add a lower stage with a Skipper throttled down to 80%, an orange tank, and an X200-16 fuel tank, and two boosters with a Skipper and an orange tank each, and you have a very reasonable rocket with payload fraction around 12.5%.

Due to the low delta-v requirements of reaching orbit and the unreasonably light fuel lines, KSP rockets often don't have upper stages at all. The same 20-tonne payload could be launched with three stacks of a Skipper and an orange tank each, with fuel lines from the boosters to the central sustainer stage. Compared to an upper stage engine, which needs to be lightweight and efficient, a sustainer engine can be less efficient, but it has to be more powerful. In the Rockomax engine series, the Skipper and the Mainsail can be used as sustainer engines, while the Poodle works better as an upper stage engine.

[Tweeker]

The Poodle is an upper stage engine. It's meant for providing the last 800-1500 m/s before reaching orbit. If you don't build rockets with upper stages like that, then you probably don't need the Poodle at all. If you do build such rockets, it's a very useful engine.

Every time I've tried to use the poodle in this role it ends up coming up short, It just doesn't have enough thrust to perform in this role. I usually end up replacing it with a skipper, or 2 or more of radially mounted lv-t30s. It isn't a matter of TWR or ISP it's just a matter of not being able to get enough velocity quickly enough to make orbit.

Interplanetary travel is the domain of the 48-7S before nuclear engines. It's marginally less efficient than the LV-909, but its substantially higher TWR means that you can carry more fuel and often have more delta-v for the same mass.

This is only true to a point. For the smallest lightest payloads, at 1 ton the lv-909 surpasses the 48-7s beyond ~4900 m/s delta-v for 2 tons the LV-909 is superior beyond ~2400 m/s delta-v as the landers get heavier the trend continues. The 48-7s may rule the probe world, but if you land anything other than the lightest lander anywhere except Gilly the LV-909s ISP will trump the superior TWR of the 48-7S.

It seems that you really want a fourth Rockomax engine between the Poodle and the Skipper, possibly making the Poodle a bit smaller and the Skipper a bit larger in the process.

I don't want a 4th rockomax engine, I really, really, don't. I suggest that the Poodle be given more thrust and it's weight be raised to maintain it's TWR.

[Murph]

I don't want a 4th rockomax engine, I really, really, don't. I suggest that the Poodle be given more thrust and it's weight be raised to maintain it's TWR.

I don't want the Poodle to do what you want it to do, I really, really don't. It's just right for a 2.5m lander at present. For Mun & Minimus, it's not too powerful, not too weak, pretty much just right for an 8 or 16 2.5m tank, 2.5m RCS tank, 2.5m lander can, legs and miscellaneous small extra bits. I suggest that the Poodle be kept more or less as-is, other than fairly small balancing as part of the final balancing pass running up to 1.0 release.

It's clearly primarily intended for that 2.5m smallish lander role. What you need is a 2.5m engine that is between the Skipper and Poodle, a 4th Rockomax engine, although personally I think the Skipper is generally suitable for non-lander stuff that's heavier than the Poodle is suitable for.

[Hodo]

I use the Poodle for a lot of my bigger landers, it is just useful mainly because of its low profile.

It isn't meant to be a first stage engine.

[Murph]

I use the Poodle for a lot of my bigger landers, it is just useful mainly because of its low profile.

It isn't meant to be a first stage engine.

Never mind first stage, it's not really meant to be any stage of primary lift engine, although final stage to orbit for a larger satellite might be appropriate. It can be ok for an upper stage on smaller 2.5m payloads, but when it's not enough, the correct solution is a Skipper (either bigger 1st and/or 2nd stage, or a Skipper 3rd stage), not calling for changes to the Poodle which make it less suited to landers.

[Jouni]

Every time I've tried to use the poodle in this role it ends up coming up short, It just doesn't have enough thrust to perform in this role. I usually end up replacing it with a skipper, or 2 or more of radially mounted lv-t30s. It isn't a matter of TWR or ISP it's just a matter of not being able to get enough velocity quickly enough to make orbit.

So it's a matter of TWR. Your payload may be too large for the Poodle, you may switch from larger engines to the Poodle too early, or your ascent path could requires a high TWR for circularization. Can you show an example of a rocket where you tried using the Poodle?

This is only true to a point. For the smallest lightest payloads, at 1 ton the lv-909 surpasses the 48-7s beyond ~4900 m/s delta-v for 2 tons the LV-909 is superior beyond ~2400 m/s delta-v as the landers get heavier the trend continues. The 48-7s may rule the probe world, but if you land anything other than the lightest lander anywhere except Gilly the LV-909s ISP will trump the superior TWR of the 48-7S.

For real missions, such as Apollo-style Duna missions, the delta-v figures are usually within 10% of each other for the same mass. The main difference is that we can have a higher TWR (and, as a result, faster and more accurate transfer burns, as well as more efficient landings) with the 48-7S.

I don't want a 4th rockomax engine, I really, really, don't. I suggest that the Poodle be given more thrust and it's weight be raised to maintain it's TWR.

So you want to remove the current Poodle from the game, even though it's a useful engine for many purposes, while being a bit too heavy and a bit too powerful for other purposes?

[prophet_01]

I definetly see the need for an upper stage engine with roughly 400kN. I don't use the poddle cause the alternative options seem superior to me, but obviously there are quite a couple of people around here that disagree. So I guess the 4th rockomax will be hard to avoid when finding an apropriate solution :/