ARM engines.

[SSSPutnik]

Great post a2soup.

[Red Iron Crown]

Career mode Is and Always has been like that, you progress the tree, You unlock better parts and therefore things get easier, The only thing that has changed is a raise in the upper limit of how big you could send up at once.

It's not the same, though. Until now, all the chemical engines save for the overpowered 48-7S have fallen on or below the same TWR vs Isp curve. The ARM engines are all significantly better in this regard, especially the KR-2L. See stupid_chris' chart for what I mean.

[TranquilTempest]

The graph does not factor in the dry mass of craft. with just an probe core the lightest engines works far better because of the dry mass at the end is so low.

Take an medium sized lander, two man landing can, landing gear and extra stuff and you find that the extra ISP of the 909 wins out, as dry mass is closer to 3 ton, the extra 0.5 from the 909 is not so important.

An LV-N on the other hand would increase the size of the craft a lot making it an bad idea, however with an kethane miner you might want to use them as long as its not just from minmus surface to orbit as the dV requirements would be to low for the LV-N

Yes it does, the vertical axis is dry mass.

[Jouni]

How the game will be 1 year from now is not relevant unless sandbox is removed, not to me at least, because reasons already stated (I think career is boring and I don't expect things like the addition of a budget to make it not boring). As long as sandbox exists there should be balance in sandbox, unless they remove sandbox.

I think Squad is going into a direction, where the career mode is the game, and the sandbox is a sandbox, where you can try your ideas without game constraints. If we don't like that, we can vote with our money and not buy any additional copies of the game.

Also, there is no reason why you could not have the engines be balanced for both sandbox and career.

I mean all you have to do is make the bigger engines more cost effective per ton to low kerbin orbit, which is easy. Here is how:

1: Maintain reasonable balance between the engines performance wise in sandbox.

2: Make the bigger engines cheaper per unit of mass in career mode

That doesn't make sense. The SLS is a result of 60 years of research and development in spaceflight. With that much effort, you are supposed to get rockets that are cheaper, more efficient, and more powerful than the early Apollo-era rockets. I'd like to see some real progress in the future career mode, instead of some nerfed tech tree, where the technology doesn't really get any better.

[Varses]

I notice that most people saying the balance is fine say something along the lines of 'in the full game they'll cost a lot and be higher up on the tech tree'. Which, to me, is a kinda implicit admission that they're OP as they are right now. In career mode, they unlock at the same tech levels as the Mainsail--there is not a significantly higher science cost. And since there's no currency system at the moment, that argument is irrelevant. EDIT: For example, yes, the KR-2L costs 4x as much as the Mainsail. But the mainsail costs the same as an LV-T30 and less than an LV-T45.

In the game as it currently is, they are overpowered. There is no argument about that. The have the same costs as the Mainsail and far superior performance. I'm getting kinda annoyed that people are being all handwavey and saying 'but it will be balanced eventually' to try to argue that they're balanced now. They're not. Not in career and not in sandbox. Maybe they will be in the future but that's irrelevant at the moment.

Edited April 3, 2014 by Varses

[magnemoe]

Yes it does, the vertical axis is dry mass.

You are right, more that I prefer the 909 over the LV-N for smaller landers as its hard to design with unless you use two and this brings it into another weight class.

[Pds314]

Let's see, comparing the new engines:

Kerbodyne Advanced Engine vs. Mainsail

Pros:

significantly higher Isp above sea level

Higher thrust per parts

Much Higher thrust per weight (best in game by a significant margin)

Cons:

Lower thrust per area

takes up a 3.75 meter node

is marginally heavier

may be overkill

The quad-engine vs. Mainsail

Pros:

Better Isp both ASL and vacuum.

Better TWR

More than double the thrust per parts.

Cons:

Takes a 3.75-meter node

Cannot have parts attached below it

Marginally less thrust per area

Sticks out beyond node size

Heaviest and physically largest engine in the game

May be overkill

Double-engine booster vs. Mainsail and vs. Orange tank:

Pros:

Better Isp, both ASL and in vacuum

Higher thrust per parts

Higher TWR if one compensates for fuel and mass of an orange tank inside.

More durable since engine cannot break off of fuel tank

Most thrust per area of LF engine (500/node vs. 375/node for mainsail, 215/node for LV-T30 or 120/node for 48-7S)

Fewer parts for the same result.

Cons:

Has a lower TWR when used without fuel

Has a lower mass ratio when used without engine

Cannot have parts attached below it.

Could possibly be overkill.

New SRB vs. Old SRB:

Pros:

More thrust

More fuel

Better TWR

Best thrust/area of almost anything (the new launch escape system technically has 750/node vs. 650, but not many sane people would use it to get into space considering it's 0.5 second burn time)

Cons:

Dry mass is pretty high

May be too tall to be practical in some cases

650 thrust that can't be turned off... Should only be used in conjunction with the new LES.

Edited April 3, 2014 by Pds314

[NecroBones]

I would like to see them add a true equivalent to the Rocketdyne F-1 (Saturn-V lower-stage engines). The thrust was about 6770 KN, at about 263 ISP (according to wikipedia).

[Hurry- Starfish!]

Yup, they're overpowered.

And I'm saying that as an avid KW Rocketry user.

[Giggleplex777]

The LFB and KS-25 cluster aren't very OP when used with the large parts. In fact, their real life equivalents are much more powerful and weigh about the same (the SSME only weighs 3.5 tons and produces more than 2200 in of thrust). They're only overpowered if you use them in a an asparagus configuration, which is true for pretty much every engine.

The KR-2L, on the other hand is OP. It's meant to be an upper stage engine, but it has a high TWR than the KS-25 cluster and is also more efficient. I'm finding that my upper stages are larger than my first stages!

[Pds314]

An interesting note on thrust/area: 125/node is about 1 atmosphere of pressure. This means that:

Mainsail: 3 atm

LV-T: 1.8 atm

LV-N: 0.47 atm

Poodle: .45 atm

LV-909: .42 atm

Aerospike/RAPIER: 1.4 atm

Skipper: 1.3 atm

Advanced Engine: 2.2 atm

Quad engine: 2.8 atm

LF booster: 4 atm

Ion engine: .063 atm

This means that, for example, the aerospike, could lift a 14-meter-high cylinder of water above it on Kerbin, while the Ion could lift just a 63 cm one (if it weren't trying to lift itself) speaking of which, did you know that the PB-ion engine is roughly the density of a comparably sized chunk of solid lead (PB)?

[Twreed87]

I don't see any problem with their power. They were designed to increase the amount you're capable of achieving. A long time ago, the only other body in this game was the Mun, and they didn't even have 2.5m parts. You could've said they were overpowered for just going to the Mun and back. But with bigger parts, came bigger goals. Now we've got orange jumbo tanks and mainsails that aren't needed for a trip to the Mun, but make going to Jool a whole lot easier. And now they've added giant Class E asteroids, so they need parts that are up to that task.

You should always build the rocket that's best suited to the task, and not much more. Right now, the way the game works, there's no reason to not go as overboard as possible in any situation. That should change eventually. Eventually, the downside to launching a tiny probe into orbit with an asparagus-staged SLS would be the massive amounts of wasted fuel, including fully loaded fuel tanks you'd probably just dump in orbit.

[Pds314]

Yes, they are better in many ways, but they are also trickier to use effectively on medium-sized rockets.

[mdosogne]

I like them. I've unlocked the whole tech tree in .23, and I expect better engines than the Mainsail (which I didn't use anyway…) Now I can build a stock Eve ascent vehicle that might actually be pointy enough to plough through that atmosphere soup.

[Pds314]

The other thing is that most tasks are too small to warrant these behemoths. You COULD spend 300000 fuel getting a tonne into orbit with a 600-part monstrosity, but it makes more economic sense to spend 300 fuel to do it with a tiny 60-part SSTO that you can then recover.

[mdosogne]

A lot of people don't play career mode at all, only using Sandbox. In Sandbox its more critical to have balanced parts.

The point of Sandbox mode is to keep you busy while Career mode is developed, and for players who prefer role-playing to career grinding. It doesn't make sense for all engines to be "balanced in sandbox"; better engines represent improvements/breakthroughs in technology; higher technology isn't available at the beginning of the space race, and costs more to manufacture. I expect these engines to be balanced by correct placement in the tech tree and appropriate construction costs.

[Mordrehl]

I don't see any problem with their power. They were designed to increase the amount you're capable of achieving. A long time ago, the only other body in this game was the Mun, and they didn't even have 2.5m parts. You could've said they were overpowered for just going to the Mun and back. But with bigger parts, came bigger goals. Now we've got orange jumbo tanks and mainsails that aren't needed for a trip to the Mun, but make going to Jool a whole lot easier. And now they've added giant Class E asteroids, so they need parts that are up to that task.

You should always build the rocket that's best suited to the task, and not much more. Right now, the way the game works, there's no reason to not go as overboard as possible in any situation. That should change eventually. Eventually, the downside to launching a tiny probe into orbit with an asparagus-staged SLS would be the massive amounts of wasted fuel, including fully loaded fuel tanks you'd probably just dump in orbit.

^^ This ....

Once there's an economy and budget ... the cost of a launcher capable of lifting 100 tons into orbit is going to prevent you from using said launcher to lift your 5 ton Mun lander. Sure you might get there a whole lot quicker with the big boy, but you're probably not going to have a sustainable income stream from contracts to keep wasting so much fuel.

It'll also probably evolve to the point where we'll be having to do debris recovery to reuse/salvage parts.

[Killerdude8]

These new parts are just that, New parts, from the Modern era of Rockets, They will be significantly better than the old Apollo Era parts and That's how it should be.

It's like complaining that the New 2013 Camaro is too much more powerful than your 76, then wanting GM to change the new Camaros to be more inline with your older model, It's new, It's better, Get over it.

[Mordrehl]

A lot of people don't play career mode at all, only using Sandbox. In Sandbox its more critical to have balanced parts.

Actually, I think the ultimate goal of this games experience will be Career mode ... so it's far better they have balanced parts for Career mode now, than it is to have them balanced in Sandbox. Sandbox modes are generally there for you to play around with every possible configuration since there's no downside to stacking as many over sized parts as you'd like. True, current Career mode is not that far off Sandbox because there is no economy/budget

[Varses]

To all the people using straw man arguments to justify not nerfing the SLS engines: I don't think anyone who's advocating nerfs wants to remove the 3.75m parts or engines. In fact, I'm even ok with them being overall better than 2.5m engines. I just don't think the difference between 3.75 parts and 2.5 parts should be as enormous as it currently is.

For example, the Rockomax 48-7s is overpowered--most people agree. But it's only slightly overpowered. Which is why people weren't whining loudly about it needing nerfs. For the most part, it was in a good place. The new SLS parts should occupy the same area--slightly more powerful than other engines but not completely outclassing them. At the moment, they completely outclass anything smaller. That's the issue.

[magnemoe]

I was against an nerf until I did this.

cargo 123 ton, large and medium 3.75 tank. mass in orbit 412 ton.

weight back on space center is 269 ton. http://i.imgur.com/1XUnaSC.png 500 m/s spare dV.

Rocket is easy to make and looks pretty good, you need some strut to separate the 6 boosters from core, 6 struts to connect bosters to next one and core at top and bottom.

Entire flight was done by mechjeb. Only other mod was service compartment to hide mechjeb, batteries and rcs.

Putting 200 ton cargo into orbit with asparagus is not new, 120 ton cargo to orbit SSTO is new.

(an SSTO who cant land safe is pointless (no you don't need to land all launches, just know that you could))

In short it removes any challenge with launches.

And yes, I did some suborbitals, an Mun flyby two Minmus missions with multiple landings, need some Mun biomes to unlock some parts, the mun rover was launched with my first SSTO who is single stack and is rated for 18 ton.

Edited April 3, 2014 by magnemoe

[ayana]

I wouldn't say they need to be scaled down. The problem I'm facing is rather that I have no payload these new engines are necessary for. If they were supposed to open up more possibilities, they have.

I look at it this way: maybe the Mainsail just wasn't the best engine around to begin with, and the improvements to TWR and efficiency are just the result of design.

But, I play with FAR and at most one onion layer, so perhaps I have a different perspective as to what's overpowered or not.

Edited April 3, 2014 by ayana

[Jouni]

Putting 200 ton cargo into orbit with asparagus is not new, 120 ton cargo to orbit SSTO is new.

(an SSTO who cant land safe is pointless (no you don't need to land all launches, just know that you could))

We already had jet-boosted SSTO rockets with payload fractions over 40%. I never built them for payloads larger than 40 tonnes, because I don't like rockets with too many engines. Still, it was possible to scale them up to an arbitrary size.

[Red Iron Crown]

We already had jet-boosted SSTO rockets with payload fractions over 40%. I never built them for payloads larger than 40 tonnes, because I don't like rockets with too many engines. Still, it was possible to scale them up to an arbitrary size.

How do you think a jet-boosted KR-2L-based SSTO rocket would compare, payload fraction-wise?

[magnemoe]

How do you think a jet-boosted KR-2L-based SSTO rocket would compare, payload fraction-wise?

Problems with jet ssto rockets is the low power during takeoff, for large payloads you need loads of jet engines, your don't need an very strong rocket engine,