LV-1 engine, does it need an ISP boost, or am I missing its use?

[mudkest]

I'm wondering about the use of the LV-1 engine, build a few lightweight probes in the VAB and it seems, apart from the an absolute light-weight probe for mun/minmus flybys I cant seem to get any use out of it that the rockomax 48-7s will do better.

I used engineer redux for delta-v display, made a satellite consisting of a cube probe core and a small reaction wheel wich is the lightest option for a controllable probe at 80kg. add some mass-less batteries and solar panels to keep it light and I noticed the following delta-v numbers

1 oscar-b tank and 1 LV-1 engine gives 1172 delta-v. a 48-7s gives 971 delta-v. Meaning if you get it into low kerbin orbit first, the lv-1 might just be able to get into mun/minmus orbit, but maybe not even that. Not like there is anything to do then anyway as its just a probe core, a reaction wheel, a battery and some solar panels. So lets add a mystery goo unit for science. Mass for the satellite core goes up to 230kg without engines/fuel tanks. Sticking to the 1 oscar tank, the LV-1 no gives 593 delta-v and the 48-7s 582 delta-v. Not enough to even get to the Mun for a fly-by. But interesting to note that delta-v difference at this point is negligible, with a whopping 11 more dleta-v for the small lv-1 engine.

Next step, add 1 oscar tank to the setups. the bare satellite with 2 tanks and a LV1 engine now gets 1841 delta-v versus 1628 for the 48-s. You can land it on the mun/minmus, maybe even get it back to crash on kerbin but again no science or anything. For the goo setup the lv-1 gives 1036 delta-v and the 48-7s 1040, making the 48-7s the more efficient choice. Not that it can do much.

so lets try with 3 tanks. Lv-1 gets 2285 delta-V versus 2111 on the 48-7s. Again adding a goo gives the lv-1 1384 delta-v to play with and the 48-7s 1414.

lastly lets compare the 2 engines with a round-8 tank instead. The LV-1 gets 1707 delta-v and the 48-7s 1486 on the bare probe. With the mystery goo added this goes to 936 for the LV-1 and 934 on the 48-7s.

considering these numbers, is there *any* use for the lv-1 engine other then shooting a small probe core on a one-way trip to the mun or minmus? as soon as you add anything other then mass-less modules the 48-7s engine gives more delta-v. or is it pointless without a boost to ISP?

[Bill Phil]

Let's just say that the LV-1 needs to re-balanced...

Maybe make the LV-1 have a bigger nozzle and give it a higher Isp?

[smartech]

I recommend reading those wonderful charts optimal engine choice for desired TWR and delta-v.

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Generally, the LV-N is usefull for bigger craft with lots of fuel, which would ammortize its large weight.

[Luis]

OP is talking about the LV-1 'ant' engine, not the LV-N nuclear engine.

[magnemoe]

OP is talking about the LV-1 'ant' engine, not the LV-N nuclear engine.

Yes, the LV-1 has become more relevant for all the satellite contracts, they are nice to put up an probe core with an antenna and two solar panels especially then they are secondary payloads.

[Decho]

I have no issue with the LV-1 itself, though the fact that it's cost is higher than 48-7S makes no sense to me whatsoever.

[Jouni]

By default, I oppose all rebalancing suggestions that involve making something more efficient. We've been getting more efficient engines in almost every update for a long time, while the challenges have remained the same or become even easier.

If the niche for the LV-1 is too narrow, it can be made wider by nerfing the 48-7S to match the performance of the 24-77. As an additional bonus, the LV-909 also becomes more useful.

[SRV Ron]

Oscar B tanks are very inefficient and expensive compared to a single FL-T100. Even the Round 8 is a better option then the Oscar B in terms of fuel carried and total mass.

Example below before the Stayputnik became a receiver only.

[zarakon]

I think the real problem is that the 48-7s is just way too good due to its extremely high TWR and low cost

[Xavven]

I think the real problem is that the 48-7s is just way too good due to its extremely high TWR and low cost

I agree the 48-7s needs to be nerfed. We have here an engine that outperforms all engines in its class and neighboring classes.

Building a lander? 48-7s

Building a heavier lander? 48-7s

Building a satellite? 48-7s

Eve ascent? 48-7s

What about all the lower stages, the mid stages, and the upper stages of an Eve ascent lander? 48-7s. Twenty of them.

As for the LV-1, I remember when it received a thrust buff last year. People said exactly the same thing: "it doesn't need thrust, it needs Isp!" In any case, now that we've reached scope completion, I hope to see more focus on game balance up through release.

[GusTurbo]

I have no issue with the LV-1 itself, though the fact that it's cost is higher than 48-7S makes no sense to me whatsoever.

This is the biggest problem. If it were dirt cheap, it would make a lot more sense. In fact, it should be the cheapest liquid engine since it seems so primitive compared to all of the other engines in-game.

[moogoob]

I agree as to how its cost should be lower. In sandbox, it's very useful = it's for when you need an engine of some sort but don't necessarily need a good one, so to save on payload weight you add the absolute minimum engine that still counts as an engine - the LV-1 "Ant".

[LethalDose]

By default, I oppose all rebalancing suggestions that involve making something more efficient. We've been getting more efficient engines in almost every update for a long time, while the challenges have remained the same or become even easier.

If the niche for the LV-1 is too narrow, it can be made wider by nerfing the 48-7S to match the performance of the 24-77. As an additional bonus, the LV-909 also becomes more useful.

I think the real problem is that the 48-7s is just way too good due to its extremely high TWR and low cost

I agree the 48-7s needs to be nerfed. We have here an engine that outperforms all engines in its class and neighboring classes.

This is the biggest problem. If [the LV-1] were dirt cheap, it would make a lot more sense. In fact, it should be the cheapest liquid engine since it seems so primitive compared to all of the other engines in-game.

I agree as to how [the LV-1's] cost should be lower. In sandbox, it's very useful = it's for when you need an engine of some sort but don't necessarily need a good one, so to save on payload weight you add the absolute minimum engine that still counts as an engine - the LV-1 "Ant".

Ever been getting ready to write something, and then realize everyone else already made your point?

These are all great points, especially Jouni's first line as far as general philosophy for rebalancing parts.

Summed up:

• The LV-1 is too expensive (though development costs should still be high, IMO).
  
• The 48-7s is just way too good. Nerfing it (IMO, both TWR and ISP) would be a better solution.
  

[Renegrade]

Ever been getting ready to write something, and then realize everyone else already made your point?

Yep! Just happened right now, exactly as you experienced, plus one!

These are all great points, especially Jouni's first line as far as general philosophy for rebalancing parts.

Summed up:

• The LV-1 is too expensive (though development costs should still be high, IMO).
  
• The 48-7s is just way too good. Nerfing it (IMO, both TWR and ISP) would be a better solution.
  

Agreed in both cases, although I'd like to caution that the LV-1 is not a useless engine and DOES have a niche already. On very small/light probes, it does outperform the 48-7S. For instance, if you made a probe for contracts without goo/science jr, it would be mostly massless parts (ox-stats, comm16s, thermometers, Z-100s, etc), an OCTO or HECS (100kg), and fuel tank and engine. If you put one or two round8s on, the ant will give you more delta-v due to it's lower mass (or upwards of four oscars). Very similar to the 48-7S over the LV-909.

I'm not saying some nerfing isn't required, just that people not go overboard least we simply swap the LV-1 and 48-7S in terms of niche size.

One alternative to messing with Isp might be to increase the mass of the 48-7S, as that would widen the LV-1's "low mass" niche some, and also address the 48-7S's crazy TWR.. although I'm not sure it's really that good to have it up at 30kn (that's almost the same as 50 afterall).. having it down in the 12-20 range would space out the thrust values for small engines a bit better. (4-12-50, 4-15-50, 4-20-50?)

(Also at the same time the stats for the 24-77 should be brought inline with the 48-7S, or at least closer)

[Dodgey]

Personally I think it should be changed to a mono-propellent engine. That would make it perfect for small probes or even an OMS.

[hazarada]

Currently we got engines that are unfairly light (or weightless) and/or have unfair amounts of thrust making others options in their usage vicinity pretty worthless. Also the nuclear and ion engines.. don't want to rag on them for no reason but they are kinda oddballs that stick out in the wrong way right now. I think all of the engines need to be rebalanced at some point since the LV-1 is just the tip of the iceberg. Also, just nerfing the 48-7s would be really bad for building probes, the dV jump for that size crafts is already ~4k to ~7k compared to ion, nerfing the 48-7s to be in line with LV-1 would just make it like 2k to 7k. Not saying that probes need to travel that far but large gaps like that in potential part performances force the players hand.

Edited January 5, 2015 by hazarada

[vidal90]

Personally I think it should be changed to a mono-propellent engine. That would make it perfect for small probes or even an OMS.

Led flood lights is very important to your home nowaday. They helps your home brighter and more security.

I agree with this idea, You should change it to be a mono-propellent engine

Edited January 6, 2015 by vidal90

[NERVAfan]

I think the 48-7S should keep the same specific impulse but lose a lot of thrust... maybe down to 15 or even 10.

[Spatzimaus]

There's another balance point the developers have never played with yet, and that's the LF:Ox mix balance. Once we get fully tweakable fuel tanks, you could easily see something like the LV-1 made more viable by the simple expedient of changing it from the default 11:9 ratio to something more LF-heavy. That'd make it a better choice for vessels that are already going to be using a lot more liquid fuel than oxidizer (i.e., spaceplanes), although who knows if it'd be enough for us to use it in spite of its other issues.

Regardless, right now it's just one of the MANY parts that no one in their right mind would use.

[hoojiwana]

As others have pointed out, the problem isn't that the LV-1 isn't good enough, it's that the 48-7S is too good, making the other options less attractive.

[Slugy]

Count me in with the "nerf the 48-7S" crowd. It really never needed the boost it got a while ago.

A moderate boost to the LV-1's ISP would be OK too. (edit: and I only just noticed it got a thrust buff ages ago...)

Edited January 5, 2015 by Slugy

[wumpus]

I agree the 48-7s needs to be nerfed. We have here an engine that outperforms all engines in its class and neighboring classes.

Building a lander? 48-7s

Building a heavier lander? 48-7s

Building a satellite? 48-7s

Eve ascent? 48-7s

What about all the lower stages, the mid stages, and the upper stages of an Eve ascent lander? 48-7s. Twenty of them.

As for the LV-1, I remember when it received a thrust buff last year. People said exactly the same thing: "it doesn't need thrust, it needs Isp!" In any case, now that we've reached scope completion, I hope to see more focus on game balance up through release.

let's be serious here:

Heavier lander? The only way you can get more deltaV out of a 48-7s than a LV-909 and >1 TWR on the Mun is with a command chair. The ISP just isn't there. The 48-7s is great for many things, but returning kerbals from gravity wells isn't one of them. Light landers are fine.

[Edit: WRONG! Note that I my tests might be correct for extremely heavy landers (note that I assumed that filling with enough fuel to the point that TWR~=1 would show maximum advantage and that advantage would hold on lighter craft). Take a LV-909 if you need to transfer, capture, decend, ascend, re-transfer, etc. 48-7s will likely make a better lander.]

Eve???? While I haven't landed on Eve yet, the math screams "USE AEROSPIKES" for lower stages. Even on upper stages there is something like a 00.8% advantage over LV-909 *in the soup* and *using a command chair* (and orange tank). When I go to Eve, I'll bring aerospikes and LV-909 (of course, by then one of these could get buffed/nerfed). [note: according to kerbal engineer you shouldn't use the poodle on Eve. Use 4 LV-909s instead].

[Edit: EVEN MORE WRONG! This is only true for verticle staging. As far as I can figure out, the rocket equation only considers the mass(empty) of the entire asparagus stage (i.e. no payload), so the fact that 48-7s wins without payload means it should be used for all lower stages as well. You aren't going to ascend Eve without asparagus staging, are you?]

While the LV-1 could really use an ISP buff, most of the cult of the 48-7s is assuming that the mass empty part of the rocket equation will be similar on other craft as it is to the last probe stage. [EDIT: Nope. The 48-7s really is that good (although you probably want to have docking ports or other tech before switching to mass 48-7s use, it still doesn't like payloads). I'll have to make sure I make an Eve ascent before it gets nerfed.]

Edited January 6, 2015 by wumpus
boy was I wrong.

[monophonic]

+1 for balancing, although I might propose a compound approach: Up the LV-1 ISP a little, drop the 48-7S thrust a little and increase it's weight a little.

[Slugy]

let's be serious here:

Heavier lander? The only way you can get more deltaV out of a 48-7s than a LV-909 and >1 TWR on the Mun is with a command chair. The ISP just isn't there. The 48-7s is great for many things, but returning kerbals from gravity wells isn't one of them. Light landers are fine.

A 48-7S has better dV, for a Mun landing and return (~2000dV) up to around 2300Kg - i.e. anything smaller than a 2man lander can - rather more than a command chair! On modest sized vessels the saved weight vs a lv909 is considerable.

It also has a TWR on the Mun of 2 with a payload of 9200Kg.

Typically I've found it to often be the "best" option for anything it has the TWR for, including 2 man landers once the weight of the launch vehicle is factored in.

Take a look at these very useful graphs, in which the lv909 is rarely to be seen:

http://forum.kerbalspaceprogram.com/threads/45155-Mass-optimal-engine-type-vs-delta-V-payload-and-min-TWR

[cantab]

Heavier lander? The only way you can get more deltaV out of a 48-7s than a LV-909 and >1 TWR on the Mun is with a command chair. The ISP just isn't there. The 48-7s is great for many things, but returning kerbals from gravity wells isn't one of them.

I think you need to check again. And remember, the fair comparison isn't to merely change the engine on an otherwise-identical lander, but to change the engine AND the amount of fuel to meet the target delta-V and TWR, then compare the masses. Do that and it's very rare for the 909-engined design to turn out lowest mass. Of course mass isn't the only design consideration.