is the nerv atomic engine usable any more?

[Confused Rock]

I haven't played in a while, and I've been confused about nerv engines ever since they became liquid fuel only. I still don't see any rockomax size fuel tanks that only hold liquid, and I don't think it's efficient to do regular rockomax tanks with the oxidizer removed. Are nerv engines actually efficient like this? do the engines use liquid fuel more than they would if they also used oxidizer or is the fact that they only use liquid fuel a direct upgrade?

[Chibbity]

It's only inefficent from a size and/or space perspective. Taking the Oxidizer out also removes the weight from the oxidizer, so the ship will be bigger than it needs to be, but that's no big deal.

Also, just use the 400 Liquid fuel only tank, you shouldn't need that many of them.

Nerv's are very efficient in space, but have low TWR. Only needing Lf is indeed an upgrade not only from an effiency stand point, but a logistics one.

[Confused Rock]

So if the poodle or literally any engine needed only liquid fuel it'd be a direct upgrade in that it still uses the same amount of liquid fuel? maybe I should've realised sooner.

[Chibbity]

Well, every engine has different rates it uses fuel in atmo vs. in space, so it's not quite as simple as that.

The Ion engine for instance, is the most efficient engine of all; but needs neither Lf or Ox.

Keep in mind the Nerv is heavy though, it's best used on long distance trips.

[Confused Rock]

Guess I'll figure out if the nerv is better or worse than it used to be, then.

[AlexMBrennan]

I still don't see any rockomax size fuel tanks that only hold liquid

The word I would have used is "annoying", but that is a correct observation - pure liquid fuel tanks are only available in 1.25m and spaceplane mk2/mk3

and I don't think it's efficient to do regular rockomax tanks with the oxidizer removed

A mk1-3 command pod with a jumbo 64 fuel tank with a Poodle gives you 5368 m/s delta V while using the same tank drained of oxidizer and a Nerv gives you 7130 m/s delta V. The break even point for this particular payload appears to be one X200-8 - if you pack more fuel tanks then the Nerv is better, otherwise the Poodle wins. [Get KER or MJ to see the numbers for your rocket]

In a perfect world you would fill the entire tank with liquid fuel to reduce dry mass per ton of fuel carried but this is not a perfect world.

do the engines use liquid fuel more than they would if they also used oxidizer or is the fact that they only use liquid fuel a direct upgrade?

I don't know - different engines use fuel at different rates, and I don't understand how you can work out which part of the difference can be attributed to the type of fuel used.

[Confused Rock]

suppose going into the files and manually editing an engine to test how it'd be on only liquid fuel would be a thing I should try.

[Manwith Noname]

If you're going to those sort of lengths, you might aswell write a module manager patch that makes a liquid fuel only rockomax tank too.

Edit:

I have not checked this but I think it would work...

+PART[Rockomax8BW]
{
	@name = Rockomax8BW_LF
	@RESOURCE[LiquidFuel]
	{
		@amount = 800
		@maxAmount = 800
	}
	!RESOURCE[Oxidizer]
}
+PART[Rockomax16_BW]
{
	@name = Rockomax16_BW_LF
	@RESOURCE[LiquidFuel]
	{
		@amount = 1600
		@maxAmount = 1600
	}
	!RESOURCE[Oxidizer]
}
+PART[Rockomax32_BW]
{
	@name = Rockomax32_BW_LF
	@RESOURCE[LiquidFuel]
	{
		@amount = 3200
		@maxAmount = 3200
	}
	!RESOURCE[Oxidizer]
}
+PART[Rockomax64_BW]
{
	@name = Rockomax64_BW_LF
	@RESOURCE[LiquidFuel]
	{
		@amount = 6400
		@maxAmount = 6400
	}
	!RESOURCE[Oxidizer]
}

Should make a copy of all the new Rockomax tanks that are liquid fuel only.

[maestro]

I used to make lots of Mun landers with Nerv engines but hesitated lately cuz I haven't played for a while.

[Mightylink]

Pro tip, use the engine plates to put liquid fuel tanks on instead of engines, then put the nerv engines on the bottom.

[andylaugel]

I routinely use "Nerv"-based tugboats for my heavy interplanetary needs. It's a bit slow to accelerate, but it works.
https://steamcommunity.com/sharedfiles/filedetails/?id=863737439