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A little twist on Launch Clamps.

AxleMC131

By AxleMC131
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AxleMC131

AxleMC131

Posted
Posted

So today I was running a very standard, run-of-the-mill Kerbal rescue mission in my KSP Career save - launch, orbit, rendezvous, pickup, de-orbit... When I had an idea.

Anyway, the rocket I use is a simple two-stage launch using low-tech 1.25m parts, but because I launch it with an empty crew capsule I have a pair of launch-clamps to keep the batteries charged for the probe core before lift-off. The rocket design has a single main LV-T45 engine, which starts with the first stage, but also two RT-10 Hammers for that little extra boost at launch. This got me thinking... What if I fired up the main engine before decoupling the clamps and igniting the SRB's, but use fuel pumped in from the launch clamps? :huh:

Well, after a little trawling through the game's config files, I discovered that the Launch Clamp part has a "Generator" module, which is the bit that generates electric charge while attached. So, on a whim, I copied the module in the config twice, and changed them to generate Liquid Fuel and Oxidizer respectively. Then I changed the "fuelCrossfeed" tag to true...

And voila! I have stock launch clamps that not only generate power prior to launch, but also fuel which gets automatically pumped into the active rocket! Now I can fire up the main engine and have it drain fuel from them rather than from the on-board tanks. :D Just like real rockets! :cool:

For those of you who are interested in this, here are the strings you need to add to the launch clamp config file. Just copy-paste this into your own one under the existing generator module:

MODULE

{

name = ModuleGenerator

isAlwaysActive = False

OUTPUT_RESOURCE

{

name = LiquidFuel

rate = 9

}

}

MODULE

{

name = ModuleGenerator

isAlwaysActive = False

OUTPUT_RESOURCE

{

name = Oxidizer

rate = 11

}

}

Also, make sure you find the "fuelCrossFeed" tag and change the value to 'true' instead of 'false'! Otherwise the clamps will generate fuel, but your rocket won't receive any!

The eagle-eyed or those experienced with config edits will notice that, although the default electric charge generator is "always active", I have made both the fuel generators not so. This was an experiment, and actually means that during pre-launch, you can click on the launch clamp and have the option to manually turn the pumps on or off! How cool is that!? :sticktongue:

Anyway, just something I did with KSP today. If you think this is cool and tried this (or something similar) yourself, do let me know!

Happy Rocketeering!

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Terwin

Terwin

Posted
Posted

Nice, but does that not also allow free fuel?

(build a ship with empty tanks, attach one or more refueling launch clamps, wait for tanks to be full, launch)

Another option might be adding a fuel reservoir to the launch clamps, that way you still pay for any fuel used. (may not always take from clamps first if your staging is wonky though)

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Corw

Corw

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Posted
Nice, but does that not also allow free fuel?

(build a ship with empty tanks, attach one or more refueling launch clamps, wait for tanks to be full, launch)

Another option might be adding a fuel reservoir to the launch clamps, that way you still pay for any fuel used. (may not always take from clamps first if your staging is wonky though)

It is a free fuel only to a point when you stage the clamps, so basically you are not doing anything but adding nice visuals to your launch.

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cantab

cantab

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Posted

If it's possible to put a vehicle on the runway or Launchpad empty and have the clamps fill it with fuel, and it's possible to recover all of that vessel for 100%, then you do indeed have launches for free.

In career it's also possible to circumvent the mass limits on the low level pad and runway. Though you can do that in stock once you have wheels and either the claw or docking ports.

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selfish_meme

selfish_meme

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Posted (edited)

Even better launch an SSTO to orbit, then spawn a fuel bowser attached to launch clamp on the runway. Land SSTO then refuel. You might need cargo doors and a truck so you can spawn cargo at the launch pad rather than on the runway.

Edited by selfish_meme
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Hotaru

Hotaru

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Point of interest: you could also have very nearly free fuel--and thus free launches if your vehicle is fully-reusable--by setting up an ISRU refinery on Kerbin, launching your ships empty, and transferring fuel to them via a rover with a claw (or via KAS if you don't mind mods). It's not quite 100% free (you still have to amortize the cost of the refinery) but pretty close if you use it over dozens of flights, especially seeing as you could always recover the refinery for 100% if you needed the money for something else.

Also, I believe the FASA umbilical tower does this as well.

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Alshain

Alshain

Posted
Posted (edited)

Good find OP. Have some rep.

- - - Updated - - -

If it's possible to put a vehicle on the runway or Launchpad empty and have the clamps fill it with fuel, and it's possible to recover all of that vessel for 100%, then you do indeed have launches for free.

But does this actually even work? I would think that the only thing it would fill is the launch clamps, which have no storage so they can't be filled.

Has anyone tried it? I can do it later tonight.

EDIT: Ok, confirmed. It does in fact fill the tanks. Launch with cheaper empty tanks, activate generators, free fuel. Unfortunate side effect, you could always just not do that if you have a strong will.

Nevertheless, if you still want to do it here is a module manager patch so you don't have to edit the part config. Just save it in a text file with a *.cfg somewhere in GameData and make sure you have the ModuleManager.dll too.

@PART[launchClamp1]
{
    @fuelCrossFeed = true
    MODULE
    {
        name = ModuleGenerator
        isAlwaysActive = False
        OUTPUT_RESOURCE
        {
            name = LiquidFuel
            rate = 9
        }
    }

    MODULE
    {
        name = ModuleGenerator
        isAlwaysActive = False
        OUTPUT_RESOURCE
        {
            name = Oxidizer
            rate = 11
        }
    }
}

Edited by Alshain
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AxleMC131

AxleMC131

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  • Author
Posted
Nice, but does that not also allow free fuel?

(build a ship with empty tanks, attach one or more refueling launch clamps, wait for tanks to be full, launch)

Another option might be adding a fuel reservoir to the launch clamps, that way you still pay for any fuel used. (may not always take from clamps first if your staging is wonky though)

It is a free fuel only to a point when you stage the clamps, so basically you are not doing anything but adding nice visuals to your launch.
Not true if you use SSTOs.... then the only cost of launch is fuel costs.

Do this, and there are no fuel costs at all.

0 funds per ton to LKO... pretty sweet

If it's possible to put a vehicle on the runway or Launchpad empty and have the clamps fill it with fuel, and it's possible to recover all of that vessel for 100%, then you do indeed have launches for free.

In career it's also possible to circumvent the mass limits on the low level pad and runway. Though you can do that in stock once you have wheels and either the claw or docking ports.

Point of interest: you could also have very nearly free fuel--and thus free launches if your vehicle is fully-reusable--by setting up an ISRU refinery on Kerbin, launching your ships empty, and transferring fuel to them via a rover with a claw (or via KAS if you don't mind mods). It's not quite 100% free (you still have to amortize the cost of the refinery) but pretty close if you use it over dozens of flights, especially seeing as you could always recover the refinery for 100% if you needed the money for something else.

Also, I believe the FASA umbilical tower does this as well.

This is a very good point you've all made, and I am fully aware of the fact that this system can be exploited to seriously reduce the cost of a spacecraft launch by generating free fuel. However, I do have the willpower to launch all my vessels with full tanks, and the amount I actually use from the launch clamp pumps is negligible - only a few dozen units of Lf+Ox for smaller launches.

It definitely is an honesty thing, but I'm not bad at that, so there. :P

- - - Updated - - -

Another option might be adding a fuel reservoir to the launch clamps, that way you still pay for any fuel used. (may not always take from clamps first if your staging is wonky though)
I usually just attach a few tanks with fuel lines to the clamps

Another good point, but this is actually why I modified my launch clamps in the first place. I had actually tried doing this first - I have nothing against putting fuel tanks and fuel lines on the clamps - but I like to experiment with config edits, and I thought this would be much smoother, more interesting and realistic. Just my personal opinion.:P

- - - Updated - - -

Good find OP. Have some rep.

But does this actually even work? I would think that the only thing it would fill is the launch clamps, which have no storage so they can't be filled.

Has anyone tried it? I can do it later tonight.

EDIT: Ok, confirmed. It does in fact fill the tanks. Launch with cheaper empty tanks, activate generators, free fuel. Unfortunate side effect, you could always just not do that if you have a strong will.

Nevertheless, if you still want to do it here is a module manager patch so you don't have to edit the part config. Just save it in a text file with a *.cfg somewhere in GameData and make sure you have the ModuleManager.dll too.

@PART[launchClamp1]
{
    @fuelCrossFeed = true
    MODULE
    {
        name = ModuleGenerator
        isAlwaysActive = False
        OUTPUT_RESOURCE
        {
            name = LiquidFuel
            rate = 9
        }
    }

    MODULE
    {
        name = ModuleGenerator
        isAlwaysActive = False
        OUTPUT_RESOURCE
        {
            name = Oxidizer
            rate = 11
        }
    }
}

Thanks for the rep! :D

Yeah, the initial obvious thought is "But launch clamps don't allow fuel crossfeed!" If you go back to the OP, you'll notice I specified at the bottom to also change the "fuelCrossFeed" tag to 'true', so the system does definitely work.

About using Module Manager, I understand that those sort of plugins make life a lot easier when it comes to these sort of edits, but I'm the kind of person who likes to do this stuff the hard way. It's far more rewarding. :D Same to the people saying "But there's a mod for that...!" So? I can do it myself! Why wouldn't I? :cool:

- - - Updated - - -

I don't think that's stock anymore.

Well. That may be the case. :blush: Still, I think it's a pretty cool feature.

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MalfunctionM1Ke

MalfunctionM1Ke

Posted
Posted
Nice, but does that not also allow free fuel?

(build a ship with empty tanks, attach one or more refueling launch clamps, wait for tanks to be full, launch)

Another option might be adding a fuel reservoir to the launch clamps, that way you still pay for any fuel used. (may not always take from clamps first if your staging is wonky though)

With 3 Million in the Bank you dont care about free fuel ;)

And you should reach this point real quick.

To Perfect the system, Squad should adapt this idea and charge you for fuel that runs through launch-clamps.

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AxleMC131

AxleMC131

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  • Author
Posted

To Perfect the system, Squad should adapt this idea and charge you for fuel that runs through launch-clamps.

Agreed. I'd love to see this feature available in the stock launch clamps, and have it charge you for the fuel you use prior to decoupling the clamps. It'd be nice, balanced, and realistic. Also just generally awesome. :D

- - - Updated - - -

Now thats neat! THanks :D

All that crap about free launches and bla bla if you want, but I'll be doing likewise with my launchers!

Can let the engines all boost up before we let go of Kerbin :D

Aint fuel dirt cheap anyway?

Haha, someone with the same thoughts as myself! :wink: And yeah, if you only have the pumps running to replace what your engines use for those few seconds prior to launch, the amount you actually use is miniscule, and the costs equally so. Personally, I'm not concerned with the "free fuel" issue, because the amount you actually get for free is entirely negligible.

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NecroBones

NecroBones

Posted
Posted (edited)

Originally I had planned to add a fuel+monopropellant feed from the SpaceY launch clamps, but people pointed out to me that this could effectively enable a form of "cheating" in career mode, since you could build your rocket with empty tanks and let it fill on the pad.

But it's definitely cool for sandbox players. Something that might be nice would be to make a ModuleManager config that adds fuel feeds to all parts that function as clamps.

Edited by NecroBones
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Hotaru

Hotaru

Posted
Posted
Beware staging launch clamps in second stage is bugged, launch clamps will spawn randomly when in flight, possibly exploding your rocket

I believe Stock Bug Fixes fixes that. (I haven't had it happen since updating them, anyway.)

Originally Posted by Hotaru

Point of interest: you could also have very nearly free fuel--and thus free launches if your vehicle is fully-reusable--by setting up an ISRU refinery on Kerbin, launching your ships empty, and transferring fuel to them via a rover with a claw (or via KAS if you don't mind mods). It's not quite 100% free (you still have to amortize the cost of the refinery) but pretty close if you use it over dozens of flights, especially seeing as you could always recover the refinery for 100% if you needed the money for something else.

This is a very good point you've all made, and I am fully aware of the fact that this system can be exploited to seriously reduce the cost of a spacecraft launch by generating free fuel. However, I do have the willpower to launch all my vessels with full tanks, and the amount I actually use from the launch clamp pumps is negligible - only a few dozen units of Lf+Ox for smaller launches.

I actually meant to agree with you: my point was that free fuel is already available, albeit requiring a bit of busy work, in a completely stock game, so adding it in this way doesn't seem like a big deal.

I already use the FASA umbilical this way anyway, if my lifter happens to have KW engines, which take a second to reach full thrust. If I don't, the rocket might settle back onto the pad before lifting off. Also it looks cool.

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keeper

keeper

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Posted

I think they are moaning because if they choose put this on then they could go out of their way to put their plane or rocket on launchpad empty, and then have it fill tanks after launch.

But it would be up to them weather they do it or not. But we're not adding it for that :D

Nothing is cheating, and I think this is proper cool. Like the real launches (probably).

Its so cool to see when the rockets take off, and all the tubes and arms come flying out all the hatches, and swinging out the way.

Squad needn't do anything here, i've used OP's post to correct my launch stability enhancers. All this talk about it taking funds off makes it so boring :/

Heres me playing on normal career with 19 mill saved up lmao got so good at doing minmus and mun missions loool

One thing i'd like to see with launch stability enhancers is the option to change the LENGTH OF THE ARMS. I sometimes have to attach detachable parts to my ship in order for them to reach some places, and on launch some parts get exploded because they are dropped.

Funny to see a ginormous rocket only be held at the bottom of the rocket, i like to put an arm a bit higher up, so it points upwards better before the big space bar bash. you know.

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AxleMC131

AxleMC131

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  • Author
Posted
Originally I had planned to add a fuel+monopropellant feed from the SpaceY launch clamps, but people pointed out to me that this could effectively enable a form of "cheating" in career mode, since you could build your rocket with empty tanks and let it fill on the pad.

But it's definitely cool for sandbox players. Something that might be nice would be to make a ModuleManager config that adds fuel feeds to all parts that function as clamps.

Yeah, it seems to be the biggest con of this little edit, which is the "free fuel" issue - not so much a problem if you can restrain yourself of course. ModuleManager would probably be easier and more fool-proof, but I like to do my own handiwork. :P

- - - Updated - - -

Also it looks cool.

Main reason I made this little edit. :D

- - - Updated - - -

I think they are moaning because if they choose put this on then they could go out of their way to put their plane or rocket on launchpad empty, and then have it fill tanks after launch.

But it would be up to them weather they do it or not. But we're not adding it for that :D

Nothing is cheating, and I think this is proper cool. Like the real launches (probably).

Its so cool to see when the rockets take off, and all the tubes and arms come flying out all the hatches, and swinging out the way.

Squad needn't do anything here, i've used OP's post to correct my launch stability enhancers. All this talk about it taking funds off makes it so boring :/

Heres me playing on normal career with 19 mill saved up lmao got so good at doing minmus and mun missions loool

One thing i'd like to see with launch stability enhancers is the option to change the LENGTH OF THE ARMS. I sometimes have to attach detachable parts to my ship in order for them to reach some places, and on launch some parts get exploded because they are dropped.

Funny to see a ginormous rocket only be held at the bottom of the rocket, i like to put an arm a bit higher up, so it points upwards better before the big space bar bash. you know.

I'm really glad you like it! :D And yeah, the stuff about cheating in "free fuel" is utter nonsense because you can choose whether or not to launch a rocket with empty fuel tanks - it's not like this is forcing you to cheat.

Also, I totally agree with you on the need for adjustable-length clamps. Having to arrange them in fancy patterns right at the base of a rocket really doesn't look too great.

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