Bleeding the engines out.

[alacrity]

Building something big and scary but need it to be empty on launch... anyone found an easy way to bleed out the fuel from engines with sitting at the pad with engines at full burn?

Thanx for the help

Alacrity Fitz

[soranno]

Some temporary engines on each side ( equal and opposite forces and all that) on decouplers and fuel lined to the tanks you want emptied? Burn out the fuel and then dump the engines

[ZedNova]

The easiest thing to do is to Launch it, save then edit the persistense.Sfs file so the fuel tanks have nothing, then reload.

[Brotoro]

One way is to sit on the launch pad and uses the engines to burn off fuel (then transfer the remaining fuel around the ship as needed before you do your liftoff).

There is a mod, but I haven't used it.

I have also just edited my persistence file to empty some tanks on a rocket.

[CalculusWarrior]

Right click on the tank you need to empty, then left click on the little green arrow for either the liquid fuel or oxidizer. It should change to a red alarm clock or something, which symbolizes that resource is 'on hold'. Then, feel free to throttle up to full power with your engine(s) of choice and the resource that you did not pause will drain, while the rocket engine produces no thrust. When the resource levels reach zero, simply unpause the other resource and watch it drain as well.

[numerobis]

Add fuel lines from the tank you want to empty to the main rocket engines, then launch.

[KerbMav]

Add fuel lines from the tank you want to empty to the main rocket engines, then launch.

After separation will the fuel line stubs remain on the tank like (as I remember) struts will do?

[tomf]

I'm pretty sure the fuel line stubs disappear. I can't think of a reason you would wan to burn fuel on the pad when you can just add a fuel line and use it during the launch.

[KerbMav]

RP reason probably - what good is a salvaging mission to pump fuel from decommissioned ships if you first burn your tank empty?

[KrazyKrl]

You can just add some heavy lift engines for stage 1, and fuel line them. Unlaunched fuel is wasted fuel. You can just, say, stick 5 mainsails onto decouplers, and fuel line them. Burn your tank dry, jettison, then you'll be at a pretty decent height.

The first 12km is the most difficult anyhow.

Fuel adds delta-v

Engines add thrust

Everything else is extra. But you need the extra stuff to make the craft do anything.

[numerobis]

After separation will the fuel line stubs remain on the tank like (as I remember) struts will do?

They do. You can probably find somewhere to hide them though? Or, edit the persistence to remove the fuel line.

[strongest_2hu]

I think I read somewhere once about a simple edit you can make to the launch clap part to make them able to give and receive infinite amounts of fuel. It isn't even cheating, considering that a good launch clamp would have fuel lines so you could throttle the engines prior to disconnecting (or drain the tanks).

I don't remember how to do it though.

[koshelenkovv]

I use KAS mod to suck fuel out of rocket to big orange tank on a wheels and burn it later in engines on top of this defueller.

[Sirrobert]

If I remember correctly there is a mod that adds empty Fuel tanks, but I don't know what it's name is

[Tex_NL]

In the past (before the big krunch) someone once suggested to edit the launch clamps to be enormous empty fuel tanks. Since before launch they are part of your ship you can transfer fuel to them draining the tanks.

But the more logical choice is to actually USE the fuel to get the tanks into orbit.

[Payload]

I vent fuel all the time. AS IT LIFTS ME TOWARD THE SKY!

Why on earth would one want/need/attempt to build a ship that burns fuel doing nothing? There is even an empty tank mod. Not sure what that accomplishes. Whatever, it's your game I guess.

http://kerbalspaceprogram.com/18-empty-stock-fuel-tanks-set/

[Sirrobert]

I vent fuel all the time. AS IT LIFTS ME TOWARD THE SKY!

Why on earth would one want/need/attempt to build a ship that burns fuel doing nothing? There is even an empty tank mod. Not sure what that accomplishes. Whatever, it's your game I guess.

http://kerbalspaceprogram.com/18-empty-stock-fuel-tanks-set/

It's not easy to get an orange tank up to your space station in such a way you can dock ONLY the orange tank.

Much easier to send the empty tank, and refuel it in small steps (or from kethane fromt he mun)

[OUScooby]

Attach rockets to your TT18-A Launch Stability Enhancer (the launch couplers) then fuel lines running from your tanks to these engines. Burn until all your fuel is gone and the launch as normal.

[Payload]

It's not easy to get an orange tank up to your space station in such a way you can dock ONLY the orange tank.

Much easier to send the empty tank, and refuel it in small steps (or from kethane fromt he mun)

What are you even talking about?

Take orange tank. Add 2.5m control package. Add Clampo-Tron Sr at each end. Use radial decouplers and attach RCS tanks and RCS thrusters to the side of the orange tank. Add an orbit insertion engine under the bottom clamp-o tron Sr. You now have and upper stage that you can dock to whatever and all you have to do is make a lifter that can get it started. The orange tank stage stays the same. Just change the launcher based on where you are going.

Once you have it docked, you have just one orange tank that has the RCS stuff on decouplers that you can jettison. You can jettison the engine because it is attached to a decoupler. You will have just one orange tank and two docking ports and the 2.5m control package.

That is not hard at all. It's actually easier than what you are trying to do now. It just takes a little thought. Heck, another orange tank and a mainsail underneath for the lifter would probably get the thing to munar orbit.

I just described a rocket with like max 15 parts that will do exactly what you want.

Edited June 19, 2013 by Payload

[AmpsterMan]

You can attach an engine on the launch clamp with a fuel line

[Payload]

Just so you know I am not pulling your leg. Whatever monstrosity you have built to do this is just lifting fuel for fuels sake.

Here is what I am talking about. Look at that Dv! That is easily enough to get to orbit. My lifter is just two SRBs.

On the pad.

In orbit with 700m/s fuel left.

After you dock you can just jettison the other parts.

[Sirrobert]

What are you even talking about?

Take orange tank. Add 2.5m control package. Add Clampo-Tron Sr at each end. Use radial decouplers and attach RCS tanks and RCS thrusters to the side of the orange tank. Add an orbit insertion engine under the bottom clamp-o tron Sr. You now have and upper stage that you can dock to whatever and all you have to do is make a lifter that can get it started. The orange tank stage stays the same. Just change the launcher based on where you are going.

Once you have it docked, you have just one orange tank that has the RCS stuff on decouplers that you can jettison. You can jettison the engine because it is attached to a decoupler. You will have just one orange tank and two docking ports and the 2.5m control package.

That is not hard at all. It's actually easier than what you are trying to do now. It just takes a little thought. Heck, another orange tank and a mainsail underneath for the lifter would probably get the thing to munar orbit.

I just described a rocket with like max 15 parts that will do exactly what you want.

My bad

It's not easy to send a FULL tank up.

Besides I'm just explaining the way I think the OP thinks, I got my fuel tanks up to my station just fine (I rather use medium docking ports though. Everything being ableo to dock to everything)

Your design is MUCH simpler than mine though. I'll keep it in mind when I need to send more tanks up for the mun base

Edited June 19, 2013 by Sirrobert