Launch with Empty Fuel Tanks

[ThreeMartiniLaunch]

I would like to launch with some empty fuel tanks.

I suppose I could thrust lightly on the launch pad before releasing the launch clamps....

I could make a special rover out of a big fuel tank and an engine. Fire the engine to drain the tank. Then drive up to the launch pad and xfer fuel via Quantum Fuel Thingy.

Edit: I could edit the persistence file.

Any other suggestions?

Thanks

Edited July 24, 2013 by ThreeMartiniLaunch

[Procyon]

Spaceport has a mod for empty tanks

Fat nose empty stock fuel tanks set or something like that

Edited July 24, 2013 by Procyon

[ThreeMartiniLaunch]

Spaceport has a mod for empty tanks

Fat nose empty stock fuel tanks set or something like that

Could you give me a clue what it might be called?

Thanks

[stupid_chris]

TAC Fuel Balancer is what you need. You can edit the amount of fuel in the tanks without needing to have new parts. It's really easy to use.

[ThreeMartiniLaunch]

TAC Fuel Balancer is what you need. You can edit the amount of fuel in the tanks without needing to have new parts. It's really easy to use.

That one seems to imply that it transfers fuel from one part to another....I'll take a look though.

Also found this:

Excess Fuel Vents. Uses a part, but the description sounds like just what I need.

Guess I should have looked a little harder before posting....

Thanks, all.

[stupid_chris]

That one seems to imply that it transfers fuel from one part to another....I'll take a look though.

It does much more. When you are on the launch pad, you can manually input the amount of fuel you want in the tank. It actually can change the value of any resource in a tank, even electricity and solid fuel. It can also be used to transfer from a tank to another, but it can do much more. There's also a dump system, so it can do like those parts you have there. The main advantage is that it uses no parts, so it really helps on the part count and produces less lag. You should really try it, it's a big customization tool for fuel tanks.

[lammatt]

just edit the quicksave file

and F9

[draeath]

lol, instead of using a very nice mod such as TAC, you recommend -editing-the-save-file- instead?

[stupid_chris]

lol, instead of using a very nice mod such as TAC, you recommend -editing-the-save-file- instead?

True. I'm still confused why people suggest complicated manual ideas sometimes when there's a much simpler and direct way to work around it.

[3_bit]

You could attach a hardpoint, then attach a structural mount and some mainsails with fuel lines and drain it that way. I imagine it might be a minor feature when the big resource update comes around.

[espm400]

True. I'm still confused why people suggest complicated manual ideas sometimes when there's a much simpler and direct way to work around it.

I think it's just people not actually reading the thread before replying (major peeve of mine).

[Geschosskopf]

There are pros and cons with TAC Fuel Balancer.

PROS:

1. No extra empty fuel tank parts cluttering up your VAB

2. Can do all sorts of other cool things like keeping fuel tanks balanced automatically

CONS:

Doesn't work in VAB/SPH so..

1. Any build-aids you use to figure dV use the full weight of the tank, so you have to do manual math to know how much dV you need to lift it--can't use Kerbal Engineer or MechJeb for that.

2. The vehicle's CoM is displayed using the full tank instead of the empty, which is especially an issue in the SPH but is also an issue in the VAB if you're going to dock the empty tank and are concerned about RCS balance

3. A rocket big enough to lift the empty tank might get squashed on the pad under the weight of the full tank before you're able to dump the fuel.

[espm400]

There are pros and cons with TAC Fuel Balancer.

PROS:

1. No extra empty fuel tank parts cluttering up your VAB

2. Can do all sorts of other cool things like keeping fuel tanks balanced automatically

CONS:

Doesn't work in VAB/SPH so..

1. Any build-aids you use to figure dV use the full weight of the tank, so you have to do manual math to know how much dV you need to lift it--can't use Kerbal Engineer or MechJeb for that.

2. The vehicle's CoM is displayed using the full tank instead of the empty, which is especially an issue in the SPH but is also an issue in the VAB if you're going to dock the empty tank and are concerned about RCS balance

3. A rocket big enough to lift the empty tank might get squashed on the pad under the weight of the full tank before you're able to dump the fuel.

I'll start by saying that I haven't used TAC in quite some time, so some of this might have changed, but about your 'Cons,' there are some fairly easy work-arounds for most of them (albeit, some aren't pretty):

1 - Since all tanks display a dry mass figure, you can simply remove said fuel tank(s) and replace with the equivalent mass in random parts to get your dV.

2 - Similar to the last one, I would use the structural girders to make a piece of (nearly) identical length and add parts to the centre to make up the dry mass. From there I would get my CoM and an approximate placement on my thrusters. Neither perfect nor pretty, but it works fairly well.

3 - The simple answer to this one is a judicious use of struts.

[tomf]

Instead of launching with empty fuel tanks could you use fuel lines to pipe the fuel down to the first stage? That way you can make use of it instead of throwing it away.