How can you tell when droptanks are empty?

[cjmdjm]

KSP noob here. So I set up a Mun lander that uses drop tanks (with the landing gear legs on the tanks). These tanks feed into a larger central tank, using the yellow fuel pipes. The central tank is the only one with an engine.

Do I have it set up correctly? Will it actually use all the fuel in the drop tanks first? If so, how do I know when the drop tanks are empty and ready to be discarded? It's easy when they have an engine on them, eg, onion/asparagus staging. When the engine shuts down, the tank is empty. But when the tanks don't have engines on them, the game doesn't give a fuel meter for them. Is there a way to do this without plugins, or a way to tell from the fuel meter for the single engine? Thanks guys!

Screenshots of the craft in question:

Edited February 25, 2015 by cjmdjm
Set prefix to answered

[RainDreamer]

In stock right now, right click them in flight to see current level of resources.

[cjmdjm]

Ok thanks. Still curious how the fuel indicator works in this case though. Does the fuel indicator for the engine (the little screenshot I posted) show the total fuel for all tanks connected to that engine? Thanks!

[Axelord FTW]

You can also click on the resource tic-box in the resource panel. It will hard-show the containers/users of a particular resource (partly).

[Mighty1]

As there are landing legs attached to them it is a good idea not to drop them before tuchdown. Now, the other thing is getting back. If you burn to much fuel you will have to get out and push the capsule but that is another story.

[QPDO]

You can also Alt+Right-Click to make the window stay open. If you Alt+Right-Click on two tanks you can also transfer the contents.

[mudkest]

It uses the fuel in teh droptanks first. You can even tell just from the recourse overview when theye are empty. You have 1 fuel tank in the center holding x fuel(in this case, a rockomax x200-8 tank holding 360 fuel and 440 oxidizer)

so look at your recourse panel, once you have 360 fuel and 440 ox left then your drop tanks are empty

[MarvinKitFox]

Your idea is perfectly sound, although by putting the landing legs on the droptanks you are somewhat limiting your options on when to drop them.

i.e. cannot drop before landing, as you lose your means of landing!

[cantab]

The fuel indicator in the staging list considers all tanks that can be accessed by the engine at the moment.

So as you burn, the engine's fuel level will decline and the fuel will be drawn from the drop tanks. When you decouple the drop tanks, the engine's fuel level meter will recalculate to consider only the central tank, so the indicator will actually jump up because it's a percentage thing.

[Rokmonkey]

If I am not completely off the mark, if you click the "Stage Only" checkbox in the resource panel it will show you the fuel remaining in the current stage, which for you would be the drop tanks. Though that may only work if there were engines under that drop tank.

Else, right click on the tank and watch it, like everyone else suggested.

[Alshain]

The fuel indicator is a weird thing at a glance but it makes perfect sense when you think about it mathematically.

Imagine I have two tanks with 100 units of fuel each. I consume 1 of those tanks so my fuel guage reads half because it is a percentage and I have 50% fuel left. However, when staging, it becomes interesting. I have 2 tanks 100% fuel, I consume 1 tank and stage it off my craft... at this point, I still have 100% fuel because it doesn't factor the tank I dropped.

This is why in asparagus staging it looks like tanks are magically "refilling" when you drop stages. They aren't actually refilling, they never emptied, but your total possible fuel containment went down when you dropped the tanks so the percentage adjusted back up to 100%.

[cjmdjm]

Wow thanks for all the quick responses. The lander works well for smallish bodies where you are on the ground before the droptanks are empty, which is what it was designed for. How do I mark this thread as answered? Or will the mods do that? Thanks!

[Norpo]

How do I mark this thread as answered? Or will the mods do that? Thanks!

This:

http://forum.kerbalspaceprogram.com/threads/85063-How-to-change-Unanswered-to-Answered