Fuel line problem

[Yakko]

Hello,

After watching some videos I decided to try to build an aircraft capable of launching a rocket. I installed a rocket fuel tank to on the aircraft itself to provide the fuel to the rocket via fuel lines until separation, but it doesnt work. The rocket keeps using the fuel from its own tanks and nothing from the tank in the aircraft. I checked orientation of fuel lines, detached and reattached the rocket and moved the fuel lines to attach to different tanks, and even the engine they are supposed to feed, but to no avail.

Here are some images:

Album a/1OIIF will appear when post is submitted

 

Edited August 7, 2017 by Yakko

[Mecripp]

20 minutes ago, Yakko said:

Hello,

After watching some videos I decided to try to build an aircraft capable of launching a rocket. I installed a rocket fuel tank to on the aircraft itself to provide the fuel to the rocket via fuel lines until separation, but it doesnt work. The rocket keeps using the fuel from its own tanks and nothing from the tank in the aircraft. I checked orientation of fuel lines, detached and reattached the rocket and moved the fuel lines to attach to different tanks, and even the engine they are supposed to feed, but to no avail.

Here are some images:

Album a/1OIIF will appear when post is submitted

 

When you click on a part and you and see the fuel there are little green marks by the fuel level you can click them so it won't drain that tank hope it helps

[Yakko]

Thanks for the answer, I will try it out!

[bewing]

If you turn on "Advanced Tweakables" in the settings, then you can assign priorities to various fuel tanks around a vessel. Fuel tanks with high priorities drain first.

 

[XLjedi]

Out of curiosity...  If I use the Advanced Tweakables to adjust fuel tank priority (and I do) does that translate to the craft file in such a way that if someone else downloads my craft file, the fuel priority comes along even if they don't have Advanced Tweakables turned on in their settings?

[Spricigo]

13 minutes ago, XLjedi said:

Out of curiosity...  If I use the Advanced Tweakables to adjust fuel tank priority (and I do) does that translate to the craft file in such a way that if someone else downloads my craft file, the fuel priority comes along even if they don't have Advanced Tweakables turned on in their settings?

Didn't occured me to check it before but now that you mentioned seemed like a good thing to do. My test and results:

I created a simple craft (pod, fuel tank 1, fuel tank 2, engine) and set higher priority in one of the fuel tanks, saved, disabled advanced tweakables, loaded a lauched. The fuel respect the priority previously set.

 

 

[Yakko]

Ok, thanks for the answers, will check that out.

[Foxster]

I've made a couple of craft with this idea. I found that it seemed to work best launching the rocket from the top of the aircraft, otherwise I seemed to get more collisions...

[Yakko]

14 hours ago, bewing said:

If you turn on "Advanced Tweakables" in the settings, then you can assign priorities to various fuel tanks around a vessel. Fuel tanks with high priorities drain first.

 

That finally did the trick! though I took some trial and error but in the end it worked as intended.

 

2 hours ago, Foxster said:

I've made a couple of craft with this idea. I found that it seemed to work best launching the rocket from the top of the aircraft, otherwise I seemed to get more collisions...

Yeah, thats problem number two, making a successful launch, I will keep your idea in mind.

 

Thanks

[Draalo]

Please take a look at your last picture again. I bet the dockingports dont have crossfeed disabled. So the engine drained fuel from the top tank, but that tank is refilled from the bottom tanks via crossfeed.

 

If you have still a save with the original craft try it again. Just place a decoupler or heatshield between the ports or disable crossfeed.

[Palaceviking]

With fuel priority settings and crossfeed ability on decouplers fuel lines are virtually redundant now.