Asymetrical Fuel usage

[MKI]

I'm continuously getting usual fuel draining issues on my Shuttle Like designs.

after 2 rebuilds and 3 totally different crafts, (but all with the same style of fuel systems) I do not believe it is build error. With different mix ups of 5-2 main engines.

Each of the crafts i design are "Shuttle like" Meaning I have the main engines on a SpacePlane setup, but most of the fuel on an external tank that is to the SIDE of the craft. All the designs have multiple main engines that need to drain fuel from the external tank, then from inside the craft once the external tank is dropped.

The problem I am continuously having is some of the fuel on only ONE SIDE of the ship is being used at the same time as the external tank. Thus resulting in my craft having less than optimal Delta-V on the SpacePlane once the external tank is dropped. On top of this problem is the issue of having fuel only being drain on only one side of the SpacePlanes tanks. Not even both symetrical sides are being drained, only one side.

I already checked and double checked my fuel ducts and they all seem in order. The Side tanks on my SpacePlanes are slightly part clipped in with symmetry, so they SHOULD have the same precedence. But in every design only one side will be used at the start of the flight, thus taking precedence over the Main external tank, even though I have fuel ducts running from the External tank, to the side tanks of the SpacePlane. In a few of my other designs that also ran into problems i mixed it up with a single middle median tank between the external tank and my side tanks, that then has fuel ducts going to the two sides of my space plane, and i still get fuel draining from the side tanks along with the median tank.

I have done designs like this before in older patches, but only now I am running into trouble.

Let me also clarify that the engines I'm using are not jet engines, and I am making a vertical take off system on the runway, in-case the fuel logic system takes craft orientation into account.

[GusTurbo]

Could you post some screenshots of your craft?

[MKI]

Here are some links to pictures i just got up. Been very busy as it is finals

Please note Kerbal Engineer, I removed this and the All pods mod i had and had the same issues. So I re-added them to provide me with some data on Delta-V as it does seem to reflect the lower fuel in higher stages and I was using this to try and hunt down the source of this problem. Just to clarify I do not use any other mods than these, and I do not use the parts for kerbal Engineer, rather I use the All pods mod and the newest version of Module Manager to apply KER to all of my pods.

These two pictures are for my MK2 sized Shuttle, where the part clipped side tanks will drain at the same time as the main external tank. Note the extra fuel lines from the External tank to the "last tank" to try and fix the problem of fuel draining from the side tanks that are part clipped in.

http://steamcommunity.com/sharedfiles/filedetails/?id=437678835

http://steamcommunity.com/sharedfiles/filedetails/?id=437678825

These pictures are of my MK3 Shuttle that was removed of a few components to try and fix this issue. Also note the very front of the craft has a median fuel tank, which leads to the side tanks , then to the back side extra tanks inside the cargo hold.

http://steamcommunity.com/sharedfiles/filedetails/?id=437678774

http://steamcommunity.com/sharedfiles/filedetails/?id=437678815

http://steamcommunity.com/sharedfiles/filedetails/?id=437678790

http://steamcommunity.com/sharedfiles/filedetails/?id=437678801

In both cases one whole side of the side tanks will be emptied at the same time as the external tank. Leaving my craft with the main fuel within the centered body, and one side of side tanks will full fuel. In the case of the MK3, the median tank will also be emptied.

[JoCRaM]

When building Shuttle like craft, I often move the root node around (to the shuttle/maintank decoupler usually). Have you moved it back to the cockpit?

[FleshJeb]

I expect it's some sort of symmetry issue. It may be that you used radial or mirror symmetry when the build structure would have preferred the other.

More likely: In older versions (not sure about current), when you re-root your craft, the build tree can get really screwed up. Parts will sometimes surface-attach when they should node-attach, leading to craft that looks correct but is actually asymmetric.