1.2 Fuel Lines?

[Sharpy]

On 21.10.2016 at 11:32 PM, Leafbaron said:

why wouldn't KER and MJ undstand the new fuel flow system. If you have 2 tanks and you drain tank 1 first and then tank 2 or vise versa the Mass_start and Mass_end are still the same. In the basic dV equations thats all that matters

If you have three tanks: the central one, and two on decouplers with crossfeed enabled - all three with engines on them - when should KER assume you stage them? When the two side tanks are empty? When all three are empty? When your apoapsis rises above 70km and you no longer need the superior thrust of three engines versus one? Before, it was simple. Tanks empty, engines flame out, stage. Currently you may wish to keep that dead weight a little longer because the engines are still burning and the savings in gravity drag may (or may not) be more than delta-v lost to accelerating the empty stages,

[Superfluous J]

On 10/21/2016 at 5:32 PM, Leafbaron said:

why wouldn't KER and MJ undstand the new fuel flow system. If you have 2 tanks and you drain tank 1 first and then tank 2 or vise versa the Mass_start and Mass_end are still the same.

Sharpy has the logistical answer:

34 minutes ago, Sharpy said:

when should KER assume you stage them?

I'll give you the programming answer. KER was written with the way things work in 1.1.3. In 1.1.3, radial decouplers do not allow fuel cross-flow, and cross-flow was unidirectional in all things that allowed it. These are two huge changes. KER doesn't calculate correctly now because it doesn't know what "correctly" is.

Edited October 26, 2016 by 5thHorseman

[Padishar]

8 minutes ago, 5thHorseman said:

I'll give you the programming answer. KER was written with the way things work in 1.1.3. In 1.1.3, radial decouplers do not allow fuel cross-flow, and cross-flow was unidirectional in all things that allowed it. These are two huge changes. KER doesn't calculate correctly now because it doesn't know what "correctly" is.

This is almost correct, but not quite.  In 1.1.3 and earlier, radial decouplers do allow fuel cross-flow from the parent part to the decoupler (actually depends on the parent part's crossfeed setting) and from the decoupler to the child part (if the child part is not an enabled container for the type of fuel).  The reason they don't cross-feed fuel on most vessels is because the child part of the decoupler is usually a fuel tank.  So, fuel never used to flow from a surface attached child to a parent part but it could flow the other way as long as the child isn't an enabled tank.

[SkyHook]

On ‎10‎/‎25‎/‎2016 at 1:15 PM, RoboRay said:

The Smart Parts mod has a fuel-level sensor that you can put on a tank to trigger staging or an action group when that tank is empty.

If you need to minimize part count, one sensor part may be able to replace several fuel lines.

Is Smart Parts still updating?

[RoboRay]

3 hours ago, SkyHook said:

Is Smart Parts still updating?

Yes.  KSP 1.2 version is here:  https://github.com/linuxgurugamer/KerbalSmartParts/releases

Edited October 28, 2016 by RoboRay

[SkyHook]

12 hours ago, RoboRay said:

Yes.  KSP 1.2 version is here:  https://github.com/linuxgurugamer/KerbalSmartParts/releases

Thanks!

[linuxgurugamer]

And I'm going to make a new thread for it