FuelFlow and FuelGuage strangeness

[MarvinKitFox]

If this has been addressed elsewhere, please point me to the link.

I simply cannot grok the fuelflow rules and fuel level indicators in KSP as of the current version 0.90

Take this simple, early science ship of mine..

As I want to recover the whole thing, and as fuellines are not available, it is built as a + shape of 5 lv-909 engines.

The core is on an FLT-400 fuel tank, the arms are each on an FTL-200 fuel tank.

All engines ignite at launch, all burn 100%. All tanks start full.

I am expecting the 4 arms to run dry exactly halfway through the burn(ignoring minor change due to altitude/isp change)

Instead, this happens:

At 43 seconds, the CORE runs dry

at this time, all 4 of the side engines show about 25% of fuel remaining.

for two of the engines, this "25%" lasts another 25 seconds, with burnout at 68 seconds

for the other two engines this same displayed "25%" lasts 75 seconds!!! with burnout at 118 seconds from liftoff.

nani????

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Looking at fuel levels at various stages in flight, i can make sense of the burn times.

It seems that the two engines under a science-jr are drawing fuel from the core tank, thus depleting the core's fuel very rapidly.

But WHY does the fuel-remaining show the same for them and for the other pair of outboard engines?

and WHY does fuel transfer if there is a science-jr above it, but not if the tank is on its own?

Is there a simple, cohesive guide to fuel flow that describes the NEW fuel rules adequately?

p.s.

Pure stock, plus Engineer..

Ok, those side tanks were attaching via the science jr. Which seems to contain teensy minimicro fuel pumps or something, bypassing the no-fuel-sideways limits for early ships. Handy, that.

Edited December 22, 2014 by MarvinKitFox

[Anquietas314]

As far as I know the fuel rules haven't changed in 0.90, at least not for this situation. That is some pretty wacky behaviour though I must say o.O.

You would probably be better designing that thing as a tall single-stack rocket though with a more powerful engine though. The Isp savings on those engines will be more than offset by the added mass of having 5 of them.

[MarvinKitFox]

You would probably be better designing that thing as a tall single-stack rocket though with a more powerful engine though.

I want to be able to recover the whole thing.

Landing a tall-n-skinny on anything other than 0.0 degree slope results in tipover == boom.

[Claw]

Hmm. You might be running into some weird clippy-ness or something. Are those side tanks just surface mounted or is there anything internal going on there? If you can, post a .craft.

Cheers,

~Claw

[Anquietas314]

I want to be able to recover the whole thing.

Landing a tall-n-skinny on anything other than 0.0 degree slope results in tipover == boom.

With 4 lander legs you should be okay there. Plus, Kerbal Engineer gives a readout of the slope you're above, which will let you find a suitable landing spot on the way down