RogueWraith909

Fuel tanks, Size vs capacity - any chance of a balance pass?

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I've been Kerballing for a while now but I never really noticed until recently that some tanks are bigger than others yet have effectively less capacity...

for example:-

Oscar-b Tank

18 LF

22 O

R-11 'Baguette' external tank

24.3 LF

29.7 O

Now as it looks from raw numbers I'm very wrong... but if you look at the physical SIZE of the tanks... you can get THREE Oscar-b's in the same space as ONE R-11... but the R-11 doesn't have three times the fuel capacity!  I'm not good at mathematics but I'd be expecting at least double the capacity for the R-11 over the Oscar-b yet it's not! 

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Anyone else thinking we need a balance pass on ALL fuel tanks in the game as well as adding a few new ones?  Sometimes you need smaller tanks for small rockets, not everyone makes huge things. 

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According to the authors of the Restock+ mod (and I think at last one other mod), the Oscar-B holds too much fuel.  So at least for that one, it should be fixed.  Restock+ patches it down to 8.1 LF/9.9 Ox - which matches your size estimate of the R-24

Edited by Cavscout74

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Interesting, though what use a tank with that little fuel would be I don't know.  Maybe that's why the original devs gave it so much capacity?  Either way some slim line tanks of a similar size and capacity to the Mk0 LF tanks would be nice anyway, end attach nodes mean we can create longer thin tanks that way for a specific appearance. 

I've used the Oscar-b's hooked together to make fuel tanks for trucks, getting the electric power for the wheels drive from fuel cells mounted along the chassis as well those parts providing plenty of power storage.  Makes a nice appearance and functionally give great range even on the 10-wheelers I've made so far for heavy equipment and refuelling trucks.  I have only installed the BDa set of mods and pre-requesits (just 3 mods in total) to keep loading times etc down. 

Here's another thought, does anyone use the tiny LF+O engines?  The low thrust makes them hard to find a use for other than very small probes perhaps?

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What’s the weight difference between the empty tanks? I just assumed that the grey one was a high pressure one (Like a scuba tank) and the baguette was a flimsy aluminium one (like a coke can) that would pop as soon as someone bumped it XD

Edited by Guest

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1 hour ago, RogueWraith909 said:

Here's another thought, does anyone use the tiny LF+O engines?  The low thrust makes them hard to find a use for other than very small probes perhaps?

Ant & Twitch? Perfect as a attitude control for engines without gimbal

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9 hours ago, Dale Christopher said:

What’s the weight difference between the empty tanks? I just assumed that the grey one was a high pressure one (Like a scuba tank) and the baguette was a flimsy aluminium one (like a coke can) that would pop as soon as someone bumped it XD

Oscar-B is 0.025t when empty, full cap is 18 LF and 22 O

R-11 is 0.034t when empty, full cap is 24.3 LF and 29.7 O (looks about three times the size of the Oscar-B and R-4)

R-4 is also 0.014t empty, full cap is 9.9 LF and 12.1 O (looks about the same size as Oscar-B tank)

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On 7/27/2019 at 12:02 PM, RogueWraith909 said:

Here's another thought, does anyone use the tiny LF+O engines?  The low thrust makes them hard to find a use for other than very small probes perhaps?

An Ant engine and a couple of Oscar-B tanks is plenty to go from LKO to the surface of the Mun, even with a few science instruments. Heck, you could probably make a good try at a return, if you can spare the weight for a heatshield ;)  Even if they fixed the Oscar-B, they're still great for small, cheap probes.

 

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The Oscar’s issue Is its fuel capacity compared to its physical volume. Assuming the same fuel densities - which is fairly consistent with other stock tanks - the Oscar B holds way too much for its physical size. 

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Oscar B is a funny tank. 0.625m diameter and maybe ~0.35 meters long, yet holds 200 kg of liquid fuel. vs 500 kg for a tank 1.25m in diameter and 0.5m long. It should hold less than half as much fuel as it does.

The result is that the Oscar-B is extremely dense. 25 kg of empty mass and 200 kg of fuel in about 110 liters. Compare the mk0 liquid tank, which has 25% more fuel and an equal empty mass, but is 307 liters.

Even if the Oscar-B is 0.4 meters long, that's still twice the LFO density of other tanks. It really seems to me like someone forgot they had both LF and O in it or something, since if you cut both its mass and capacity in half it would be at least very close to identical in density to the other tanks.

Edited by Pds314

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