[0.23.5] Spherical and Toroidal Tank Pack (Updated 05/02/14) (New download link)

[legolegs]

So in the end, the skin thickness is proportional to the radius

Right. I have found some engineering books about cylindric tanks a they gave skin thickness formula like

Ä = Pr_i/ÃÆ’

(with some coefficients and margins of safety).

the mass of the tank is proportional to its volume

Wrong. ...after doing math... Also true When I said "larger tanks must be more efficient" I was wrong but thats because I was thinking about storing liquids. For storing liquids P=0 and Ä is constant. If we neglect weight, which we shouldn't. How much math may involve rocket science, anyway?

tanks have extra support material: the arms and the inner ring. They will have more mass than the end caps if you don't want them to be as flimsy as paper

Well, here I disagree with you. You can use ropes, they're very capable if you need to support something heavy. Edited January 11, 2014 by legolegs
darn bbcodes

[Talisar]

Just popping in here to say that I've been watching this discussion and it is fascinating. I am learning much, but don't have the background to add anything substantial to the conversation. That being said:

I will now go back to the drawing board and rework the torus masses and volumes (even that looks a little iffy to me).

I'll finally do the official update when you have the chance to do this As always, I appreciate your l337 math sk1llz

[taniwha]

Well, here I disagree with you. You can use ropes, they're very capable if you need to support something heavy.

In general, agreed. I'm talking about these tanks .

Anyway, using KSP stock tank wall mass densities (ick, but it's either match or fix every tank, and that's RF's job), it looks like the toroidal tanks will have a mass ratio of 3.64. Still pretty bad, but better than TO-S-1's. I Think I'll up it by changing some assumptions about the internal designs of the tanks: make use of the space in that bicycle rim on the tanks and in the arms. I already have them hollow (to cut down on dry mass), so might as well use the space, though the ratio will never get all that high.

[taniwha]

OK, I've done my homework...

I won't bother with screenshots, but I will describe what I've done. First, I determined the intended size of the base toroidal tank model (as used for the large tank, as it turns out): major radius 3m, minor radius 0.5m. This gives a torus volume of V_real=14.804m³ (this will be used later on.

I then edited the model by deleting all non-visible parts, moving the "arms" (and hoops) and the tank section itself apart (for ease of working). I cleaned up the tank part (tire plus rim if thought of as a bicycle wheel), made sure it was all manifold (ie, no openings) and used blender's volume tools to get V_outer=14.409m³. I added a solidify modifier with a thickness of 0.009 (9mm) and got a volume of V_shell=0.509m³. Subtracting gives V_inner=13.900m³.

It was then that I realized this was too far out from a real tank of such design (it would be smooth curves rather than faceted), so I cleaned up the tank to be just a torus shape (ie, deleted anything outside the 0.5m minor radus and filled in the holes). For this I got V_fake=13.976m³ (no solidify modifier). I figured that "close enough is good enough" and just used the ratio of the real and fake volumes to scale everything. Thus...

V[sub]tank[/sub]   =V[sub]shell[/sub]*(V[sub]real[/sub]/V[sub]fake[/sub]) =  0.509*14.804/13.976 =  0.5392m[sup]3[/sup]
V[sub]contents[/sub]=V[sub]inner[/sub]*(V[sub]real[/sub]/V[sub]fake[/sub]) = 13.900*14.804/13.976 = 14.7235m[sup]3[/sup]

I did similar shenanigans with the arms (and hoops), but didn't bother with any correction factors. I capped the ends to get the total volume (0.183m³), remove the caps and added a 9mm solidify modifier to get the pipe shell volume (V_pipe=0.069m³) and subtracted to get V_arm=0.114m³.

Thus:

V[sub]t[/sub]=V[sub]tank[/sub]+V[sub]pipe[/sub]=0.5392+0.069=0.6082
V[sub]c[/sub]=V[sub]contents[/sub]+V[sub]arm[/sub]=14.7235+0.114=14.8375

The scales (as best I can tell) are, from small to extra-large: 0.25, 0.625, 1, 1.5. Thus, using a density of 7.8t/m³ for the shell...

Name    Capcity   Shell  Dry Mass
TO-S-1   0.2318  0.0095   0.0741
TO-M-1   3.6224  0.1485   1.1582
TO-L-1  14.8375  0.6082   4.7440
TO-XL-1 50.0766  2.0527  16.0109

Capacity and Shell are in m³, Dry Mass is in tons. Shell is given only for independent verification .

All tanks have an LFO wet/dry mass ratio of 4.128 (lousy, but that's geometry for you). If you want a better mass ratio, talk to NathanKell (he'll give you titanium alloy tanks:cool:).

[edit]D'oh: forgot to add the tank mass to the fuel mass for the ratio (3.128->4.128)

Edited January 12, 2014 by taniwha

[Talisar]

Officially updated to v3.11 with the updated models and taniwha's dry mass figures

v3.11

- Updated models, should fix issues with tanks resizing when used as root node

- Updated dry masses of toroidal tanks. (Thanks again to taniwha for the maths)

[SimpleMajority]

I am having a issue with modifying the contents of the tanks in v.23 as well. I noticed that the tool-tip I get in game only talks about the colors and does not discuss the alternate fuels that the tank can support (as indicated in the OP picture). It also says LF xxx.xxx (x = quantity) and Oxidizer xxxx.xxx on the tool-tip. When I switch to action groups and select the tank, no new windows or icons appear anywhere on my screen. I have installed several different tanks with the exact same outcome each time. I am also using the tanks found under the propulsion tab and not the tanks found under utilities.

When I installed I took the two folders and copied them into the GameData directory.

[Talisar]

Do you have the Modular Fuel Tanks mod installed? That's required in order to be able to change the fuel types, but is not included in the pack. Without it you'll be limited to the LiquidFuel and Oxidizer.

[SimpleMajority]

I just downloaded and installed it, but the OP doesn't specifically state that you need to have this plugin installed for it to work. No matter though thank you for pointing that out to me.. Now for another failed return attempt from duna lol.

[Mitchz95]

Do the "structural" versions of the tanks have any use in the stock game? I can't transfer fuel or anything into them.

[K3-Chris]

Any updates on the cylindrical frames we talked about in http://forum.kerbalspaceprogram.com/threads/65042-Wireframe-Cylinders btw? Tried to PM you but you're over your quota it says.

[Talisar]

Do the "structural" versions of the tanks have any use in the stock game? I can't transfer fuel or anything into them.

They will only be able to be filled if you are using Extraplanetary Launchpads and/or TAC Life Support.

Any updates on the cylindrical frames we talked about in http://forum.kerbalspaceprogram.com/threads/65042-Wireframe-Cylinders btw? Tried to PM you but you're over your quota it says.

Sorry about that, I had to delete some messages again. It's clear now. As far as the frames, I've been slacking on those. I'll give you an update on what I have so far after work today.

[K3-Chris]

This pack enables some interesting lander designs btw:

Cool that engine exhaust/engine nozzles can fit through the gaps in the toroidal tanks like that.

Can't get spoiler tags to work :\

[NeoAcario]

Do you have the Modular Fuel Tanks mod installed? That's required in order to be able to change the fuel types, but is not included in the pack. Without it you'll be limited to the LiquidFuel and Oxidizer.

You really need to fix this Talisar. I've tried twice now to get this working with Modular... but they've broken up their mod. Please just include the required assistant mod in the Download. You're making it more difficult for us. Loved this mod... I'd like to use it again without the extra hassle.

Thanks,

~Steve

[K3-Chris]

The reason he doesn't include it is so people can pick modular or realfuels, and the tanks work on their own don't they without either if you just want Fuel+LOX?

[Talisar]

You really need to fix this Talisar. I've tried twice now to get this working with Modular... but they've broken up their mod. Please just include the required assistant mod in the Download. You're making it more difficult for us. Loved this mod... I'd like to use it again without the extra hassle.

Thanks,

~Steve

The reason he doesn't include it is so people can pick modular or realfuels, and the tanks work on their own don't they without either if you just want Fuel+LOX?

This is the case. Another issue that comes up is if they update MFT, then having an old version included with my download can cause more issues. The tanks are if fact set up to default to LF+O if modular fuels or realfuels isn't installed. This way people won't have to wait on me to update the pack every time NathanKell or taniwha update their respective plugins. It will just work with their updates automatically.

I will, however, add links to their respective threads on the OP and ensure that it is more clear that their plugin will be required to get the modular fuels functionality. I understand the frustration of having to download additional mods, and that's why I initially included the plugin with the download, but differing development cycles makes it very hard to keep everything on the same page all the time, so separate downloads is really the best way to go.

[Talisar]

This pack enables some interesting lander designs btw:

Cool that engine exhaust/engine nozzles can fit through the gaps in the toroidal tanks like that.

That is a cool looking lander. What pack is that white dome at the top of it from?

[K3-Chris]

That's a conical stretchy tank from http://forum.kerbalspaceprogram.com/threads/57422

[likke_A_boss]

Speaking of interesting landers,

[K3-Chris]

... You know the game has a screenshot feature right? XD

[NeoAcario]

EDIT: Apparently the error was between the chair and keyboard.

Regards

~Steve

Edited January 25, 2014 by NeoAcario

[NathanKell]

Not working *how*?

[Talisar]

EDIT: Apparently the error was between the chair and keyboard.

Regards

~Steve

I often find that my chair to keyboard interface has major issues

[NeoAcario]

Hey Talisar,

You may recall me... I've been following this mod for quite a while now. You may recall me as the one pushing you for more toroidals a while back. I was just wondering if you're familiar with zzz and his artwork. Mainly I'm curious if you'd even accept letting him do a couple skins for you (one for Spherical and one for Toroidal). I'm thinking about asking him seriously or tossing him a few bucks for it. Or would you rather I didn't?

He does a few skins for mods like KSP Interstellar. Here's a sample if you're unfamiliar:

~Steve

[zzz]

Sorry that I interfere, but I not sure what I can make and not really very intresting in making something at all and such thing in particular. All this is little confusing, I never said I looking for such opportunity, end even if I will, you not need to ask for me -anyone can paint it as he want without permission, by license(or not? whatever), Tal's even has provided all nesessary uv layouts.

I didn't read carefully, I was confised, no, you not need to ask me, seriosly. It's completely not about asking harder

Edited January 26, 2014 by zzz

[NeoAcario]

In no way interested even for a commission. I guess that answers that. Thanks anyways zzz. And keep up the amazing work, when you decide to do it!.

~Steve