Largest Tanker Size?

[Burke112]

So I was experimenting on launching large refueling tankers, to see just how large I could make them, without using cheats or modded engines, of course. My largest was almost 80,000 units of fuel -- I had to use a fuel-emptying mod to drain the fuel out of most of the tanks to get it into orbit; only leaving enough fuel to get the tanker to its orbit around its intended destination (Eeloo) using its nine nuclear engines. I experimented with larger units, but gave up after they all collapsed under their own weight, even when I used multiple modded struts to strap them together.

My whole plan is to get the tanker to Eeloo, and refill it with liquid fuel converted from Kethane on the planet's surface.

So, what's the largest tanker you guys have managed to get into space without cheats or specially modded engines (unusually high thrust or isp)? I'm pretty new to the game (only been playing for a few weeks), so I'd be willing to bet the more experienced players out there have managed to kludge together some REALLY crazy designs that manage to work better than mine.

[Tristavius]

Wow, that's a huge fuel capacity, though of course when empty that's not so much weight. My station has around 25,920 LF capacity and I thought that was large.

For launching FULL tanks however, I have three primary refueling vehicles...

1 Payload of 14,400 LF (5 full orange tanks) designed as a LKO use-and-dispose refueling depot for large interplanetary crafts. Self propelled on a NERVA using a smaller tank (payload stays 100% unused). Massive quantity of fuel but the launch vehicle is HUGE and rather prone to Kraken attacks, so not used often.

1 Payload of 8640 LF (3 full orange tanks). Designed as a modular attachment for my space station. Launch vehicle gets them to LKO then a tug from the station collects them for the docking transfer (not self propelled). All 3 arrive full. Once used they are detached from the station and De-orbited by a tug. These were built due to the unreliability of the large 5 tank system. Much more Kraken-proof.

1 Payload of 2880 LF (1 full orange tank). Self propelled on 1 NERVA (with separate smaller tank for the NERVA). Used to send fuel to craft stranded around other worlds. Arrives full to most locations, occasionally uses 5-10% of the payload fuel to get to hard to reach craft. Very easy to launch.

All my spacecraft are 100% stock (apart from some probes with ISAMapSat).

[Sephta]

I have a "mobile staton" (Kethane processing, tanks, Solar arras, many, many docking ports of all sizes) and it has 3 orange tank capability (in six grey ones). It can reach any planet and brings a Kethane mining vessel with it.

It works, and I found, I don't need more than 3 orange tanks as capacity: refueling with Kethane on a moon takes soooooo long...

[FlamedSteak]

I use a three orange tank vehicle which I launch separate to my lander for missions outside of Kerbin.

I launch two of them to a 100k orbit, dock them and transfer all the fuel into one. Then I'll dock that with a lander before heading off on a mission. That usually nets me one full orange tank, with two half full tanks on either side. So a touch over 5,000 plus whatever is in the lander, usually approx 3,000. So a bit over 8,000 all up give or take.

Also using all stock parts, the launcher starts on the pad with 6 mainsails and 12 large SRB's.

The SRB's drop around 6-8,000 and I run the 6 mainsails up to 20k. Then the core kicks in with two of the 650 thrust engines (the name escapes me) burning on the two outside tanks. That will get it into orbit, with about 40 seconds of fuel remaining in the outside tanks and the central one full.

Once all the dockings and fuel transfers are complete, I shut down the 650's and run it on a 3 engine central cluster of LV-N's for kerbin escape and interplanetary transfers.

Edited June 19, 2013 by FlamedSteak

[Burke112]

Wow, that's a huge fuel capacity, though of course when empty that's not so much weight. My station has around 25,920 LF capacity and I thought that was large.

For launching FULL tanks however, I have three primary refueling vehicles...

1 Payload of 14,400 LF (5 full orange tanks) designed as a LKO use-and-dispose refueling depot for large interplanetary crafts. Self propelled on a NERVA using a smaller tank (payload stays 100% unused). Massive quantity of fuel but the launch vehicle is HUGE and rather prone to Kraken attacks, so not used often.

1 Payload of 8640 LF (3 full orange tanks). Designed as a modular attachment for my space station. Launch vehicle gets them to LKO then a tug from the station collects them for the docking transfer (not self propelled). All 3 arrive full. Once used they are detached from the station and De-orbited by a tug. These were built due to the unreliability of the large 5 tank system. Much more Kraken-proof.

1 Payload of 2880 LF (1 full orange tank). Self propelled on 1 NERVA (with separate smaller tank for the NERVA). Used to send fuel to craft stranded around other worlds. Arrives full to most locations, occasionally uses 5-10% of the payload fuel to get to hard to reach craft. Very easy to launch.

All my spacecraft are 100% stock (apart from some probes with ISAMapSat).

Yeah, it tends to absolutely destroy my graphics card, though. I was originally planning on putting five of the behemoths around a central docking node, and having incoming ships dock to the central node, but since that would probably give me about a frame rate of one frame per ten seconds, I guess it's not that feasible a plan...

That, and I'd probably have to drain half the Kethane on Eeloo to fill it up.

Surprisingly, I didn't have to spend an inordinate amount of time waiting during my injection burn. I was expecting it to take much longer, especially since I had seen several of Scott Manley's videos where he mentions the nuclear engine's low thrust and slow acceleration. Unfortunately, my Kethane miner didn't have as high a TWR, so I'm currently waiting for it to complete its almost forty minute long injection burn. Still, it's definitely better than an ion drive...

[Xraybroadcasterfromvenus]

Being a relative newbie, I've not advanced very far yet- sticking to LKO. After a mun landing and return, I'm constructing a big station in preparation for further trips. One part of it however, is a refuelling node with 7 large tanks, which I brought up in one piece, stock only. One tank as a central column (with a small tank and an RCS tank sticking out on each side) and 6 around that. For logistical reasons however, I did use most of the contained fuel to actually get it up there; It arrived with only the central tank filled. I can tell you, the logistics of all the fuel lines needed to feed the launch vehicle was quite something.

Once all was docked and dandy, I realised I didn't actually have a tanker yet. So currently I have a lovely empty refuelling station that I can't fill yet

[ASnogarD]

I have been pretty obsessed with trying to find a 'elegant' solution to getting fuel to LKO with only stock parts, but failed miserably... hell even my *koff hahaha koff* 'heavy lifter' could not take up 1 lousy tank WITHOUT using every drop of fuel in the bloody tank...and still failed to get to a stable orbit.

The close calls were uncontrollable ... a few times got so turned around I was on a counter orbit path.

Probe controlled craft, and I use the word controlled loosely here, are a pain to even gravity turn with or without SAS and / or MechJeb2 ... bloody things are all frustrated spinning tops that got forced to the rocket career instead.

The craft parts all seem to be connected with spit and chewing gum, I actually had a nuclear engine simply drop off the bottom of the craft... just like pop, you didnt really need that did you ... BEFORE launch.

Docking port connections act like trampolines, even the Snr ones, the large ring ASAS likes to collapse on itself at random.

VAB likes to play silly buggers when you are trying to put on parts... you dont really want to put this tank on top of this one do you, thats boring...lets flip it 90% to the side and 45% to the left...now thats art, yeah man.

... so getting that fuel up to LKO has eluded me so far, but to be fair I am still a new player and really need to just forget about large projects and stick mastering orbiters first, then Mun runs, then stations and... perhaps someday, get fuel to LKO

[AYes]

My tanker:

Parts:

[Xraybroadcasterfromvenus]

Indeed ASnogarD, start small! Get those satellites up around Kerbin. Then, try getting a satellite around Minmus or Mun. Then, a Kerbal in orbit... and so on. If you take small steps and follow a natural evolution, you'll get there!

As for large things in general, not just fuel tanks: yes, the kerbals don't seem to be very good welders. In fact- their metal seems to be the equivalent of butter-soaked waffles. To give you an idea- that one-piece fuel depot was so heavy at launch, it was JUST holding together on the platform. As soon as I fired the engines, the central column would collapse- I had to install a few boosters around the top tanks just to take the weight off of the second stage, until some fuel was spent.

[Klajan]

Currently my largest Tanker in Orbit holds 276480 units of fuel.

It is build out of four tankers holding 69120 units of fuel each. Obviously I launched them using the fuel these contained. Refueling was done relatively (not accounting the damn lag of over 1.5k parts) fast. I only had to launch 8 times to fill it completely.

[mellojoe]

I had successfully gotten 3 orange tanks into space orbiting around Kerbin. However, I had used most of the fuel, so each tank only had about a 1/4 fuel. Not quite enough to call a full orange tank full.

However, the spact station I was docking to insta-exploded. So that ended that.

[Akalaël]

I'm using a 160t launcher stock-parts made to put 4 orange tankers in LKO... 465 parts, it hurts my CG.

Back in the 0.18, with the empty-tank technique I made a space station made of 14 orange tanks...

[technicalfool]

That launcher will get this into orbit with plenty of room to spare:

Problem being that as of 0.19.x, I couldn't even think of getting within 2.5km with anything else without horrific uneven frame rates. I can handle 0.5fps. What I can't handle is the frame rate jumping up and down like a yoyo.

Might try again now 0.20.2 is out and things run a little smoother.

(also yes, I know, it has Jumbo 64s connected directly to Mainsails. I didn't know the overheating was a bug at the time. Oops.)

Edited June 19, 2013 by technicalfool

[Spatzimaus]

My largest single-launch tanker is ~450 tons, holding 33362 liquid fuel and 40776 oxidizer, plus a supply of monoprop and xenon. It's a combined 400-ton tanker plus a 50-ton detachable lander (which has an onboard kethane refinery):

It uses quite a few mods, mainly KW Rocketry (for the 3.75m tanks), the Ion Engine mod (for hybrid engines, which I prefer for maneuvering use) and the Kethane mod (for refueling), although other than the Kethane none of those are critical to its operation. It's lifted by my 4000-ton heavy SSTO booster, which can either put one of these in Low Kerbin Orbit safely, or get it nearly out of the Kerbin SOI with a vertical launch. I now have three of these around Mun and three around Minmus (my practice attempts), one at Duna, one at Eve, and three at Jool (one orbiting Laythe, one in Jool orbit near Vall, and one in Jool orbit near Pol).

I could make something much bigger by docking many tanks together, I'm sure, but this design seems to fall at a sweet spot for thrust, maneuverability, and capacity. The version pictured there is actually a bit outdated, and is one of my earlier Mun versions; the most recent version, which is the one I placed around the other planets, carries a bit more fuel, has four robot arms to help with docking, has a better electrical system, and the lander is much more stable. When I get home I'll see about posting a more recent picture.

[Burke112]

I know this is kind of a nooby question, and it isn't directly related to tankers, but how do you guys manage to land your Kethane miners exactly on the deposits? It seems difficult to get the landing point correct, because of the rotation of the planet/moon you're landing on. Also, how exact do you have to be?

[Spatzimaus]

I know this is kind of a nooby question, and it isn't directly related to tankers, but how do you guys manage to land your Kethane miners exactly on the deposits?

It depends which body you're asking about. Most moons are tidally locked to their planets, and have no appreciable rotation; landing on a specific spot is therefore pretty easy, as long as you can dodge the terrain. It's much more difficult to land on a specific spot on a planet, since they're rotating under you as you descend, but with a little practice (and/or a quicksave) you can get the hang of it. If the planet's got an atmosphere and your design is winged, it becomes much easier as well. The most difficult places to get Kethane were planets with no atmospheres, high rotation rates, and decent gravities, like Moho.

Also, how exact do you have to be?

Not very. The deposits are pretty huge, and there's no benefit to landing in the center of it. On airless low-gravity moons, it's not hard to kill most of your horizontal speed and all of your vertical, and then just drift over the surface until you hit the deposit you wanted before killing the last of your horizontal. On something like Gilly, this is easy and doesn't take much fuel; for a high-gravity moon like Tylo it's a lot harder.

It also helps if you have a more mobile design. My latest Kethane extractor design is actually a giant mobile refinery/factory, a la the Sandcrawlers from Star Wars. It can drive to the deposits easily, fuel up, and then drive to my nearby landers.

[Burke112]

It depends which body you're asking about. Most moons are tidally locked to their planets, and have no appreciable rotation; landing on a specific spot is therefore pretty easy, as long as you can dodge the terrain. It's much more difficult to land on a specific spot on a planet, since they're rotating under you as you descend, but with a little practice (and/or a quicksave) you can get the hang of it. If the planet's got an atmosphere and your design is winged, it becomes much easier as well. The most difficult places to get Kethane were planets with no atmospheres, high rotation rates, and decent gravities, like Moho.

Not very. The deposits are pretty huge, and there's no benefit to landing in the center of it. On airless low-gravity moons, it's not hard to kill most of your horizontal speed and all of your vertical, and then just drift over the surface until you hit the deposit you wanted before killing the last of your horizontal. On something like Gilly, this is easy and doesn't take much fuel; for a high-gravity moon like Tylo it's a lot harder.

It also helps if you have a more mobile design. My latest Kethane extractor design is actually a giant mobile refinery/factory, a la the Sandcrawlers from Star Wars. It can drive to the deposits easily, fuel up, and then drive to my nearby landers.

I'm trying to do it on Eeloo. There's no atmosphere, so a winged design is out. Does anyone have any experience on how accurate the MechJeb auto-landing system is, and whether or not it accounts for rotation etc. and could land someone on a deposit? My experience has been pretty mixed -- one time, it got me down to just eight meters away from my specified landing point. Another time, it was almost ten kilometers off.

BTW, I remember reading somewhere that, in future versions, KSP would have interstellar, not just interplanetary, space travel. In that case, it would seem that a base around Eeloo (or whatever planet is the furthest out from Kerbol on future KSP versions) would be pretty useful, since it could act as a final pit stop to refuel spacecraft on their way to targets much further out. Has anyone else heard any information on whether or not interstellar travel will be implemented?

[Spatzimaus]

I'm trying to do it on Eeloo. There's no atmosphere, so a winged design is out.

When I did my Kethane-powered Grand Tour, landing on the deposit I wanted on Eeloo was not easy because of the rotation. But Eeloo's gravity isn't terrible (only 0.17g, almost identical to Mun), so the drifting method works fine; once you get close to the surface, kill your velocities a thousand or so meters up, then figure out which direction to go to get to the deposit you were aiming for, and just drift over to it. It's not a very fuel-efficient method, but the beauty of a Kethane design is that you'll just refuel as soon as you land anyway, so who cares how much fuel you spend on the descent?

In that case, it would seem that a base around Eeloo (or whatever planet is the furthest out from Kerbol on future KSP versions) would be pretty useful, since it could act as a final pit stop to refuel spacecraft on their way to targets much further out.

Maybe not, depending on the exact mechanism for FTL travel they use. If all you need to do is get beyond a certain distance, then a fueling station at Eeloo would be a bad place for outbound vessels; they'd have to spend a lot of horizontal velocity circularizing to match the planet's orbit before fueling up, and Eeloo's SOI is small enough to make that difficult. Plus, accelerating away from Eeloo to escape would take a lot of energy, whereas if they fueled up at an inner planet like Moho and then headed straight outbound, the Oberth Effect could be used to maximum advantage. But honestly, I've found that it's better to plan your fueling stations around where it's easiest to get the fuel TO the station, and not worry so much about the ships that'll be refueling there. A fuel station around Pol is really easy to manage, as the moon's rotation is negligible and its gravity is low (but not Gilly-level low), and it's much easier to get to/from as Jool has a large SOI.

This is also why my fuel station is a two-part vessel. The big tanker gets placed somewhere nice and convenient, and the lander has two purposes: refining new fuel, and traveling to meet vessels that can't easily get to the tanker. When I did my Grand Tour, I'd place the landers wherever I knew my main vessel would have problems with the ascent (like Tylo or Laythe), so that it could refuel quickly without having to travel to the Jool-orbiting tankers. Sometimes, it's just easier to plan things in that direction; sure, Eeloo looks like a good place to refuel on an outbound trip, but your outbound vessel should have more than enough fuel to get from somewhere more convenient out to the FTL point.

[leax256]

That, and I'd probably have to drain half the Kethane on Eeloo to fill it up.

three words: Kethane Debugger

[M5000]

I don't really have tankers, as I don't really have much orbital operations underway right now (most of my time is spent in the VAB, specifically, messing with staging, not even building) but I did just put up a 114-Ton fuel node, it only holds 6424 units of fuel, 810 of which can be directly accessed by a KSPX LV-NB which it uses to adjust itself. The rest of the fuel is separated by a decoupler so that the fuel available to the engine is controllable. It holds a single Clamp-O-Tron Senior port for large vessel docking.

Really, the only reason I launched it was basically a placeholder for my 114-ton lifter, the Betelgeuse-V Ultra-Heavy.

I know, 114 tons really isn't that big of a payload for most people, but you have to remember, this is a stack-based rocket. That's 114 tons sitting on top of basically everything else, no fancy tricks except asparagus staging on the boosters. I think I calculated the payload percentage and it was about 14% payload. It JUST barely makes it to orbit, and is exactly as hard to control as you may imagine. It's not really something that's regularly usable, but if, for some reason, I need to get 114ish tons to LKO, this baby will do it... Also, I needed some way to live up to my user title as the "Avid Griffon XX User." Note how this rocket uses five of them.

But yeah, that's really my biggest thing that could be considered a tanker...

Now, if you were to refuel this thing...

It would hold almost 100K units of fuel, as shown in the picture. This isn't a tanker, but it totally could be. That's the most could-be fuel I've ever put into orbit, though that was an SSTO.

I never actually built the interplanetary ship that that big thing was supposed to go on. Made it to LKO with no fuel and as I built the ship, I'd dump all extra fuel into the tanks. Did a few refueling missions. Dropped an orange tank or two into there and the fuel meter basically didn't even budge.

Also, the four black/white boosters are supposed to come off, it's supposed to just be the orange part on the ship itself..

This was the prototype for the Archernar-I, pictured above, the NVMSS Tuxaedo:

There's all the significant quantities of fuel I've ever put into orbit..

Edited June 20, 2013 by M5000

[Burke112]

Maybe not, depending on the exact mechanism for FTL travel they use. If all you need to do is get beyond a certain distance, then a fueling station at Eeloo would be a bad place for outbound vessels; they'd have to spend a lot of horizontal velocity circularizing to match the planet's orbit before fueling up, and Eeloo's SOI is small enough to make that difficult. Plus, accelerating away from Eeloo to escape would take a lot of energy, whereas if they fueled up at an inner planet like Moho and then headed straight outbound, the Oberth Effect could be used to maximum advantage.

So, in that case, wouldn't it be a question of whether or not the Oberth effect outweighs the advantage of starting from a "high point" where you've already gotten an advantage from your previous burn? (i.e. your craft's effective delta-V is the 2100 needed to get to Eeloo plus the value it actually has after it is refueled)

Now that I think about it, though, would the fact that you had to slow down so significantly to get into orbit around Eeloo nullify the advantage of expending so much delta-V to get into that high an orbit? Or would the high orbit (in relation to Kerbol) you'd be starting off from still outweigh the Oberth effect you'd get from the sun if you left from Moho?