Fuel Lift concepts

[milosh]

Hi all,

I thought first to post this as a challenge, but as I'm not able todo it myself yet, I rather post it in here. I'm looking for a way to bring 5 orange tanks with an RCS tanks attached to each of them into an orbit above 600km efficiently - with stock parts only. My station has 10 designated fuel ports and I want to be able to completely refuel it with a maximum of 2 launches. So far I'm able to bring 3 orange tanks up, with 5 I cannot get beyond 45km. I tried several setups with asparagus or (what I prefer) simple onion routing but it always ends the same way, around 40km I reach the final stage which has too low TWR for athmospheric flights. I feel like I'm pretty close but after at least 5 different designes I still cannot escape Kerbals gravity.

So if you have a fuel lift that can bring 5 (or more) orange tanks into orbit, please post a pic and maybe write something about the concept behind like, stage 1 boosters, stage 2 asparagus, stage 5 space flight and so on. I'm not looking for a craft file to use 1:1, only for some inspiration so I (and maybe others) can come up with something that actually works too.

have fun

Edited March 4, 2014 by milosh

[Highlad]

Five is quite a push, sometimes you just have to settle for more launches.

[Kasuha]

About the best payload fraction you can get when getting things to orbit is 20%. That means efficient engines (no mainsails) and smart steering.

Therefore you need at least four but likely more orange tanks of fuel to get one orange tank of fuel to orbit. If your machine can handle it, you can just build your lifters side by side and launch them all at once.

Here's a flat one-orange-tank-to-orbit lifter of mine, you can perhaps stack them. But different design might probably be better.

Edited March 4, 2014 by Kasuha

[kelmv]

I don't see why 4 orange tanks would be that hard to lift. I believe 2 is fairly common, so I'd imagine that the issue would revolve around not how hard is it to lift, but can your computer handle the partcount needed to do that.

[SRV Ron]

So much easier to launch up one at a time with capability to return the booster and fuel can for reuse.

And, if you don't wish to return them, one can even be sent to Mun as in this older design using some mods.

[magnemoe]

The lifter I used in my Jool lander project worked well even if it looks weird, it lifted 5 orange tanks into orbit but only 80 km.

http://imgur.com/a/dahmU#3

Replacing the central mainsail with four LV-N might improve reach but will lower TWR, its an four stage asparagus with two sets of SRB, Drops the highest boosters first, then the other expanded and continues.

[Tank Buddy]

You're asking for a lot:

5 orange tanks are quite massive (literally), weighing 180? tons. So that's quite a payload.

600 Km is pretty high up. Considering you have a massive payload, that is going to require a lot of fuel.

The best thing to do would be to design the orange tanks so they can be docked together in orbit. I can get pictures, but I'll explain. Make a new ship with the root part NOT the orange tank. With the "BZ-52 Radial Attachment Point", using 4x symmetry, make 4 sets of attachment points. Then place normal docking ports on the attachment points. The reason for the attachment points is so the outer tanks do not have to have docking ports on the outside (Otherwise you would have to risk skewing up the alignment changing the symmetry.) Dock and enjoy.

Edited March 4, 2014 by Tank Buddy

[psyper]

I built a fuel station with 12 senior docking ports (3x4 radially) and then sent up 4 empty tanks in 3 trips - took an age. Then I sent an kethane miner, converter and fuel transporter and got the fuel needed from minmus - more work? probably, more hours of gameplay? most definitely, more fun? totally.

I'll do some screenshots when I get home.

[Alpheratz]

Ok, I don't have access to the launcher data, but I can get this in a 400km orbit, which is 5 1/2 tanks:

The launcher is made out of a simple asparagus staged rocket with 24 boosters. Boosters are made out of 2 orange tanks + a mainsail. Asparagus is designed so that 2 symmetric boosters are jettisoned at a time. Yeah, this means lots of staging! And you must add lots and lots of well placed struts, especially X between adjacent boosters. Here is an image of a smaller version of the rocket:

And expect some lagg...

[milosh]

Wow lots of different ideas Alpheratz I think that your design comes closest to what I'm trying to build.

But first, now that I'm at home I can post a pic of the payload I'm trying to get into orbit, 216t:

It turns out that the old saying "just add more" does help indeed After looking at what you guys came up with I did some thinking and went back to my first design that was able to reach 45km. I just added another stage and guess what, I finally could escape Kerbins gravity. I raised my apo to 400km then I've killed the flight, because I've only reached 68km with the final lifter stage, then I had to turn on the poodles of the payload. I would still end up with 9/10 of each tank full I think but I want to get to 600km without the need of a single drop of fuel from the payload.

Anyways, this 1300t beast seems to do the job, just some finetuning needed (don't mind the left over holding port, I've fixed that already):

Every stage consists of four engines with two orange tanks that are fuel linked to the tanks of the next stage (onion, not asparagus). It might be enough to asparagus the second stage as it has enough left-over TWR or I just add another stage

But I probably wont be able to improve it today as I'm going to watch now Gravity in 3D with my wife

[ScottyDoesKnow]

My interplanetary transport/refueling stations have a 7 orange tank version that can get to 75km, which should be enough to get 5 tanks with RCS to 600km. Just be warned, it's 1114 parts on the ground so get ready for some slow launches.

http://forum.kerbalspaceprogram.com/threads/58885-Interplanetary-Transport-Refueling-Station-X0-%2846t%29-X3-%28176t%29-and-X6-%28308t%29

[Kasuha]

That's an awful lot of monopropellant, are you sure you will need it all? My whole Jool-5 mission was alright with just one such container and it even deorbited the tug with quite a few monopropellant still in it.

[psyper]

My fuel depot in low kerbin orbit. Its got auto-fuel transfer set up so as soon as I dock it starts draining equal amounts of fuel from all the tanks inc monoprop. I sent it up with empty tanks and then filled them up from a kethane mine on minmus.

Javascript is disabled. View full album

[milosh]

that's a nice concept you have there psyper even if it doesn't quite solve my problem. I haven't played around with kethane mining as I'm still pretty new to Kerbal but I might use this technique for my next station.

How do you setup auto-fuel transfer, can you do that without any mods? Manually refueling can get quite annoying with several tanks, a way to automate it would help alot

[Jart]

Certainly not my original idea but the importance of getting the fuel tanks up that are full is way overrated . If you are really going to be using a fuel station then you are going to be around it a lot. Get the tanks up there empty is fine and very easy. Dump all your excess fuel into it from missions returning to Kerbin. Never come down with fuel. You spent too much getting every last drop up there.

An example with t-800...

Same principle to be done with orange tanks ( I do not have them yet). If you really need to get them filled for a particular purpose, make an easy lifter to get one or two full tanks up which can be repeated with ease and very quickly with very little real life game time invested. For me, anyways, getting a lot of full tanks up was wasted playing time in the long run.

[Greenspan]

Suggest you see my topic:

Launching Multiple Orange Tanks

I asked pretty much the exact same question, there was a lot of good feedback from the community. This is what I resulted with:

It aint pretty but it works! Gets 5 Orange to Orbit along with 4x FL-T800 4xNERVAs and 4x LVT-30s, plus misc torque/docking/monoprop. I generally just try to get to 100km, but it should be easy to add a little more fuel and get up to 600km.

[milosh]

Yes I did it!!! As I said, just add more It's quite a straightforward design, layer after layer is peeled away until the final stage takes it to orbit, onion's the way to go

Here is the 1773t monster sitting on the launch pad:

First stage gone:

One stage later:

Up up you go:

Last lifter stage:

I was still missing 22 DeltaV for a 0.0001 ecc orbit so I took some drops from the payload:

But honestly, who cares - had the wind blown in a different directions I'd have had maybe those 22 Dv left

I'll post some pictures tomorrow of the complete station, need to go to bed now...

Thanks again for sharing your work and providing lots of inspiration. There's another thread asking if KSP is deserving it's hype - I say, damn sure yes, fantastic community and the grin on my face when reaching 600 wont vanish that quickly

[EDIT]: just realized my final inclination is quite a bit off, it should've been 0.015 - so there are my 22 Dv

Edited March 5, 2014 by milosh

[Greenspan]

Congrats! Just strap some SRB's or Jet Engines on the side, that should make up for the 22 m/s and then some.

[MarvinKitFox]

About the best payload fraction you can get when getting things to orbit is 20%. http://i.imgur.com/ulpxH99.png

Wise words. Realistically, unless you are among the elite, the likes of Manley or Kasuha here, you need to bargain on about 12.5% mass fraction. And that is to low orbit.

You want 600Km, and an accurate intercept? Throw away another 20% of efficiency.

So your 5-orange goal will need about 50-orange at ground launch. or 25 each, for 2 launches.

Can be done. I advise struts. Lots of struts. And dry ice.

The ice is to keep your CPU from meltdown.

I will post my "solution" later today, assuming i manage it. But as I've managed to put 72 half-oranges in LKO in one launch, it should be doable .

P.S.

Would you mind if the design uses half-oranges, instead or orange tanks? oranges are more delicate than double-stacked halves.

[milosh]

Marvin as you can see from two posts above I have already a working modell that can reach 600km with "only" 44 orange tanks if I counted correctly (41 orange tanks + the grey ones which add up to 3 orange tanks). I used 4 struts per tank though I'm not sure if I'd really need them all, I just wanted to be sure

As some have suggested different techniques for my "problem", like kethan mining or putting empty tanks into orbit I need to clarify maybe what I intend to do with them. Which is not per se refueling my SSTOs or similar but to populate the system. I want to put a station around every planet and the Kerbin station is the launching port for it. So next I'll fly up a small station, get one or two orange tanks from my Kerbin station and then continue to Eve or Duna. Then most of these tanks go to Duna and I continue on to the next planet like wise. That's why I need (want) to bring as many tanks with as little launches to my station. Once I've done that I will think about optimizing my stations by kethane mining or similar, but I'm still new to KSP and want to progress with baby steps

That's not to say you should stop posting your ideas, please do so, I'm always happy to learn new things or get inspired. When I started this thread I thought this to be a common problem that all veterans here have solved already, which, given the responsens in this thread, is not the case, there is no "golden" way. But for now I will stick to my design, I've put to much thinking and try-and-error-ing into it to just go with a completely different approach. I'm now in the tweaking phase but the basic concept I came up with under the shower, works

Edited March 5, 2014 by milosh

[SRV Ron]

One SAS ring, One mono prop tank, Five full orange fuel cans. 1452 ton launcher with onion staging and 21 Mainsail Engines.

Five full fuel cans in orbit with core engine and fuel enough to push to higher orbit.

[Kryxal]

If that is meant to dock to something then decouple the last Mainsail, might you be better off to put the probe in the stack under the decoupler? This might allow you to deorbit that last can, too, depending on fuel remaining.

[SRV Ron]

If that is meant to dock to something then decouple the last Mainsail, might you be better off to put the probe in the stack under the decoupler? This might allow you to deorbit that last can, too, depending on fuel remaining.

This was a concept design to see if it could be done without building an overly complex launcher. It has a Sr docking collar and thruster set for docking the five full fuel cans. The thruster fuel, if not used excessively during docking, can deorbit the empty five fuel cans.

There is room to add the controller to the booster below for deorbiting back to Kerbal as was done in this single can rocket.

[MockKnizzle]

I would suggest being a little more thoughtful with the engines you use. Just slapping more fuel and more Mainsails on your rocket might work, but it certainly isn't very realistic or efficient. Once you're lifting truly massive payloads, a single Mainsail on your core stage simply doesn't have enough thrust. Additionally, the Mainsail is a very inefficient engine and you're firing the one on the core for the entire duration of the flight.

My recommendation is to look into engine clustering on your core stage. A cluster of 8 LV-T30s with 4 LV-T45s in the middle gives you 70% more thrust than a Mainsail with a specific impulse of 370s instead of a measly 330.

[SRV Ron]

I would suggest being a little more thoughtful with the engines you use. Just slapping more fuel and more Mainsails on your rocket might work, but it certainly isn't very realistic or efficient. Once you're lifting truly massive payloads, a single Mainsail on your core stage simply doesn't have enough thrust. Additionally, the Mainsail is a very inefficient engine and you're firing the one on the core for the entire duration of the flight.

My recommendation is to look into engine clustering on your core stage. A cluster of 8 LV-T30s with 4 LV-T45s in the middle gives you 70% more thrust than a Mainsail with a specific impulse of 370s instead of a measly 330.

There was a cluster of four orange tanks and mainsails onion staged to that single one. Those got the payload to apogee with fuel left for 2/3rds of the final insertion burn. The single mainsail finished the job. Actually, five LV-T45 would be enough for the core as any more would interfere with staging.

The Novapunch and KWRocketry gives a much better performance level overall without creating frame rate killing additions of all the engine clusters. This 110 tons to orbit example shows that better efficiency even with SRBs

Anyhow, it was a first effort to see if it could be done. I did this in stages. First was the test of the core and four boosters onion stage. Then, the second ring to a suborbital test to work out the bugs in bracing and fuel line placement. Finally, the outer ring to push this into orbit and having to fix issues with lost braces and boosters falling off on the pad. Final fix to brace the decoupler under the payload which broke during the insertion to orbit burn. Once done, a good launch to orbit.

Want to talk about inefficient, check some of the other designs being used to place the same payload into orbit. In most, there is way too much fuel being thrown into lifting the payload into orbit with the results of launchers being way too big and inefficient.

Last night's flight, at 1,452 tons during launch, placed 216 tons into 100+K orbit. That is a ratio of 6.7 to 1. If aimed at the payload of 185 tons to a 100k orbit, I am sure that this ratio can be brought down to six to one or less.

Edited March 8, 2014 by SRV Ron