capi3101

That is what I meant; sorry if that wasn't clear. Did the math on one LV-N drawing off of one X200-32 tank versus five LV-Ns drawing off of it. Average Isp for both in vaccum is 800s, of course. Wet mass of an X200-32 is 18t, dry mass is 2t. Mass of an LV-N is 2.25t, mass of five LV-Ns is therefore 11.25t. Given dV=ln(m0/m)*9.81*Isp, the delta-V for one LV-N is 12,252.58 m/s. The delta-V for five LV-Ns is 6,214.69 m/s. That's assuming no payload. I need the higher delta-V worse than I need the thrust for my purposes. I may play around a little more with the design, though. Yeah, I figured that one one pretty quick. I've pretty much abandoned my earlier design though I've still got it in orbit. I was thinking about re-purposing it. The next iteration of "flying gas can" had 12 RCS thrusters on it, one set fore, one set aft and one set along the center of mass; handled like a charm. I should really get more pics up. Too bad I still can't post attachments...

You add a docking port and make that two X200-32s and you'd have enough gas for a round-trip flight. Wouldn't be able to push much, but it might be enough for a small lander.

I'd imagine Mechjeb or no you'd want to wait until the destination planet is in phase with Kerbin; Duna needs to be about 45 degrees ahead of Kerbin's orbit for the trip there and about seventy degrees ahead for the trip back.

Hmm...interesting idea. Wouldn't that reduce the potential delta-V, though? I mean, you'd have five engines burning off of one tank, so they'd each have only about 20% of the delta-V that a single engine would have for the whole tank, right? Definitely going to have to take another look at those BZ-52s; I didn't realize you could pull stuff like that with those things...

I've had that very problem myself lately; still haven't come up with a good solution for it.

Still no attachments...okay, this is getting ridiculous. I'll post some links to some pics of the problem I put up on a different forum: Ugly SOBs, aren't they? I added more RCS thrusters to help with the steering in the next iteration. Might be part of why I was having so much trouble in this iteration. Anyway...

I'm currently working with a design to build a multi-part ship for interplanetary voyages. I've recently decided to go a different route on getting the fuel up there, but what I was working with was essentially a flying gas can; it was an OKTO probe with 4 PB-NUKs stuck radially on its sides attached to a Mk2 adapter, attached to an FL-R1 RCS Fuel Tank, attached to a Rockomax X200-32 Fuel Tank with Clamp-o-Trons at both ends (on the bottom of the fuel tank and one sitting on top of the probe). It had 12 RCS thrusters and that was it; four at the top, four at the bottom and four along the center of mass of the whole thing. A real simple design as a whole. Total mass was 22.66 tonnes, so you'd need a reasonably hefty rocket to get it into orbit but after that it could maneuver on RCS. You might try something similar in this case; you need the RCS thrusters at both ends and along the center of mass to dock successfully. I tried the same design with just the center-line thrusters and the damn thing handled while a whale (no rotational torque, you see). Just put them on the ends and you haven't got good translational capabilities (the thing tries to turn one way or the other).

If you're playing the vanilla game, the only way to do this is the hard way: go EVA, turn on the jetpack, fly to the other hatch and climb in. Make sure you're not rotating and say the Sheppard's Prayer before you begin.

I haven't gone mucking around with mods yet; multiple ports are still necessary for folks who're playing the vanilla game.

This may just be the way I'm looking at it, but those ports look upside down in your picture...

Related question: if you ever wanted to get something like that undocked, would you have to select all five ports individually? Can you even undock something like that? I've got a multi-part ship in mind instead of a space-station but I want to apply the same general principle, five ports in an x-shape.

Still can't post attachments...this is getting annoying. Quick update; I've gotten rid of the ship I was using in favor of a single piece thruster stage. I wasn't sure it would make it to orbit due to the load; my original booster design had failed with that much weight attached originally. Three tries and more struts later, though, I finally got it up into orbit safely. That's not to say I don't want advice on how to do this sort of "sideways docking" maneuver in the future, though...

I'd start by slowing down once you're within 100 meters. Get down to something like 0.5 m/s or so. Once it looks like you're aligned, turn towards your target; do this on torque only, don't use RCS or you'll drift. Line it up and thrust forward. And be glad you aren't trying to do the docking sideways...

Working on a round-trip manned Duna mission myself at the moment. I'd suggest docking; stick a docking port on your lander and boost a corresponding unmanned transfer module into orbit to rendezvous with it. You should still be able to use the same boosters you've got if you don't try to lift it all into orbit all at once. Would love to see a pic of your lander; I have yet to build one that will achieve Kerbin orbit all on its own.

Thrust to weight ratio is the easiest way to figure out how much your rocket can lift; that's simply taking the total mass of your rocket, multiplying it by Kerbin's surface gravity and dividing the total stage thrust you're outputting by the result. A result greater than one means you can lift it; less than one means you're not going anywhere. Now, if you're asking "can this rocket get my payload into Kerbin orbit", that's a tricky question; it's dependent on a lot of different factors, including the specific impulse values of your engines, the amount of delta-v you want your rocket to have in aggregate, the amount of thrust you want to be able to generate, and the mass of everything. The best way to test it is to take the delta-v you want, divide it by the specific impulse of your engine, divide that by 9.81 and take the inverse natural logarithm of that result; you wind up with the ratio of wet mass to dry mass. For example, if you're using Toroidal aerospikes (388 Isp) to acheive Kerbin orbit (4500 m/s delta-V), the mass ratio you want is 3.26 (4500/388 = 11.579/9.81 = e^1.82 = 3.26). As long as you can keep the ratio above that amount, you should have sufficient delta-V to reach orbit (but be sure you still have a TWR over 1!!)

I'll be sure to put a picture up when I get a chance. Craft file too. The fact that you can cross-feed an engine is encouraging; it means I could put together the engine assembly on the ground and just add tanks; that's essentially what I was planning anyway but that means that I don't have to have a tank with the actual engines, right? The bitch'll be to get it the whole thing under the weight capacity of the booster... (BTW Pyotor Gagarin, I wasn't putting the ship together in the VAB. Thanks, though).

It is possible to get to the Mun and land in the demo; getting that down is what ultimately convinced me to buy the full version. I am confused as to why you would need electricity in the demo; the only command pod available is the Mk-I (so it's manned missions or nothing). If you run out of fuel (and yes, that CAN happen), you're pretty much s.o.l. Here's what I'd suggest: take the command pod, stick a stack decoupler under it, then throw on a SAS module (not ASAS) and an RCS fuel tank followed by a T-400 and an LV-909. Add a set of four landing legs and enough ladders for you guy to get all the way down. Then add a stack decoupler, followed by two of the T-800 tanks and an LV-45. Put on a set of 6 radial decouplers and attach two T-800s, a winglet and an LV-30 to each. Make sure to strut that sunuvabitch up tight, add add RCS thrusters as you see fit. Finally, on the bottom of both the LV-45 and the LV-30s, attach stack decouplers and a set of 7 RT-10s. Strut them up and add another set of winglets, and you've got yourself a rocket that will make it there, down, up and back. Then you just gotta worry about not screwing up the landing. Key to that: start your braking burn around 6,000 and go IVA occasionally ("C" key) to take occasional glances at your radar altimeter; it'll give you a good idea of the elevation of the deck. Don't try suicide burns until you get good at actually landing. Watch your fuel, though; with the design I've laid out here, be thinking of heading back to Kerbin when the T-400 gets to 90 units of fuel; when it hits 80. you need to abort; when it hits 75, you can still make it back but you're going to have to fly it very carefully, and when it hits 70, you might as well land because you're not making it back no matter what...

Hello all, welcome back to the forums. Alas that my account was created just last month; I get to start completely over... Anyway, I've been playing through the awesome historical tutorials on the wiki and have completed the Gemini 6A/7 tutorial (the one that teaches docking). I've been playing the game for a while now and I've been looking for a good way to get to any target I choose, and I realized that docking might be the way to go. So, I came up with a design for each of the modules of the craft I'd need, designed a booster that would get them into orbit, and began launches. I'd show you guys a picture of my problem, but as this is my "first" post, the forum won't let me. So here it is: the design calls for five engines in a cross-shaped pattern. I can't get the damn things to line up properly. Any suggestions? I realize that's nothing to go off of; can't post the damn craft file either. One thing real quick - if I have two modules docked together, one of them has a fuel tank and the other one has a fuel tank and an engine, will the engine draw fuel from the first tank without me having to pump it around manually? Thanks y'all.