capi3101

^^^ That depends on what you want to do with your plane. One-man orbiters? Yeah, you can get there with one engine and one Mk2 fuselage just fine. Cargo plane? You're gonna want more than that. I have examples of both if I can find the screenies...

Still the wheels even after your tweaks. Get 'em lined up right with the center of mass and you should at least be able to lift off. If you've got problems with tail strikes, keep the angle down (5-10 degrees at most) when you go to take off. You're using mod parts, and I don't know how heavy your plane is, so I can't offer more specific advice. You do want the CoL behind the CoM though unless you want the thing to be flip happy (and getting worse as you burn fuel). Vertical alignment of the two is not terribly important; a CoL below the CoM increases maneuverability, above the CoM increases stability.

OP: I suppose the first think to ask is what exactly you're looking to build - a spaceplane, or a single-stage rocket. The term SSTO applies to both. I'm a specialist in SSTO booster rockets, at best an amateur with SSTO spaceplanes. But I'll pass along what I know about both. Both types of SSTO start with the payload, of course - the bit you want to get into space - and more importantly, its mass. The payload part does absolutely nothing while the rest of the craft is tasked with getting it into space. So you figure that up first. For spaceplanes, the payload is everything you want to add except jets, jet fuel tanks and intakes. For rockets, it's everything except the fuel tanks. Now, for SSTO rockets, the general guidelines are as follows: 1) Your payload fraction is 4%. These are super-inefficient rockets we're talking about here, the opposite end of the spectrum from asparagus. So, if you've got a 10 tonne payload, you can expect to launch it with a rocket that has a total mass of approximately 250 tonnes. 2) Your launch TWR is going to be 1.2. This helps you figure out how much thrust you're going to want at liftoff using the standard TWR equation (TWR = T/Mg, T=TWR*Mg). That 250 tonne rocket will require 2,943 kN of thrust to take off, so you're looking at two Mainsails (12 tonnes) or five Skippers (20 tonnes). Design-wise, the Skippers are easier. That ups your deadmass to 30 tonnes -10 for the payload and 20 for the engines. 3) Your Isp for the entire launch is going to be the atmospheric Isp. This isn't true but it generates a fuel reserve. For the Skipper, that's 300. Now you just solve Tsiolkovsky backwards to figure out how much fuel you need to generate 4500 m/s of delta-V, using the assumption that the fuel tanks have a 9:1 full-to-dry mass ratio (i.e. M=9Md), and that part of both M and Md is the deadmass: dV=ln(M/Md)*9.81*Isp dV=ln(9Md+x/Md+x)*9.81*Isp ln(9Md+x/Md+x) = dV/(9.81*Isp) (9Md+x/Md+x) = e^(4500/(9.81 * 300)) = 4.613801 9Md + x = 4.613801Md + 4.613801x 4.386199Md = 3.6138019x = 3.613801*30 = 108.41403 Md = 24.71708, M=9Md = 222.45372 tonnes Take that figure and divide by the number of stacks you want - one per engine, so 5. Each stack will need about 44.491 tonnes of fuel in it - take that figure and divide by 0.5625 (the mass of an FL-T100 fuel tank) and round up - you'll need 80 FL-T100 fuel tanks per stack. Then its just a matter of picking a combination of tanks that will give you that much fuel. In this case, you want an Orange tank (64 FL-T100 equivalents) and an X200-16 (16 FL-T100) equivalents) in each stack (64+16 = 80). All told you have 200 tonnes of fuel, 25 tonnes of fuel tanks, 20 tonnes of engines and ten tonnes of payload, for a total rocket of 255 tonnes (so the 250 estimate wasn't that bad). Empty, that sucker's mass is 55 tonnes, your Isp is 300 - so working Tsiolkovsky forward, it has 4,514 m/s of delta-V. You have five Skippers for 3,250 kN of thrust, so your launch TWR is 1.299, a good starting spot. Flying a single-stage rocket is a matter of playing with your throttle - you won't need all that thrust once you're up in the atmosphere. Fly it like you would a normal rocket but watch your gee meter as you ascend, and keep it right at the top of the green zone; if it goes above that level, throttle back. By the time you're high in the atmosphere, you should be burning horizontal around one-third thrust. My notes on SSTO spaceplanes are a little less comprehensive - the general guidelines I go with are: 1) One turbojet engine per 9-12 tonnes of payload (depending on the number of intakes you add). Include any rockets you intend to make the final push to orbit in your payload calculations. 2) One Mk1 or Mk2 fuselage per turbojet engine (preferably the Mk2, but in practice the Mk1 is easier to work with) 3) One pair of swept wings per 6 tonnes of craft. Delta Wings are the same but they don't have as good of a mass to lift ratio. 4) No fewer than three Ram intakes per engine. Each whole number increase in the ratio of Intakes to Engines adds another half-tonne to the amount your jets can handle. (i.e. 3:1 gives you 9 tonnes per engine, 4:1 = 9.5t, 5:1 = 10t, 6:1 = 11 t, 7:1 = 11.5 t, 8:1 = 12t - note that this is a guideline, not a hard and fast rule). You want your center of lift slightly behind the center of mass. Slightly above is also good for stability. Your control surfaces need to be as far away from their axis of motion as possible to ensure good control. Rudders need to be as far back as they you can manage and not lined up with the center of mass. Ailerons as far out on the wings as possible, elevators as close to the tail as possible. If you do elevons (combination aileron/elevator), put them somewhere in between. A pair of small control surfaces offers more lifting power than a large control surface for half the mass. Gear must be perpendicular if you want to make if off the end of the runway (actually, if you want to make it as far as the SPH taxiway before exploding); the rear gear need to be lined up with the center of mass if you want to take off without relying on the "ski-jump" design of KSC's runway. Expect to go into the drink the first dozen times you try to make a new design take off. Good luck.

Quoth the wiki: "It is currently possible for a craft to approach to roughly 1300 meters altitude before it explodes due to overheating. No known way of landing on Kerbol exists. " Good luck getting there, though; it takes a lot of delta-V to approach Kerbol. Best I've ever done is to put a probe into synchronous orbit.

Auk-delivered Thunderbolt refuel and landing again. First operational test of the crash cart - tow and refuel went well right up until I unhooked the pipe; the rear engine was clipped into the front of the crash cart, so it promptly fell off. Alas. I still think the design can make it into orbit on six engines; I'll make the attempt at re-launch this evening (knock on wood).

Played around with my tow cart some more for the Auk VIII; tried KAS pipe attachments instead of the winch cable and that seemed to work really well. Was able to refuel the Auk and tow it from the SPH taxiway about halfway back to the start of the runway. Got to going too fast - 'splosions were involved. Went ahead and flew a different Auk to orbit for good measure. Tonight I'll do an operational run of the tow cart refueling system after dumping the Auk's supplies off on a Thunderbolt in orbit.

Pipes seem to have done the trick. The plane had tipped up onto its engines prior to this shot; I was able to use the electromagnet to straighten it out and I left it connected while I hooked up the pipe. Refueled the Auk, then began the process of towing it back to the near end of the runway. I did have to disconnect long enough to reorient both plane and tow cart when they got to the center of the runway proper - lousy steering, and then later when I was towing it back I got going too fast. Damn near lost Jeb when the tow cart rolled and started exploding, and of course the back engine assembly fell off. I probably could've still made orbit but the ballast for the launch would've been off. So...next questions. I'm assuming at this point that it'd be better for me to tow then refuel, instead of the other way around. Inertia and all that. I'm also wondering if I'd benefit from switching from the ruggedized wheels to the big ones considering the mass of the tow cart when it's full of gas. Any other critiques (read: scathing criticisms) of the tow cart design would be welcome.

You could use BZ-52s (that's the part that Claw posted above; it's one of the stock Strutural parts) to set a position for your ports and then attach them there. There's also the Inline Clamp-O-Tron, though I've never seen folks using it and I don't use it my own self.

You've got the Science; absolutely I'd grab Advanced Sci Tech if I were you. I'd have to compare your tree a bit more to the full tree to make other science suggestions. You've definitely got enough tech for an interplanetary flight, no doubt. I'd next get Specialized Construction so you've got at least basic Clamp-O-Trons and then follow it up with Advanced MetalWorks. Only another 480 science. That'd open up a possible lander - transfer stage combination. You could build a transfer stage pretty damned easily - like this: Actually, you don't even need the BZ-52s to do a design like this; you could do it with the Modular Girder Segments, which are Starting Tech. They allow fuel cross feed and are still reasonably sturdy. You'd just set them down parallel to the edge of the central tank. Only drawback is that they look ugly. In your case, you'd replace the large probe core with an OKTO probe core and the Clamp-O-Tron Sr. with a standard Clamp-O-Tron. I'd recommend sticking the panels and batts to the sides instead of the tops like you have them. That's only 42 tonnes - easily launched with the tech you've got. You could even launch it single stage - your booster would consist of a stack decoupler and seven stacks, one centerline and six outboard. Each individual stack would consist of - 5x X200-32 Fuel Tanks 1x X200-16 Fuel tank 1x LV-T45 (center) 6x LV-T30 (outboard, on BZ-52s just like that transfer stage design) Plus enough struts to keep the whole thing from pancaking. No fuel lines - this ain't asparagus...which you could do and it'd be way more efficient than the single stack to boot. If you need to see what the actual design looks like, holler; I haven't got this actual design built but it'd be pretty easy to do. That oughta get you a transfer stage into orbit with enough juice to haul a lander with a mass of up to 58 tonnes to Duna and back with a big enough margin for error to cover everything except for extremely poor piloting (for the record, the round trip bit under optimal conditions requires 1,710 m/s of delta-V and the 58 tonne figure would give you 150% of that). I don't have any RCS anywhere on that transfer stage so she won't turn very fast unless the engines are lit; that should only be a consideration when it comes time to dock. Which just leaves you to design a lander with the specifications you want. It'd need about 1500 m/s of delta-V all told, more (2600 at least) if you don't add chutes.

I need to know your level of tech before I can offer any kind of solid advice, especially if you're looking for a specific design. Otherwise all I can offer is design suggestions.

So something grabbed with the grappling hook counts as "docked"? I'll have to try that; it'd be a time-saver. Can you disconnect a pipe once it has been connected? How does that work? I haven't played around with the pipes much yet. I'll give the Infernal Robotics mod some consideration. Noted for future reference - may I have a moderator please move this thread to the correct location?

Good morning, all. This will be the first time I ask a question regarding usage of a specific mod, and regretfully I will be doing this without access to either screenshots or craft files for now. If y'all will bear with me, I can have both available later this evening (probably after 02Z). So, I've installed KAS, and for my first task I've been attempting to build a combination tow cart / refueling tanker for my Auk VIII spaceplane. I do have some screenies of that craft: The second shot is an updated version of the craft, one where I'd ironed out most of the kinks in its original design (i.e. the first screenie). I have since made one addition to the craft, and its for KAS - I've added a radial connector port on the aft RCS tank centerline, below the central engine. Now, my tow cart design is based on a Jumbo-64 tank. I've added a probe core for primary control and a Mk1 Lander Can for Jeb to climb in and out of (figured out early on that I had to have a Kerbal present in order to actually plug in the cables if I wanted to do actual fuel transfer). It has a series of I-beams on the top with a winch and electromagnet on the end; this is meant to serve for towing. On the underside is another winch; this one is meant to act as the refueling cable. The idea is that after the plane lands from making a delivery, the tow cart puts it back at the beginning of the runway and refuels it to full, then gets out of the way. The plane then takes off for another mission. I realize I could just "recover flight" and go from there; I'm mainly just doing this for the lulz. The problem I'm experiencing is that inevitably when I attempt to tow the plane anywhere, the plane inevitably tips up onto its engines and knocks off the rear RCS tank, rear fuel tank and centerline engine. I'm not sure why it's doing this, and I'm concerned it has something to do with how I'm attempting to tow it. I guess my question is - for towing purposes, is it better to push or pull? And how would you go about pushing with KAS? And is there someway to fix the length of the winch cables so they hold tension? Is there a tool that is better for towing than the electromagnet? For reference, I'm attempting to put it on the orange tank just forward of the rear engine/RCS ballast assembly. The I-beam assembly is long enough that it does have the reach it needs. I suppose while I'm at it, is a Kerbal strictly necessary for plugging in cables and "docking" two craft together? Any help would be greatly appreciated here.

Screenies - hit the F1 key. It's saved in a subfolder of your KSP main folder called "screenshots". You can then post them to a hosting site like imgur and link it in to the forum.

That certainly sounds like you don't have the gear on perpendicular to the ground. KSP's kind of annoying about that sometimes. The other possibility is too much weight on the gear - that one's a little harder to quantify. May we see some screenies of your designs?

With that design, your vertical control surfaces are aligned too closely to the center of mass, thus you have lousy yaw authority. Not sure how you could go about correcting it without adding a tail section; if you're going for TIE Advanced, you may simply be out of luck. Actually, some "lasers" forward might help - maybe a pair or quad of RCS cylinders. Move your center of mass forward a bit. Worth a shot and it wouldn't screw up your design too badly. Your CoL is already ahead of your CoM which means the design should be flip happy as it is.

Okay...so from your craft file, it looks like you've got an interplanetary spaceplane SSTO design (gotta be specific - you CAN make single-stage rockets, and those ARE SSTOs). Starts pulling to the right at 25,000 meters going 1700 kps....what's your IntakeAir status at that level? Is it less than 0.21? I see that you're using three Turbojet engines - so I automatically suspect asymmetric thrust prior to flameout. 16 Ram Air Intakes - five per engine. Yeah - suspect you're getting close to the operational ceiling of the jets. Here's what you do: when the pull begins, throttle back to 2/3 and see if you can get it back on course. If you can, then that's definitely the issue you've got. If not, then something else is going on. Every time it starts to pull to the right, throttle back another tick. Eventually, you'll get to the point where you're no longer accelerating; that's when you light your rockets. Continue throttling back until you're no longer accelerating with the rockets lit. Then kill your jets, close your intakes, throttle up full and make the final push for orbit. Try that; see if it works. If so, great. If not, we'll discuss your craft a bit.

Flew the Auk VIII up to Typhon 2, what its intended destination was supposed to be last night. Had a beautiful docking, resource transfer, rendezvous and landing on the KSC runway. I went ahead and pulled the plane off onto the taxiway so that I could call up the tow cart. Evidently the engineers in the SPH were drunk the day they put together this particular tow cart; the design was fine last night but awfully wobbly today. Once I had it out close enough to the Auk, I had Jeb get out, walk over and plug in the winch cable so I could start refueling. Damn rear RCS tank promptly fell off. So far, I'm not particularly liking KAS.

Five tanks at once, eh? 180 tonnes...that's a helluva payload you've got. With something that massive you might consider one of two options - 1) Consider having the vehicle launch itself. I've got a design like this, the Thunderbolt Very Heavy 7, that's the equivalent of four orange tanks plus change (it uses six NERVA engines); it incorporates a series of LV-T30 engines in separable boosters. Now, the boosters don't have enough juice to make it all the way to orbit with the rest of the craft, but it gets it up there far enough and fast enough that the nukes can finish putting it in orbit. 2) Empty the tanks out in the VAB before you launch them. Your 180 tonne payload becomes 20 tonnes, and a trained chimpanzee could launch that pretty easily. Note that in either of these cases, you'll have to refuel the vehicle once it's in orbit. I have yet to see anybody who has a booster design rated for 180 tonnes, though Temstar has one that can do 160 or so.

I'm gonna get ninja'd on this post anyway...so be it. Interplanetary is pretty much a function of "what do you want to do first". What you might try is a combination craft - do two or three launches and dock them in orbit. Have one for the transfer stage, one as the lander/excursion module, and possibly a supply stage for extra fuel if you think you need it. Here's a good method for building a transfer stage - You can also do it in one big thwack, though by necessity that means building bigger rockets. I sent these off to Duna after doing a number of tests on Mün for a challenge: So what exactly would you like to do first? EDIT: Yep. Ninja'd. Taki117 has given you the tools you need to do planning for interplanetary missions; hopefully my first imgur album will be of some use as well.

Last night I finished tweaking the design of my tow cart/tanker. Jeb can now get in and out of the cab, climb down, go plug in the winch cable and climb back in. I haven't actually used it in an operational situation yet; that was supposed to happen last night, when I sent the Auk VIII on its first operational mission to refill a Thunderbolt Very Heavy 7. For some reason, the aft ballast tank fell off the plane after I switched over to IFR, taking the center jet and its fuel tank with it - the winch plug was on the center jet's fuel tank. So, so much for the notion of filling up the Auk and towing it back to the near end of the runway this time around. Actually, that flight had a lot of weirdness to it - aside from the engine falling off for no apparent reason, when I came back to atmo, at 10,000 meters and 400 m/s, over 1 full unit of IntakeAir, I fired up my engines - one of them refused to output more than 7 kN of thrust, so I had to kill the corresponding engine on the opposite side. Landed the Auk on four engines; just glad I didn't lose any more. And then I couldn't keep aligned with the runway; I knew I was high coming in and I had a pretty hairy landing on the taxiway. But at least I didn't blow her up. To top it off, I refueled the wrong target - I wound up going to an older version Thunderbolt in orbit (one with a quad port that I had attempted (and failed) to dock an adapter module to. Plus side of that - I have an excuse to make another flight today, see if the engine falling off is going to be a persistent problem or if it was just a fluke. I'm still anxious to see if the tow cart is going to be able to do the job I want it to do or not.

BTW, I've heard it said that you should not attempt to fire up your jets after re-entry until a) your surface velocity is less than 400 m/s or your altitude is becoming "critical" (which I define as about 10,000 m). That said, if you're tumbling at a consistent altitude, you might try firing up the engines just before then; thrust vectoring might be sufficient to prevent loss of control. Monoprop (RCS) makes good ballast; lemme say that. Cylinders in particular.

Might suggest you take a look at keptin's illustrated thread on spaceplane design. Helped me out a lot. It's not necessarily an unrealistic goal; in fact things are simplified somewhat because you're not going to space, and now that we know that we can give you advice that's better tailored to your specific situation. General rules - one engine per 9 tonnes of payload (anything not a wing, intake, or jet), one Mk1 or Mk2 fuel tank per jet (preferably Mk2 if you can manage it), one pair of swept wings per six tonnes of craft, one Ram intake per tonne of craft (or at least no fewer than three intakes per engine; 6-8 is better). EDIT: (Hope OP doesn't mind a momentarily hijacking of the thread) - BTW, Claw, Auk VIII needed the third set of forward canards to hold its pitch angle; without it, I'd have to sit there and hold the S key the whole way up. And it'd still slowly pitch downward until finally starting to go downwards.

Nope. Your options are 1) install a mod like Crew Manifest or 2) bite the bullet and jetpack them on over. Having done an Apollo-style mission before, I'll tell you that two EVAs is really not all that bad. Not compared to six anyway.

Kids these days... My own evening's efforts were wasted on playing around with KAS. I think I've figured out how to make a semi-reliable tow cart for spaceplanes and if I can figured out how to use it without tearing the engines off that'd be awesome. Getting the same vehicle to act as a tanker has proven perplexing; I suspect it's because you actually have to have a Kerbal out there to plug in the winch cable. And a crane operator I am not, apparently.

OP: I'm right there with you. In fact, you might be able to learn a fair amount from my woes with the Auk VIII and I daresay if Claw gives you any future advice on this thread, I'd follow it without question. Follow Rodyle's advice - and while you're at it, take the wheels off your spaceplane. Wheels have mass in the SPH but not in flight, so they throw off what the game is telling you about its location. Obviously you don't want to save after you've done this; you're just looking to see what's happening to your center of mass as the flight continues. Positioning of your control surfaces can also be crucial. To help you with that, we'll need to see some screenies.