capi3101

I'm glad to have been of assistance; good luck in your endeavors.

Shuttles are a royal pain; anything they can do you can usually do easier with a regular rocket. I suppose that's the challenge... Nice looking plane. Definitely atmospheric only...though I image if you were to replace the jets with RAPIERs and add some intakes (say, another twenty or so of those Structural Intakes), that design might make orbit. I'd have to look to see how well balanced it'd be through it's flight to say for sure, though.

Both Cirocco and Spatzimaus have given you sound advice for the lower part of the ascent (myself, I kick it up to 55-60 degrees for the first 10,000 meters - with the hope that the prograde marker will get up to at least a 45 degree angle - and then bring it down to 45 degrees afterwards before following the speed profile given). I will mention that, having flown your plane, yours will kick over to closed cycle mode around 26,000 meters (a bit low for the comfort of most spaceplane enthusiasts - if you want it to be higher up when it kicks over, add some more intakes - the general rule of thumb is three Ram Air Intakes per engine). When I flew it, it was going about 1750 m/s when that happened. When a RAPIER equipped spaceplane does that, it's a rocket at that point; you'll want to close the intakes and pull up to about 45 degrees so you can get out of the atmosphere as quickly as you can. Guideline for landing at KSC - put a flag out on either end of the runway, just off the little raised area so the game doesn't think it's debris. Put a maneuver node such that the periapsis is about 44,000 meters above either flag (assuming you're in a 100x100 orbit; go for a slightly higher periapsis if you're in a lower orbit, or vice versa), and then if you're more than a minute or two from that node move it ahead about 1 degree per additional minute. Burn to retro as indicated, go ahead and switch your plane's engine back to air-breathing mode and open the intakes. You should wind up in the vicinity of KSC at a minimum - and if you're spot on, you should be able to glide right in. Myself, I haven't had that kind of luck just yet. As for myself with KSP last night, I spent the evening farting around with the Waste of Time 7, a transporter VTOL airplane designed to take a habitat and two Hellhound rovers to the island in the center of the crater on the far side of Kerbin. Last night I attached the payload for the first time. Plane is still having control issues in horizontal flight due to how the wings are set up (structural issues mainly - they're twisting a bit due to insufficient strutting; I'm going to have to fix those soon). Still have yet to add the VTOL engines.

Well...you could always deliver the fuel by spaceplane. Back in 0.23 I farted around with the idea of building a massive transfer stage based on a cluster of 25 LV-Ns that would lift itself into orbit (using SRBs to help get it off the ground). It'd then need to be refueled before it could be used. Dumb idea, of course, but I'd decided then to go ahead and use spaceplanes to refuel it. The idea was that the spaceplane parts could be fully recovered (sans the fuel). Back then it was role-playing; in 0.25, that's actually a pretty damned start strategy if I say so my own self. So I had a plane capable of doing the job - sorta: the Auk VII. This is a good example of how NOT to build a spaceplane, incidentally. Lousy lift, lousy thrust, imbalanced all to hell - I could never deliver the full load and land safely at KSC. But you get the concept. If you want to try this route, I suggest taking a look in two places - keptin's Basic Aircraft Design - Explained Simply, With Pictures for the basics and DocMoriarty's KSP Space Plane Construction and Operation for specifics (the only thing I'll add there is that the new Wing Connectors are functionally equivalent to Delta Wings, something to bear in mind. I should try again with the Auk; now that I know more, I might be able to build a completely functional plane this time around... EDIT: I'm pretty sure that's not the Auk VII in the picture...trying to remember which one that was. The VII was unmanned.

Some general information about your designs would be helpful. Let's go basic information only - how massive is the payload? If you don't know that, take what bits you're using for the booster off the payload, put it on the pad by itself, go to the map view and click the little information tab on your craft; the part count and mass will be there. Once you've got that information, let us know. The specifics of your payload don't matter so much as that one key piece of data. Then we can pick which route to go - rocket or spaceplane. That's your preference - rocket's generally easier to build, spaceplane is generally more efficient and cost-effective. Your choice.

You guys have got to link me to these awesome mods that make your rockets look like pencil sketches... I actually did the math for a booster like the one you designed, Pecan. Turns out that two J64s and an X200-32 are more expensive than the S3-14400/S3-3600 combo by about √2000. Over six stacks, that comes to √12,000. Still...that booster's a hundred large cheaper than mine. Definitely worth considering. Might see what the SRBs can do. Just for the hell of it.

My first launch was the piloting tutorial. I couldn't figure out why the stupid thing would only go up a few thousand meters before it crashed. Then I started reading about delta-V, and I designed and flew a rocket that made it all the way to space! Yes! Orbit!! Except.......not. Learned quickly that "in space" and "in orbit" were two different things...but at least I remembered the chute. I remember the first time I killed a Kerbal - I decided to add these cool looking "launch clamp" things to my rocket to see what they did. Didn't know they were supposed to go on the bottom-most stage. Hit the SRBs and couldn't figure out why my rocket didn't go. Hit the controls for the next stage...with the SRBs still burning..........

Somebody posted about the 0.18 demo on the Wing Commander CIC forums - so I checked it out. Bought the full game once landing on the Mun became old hat - this in the days before I had KER and before the Mun was so bumpy...

Spent most of the weekend working on super-heavy booster designs for folks that wanted them (I imagine for orbital fuel depots, but I honestly didn't ask). Ultimately designed one that should be able to handle 180 tonnes, though it's only been tested at 150 tonnes so far. Cost about √375,000 or so. Big thing I've been trying to do is build a DocMoriarty-style transporter VTOL plane to deliver a habitat and two Hellhound rovers to the crater island on the far side of Kerbin. I've got some issues to work out with SAS and wing-loading, and I've yet to put the VTOL engines on the craft. Other than that the design process has been going pretty well so far. Definitely going to have to put up some screenies of it when it's all said and done.

This one should be able to do 180 tonnes. It was designed for 150 tonnes and has been demonstrated to be capable of getting that payload to orbit. And it should be simple enough for you to construct on your own - Root - Rockomax Decoupler RC-L01 Remote Guidance Unit Kerbodyne ADTP-2-3 (Adapter) - w/ 4x Roundified RCS Tanks and 4x Z-100 batteries S3-14400 Fuel Tank (put 8x RV-105 RCS Thruster Blocks on the top and 6x TT-70 Radial Decouplers near the bottom) S3-3600 Fuel Tank (put 8x RV-105 RCS Thruster Block on the bottom) S3 KS-25x4 Engine Cluster Boosters - 6x S3-14400 Fuel Tank (place a Sepratron on top of each) S3-3600 Fuel Tank Kerbodyne KR-2L Advanced Engine Plus plenty o' space tape... Get the engine bells directly on the ground or you'll toast the launch pad.

Got some good news for you: So, pre-0.23.5 when the biggest tanks were the Jumbo64 and the strongest engine was the Mainsail, there was this bug in the game that would make a Mainsail explode if you placed it directly underneath an orange tank. It had something to do with the proximity of their respective centers of mass to one another and the way the game calculated heat dissipation from the engines. I had the thought that this could be what was happening with your booster, just scaled up to the next set of record-holders for large parts (ie. the S3-14400 and KS-25x4). The solution in the olden days was to set a smaller tank between the Mainsail and the J64, so I did an analogue - I put an S3-3600 between the S3-14400 and the 25x4, in the core, set up the rest of the booster like the last time, and flew it. The boosters got hot, but the core stayed cool all the way up. I reckon if you do the same with the boosters - put the big tank on top, the small tank in the middle and the engine on the bottom - the engines wouldn't overheat at all. In any case, the redesigned booster makes orbit. Final problem remaining: I haven't launched this sucker yet where it didn't destroy the launch pad in the process. But I think that's my issue, not yours; I just wasn't careful to make sure the engine bells were sitting directly on the ground. Final configuration. This is what made orbit. For the hell of it, I did go ahead and tweak the mass of the NREP testing weight upwards to see how far it'd go... That I believe is the maximum practical payload mass for the revised booster design - 180 tonnes. At that point your margin of error for delta-V losses is a little narrow, and the core TWR is very low (though not yet below the 1.1 threshold). You'd have to fly it perfectly to make orbit with that much mass. One thing to note - with the 180 tonne shot, the boosters are still set to 87% thrust, so you could tweak them to full power and probably get the same TWRs you had at 150 tonnes. So hopefully that addresses the issues you were having with your bottlenecks. We've knocked out a little bit of the cost in the process too...the booster is still expensive, but I think that's going to come with the territory of a massive payload launch like this one. Best of luck in whatever it is you're doing.

Got some good news and bad news for you, OP. Good news is that you can adjust the rocket the way I suggested. The numbers (by which I mean KER) say you should make it. I did go ahead and replace the big RCS tank with a couple of roundified tanks (really, nobody ever truly needs the big tank except maybe for docking maneuvers) and that helped matters a bit. As much fuel as I was able to take out of the S3-7200 tanks, you might consider replacing them with S3-3600s. Seriously. Now for the bad news: when I went to test fly the design, I noted the x4 in the center was dangerously overheated pretty much the entire way up. When the third stage boosters separated, the x4 immediately went critical and exploded. Why it did this I don't know; I'll have to investigate further. Might've just been a fluke.

Okay...so we're trying to isolate the cause of the TWR bottleneck for 150 tonnes, right? That's easy - your core is too weak for the amount of fuel in it. Temstar's Supernova - in fact his entire Zenith series - was based on a set of design formulas and philosophies which his booster set follows. Based on that philosophy, we'd design an asparagus staged rocket as follows: 1)150 tonnes is the desired payload. Assume 15% payload fraction - that means our final vehicle will be around 1000 tonnes (150/0.15 = 1000) 2)Shoot for a TWR between 1.6 and 1.7 at liftoff. So we'll need between 15,680 - 16,660 kN of thrust (1000*9.8*1.6=15680, 1000*9.8*1.7=16660). 3)Shoot for 22% of your launch thrust in your core and divvy the rest among the boosters. That works out to 3449.6-3665.2 kN in the core (just multiply the values time .22) and for three booster pairs, each booster should have between 2038.4-2165.8 kN ((15680*.78)/6 = 2038.4, ((16680*.78)/6=2165.8). 4)Subtract the mass of the engines you need and the mass of the payload from the estimated weight. The remainder is your estimated fuel mass. So let's ignore the cost factor for a moment. Thrust wise, a KS-25x4 is what you should have in the core for the payload you want. For boosters, I'd recommend a single KR-2L set to about 87%. There's your thrust requirement. Now, the total mass of your engines with that configuration is 9.75+(6*6.5) = 48.75 tonnes. So our rough fuel mass should be 1000-150-48.75 = 801.25 tonnes. Divide that evenly among seven stacks; you get 114.46 tonnes each. Looking at your design - you have an S3-14400 and an S3-7200 in each booster stage. I assume you've also got that in the core, plus another S3-7200. If they're full tanks, that's 123 tonnes of fuel in the boosters and 164 tonnes in the core. And if they're not full, the assumptions of the design might not hold because the mass ratio of the tanks you're using isn't 9:1 - it's 8.2:1. Your options are to change your tank setup - three orange tanks and an X200-16 will give you what you need - or to reduce the amount of fuel in the S3-7200s to about 90% (that should be, if I'm doing the math right, 2916 units of liquid fuel and 3564 units of oxidizer each) and take out that topmost S3-7200 in the core. This is assuming you swap out the dual Mainsails with a single KR-2L in any case (two mainsails are 12 tonnes, a single KR-2L is 6.5 tonnes, so the KR-2Ls fall in the "more efficient" category in this case). I'll tell you what - I'll go ahead and replicate your booster with the tweaks I've proposed, to see if just adjusting the fuel will do the trick or not (I'm concerned about hitting an early delta-v bottleneck). Bear in mind that Temstar's designs generally wind up with a 1.3 TWR in the core once all the boosters are separated. If you've got that, you're golden. Now, SSTO transporter spaceplane might be an option as well. DocMoriarty has put out what I consider to be the definitive guide to transporter spaceplanes and his guidelines have proven themselves most useful in my own fights with flight. A good rule of thumb for a transporter spaceplane is a 25% payload fraction - so for a 150 tonne payload you'd want to shoot for a 600 tonne spaceplane. His guide says that the max take-off weight per RAPIER engine is 13 tonnes...so you'd need 47 engines. All I can say there is "good luck" if you wanted to try that route...

'>Link to the Zenith family. The Supernova is the big one on the right, obviously. At a glance, I'd say a big difference between y'all's designs is in the cost of the individual parts, in particular the engines. You've got seven KS-25x4 engines there, right? Those things are √32,400 a pop, for a total cost of √226,800 just in engines. In contrast, a Supernova has nine Mainsail engines at √5650 each, for √50,850 total engine cost...22.4% the cost. I might also mention that '>Temstar's design philosophy comes from the days prior to thrust limiters, so it is possible nowadays to build a simpler design that's less reliant on engine clusters. Engine clusters remain more efficient in terms of cost of the design, though. I designed a booster for a 165 tonne payload just this evening, and I used Temstar's philosophies to do it, so they're still very much valid. My booster came in at just over √450,000 if anybody's interested. Using the extra large fuel tanks is doing you no favors...their full mass-to-dry mass ratio is 8.2:1, as opposed to 9:1 for the FL-T and X200 series tanks (including the Jumbo64, the orange one).

Thought I'd had a solution for the OP there for a minute...had the proofing payload set to the wrong mass......well, back to the drawing board. EDIT: Okay...will this do? Basically this is the design I described earlier today, except that each booster rocket received an X200-32 and an X200-8 instead of a third orange tank. There are 16 RCS blocks in the core with two roundified tanks for fuel, an RC-L01 probe core and a Z-4k battery for self-control. The boosters are on the ends of XL girder segments and use Hydraulic Detachment Manifolds for staging boosted with single Sepratrons. 995 tonnes as is - for a payload fraction of 16.58%.

I use RCS Build Aid myself for spaceplanes, though I've only been using it to determine how far my CoM will shift during flight; I didn't know about the whole first stage thrust thing. Going to have to try that out my own self.

I don't know if this actually will work or not, but try temporarily turning the thrust limiter on the pushing engine to zero. Don't forget to reset it before you launch unless you want a nasty surprise... Alternatively, you could try temporarily replacing it with a set of non-thrusting parts of equal mass. Three Engine Nacelle in series have the same mass as a Turbojet or RAPIER, two with a drogue chute have the same mass as a Basic Jet.

Kinda vague...are we just talking general death here, or is there a certain degree of flair required? I mean, one of y'all will have this licked before I finish typing up this post...

Not necessarily...I did a set of boosters the other day for a guy who was only lifting twenty-five tonnes, an SSTO rocket and an asparagus. The asparagus design was almost half the cost of the SSTO. Makes me wonder how a transporter spaceplane would fare.

Hmm...165 tonne payload, eh? Yeah, that one defies the standard limits of design a tad bit. Conventional wisdom would say that an asparagus-staged rocket has a 15% payload fraction (the final design would weight 1100 tonnes, which is more than the OP's - I'm going to assume "personally mandated" - weight limit, while a transporter spaceplane can do roughly 25% if you design it right - for a 165 tonne payload, that's a 660 tonne plane, and with conventional wisdom saying 15 tonnes max takeoff wait per turbojet that comes out to no less than 44 Turbojets, so I imagine the part count there would be effin' horrendous...provided the plane itself didn't break the runway as soon as the physics engine kicked in due to its mass. So with that said...let's try the asparagus option. Temstar had a booster design back in 0.20 that could do 160 tonnes based on his '>asparagus design philosophies of the time (before the days of thrust limiting), so it should be possible to do a booster for 165 tonnes. Based on his philosophy, you'll need an 1,100 tonne rocket (assuming a 15% payload efficiency), with 3795-4032 kN of thrust in the core and 2242-2382 kN of thrust in the boosters (assuming three booster pairs). The boosters are easy - you'll want KR-2Ls there set to between 90-95% thrust each (go with 95%). The core is the tough bit; nothing outputs that much thrust on its own, so you will need an engine cluster there. I'm gonna suggest a KS-25x4 coupled with six Mk-55s; that should give you 3920 kN, which is in the acceptable range. 73.65 tonnes of engines + 165 tonnes payload = 861 tonnes leftover for fuel and extra crap. Say it's all for fuel - dividing the fuel evenly among seven stacks gives 123 tonnes per stack. Three orange tanks plus one X200-16 and one X200-8 (the small and medium 2.5 meter tank) each comes close to that, for 121.5 tonnes per stack, which gives you a 10.85 tonne budget for extra crap like decouplers, I-beams (which you're going to need if you couple those extra large engines with the 2.5 meter tanks), RCS capabilities for the core (use a couple of cylinders - that should be more than enough) and whatever else you need...maybe a probe core and a couple of Z-100s and OX-STAT panels so that when it's all said and done you can deorbit the final stage of the booster and self-clean. I'll have to test this design to see if it'll make orbit. Unfortunately tonight is Halloween, I've got kids of the appropriate "promote tooth decay" age and I'm at work up until then, so it may be tomorrow before I can try it out. You're welcome to try out the design in the meantime; I'd love to know if I've steered you wrong or not, OP.

Took JebNeedsHelp's spaceplane design from yesterday and tweaked it; swapped out the Tail Fin for an AV-R8 and the Mk1 Cockpit for a Mk1 Inline and a Shock Cone Intake. Made orbit. The CoM doesn't shift much (ever so slightly forward, actually) and the design handles reasonably well, though its atmospheric flight ceiling was a bit lower than I prefer (around 27,000) and its switchover speed was lower than I prefer (just less than 1800). Landing was rough - the handling became a bit slugglish once she was lower on fuel - so I might add an Inline Stabilizer to my list of recommended tweaks for the design. Wound up landing it immediately to the north of the runway, close enough that I was able to drive it up there once I'd slowed down a bit. Overall, I'd say the original design was excellent - particularly for a plane designed by a spaceplane rookie. It just needed some air. Got started building a DocMoriarty-style transport spaceplane for a fifteen tonne payload. And by "getting started" I'm being literal - I time enough to build only the frame before I had to shut the game off last night. Hopefully things will be able to pick up there pretty soon; I'm excited to see if this design will work out the way I hope it will.

I'll tell you this much - you don't want to go in very much at all; Jool's aerobraking envelope is thin. Jool's atmo starts around 150,000 meters. I sent a probe carrier to aerobrake at 140,000 meters once; it went in. Reverted and set to 148,000 - it didn't aerobrake enough. Yeah, Ashflare's given you the link to the aerobrake calculator; that's your best bet.

In KSP, there is very little that qualifies as a cheat. Maybe overuse of the debug menu. Definitely NOT using Mechjeb, KER, KAC or any other mod. Besides, there is a scientific test there if you think about it - you could be testing a design to see how it responds to increased drag or something, whatever role-playing you want to do there. "What will happen if we pull the chute NOW instead of LATER? Will the capsule tip over? Will it explode in a big fiery ball?" Folks around here tend to live for the 'splosions. Point is, I think we've all of us here had to test the chutes on the way up at one time or another. Only thing I'll say about doing it is that your test chute, if you're testing it going up, probably should not be the same chute you intend to use the recover the craft...in my experience the chutes have a tendency to vanish at apoapsis.

Totally cool with that. Now to design that probe...

Think I'm going to do Jean Deaux's challenge anyway, just because of the way I was thinking of doing it...