Jarin

Yeah. With the 120 cargo bay, it was seeing 1500+kN (which I assume is the front face open to the airstream), but when put in just about any other configuration, it gets about 1/10 of that, which is about on par with similarly-sized fuselage sections. I'll take the other tails out for a spin with @sh1pman's designs and let you know what I find.

That makes a lot more sense. Thanks for clarifying. Edit: I should note that the tailpiece drag did only occur behind the short cargo bay. Its drag was perfectly fine in all other situations I could test.

Wait, they're what now? Do stock parts do that too? ... reminded of the old physics joke "first consider a spherical cow..."

The drone core had 0 drag in both tests, so I'm still leaning towards the cargo bays being the culprit. The tail works fine with other configurations.

Okay, testflight of @sh1pman Spaceplane 1, amazed this can go supersonic at all, but it flies like a dream. Impressive. 300+kN drag on front pieces, 700+ on middle fuselage and each cargobay. Nearly 5kkN drag on the whole craft at mach 1. And it barely needs half throttle to hold there. That's some hefty thrust. Let's compare to Spaceplane 2. Same flight profile, holding at mach 1 at sea level... and at full throttle it hits a wall at mach 1.06. Let's see what the problem is. The cargo bay drag looks just like it should, each of the bays having about half the drag of the double-length ones, so there's one theory gone. Total drag is through the roof though; way higher than Sp1. And hello, the 'iguana' tailpiece has over 1500kN drag just by itself. That looks to me like it's not occluded. Let's test that... and on the SP1, it is completely occluded. The tailpiece on Spaceplane 1 has 0kN drag. So the question isn't just "how come Sp2 can't get to orbit" it's also "how come Sp1 can?" It obviously thinks that the tail is fully protected by the cargo bay, somehow. I re-attached everything on the rear to confirm that all nodes are in the right spot, but I'm baffled here. Bottom line, Mk4 'iguana' Tailpiece, when connected to a CRG-120 cargo bay is not occluded at all, and performs like a brick wall in the airstream. While the same piece attached to the back of a CRG-240 is completely occluded and treated as if it's inside the bay itself, with no aerodynamic effect at all. I have the same tail on my Mk4 testbed craft, but it seems to be jut fine there, so I would say the issue is something on the rear node of the cargo bays. Edit: Tested a bit further by stuffing a Mk4 drone core between the bay and the tail. On Sp1, the core has 0 drag and the tail has 'normal' drag in the 150 range. Craft comfortably goes supersonic. Same edit on Sp2, the core has... 0 drag, tail has normal drag. Craft comfortably goes supersonic. Whut @Nertea, help, this is breaking my brain.

This, of course, depends heavily on your preferred playstyle and design philosophy. Let's break it down a bit- Since you bought everything at the 45 tier except Aviation, I'll assume you're not particularly concerned with aircraft right now. If that changes, I highly recommend picking up Landing shortly thereafter, as the retractable landing gear makes life much easier. Other than that, let's start from the top: Heavy Rocketry also requires Fuel Systems to be useful, as you don't have any 2.5m tanks to go with those engines otherwise. The reverse is not true, as Fuel Systems has the FL-T800 and the fuel line, although with crossfeed changes in 1.2, those are far less necessary than they once were. Regardless, combining the two is a solid 180pt choice for building larger rockets to loft bigger payloads if that's the way you want to go first. Propulsion Systems goes the other direction, giving you lightweight probe engines, letting you get more use out of less payload weight. This is a good first choice if you have a favorite mk1 rocket that you like using to launch satellites and the like, and don't want to retire the design yet. Advanced Construction's primary benefit is opening up your first faring. Enclosing your payloads in a aerodynamic shell both protects them and lets you build more efficient and less draggy rockets. Important for a more satellite-focused career, and a good complement to Propulsion Systems. Aerodynamics can be safely ignored for now if you're not building planes. In fact, all you're going to find down that entire line is some control surfaces to help with controlling larger rockets, and the best one there is probably the standard canard at the 160 level. It can wait. Landing gets you nothing you need at the moment unless you're making much heavier landers. Advanced Flight Control gives you RCS and the ever-useful advanced inline stabilizer, along with the excellent Mk1 lander can, which has the distinction of being the lightest kerballed control pod. Pick this up when you want to focus on living space exploration over satellites. Space Exploration gets you... nothing much aside from your first ladder and a light rover wheel. Not terrible, but of questionable necessity. Miniaturization - pass. You already have Electrics, so let's look at Advanced Electrics at the 160 tier. While very useful, this would eat almost half your available science points right now. It can wait. 341 points lets you buy three 90pt nodes, so let's look at options. Heavy Rocketry + Fuel Systems for larger rockets. Pair with Advanced Flight Control for the best results in putting kerbals on Mun and Minmus. To focus on probes, go with Propulsion Systems for lightweight engines and fuel, and Advanced Construction for a fairing to keep your fragile probes intact on top of your rockets. From there, you can buy the less-useful Miniaturization to start moving towards lighter probe cores and better antennas further down the tree. Any questions?

Oh hey, I completely forgot this was a thing, but is Deep Freeze allowed? It sort of shortcuts the life-support requirements for the long trip.

This is so much more than I dared hope I would get here. Thank you for the amazingly informative answer. Any pointers on where to start on figuring this out? I've not touched config editing at all, aside from like, two mm patches (that someone else wrote for me)

- and this was the first time I'd had four running for any length of time, so the heat built up in the background until it exploded the lowest-tolerance item on the base as soon as physics loaded. I didn't realize there was a limit there, I just figured "more radiators" solved everything. Granted, I had something like 10 drills running, so I could have just overloaded it in general. I need to crunch some numbers...

Any perspective on how those interact with KSP Interstellar Extended? Like I said, that's probably gonna be the core of this playthrough. I use EL in everything, but I know that USI pulls out most of the guts and replaces it with a more complicated production chain. For conflicts, I'm mostly talking about "these two nuclear reactors use totally different resources, and only one can be used with that nuclear motor over there". I assume none of it is actually game-breaking, if only because KSP mods tend to play fairly well together codewise. I know the broad strokes of what most of the major mods around here do, I'm just looking for the perspective of someone who's used them alongside eachother.

No problem. I'll go figure out procedural wings in the meantime. Never used it before, myself.

Just wanting to know what I'll need to test them if you upload the .craft files

Looking at how actual lifting body craft are designed, it might be best to drop that wing area a bit. Despite KSP wings just being "drag + angle of incidence = lift", they're theoretically abstracting actual wings, and fuselage components aren't shaped that way. The Mk4 is really just a widebody cargo craft. It's the same problem the Mk2 stock pieces have, just writ large. Actual lifting body craft (as opposed to shuttle-type designs which are supposed to be draggy as hell) are supposed to get a higher lift-to-drag ratio than traditional wings. They also look closer to flying wings than widebody aircraft. Please. I'd be happy to put them through the wringer and figure out what's breaking. (Also, is it all mk4, or are you getting engines and other parts from another mod?)

Yeah, that's what I was thinking. Those fuselage parts have as much lift as most wings. I need to experiment with Mk4 in more lifting-body design and compare drag to traditional craft.

So I've finally finished dabbling in the shallow end of tech mods and am finally looking at diving into the complicated stuff. Just one quick question if anybody has in-play experience with it; how well does KSPIE work alongside the USI suite of mods? Both technically and thematically, I mean. Complement? Conflict? Awkwardly different processes to similar results? I'm looking over the functionality of both, but I don't think I'm going to grock any of it until I put it in play, and I'd like to know if I'm headed for issues and should leave off USI for another career before I dive in deep. On a similar note, how do the above work with NFT/B9, etc (NFT especially, since it has a lot of power like KSPIE does)? Or am I just asking for editor and brain overflow looking at all those at once? My general goal here is to finally do a proper high-tech career, with KSPIE as a central focus (I'll probably be starting with tech researched up to the 160 level or so). For that, I need complementary mods for life support, offworld industry (for deep space craft construction), and general rocket part selection. I was looking at USI because it handles 2 of those 3, and is an interesting set of systems in its own right. Any recommendations towards that end would be greatly appreciated. Also a tech tree suggestion? I know there's several alternate trees out there that use the CTT as a compatibility framework.

On a related note, is there any recommended amount of radiators per drill or ISRU unit to work at ideal temp (I know you can just add them to the point of overkill, but I'm looking at efficiency here)? I recently had my drilling outpost explode a thermometer as I came into physics range, and all the radiators were at almost max saturation. I've since gone "overkill" to avoid further trouble, but it made me curious.

There's a reason I call it an abomination. I typically just use the "heat spike" of sticking a collapsed whip antenna on the nose. Functional, and looks realistic. Granted, that's just for Mk1/2. Mk3s are already snowplowing through the air, so those just get more engines to kill drag.

To run this on my toaster laptop, I'll probably have to make extensive use of UbioZur Welding, but this sounds like a challenge I need to try out.

Should probably toss this image into the OP. It demonstrates what the mod is about better than the majority of the imgur album. Liking what I'm seeing so far. Will definitely be watching this mod's progress.

Fuel, labs, looking damn pretty. Also orbital construction in late-career.

ftfy

Shock Cone and a couple others I can't recall are currently tied for least draggy mk1 endcap. It can still have heat issues, but only at the edge of the hypersonic flight envelope. What atmospheric performance are you looking to reach?

Pretty much any construction mod is allowed. You just get a 4x score multiplier for stock.

My last trip to the mun somehow was so abysmally planned that the lander ran dry of fuel 70m/s shy of landing. Some creative lithobraking meant that the pilot survived... even if little else did.

Yeah, that would do it. Subassembly and merged parts can only connect by the root. Since your probe core (obviously) doesn't have any nodes open, you're outta luck. Re-root to an endpiece. A decoupler or jr docking port are my pieces of choice. It doesn't matter much though, since you can edit to your heart's content once it's properly attached. redundant post is redundant, I just wanted to add the bit about being able to edit it all after attaching, so the specifics don't matter as much