IronMaiden

As far as design goes, you have too many engines. 2 RAPIERs is more than enough for a plane this size. You've also got way too much oxidizer for a RAPIER/Nerv plane. A good starting point is about 10:1 liquid fuel to oxidizer. Also, angle your wings up at least a few degrees to minimize body drag and swap radial monoprop tanks for an inline one to decrease drag. As far as the ascent goes, fly at sea level til super sonic then slowly allow the nose to rise and the plane will climb. Your pitch shouldn't go much above 15°. Just to be clear, angle of attack is not the same as pitch angle. Angle of attack is how far your prograde marker is from your pitch angle, your pitch angle is how far your control point is angled up from parallel to the surface. Your angle of attack shouldn't ever be much more than a few degrees off of zero and ideally less than 0.01° from zero once past 15km or so (this requires wing incidence as explained in the design part above.) Once your plane has climbed past 10km start leveling out. You want your pitch and angle of attack to be about 0° by the time you reach 15km or so. Here you want to accelerate on air breathing mode as you very slowly climb. A good target is 1700m/s at 22km. NEVER PITCH ABOVE 5° ONCE PAST 15KM! Once you've reached mach 5 and your acceleration in airbreathing mode is starting to peter out, activate your Nerv and continue accelerating up to mach 6 (should be close to target above). Once there switch to closed cycle for the final acceleration to orbit. DO NOT PITCH UP. KEEP PITCH BELOW 5° ALL THE WAY TO ORBIT! Wait for your apoapsis to get to 70km or so (by this point your periapsis should be close to if not already above sea level). Circularize (should take less than 100m/s). If you do this right you should easily have 5000m/s+ left once in LKO, probably closer to 10,000m/s.

Hopefully this answers all of them :P

I made an SSTO a while ago literally called "5 Orange" that does exactly this.

KSP is awesome, KSP2 should be awesome too. Take all the time you need to make it right, we still have KSP.

Don't get me wrong, wing area is very important, but the Albatross's is way overkill. In my experience, a wing area of about 1m^2 per 5-6t of plane and 5° of incidence seems to be a good start. The Albatross has 1m^2 per 1t, that's 5x more than you need! That's a whole lot of unnecessary drag and mass. If you're looking for an early game SSTO, here's an example of a Juno-Terrier design that doesn't require any building upgrades.

Vastly improved weight distribution dude, well done!

What do you mean fly without any pitch? You mean that it takes off the runway without any input? That's because it has a built in pitch of 7° on the runway due to the placement of its landing gear and 4° wing incidence on top of that. So yeah, you're not going to need to pitch up when your wings already have an AoA of 11°. It still requires lots of pitch control once airborne. The easiest way to get a plane to require barely any pitch control is to put the CoL right on the CoM and use wing incidence. And by CoL I mean true center of lift, not the one in game that only acknowledges wings and control surfaces. The albatross is a poor model for an SSTO because it has way too much wing area. Yeah you can make it work, but you could make it so much better as an SSTO by using less wing and surface attachments.

Your problem here is as Jonny0than mentioned, your CoM is too far back. That's an inherent problem with putting engines on the back of your plane. It gives your cockpit way too long of a lever arm to torque your plane around and it gets even worse as you drain fuel. The problem is hidden by the fact that the game only used wings and control surfaces in the calculation of the CoL. Mk2 parts are considered wings as far CoL is concerned but they create more drag than regular wings and that's not accounted for. It is a center of "lift" after all, not a center of "pressure" which is what we're really after. The best way to accommodate for this is to put your CoM in the middle of your plane so that your fuselage is neutrally stable. Here's a little guide which goes more in depth on this issue. There is a way to help the design a bit if you absolutely must keep the engine in the back aesthetic. That is to move your main wings further back and use wing incidence to move the CoL forward at low angles of attack, and backwards at high angles of attack. Wings further forward should have higher angles of incidence and the angle should get closer to 0° as you move back. Now at low angles of attack CoL moves forward for efficient and balanced flight, but if you try to pitch up or down too much the CoL will move backwards to put a stop to runaway pitch. It is self correcting and the plane will tend towards a few degrees of prograde. This is not as efficient as having a properly balanced plane but it's not bad for hamfisting some stability on to an aesthetically pleasing but not necessarily aerodynamically pleasing design

Here's a basic introduction to the drag model. This was made a few versions ago, so the data is presented in a little different way now, but all the concepts are still true. As for differences between wings, there are none when it comes to creating lift. The only thing the game cares about is the surface area, the angle of attack and equivalent airspeed. The "basic fin" has the best area to mass ratio, but it has the heat tolerance of flash paper so is completely unusable in SSTOs. By far the best wings to use for SSTOs are the Big-S wings, as they have the same mass to area ratio that most of the wings have but can also store fuel for free, the wing strake being able to store more per mass than the delta wing. No, KSP does not model wing sweep or telescoping. It's 100% or 0%. The only way to reduce the drag on a radial part is to put it in a fairing/payload bay. I have done a few experiments in the past and there was no statistically significant difference in any of the wings' lift/drag. Area, AoA and EAS is all that goes in to the lift/drag calculation. Here's a tutorial where I explain and show how to build and fly large SSTOs. The one in the video is 180t and carries 90t to orbit but the design is very scalable and I provide all the math you need to scale it up.

This is a water landing and takeoff SSTO I made a while ago. It can SSTO on Kerbin too, so it's more than capable for Laythe. I've found the best way to do it is to use wing incidence or flaps to create a lot of low speed lift without having to pitch. I.e. your plane can be flat in the water (lowest drag) and still create a lot of lift because you have wings or control surfaces that are angled up into the airflow to create lift. The way this works is you start your engines, begin accelerating and then deploy your flaps (or have wing incidence), these create some lift and get your plane a little further out of the water. This means less drag, which means you can go faster, which means more lift, less drag, more speed, more lift, etc.. until you're out of the water. Only then do you pitch up, if you try to pitch up out of the water you're just jamming your tail down into the water and killing your speed, you need to LIFT out of the water. Once airborne I retracted the flaps for less drag so I could accelerate to orbit. This was a while ago, if I were to make something like this again I'd just use wing incidence and maybe a couple flaps.

Sounds like you're pretty close, retracting your flaps should help a ton lol. I quick thew this together based on your description. I used a couple engine nacelles as well as the circular intakes to make sure there was enough intake. They also provide more than enough liquid fuel so I swapped the mk2 liquid fuel tank for a rocket fuel tank. There's nothing in the cargo bay but based on the Δv remaining in orbit it could probably take a small (<3t) satellite to orbit. Not sure how much drag you're getting at 25km but you can see below that I'm getting about 12kN. It had no problem accelerating between ~12km and 25km.

Try going with less wing area but more incidence, up to 5°. I go with about 1m2 per 5-6t of plane. That should give you the best lift/drag during the most critical part of the flight, when the Terrier takes over. AoA should be negative at low altitude and supersonic speeds since you have excess thrust, you want to optimize the plane for the speed run and the switch to Terrier at higher altitudes. I also wouldn't fly with SAS unless you're using prograde hold, trim results in a lot smoother and therefore less draggy flight.

Oof, yeah you don't want to have that much AoA, ever lol. Use some angle of incidence, that way you can hold prograde for super low drag. You can see my AoA when I switched to the Terrier in the plane I linked above was 0.003° and never went above 0.008°, and pitch never went over 4° until nearing orbital velocity. Don't think of it in terms of giving your Terrier "enough time" to circularize, instead you should take a more shallow trajectory (never pitch over 10° once you get past 10km, preferably never more than 5°), then you just need more thrust than drag and you will go to orbit. Notice when I switched to the Terrier at mach 2 and 10km, I had 25kN of drag, less than half of my thrust. And drag continued to drop and thrust continued to rise the further I got. Down to 10kN at 20km and 4kN at 30km. Edit: I forgot about the new Terrier model. I used the old model Terrier here because the new ones are bugged and create a lot more drag. Same with the Poodle and Spark. Probably the Skipper and Mainsail too but I haven't tested those. You can access the old Terrier through the advanced menu. Wing incidence is more important though.

You can make a good SSTO with Panthers and Terriers. The Reliant wouldn't be a good idea, Panthers can get you up to at least 900m/s and 15km. At this point Terriers are near max Isp and are thrusty enough to get a well designed plane into orbit, the Reliant would just be useless, inefficient mass. Here's an example of a Juno-Terrier SSTO.

Huh, you got me then, that is really weird. I did a mission where I drug a capsule from a previous mission to many destinations, did the ol' release and catch, and got the station/base building milestone every time.

The vessels need to be from two different launches. Did you launch them together for the Minmus one and then just pick up the Minmus lander to take to all the other destinations?

Looks like you're missing base building (docking vessels from two different launches on the surface), splashdown (where applicable), and crew transfer.

Very nice! You went a bit higher than I did, maybe 2m/s worth?

Try to change your mindset. Don't think about it as "getting your apoapsis up to 70km", think about it as "getting your horizontal velocity up to orbital speeds." The most efficient space plane designs will reach orbital velocity well inside the atmosphere. You have wings so use them, let them handle the altitude by creating lift and let your engines focus on your horizontal velocity. In other words, keep your pitch low. You should never be above 10° after reaching 15km, preferably below 5° but this will require some wing angle of incidence. The most glaring problem with your design is the engine mass. Your plane's total mass is 27t, and you have 9.6t dedicated to engines. That's over 1/3rd of your total mass, not even rockets need that much thrust. You could either get rid of engines or carry a lot more fuel and still have plenty of thrust to get to orbit. You'd benefit greatly from some wing incidence, this will allow the plane to have a lower pitch (less drag) but still create enough lift to stay airborne. You also have a lot of extra drag with the solar panels and RCS blocks, and the non-inline version of the cockpit is more prone to over heating which requires a less efficient ascent profile. Flawed as it is though, it should still be able to reach orbit if flown correctly. The flight profile should look more like this: climb past 12km and drop pitch below 5° accelerate up to at least 1400m/s, preferably closer to 1500m/s as you very slowly (no more than 50m/s vertical speed) climb up to around 18km as you approach 1400m/s and your acceleration slows, start the Nervs maintain a slow, steady climb as you continue to accelerate; as long as you have more thrust than drag you will reach orbit this is all much easier with trim (alt+q,w,e,s) than SAS, unless you have wing incidence, then it's even easier to just lock surface prograde all the way to orbit If you want a lot more tips like this and more indepth stuff, check out this SSTO tutorial. I use RAPIERs in that design but all the concepts are valid, just the numbers will need to be tweaked a bit since the Whiplash isn't as fast or powerful.

Sort of, as long as you're at orbital speed. However, remember the Oberth effect, it's more efficient to raise your apoapsis from 30km than it is from 70km even though you'll get a little more drag. As a general rule you shouldn't throttle down until you're raised your Apoapsis to the desired altitude and you should be as aggressive as possible with your gravity turn. In a craft that has been properly designed to reasonably limit drag and have a reasonable TWR, you often circularize at 30-40km. In more extreme examples with crazy high TWR you can circularize at 20km or even 10km but you'd need to abuse the aero and shock heating model a bit for that to be the most efficient ascent. That's an interesting idea, but I'm not sure at what fairing mass it'll start being worth it. As I mentioned above, there's also the Oberth effect. If your fairing is half your payload mass then yeah it might be worth it to do the last 100m/s or so at a lower speed with a significantly lower mass but with your setup here I don't think it's worth it. I'd love to be wrong though

Throttling down is not a good idea, in fact you should maximize thrust on the SRBs too, more thrust means less Δv to orbit as less is lost to gravity. There's no changing your engine mass so take advantage of it. You should be max throttle until your apo reaches 100km, and at orbital velocity at that point as well. Gravity turn should be as aggressive as possible without needing a positive angle of attack to prevent falling back to the planet.

I suppose I should post it here too Here's mine with 3446m/s remaining at 100km circular orbit. Changes: I maxed thrust and gimbal range on everything and rotated the craft 5° to the east. Changed fuel flow priorities, drain from bottom up on both stages. Flight: Max throttle and lock surface prograde after clearing the "tower." Circularize and push apo to 100km at around 30km. Stage fairing once in space. No mods. There's room for improvement, I could've been more aggressive with the gravity turn.

The Whiplashes are turboramjets. They need to get going supersonic before their thrust really starts ramping up. So stay at sea level until you reach ~mach 1.3 then slowly pull up to about 15°, no more, and climb to at least 15km. There you'll want to level off and start accelerating in the thin atmosphere. Aim to get to at least 1400m/s with just your Whiplashes before allowing your altitude to reach 20km. Then keep your pitch nice and low (<5°) and light up your rocket engines. Remember, orbit is about going fast, not up, the only reason you need to go up is to keep from blowing up. Drag is basically negligible if you keep your angle of attack close to 0° so let your engines focus on building up that orbital velocity and let your wings handle keeping you in the air. Aim to roughly circularize around 35km, maybe a little higher since this cockpit is prone to overheating as it takes the brunt of the heat as the front part, the inline cockpit allows for much more efficient ascents. Your plane has way more thrust and fuel than it needs, both open and closed cycle, so you can definitely take this plane to orbit if you pilot it right. If you want you can check out my SSTO tutorial video. I use RAPIERs in that design but the ascent profile will still look the same, you'll just get a few hundred m/s less out of open cycle and therefore your payload fraction will be significantly smaller.

No I figured everyone would just burn it off on the pad since it's just worthless mass for this challenge The drag is a bigger factor if you take a more aggressive gravity turn which the TWR of this craft definitely allows. Here's a fairing flight with 3655m/s remaining, I would've had about 3685m/s had I not accidentally hit Z and shot my apoapsis up to 116km so that's about a 230m/s difference the fairing makes. Another change you could make would be to revert the poodle to the old texture which causes far less drag. You can get the older version through the advanced mode. So anyone trying this challenge in a version older than 1.6 is going to have another 130m/s or so, not accounting for any changes made to the aerodynamic model since then. Here's my old poodle results. After the poodle, the next biggest culprit is the ladder, get rid of that and this thing flies much better.

This thing has way higher drag and TWR than I'd ever use which makes this more/less interesting depending on your approach Simply getting rid of the ladder will do wonders for the Δv as you'll be punished less for taking the appropriate gravity turn for the TWR. My first attempt was closer to an ideal gravity turn for the given TWR ending up at 45° by the time I reached 5km, this caused an awful lot of drag and as a result I got to orbit with around 3440m/s remaining. If I could add a fairing I could probably save another couple hundred or so m/s. My second attempt was a bit less aggressive, the drag was still bad but I ended up with 3477m/s remaining. You can see my profile in the album but basically start pitching over immediately after takeoff then lock prograde, ending up at 75° by 165m/s, 60° by 265m/s and 45° by 8km. If I were to try to improve on this more I'd take the 1 time drag hit and pitch down off prograde somewhere around 20km to be more aggressive once the atmosphere really starts to thin out.