camacju

I never use the tiny landing legs, I prefer to use struts or just engine bells since they're lighter. I prefer the small landing gear because I rarely use large planes, so the larger landing gear are excessive.

I like Laythe and Eeloo because they are good gravity assist practice without being too hard to land on.

This link may be helpful: https://www.speedrun.com/ksp

Nah, with stacked service bays you can definitely do a sea level sundive

@Brikoleur I would like to un-claim paraglider technology and let any other participant use it, in order to see what direction other people take it. As for the air intake, it's flipped around and clipped inside the Juno engine. This produces less drag but it wasn't really necessary. One thing to note, that I didn't actually take advantage of, is that deploying a Kerbal's chute actually reduces their drag a good amount. However the lift from the chute makes the plane have a tendency to nose up.

I didn't use Mechjeb for any autopiloting, only for information readouts. In that sense it's the same as Kerbal Engineer which is explicitly allowed @Weak Player

https://imgur.com/a/Umtb0kf Here's a manned mission to Pol and back

This was a fun challenge! I'm not used to designing tiny planes so this was something new and interesting. I aimed to optimize for cost, mass, and part count, but not time. Craft in VAB. 2375 funds, 9 parts, 688 kilograms mass. The parts are three elevons, a Juno, an air intake, a basic fin, a command seat, a liquid fuel tank, and a small hardpoint to act as a landing skid. This craft is actually pretty fun to fly. I'm not used to flying without SAS so it was a bit annoying at first. Cruise at 200 m/s. Kerbal drag is really really high so I couldn't really go any faster. EVA parachute deployed to slow down. The landing skid has a high impact tolerance so I can come down pretty hard. Landed at the island airfield. The craft landed at a tilt so Bill had to get out and push it back to vertical, then push the nose around. Approaching KSC Chute deployed. I don't need to worry about how I land here as long as it's in one piece. Landed at 6:32 Possible part count improvements: I can't think of any. Maybe removing the basic fin and using a V tail but not sure how good that would be. Alternatively you could remove the landing skid but that would make landings a lot harder. Possible mass and cost improvements: Switching out the fuel tank and/or changing the fuel fill level. All other parts are pretty much as optimized as they can be. The only possible major improvement over this design would be to forego jet engines entirely for a Spider or Spark powered plane, but I'm not sure about range or fuel efficiency.

I like Laythe and Eeloo because they're good for practicing gravity assists.

I was wondering when you'd turn up. With exploits allowed you can go to -250m on kerbol

My point is that that's basically the exact opposite of what @Snark was claiming, which is that constant altitude landing/ascent is easier but less efficient.

A secret nobody's probably realized is that my time warp is at 100X which is a lot better for cooling. It's because at 100X time warp the heat calculations are done as if the craft is a single part, massively improving heat conduction between parts.

The math is a bit tricky, so the best way to test this is empirically. I've done both constant altitude landings and constant retrograde landings, and constant altitude landings are more efficient. In a similar fashion, constant altitude ascents are more efficient. And for some reason, ascents are a lot more intuitive for me, so maybe the following explanation will be sufficient: For an ascent on an airless planet, the only thing that matters is horizontal velocity, since you don't need to climb above anything. (Assume that you start from a mountaintop or something, for the sake of argument. Obviously this will be different if you're in a canyon and you need to climb out of it). However, for the sake of argument, we also assume that altitude cannot be lost at all - it must be at least the height of the launch. Then the key will be to gain horizontal velocity as quickly as possible. The earlier you gain horizontal velocity, the more effective the later segments of the ascent will be, because of the Oberth effect. This means that you want to be burning as horizontally as you can for the entire ascent. And that means burning at an angle to prograde, just enough to counteract gravity, while the remainder of your thrust pushes you horizontally. If that's not enough to convince you, here are some screenshots of a constant altitude vs. gravity turn ascent from Mun. (Gravity turn is the inverse of a constant retrograde suicide burn) Starting point: 1843 m/s of delta-v remaining. Constant altitude ascent In 9km - 4.3km orbit, 1274 m/s left, 569 m/s of delta-v expended I use MechJeb's gravity turn utility for the gravity turn ascent. In 6.3km - 5.7km orbit, 1264 m/s remaining, 579 m/s spent In conclusion, the constant altitude ascent let me reach a higher orbit using less fuel, so it seems more efficient.

That's why you want to come in completely horizontal, so you're always doing the exact minimum amount of fighting gravity. Pointing retrograde is fine if your TWR is really high, but for a low TWR landing (such as, trying to land on Tylo with nuclear engines), you won't be able to land at all, much less land efficiently. That's why you should burn a bit above retrograde, so you have more time before you crash. And even so, a constant altitude landing and a constant retrograde landing asymptotically approach one another as TWR increases, but the constant altitude landing is always more efficient, and the advantage increases as TWR decreases.

https://imgur.com/a/gr3CldN This is probably the closest that you can go to the Sun without aerodynamic exploits

The craft would probably work fine even without clipping of the fuel tanks. I only did that so I could have a lighter fairing

This wasn't today, but I'm still proud of this. I launched a single stage craft to orbit and then landed at KSC ... eight times in a row. https://forum.kerbalspaceprogram.com/index.php?/topic/11189-the-k-prize-100-reusable-spaceplane-to-orbit-and-back/&do=findComment&comment=3956589

My favorite first is probably when I had a SSTO, I landed at KSC, and I realized that I had enough fuel to do it again.

It seems that the limit for Cat 2 has been reached. With some trickery, I suspect that a bare hitch hiker with some flags can complete Cat 1. Basically you put it onto a collision course with Moho, and then lithobrake using the flags for a technically captured orbit.

The best way to measure ascent efficiency is in terms of mass fraction. For example, an ascent that reaches orbit with 86% of the original mass remaining (such as an efficient SSTO aircraft) is better than an ascent with 47% of the original mass remaining (an efficient single staged rocket). This is because mass fraction directly computes the actual fuel expended by all engines instead of having to rely on vacuum and surface delta-v readings. This technique is even better when you have multiple types of engines, like a SSTO craft which uses Rapiers and nuclear engines, or a rocket which uses KS-25s and nuclear engines, so you can't use delta-v readings at all. So you'd have to actually fly the mission but you get better information that way. You can see your craft's mass in the VAB, or in flight you can go to the map screen and go to the vessel info tab. However, I prefer to use Mechjeb for that because it's easier.

I mean the most efficient plane change uses gravity assists to do it for much less than anything else

The most efficient way to land on an airless body is as follows: -find the highest point on the equator and start from an equatorial orbit - this gives you some free velocity due to the body's rotation -start in a circular orbit at exactly that height -your landing burn will be all in one go - time it carefully and look for landmarks -landing burn will be pointed above the horizon such that your vertical velocity is always zero - you neither gain nor lose height during the entire burn. You lose a bit of efficiency to cosine losses but you would lose more to gravity losses if you didn't do this. -if you time it right you come to zero velocity exactly as you reach the body's highest point To take off you do the reverse of this. Point above prograde such that vertical velocity is zero the whole time until you're in orbit.

This was a thing already.

Just doing some quick calculations: Since magic wings aren't allowed, we should expect a subsonic lift/drag ratio of 6.5 and supersonic lift/drag ratio of 4.4 (more might be possible but these numbers are fine for now) This means we need a thrust/weight ratio of 0.154 subsonic and 0.227 supersonic in order to even maintain level flight. This translates to a full throttle TWR of 15.4 subsonic and 22.7 supersonic. I doubt you'd be able to break the sound barrier this way.

What's the atmosphere like on this exoplanet? Is it enough for winged flight? I'm asking because I want to do this with a stock parts SSTO