Brandano

I don't know if I posted my earlier SSTO (s) in this, HUGE thread, but here's the family of SSTO's I am currently using to ferry stuff from KSP to a stable 120k orbit. They can reach higher orbits, of course, but I am not aiming yet for that mission profile. The first one does not really have enough wing surface to reach orbit with the tanks full, but the other ones can manage just fine My first SSTO, a few versions back, was based on this little spaceplane, replacing the liquid fuel tank with a small rocket tank and adding a couple of Rockomax 24-77 small radial engines. What you see in the picture is an accidental sub-orbital hop, but the periapsis was above 30k, using only an air breathing engine:

The reason I added a solar panel is because the small radial rockets don't generate power and the jet engine uses up almost as much power as it generates above 30k. With a probe core and a lander can it could be used as a single passenger taxi, I guess. Hmm, I think I might try and make a single stage to Minmus design, just to see if it's feasible. Just a hint: if the mission ceiling is under 20k you don't need to spam multiple intakes per engine, I bet a single intake for two engines will work just as well.

This probably breaks several rules. Assembled in the SPH, but launches vertically from the runway, has no wings or control surfaces, and a total part count of 4. 1744m/s in 4 minutes, but could probably do better with more care, a probe core in place of the cockpit (though it needs the reaction wheels for control) and a RAM intake. A derivative of this turned out to be my smallest SSTO with a part count of 8 (I added a bigger fuel tank, two small radial rocket engines, a solar panel and a parachute)

Or you could subtract a little point for every docking port used, since using them to replace decouplers will likely require more of them. Actually, subtracting points for decouplers or docking ports probably would be fairer than for staging, which is rather arbitrary.

An MK1 command pod, not a MK1 cockpit. Sorry, I wasn't very clear. One downside of using the fuel tank as root node is that now I can't easily swap it for a rocket fuel tank, to convert the design to an SSTO. Getting the wings and gears aligned properly isn't exactly easy. There ought to be an option to "swap" the root node if nothing is attached to it, I think.

I think I'll consider this to be outside the challenge, it seems unfair to have unlimited attempts, and I already have two entries. However, just for the sake of it: Flight is still in progress, so far I have conventional takeoff, conventional landing at the island, pic next to my 2nd plane that is still parked at the island along with Jeb, takeoff from the island and vertical landing (a bit hard, a tad over 10 m/s, but the wings held), vertical takeoff and zoom to altitude, 87k Apoapsis (periapsis never went positive, this one has only one air intake) and now I am coasting back down toward the desert. I'll try to get a landing near the pyramids, but I have never been there, so it might not happen, and then another hop back to KSC. Part count: 1 x cockpit 1 x jet fuel tank 1 x intake 1 x jet engine 4 x swept wings 3 x landing gears 11 parts total Will link the file once I recover it, though I guess I can grab the auto-saved ship. Surprisingly well behaved, though it tends to sideslip a bit. it helps limiting the engine thrust to 50%, it won't really limit the top speed either. (edit) Hep! Spoke too soon. I got close to the pyramids, but lost control while attempting to brake to a vertical landing, and I didn't have a quicksave handy.. I never even realized I was still under acceleration either. Even with that it managed: 100 : Success 90 + 50 : High Flier 70 : Islander 50 : Conservationist 250: VTOL So it would be 610 points even without the Lander and Magellan achievement. I think that getting all achievements except for SSTO and Whackjob in one flight is achievable with this design. Here's the .craft file: https://drive.google.com/file/d/0B_Tszjgnsur4b2tGNGdIbUVRaWc/edit?usp=sharing I accidentally discovered that you can now build a plane without starting with a cockpit, and the root node of this craft is athe fuel tank. The first version model had a MK1 capsule to save weight, but I needed that intake and radial intakes just don't cut it at high altitude.

No, I mean, keep your design as it is, as a tail sitter, just shifting the rear wings back and the front wings forward. And place the ant engine so that it is aimed at the CG, since you only really need it when you are out of the atmosphere

You can place a single engine under the fuselage and aim it towards the center of mass. And use the wing tips and a single landing leg to VTO, with a lot of care. I see that the ANT engines have been seriously buffed up in 23.5

As far as I know ANT engines don't produce electricity, though

Hmm, you can take off horizontally, land vertically, then take off vertically... you just need to add another set of landing gears and give it an action group binding.

Actually no, it won't. It will just make the parabolic trajectory steeper, and the reentry angle will follow suite. You can reach a 100k apoapsis and then circularize with a rocket engine, and it doesn't really take much to circularize, as Aqua showed with his two ant engines. On the subject of ant engines, I do have a spaceplane that is ONLY control surfaces, so definitely not eligible for this challenge, here: http://forum.kerbalspaceprogram.com/threads/69053-My-tiniest-rocket-plane

*Aqua*, with three intakes and grossly overweight I managed almost 100k, by keeping the prograde indicator at 10° above the horizon from any place above 20k, and reducing throttle as the altitude increased. You can limit the turbojet thrust to get finer control on the throttle at high altitude. As the atmospheric resistance decreases the plane will keep accelerating even when barely above idle at 70k altitude, and you will find your camera in orbit mode almost with no warning. Slowing down is the real challenge, as it can be quite hard to get the thing back under control before it drops under sea level. I am going to try it again without the droptanks and with a single intake to see if I can make another "almost SSTO" hop, though outside the challenge. Oh, and getting there barely used two thirds of a tank, probably less if I had used a more careful climb profile. I think the best option is to zoom above 15k as fast as possible, and try to level off by 20k to a stable climb at reduced thrust.

Impressive indeed *Aqua*! As Keldaria mentioned you might even decide to ditch the LFO tank and the ant radial engines to get both Magellan (100 pts) and High Flier (90 + 50, if you peak over 70k ) achievements, while losing the SSTO (150 pts) achievement. That's 90 points more than the SSTO achievement alone.

I also did think about using multiple capsules as well, it's a trick already seen in career mode to obtain more battery charge early on in the tech tree. Actually, using the 1 place capsule in place of the spaceplane cockpit really helps keeping the weight down, but I like my planes to look nice

Does it count as an ssto if it can't achieve true orbit? My second plane can orbit the world, but it's doomed to reentry since the periapsis can never be outside the atmosphere

Here's the link: https://drive.google.com/file/d/0B_Tszjgnsur4WVh6ZDBHeGNCNzg/edit?usp=sharing And here's a ton of piccies: It's missing the takeoff because this was actually still a test of the landing gear alignment. I hadn't even renamed the plane. Actually, the linked file is the auto-saved ship file renamed and with the ship name edited. To fling yourself in orbit put the velocity vector marker 10 degrees above the horizon, and increase throttle to almost full. As you climb over 20000 throttle slowly back to prevent the engine from flaming out, until you are barely above idle at 50000, and still accelerating above 2000 m/s. No rocket engines, so once you are out of the atmosphere you can only sit there and hope the cockpit battery will last (no solar panels either).

I have updated my design with two droptanks, three ram air intakes in place of the single standard intake, and a turbojet engine in place of the standard engine, to try and get the "Magellan" achievement, though losing the low part count. I ended up flying around the world twice, because one of my suborbital hops ended up in an orbit with a 100k apoapsis and a 55k periapsis, even though I only had one air breathing engine. Does that count as an SSTO? I ended up using less than one fuel tank for both loops too.. very hard to fly, almost no pitch response, and landings are a bit "hot", and bouncy. But I managed to land back at KSC, and then to take off again and to hop to the island. And to taxi to the mk1 capsule in the hangar, get off the plane and get Jeb to play the tourist and pose for a picture. I actually didn't put on a ladder, so I had to retract the landing gear, and to get back in with a jetpack assisted hop! Should I post file and pictures?

Do you have to achieve all the goals in one flight? Here's my entry: Craft file, 13 parts: https://drive.google.com/file/d/0B_Tszjgnsur4NGJzUVpZRE1GVmc/edit?usp=sharing Pics: First flight, taking off at 1/3 throttle, hopping over to the island runway, taking off again in the opposite direction then facing east to attempt a long range flight. Only made it about 1/3rd of the way around the world, but with a better ascent profile probably can make it to one of the poles: Second flight, zooming up vertically to high altitude, then diving back to a landing at KSC runway. Notice how the pics at high altitude are with the engine shut down and the plane still climbing...: (craft file slightly modified to align the fins better to the airflow. This is the version in the .craft file link)

I like that ejector seat, I might add something like it to my gnat microplane!

Now make a shuttle out of it... That sounded like a challenge, so I figured I'd give it a shot! Here's my very lightweight vector just right after takeoff: The first stage might be of interest for other designs. It really helps getting out of the thicker part of the atmosphere without adding excessive weight to the ship. Here's the three engines still going strong, even though intake air has gone down to 0 , since we are over 20000 meters: They will flame out at about 25000 meters. They are angled toward the rocket's centre of mass, so the flameout is a non-event. But in case they are reused in another design the angle must again be finely adjusted. Just in case the radial separators will take care of cutting the engine fuel supply when they are triggered, so at the first sign of air starvation hitting the spacebar will bring things under control. Let's skip a bit ahead. To board the (now) spaceplane all you have to do is extend the ladder, go on EVA and climb up. Once close enough rotate the camera so that it clips through the plane's frame to select the command seat and board it. Trigger the decoupler and you are free: On a circular orbit at 100km altitude or thereabout. I had to modify the gnat, it needs a way to re-orient itself in space, and for that you need at least reaction wheels. There's no standalone reaction wheels in that sort of size, so I had to add a probe core behind the fuel tank. And a couple of solar panels. It is the bare minimum, and unless you plan ahead you can end up without electric charge and with both panels perpendicular to the sun. In that case your only hope is to get out and push, and when you do re-boarding the plane is a challenge. Burning retrograde for about a third of the tank will be enough to de-orbit to the thicker air. Probably it's possible to use even less fuel than that, this thing is very lightweight, even with the added probe core. But it's worth it to waste some more fuel and ensure that you land in the sunlit side of the planet. From there on, the re-entry is fairly simple. Just make sure you keep a positive AOA while still flying faster than 100 meters per second, or the plane will tuck under and start to tumble. Wait until the speed is slower than 60m/s (this will take a looooong time!) before opening the parachute, or the pilot will be tossed off the plane. Or just fly it for the next hour until it is low and slow enough for a landing. In my case it was a splashdown, at barely more than 10m/s. Jebediah seems rather pleased: As usual here's the .craft file to play with: https://drive.google.com/file/d/0B_Tszjgnsur4dlNFazI0RFFxbEk/edit?usp=sharing

Bernoulli is often misquoted. The "equal transit time" explanation of lift generation fails miserably when considering symmetrical wing profiles, and even on asymmetrical wing profiles it doesn't explain why in the real world the air on the upper surface reaches the trailing edge before the air from the lower surface does, rather than in the same time. Or why at positive AOA the stagnation point travels back from the wing leading edge on the lower surface, meaning that some air will hit the lower surface, travel in a direction opposite the relative wind to the upper surface and then back along the upper surface. Wings create a pressure difference between the upper and lower surface. And displace a volume of air in the direction opposite lift. What is the cause and what is the effect is hard to define properly, but the system as a whole does definitely both things.

That's why I was suggesting to adapt the prediction mechanism to create new "rails" to run the throttled ship on. the problem is when the thrust suddenly stops, because there's no more fuel or power. In that case at the very least the simulation would have to fall back to realtime to recalculate the new situation. At least, the fuel consumption is a constant rate, but while power consumption is too constant, power replenishment is not. It does however seem that power generation from solar panels and the like is still calculated while the simulation is running in an accelerated state.

Currently warp is only good for long coasts, though. The biggest issue would be to get the users to understand how incredibly useful could be an engine that has negligible thrust but can be burning for days. But I did not consider electric power usage, and that adds a lot of complication to any path prediction.

If the ion engine thrust and fuel consumption is assumed to be constant, it ought to be possible to calculate the "running on rail" path for it before entering time acceleration, though this increases the path prediction complexity a fair bit. It would also help a lot when planning an ion "burn", since you would be seeing the predicted path rather than the instantaneous projection.

In this line of thought, can I suggest a very rough tweak for the current drag model? Modify aerodynamic fairings and nose cones so that they subtract a certain amount of drag from the part they are attached to if they are leading them relative to the direction of flight (possibly adjusted by multiplying by the cosine of the angle between the velocity vector and the line connecting the two part centers). It's still a silly drag model, but at least it would make aerodynamic nose cones useful.