Spatha. Six kerbals. 4km/s. 65 parts. One stage.

[AppleDavidJeans]

I just designed my first working SSTO today and I see this? Awesome!

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Careful, it may reach critical mass and collapse into one tiny superdense engine

You could teach a clipping-class on how to stack things inside other things...

inigma has done this before, I believe. And it worked out fine!

[TheGamingNoobster]

Actually, you can probably do better if you learn to stay with a lower vertical speed longer. In this design, it is perfectly reasonable to get to 1,800m/s (surface), with the jets engines still providing thrust, and though that happens at about 32kms, by 30 you should already be well over 1,600m/s. Maybe you are giving up on them early? You can perfectly well ride the slight thrust asymmetry when the engines are starting to spool down, and that lets you keep them lit almost until you apo is outside the atmosphere.

...mmm let's see if I can guess what is going on here. You are having some trouble with high altitude flight in the stock atmosphere? If so, that is probably because you are accustomed to fly high TWR designs, things that don't really need the wings and could go on a vertical climb without issues. Well, this is not one of those things! TWR is never over one, I think, so you need to know how to use those wings to actually do useful work. That is also the source of it's enormous delta-v, BTW, I save a lot of engine weight! But the problem comes when you get to the high atmosphere: due to it being modelled as it is (lift scales with v, not v^2 as in RL), the wings pretty much do nothing there and you can't trust them to keep you going up. And, as I said, you don't have TWR over one so you can't just point up. So how the hell can this go to orbit, then? Well, simple, but simple does not mean easy: a proper zoom climb. That means you keep momentum going up always, and as long as you can keep you time form apoapsis from going down, you can make orbit with TWR 0.8 or 0.7. Re-read what I said about the climb profile: vertical speed of ~10m/s at 25kms at ~1km/s (surface), then 50-100m/s at 25kms and over 1,500m/s (surface), then let it stick to that last heading, light the nukes and watch vertical velocity climb as kerbin's gravity starts being more and more counteracted by your "centrifugal" (centripetal, actually) acceleration. Oh, and keep the turbojets lit until one of them gives out completely: I worked the intakes so after a slight imbalance, the engines will spool down on their own as the air starts to run out, and that way you can keep the nuke going full blast beside them, and you can keep accelerating quickly. That should leave you with a >60kms apoapsis, >1,800m/s (surface), or in other words >2,00m/s (orbit), and more than a minute to raise it over 70 and circularizing on the nuke.

Rune. Of course, this should all change for the better with 1.0, when wings give proper lift all the way to the Karman line. I can't wait to get a plane with a TWR of 0.5 to orbit!

Guilty as charged!

[Rune]

Found a triple stack example from last year; http://forum.kerbalspaceprogram.com/threads/43086-Open-Source-Construction-Techniques-for-Craft-Aesthetics?p=943756&viewfull=1#post943756

I may have to try a turbo-nuke some time... there might be potential for a really light drone that could carry a nerva. No other way of having just 1 jet engine and 1 lv-n without horrible thrust imbalance.

All I need now is a contract that can be fulfilled by an MK2 plane... seem to only be getting stations with science labs at the mo, and that called for something a bit bigger

I just designed my first working SSTO today and I see this? Awesome!

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inigma has done this before, I believe. And it worked out fine!

Glad you both like it! And yeah, that "Turbo-Nuke-RAPIER" could work, sure. Now all I need is ideas about the rest of the SSTO! Maybe something that can work like a plane on oxygenated atmospheres but turns into a tailsitter for airless moons? Now there's an idea...

Guilty as charged!

Then I hope my advice was helpful! Once you "get" SSTOs ascents, the whole thing becomes much easier, since you start designing for the hard sections of the flight, and can judge the problems of a design much sooner. My personal yardstick to check the sanity of a rough design is: if it can keep on climbing at 10kms, and it has enough delta-v, then taking it to orbit is a matter of balancing it.

Rune. At least, until 1.0 and proper lift comes.

[B.O.B.]

that "Turbo-Nuke-RAPIER" could work, sure. Now all I need is ideas about the rest of the SSTO! Maybe something that can work like a plane on oxygenated atmospheres but turns into a tailsitter for airless moons?

Wait... a plane powered by a Turbojet, LV-N, R.A.P.I.E.R. combo with additional landing struts on it's tail for airless lower-gravity moons? Perhaps i should start the mass production and taking pre orders before you come up with a more efficient design. klick

(Unfortunately my graphics card melted, so no test flights for the next week...)

Edited March 7, 2015 by B.O.B.

[Rune]

Wait... a plane powered by a Turbojet, LV-N, R.A.P.I.E.R. combo with additional landing struts on it's tail for airless lower-gravity moons? Perhaps i should start the mass production and taking pre orders before you come up with a more efficient design. klick

(Unfortunately my graphics card melted, so no test flights for the next week...)

Hahaha! You gave me a further idea! Small bay to put a rover, KMU, or something. There is a Spatha version with a cargo bay instead of a crew cabin, BTW... I just thought it was really easy to convert yourself if you wanted. And yeah, don't worry, I make it'll look "a bit" different. I'm thinking single seater, and go for maximum range on a single engine combo, so about half the thrust class.

Rune. But this all very preliminary, might end up in the bin.

[Okie Rocket]

Hey! Long time lurker, not quite first time poster. I was looking at the fuel system on this after a flight and noticed that the two fl-800 tanks had managed to become unbalanced. I did some picking and pulling at parts in the hanger. It looks like the nuke is pulling oxidizer the way it should but if there's any liquid fuel left it the mkII adapter it pulls from there and the tank on the left while leaving the LF in the right side untouched. Depending on fuel levels and how long it goes unnoticed, it probably wouldn't be a big deal. (If I'm mistaken somehow, feel free point and laugh. )

On the whole though, this is sweet as usual. I have something that's functionally very similar but considerably uglier!

[Rune]

Hey! Long time lurker, not quite first time poster. I was looking at the fuel system on this after a flight and noticed that the two fl-800 tanks had managed to become unbalanced. I did some picking and pulling at parts in the hanger. It looks like the nuke is pulling oxidizer the way it should but if there's any liquid fuel left it the mkII adapter it pulls from there and the tank on the left while leaving the LF in the right side untouched. Depending on fuel levels and how long it goes unnoticed, it probably wouldn't be a big deal. (If I'm mistaken somehow, feel free point and laugh. )

On the whole though, this is sweet as usual. I have something that's functionally very similar but considerably uglier!

o_O. Well that sounds like a part parent problem! And surprisingly, I totally didn't notice it, and I have flown several of these extensively... maybe I broke something in the file I gave for download

Anyhow, the only solution would be to take it apart and put it together again, I will look into it and the file might at some point be updated. At least engine tests at ground level are slightly shorter to do...

Rune. Don't have a lot of faith, though, my free time is lately quite limited.