The Race to Publish the First KSP 1.0 Compatible Spaceplane SSTO

[Roflcopterkklol]

http://forum.kerbalspaceprogram.com/threads/117025-The-Race-to-Publish-the-First-KSP-1-0-Compatible-Spaceplane-SSTO?p=1878270&viewfull=1#post1878270

So small!

Gotta get your ascent profile just perfect; keep practicing!

i have been pitching at 50 degree from launch, leveling out at 12km and getting to 850m/s then pitching to 30 degree to orbit, how are you going about it?

[Redshift OTF]

God damn... even if an SSTO can be made in 1.0 it will be 100% useless, there is no way an SSTO is going beyond LKO that is certain and one will never carry a payload.

http://i.imgur.com/cTMfUNA.jpg why did they nerf jet engines so much in the upper atmosphere? 1200m/s is the fastest you can possibly get a jet to go, you can not get one faster it blows up and going higher than 20km kills the engines.

With FAR in 0.90 you could do 2400m/s with jet engines at 30+km.....

Did they even test jets?

because i am feeling like they did not test jet engines at all, even the animations are broken, the heating animation doesnt happen until the engines burn out and turn off and then they never cool down they just keep glowing red.

Annoyed about this, SSTO's were the only thing i liked about KSP, now they are low kerbin orbit only rapier engine only hunks of crap.

Yeah I agree with this. The only way round it is to find new methods protecting against heat damage so you can go faster before the jets die.

[eddiew]

how did you get something so small to orbit?

i cant get anything with that little fuel out of the atmosphere never mind with a payload lol

Don't know what to suggest except repeat my ascent steps xD It's a very fine line between burning up by being too fast and low, and not getting enough out of your air breathers for the rockets to be effective.

I have a background of making spaceplanes with FAR, which I suspect is setting me up for a better ascent profile under nuStock than those who came from the old aero. To my eye, your craft is carrying a lot of wing that's giving you a huge amount of drag and heat, which will be making you kick to rockets quite early and take a very steep ascent. Good under old stock, but FAR would have pulled it to pieces

Also, a lot of people are saying to go closed cycle on the rapiers at very low altitudes, like 20km or even less - from what I've observed, they produce useful thrust up to at least 25, which makes a lot of difference. At this altitude, they were showing 40kN each on right-click, the combined total of which was still more than the nerva on the back end. When your plane is light and you're in an already rapid ascent, this is plenty to keep pushing your AP out, so there's no reason yet to switch to closed cycle. I didn't kick them to CC until they fizzled at 27. The LV-N on the other hand, is a much more efficient rocket than the rapiers, and seems to do well from 20km up, so there's little reason not to light it relatively early.

Using alt-F12 you can add thermal readouts to right-click on parts, too, which is very helpful for monitoring. It may take a few runs, but eventually you get a feel for when you need to be getting the nose up and out of there*

* Disclaimer: it might have been a lucky accident. I'll try again tonight with a satellite payload and see how it goes.

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Yeah I agree with this. The only way round it is to find new methods protecting against heat damage so you can go faster before the jets die.

There's always the slider when you set up your game - I'm sure it'll be a simple multiplier in the save file that can be edited later on, too. I'm still uncertain as to whether I'll keep the heat on full or not, because while it's interesting to figure out how to beat it, it may also prove to be excessively limiting and thus fail the 'is it fun' test.

[Roflcopterkklol]

Someone want to test fly white lightning mk6 for me?

http://www./download/1u6x535yh773kgb/White+Lightning+mk6.craft

see if its not just my flying lol i can only get it to a 70-80km orbit.

action group 1 toggles turbo jets

action group 2 toggles rapiers

action group 3 toggles rapier mode

It is fairly easy to fly and stable considering it weighs 69 tons so don't stress too much about keeping it under control, thanks in advance to anyone who has a crack

[eddiew]

i have been pitching at 50 degree from launch, leveling out at 12km and getting to 850m/s then pitching to 30 degree to orbit, how are you going about it?

I'd be wary of the term "levelling out". I'd go for "controlled ascent to 900-1000m/s by 20km", with whatever vertical speed adjustments that may require as you go. Being level at 12km and 850 will leave you very hot, and still with a lot of atmosphere to get past before you can start to cool down again.

[Roflcopterkklol]

I'd be wary of the term "levelling out". I'd go for "controlled ascent to 900-1000m/s by 20km", with whatever vertical speed adjustments that may require as you go. Being level at 12km and 850 will leave you very hot, and still with a lot of atmosphere to get past before you can start to cool down again.

Yeah i do suspect im speeding up wrong im only managing to get to 900ish m/s before changing the rapiers to LF/O

[Yorz]

Been playing this game for a while but never registered here so as my first post I give you guys this.

Aerobraking seems to work well

About to overshoot so going a bit more drastic

Looking good

About to touchdown, nice and steady, lovely to fly.

Biggest problem I have is uneven fuel flow and I'm not sure why that is but I'm balancing all the time in flight. Good enough for now.

[eddiew]

Yeah i do suspect im speeding up wrong im only managing to get to 900ish m/s before changing the rapiers to LF/O

That's on the low edge of what I've been getting to; but by that speed I'm 20km up and hauling back on the stick. A lot of people seem to still be down at 15-16, meaning they need more thrust than jets can give them in order to clear the thick atmosphere before they burn up.

IMO, the key seems to be to pitch up while you still have some headroom to let the jets get you some decent momentum; but not so much that you can't dig yourself out of the thick atmosphere before you overheat Rapiers are definitely better than turbojets now though, the TJs quit out really early. I may try to make a turbojet spaceplane, but not until I've got a few working rapier models to get the knack.

Bit of a tightrope walk along the altitude/speed line really, but I imagine the keen spaceplaners around here will soon figure out an optimal flight plan that involves minimal heating and best use of jet engines

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Been playing this game for a while but never registered here so as my first post I give you guys this.

Nice design, and well done for making it with turbojets and a low tier rocket! Your next challenge; carry a cargo - with only turbojets and a low tier rocket

I think your fuel flow problems would go away if you remove the fuel lines that are aiming out from centre. Circular pipes tend to confuse things. You can always manually pump fuel back to the nacelles after your deorbit burn, so I'd be inclined to have the lines running towards the rocket only.

[Teutooni]

For all those people having trouble building SSTOs I hope this design can give some useful insights into how to do it. It's an all-stock (I have not touched any mods yet in 1.0, even kerbal engineer) mk3 hull spaceplane with refining equipment as payload and enough delta-v to take off from KSC and land on minmus. It's very much a skylon inspired plane.

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Dropbox link for the craft file.

Ascent profile is pretty much 20 degrees till ~5km, turn on poodle and start leveling out a little to build up speed. Once in speed hits 450m/s turn off poodle and start climbing again at 20 degrees. At 15-17km turn poodle back on, and switch rapier mode when their output drops below 170kN (20-21km). After circularization of 75km orbit I had over 3k+3k LF+O left. Probably around 1.5km dv.

Edited April 29, 2015 by Teutooni

[eddiew]

For all those people having trouble building SSTOs I hope this design can give some useful insights into how to do it. It's an all-stock (I have not touched any mods yet in 1.0, even kerbal engineer) mk3 hull spaceplane with refining equipment as payload and enough delta-v to take off from KSC and land on minmus. It's very much a skylon inspired plane.

Impressive range, that may be the first one I've seen that goes beyond LKO in 1.0

Be interested to know if you can eek out a little more dv by kicking the poodle in before the rapier's change to CC mode; it's the more efficient rocket, and might just buy another couple of km on air

[Rune]

So, yesterday I spent a loooong time trying to make the impossible happen. Obviously I didn't succeed, but I did learn the limits of the possible, or at least I saw them off in the distance. So what did I get out of four hours of fiddling with SSTOs and KER's numbers? Well, I have a Mk3 SSTO shuttle with 10mT payload (low density, 2.5m radius) and spacious pressurized seating for six kerbals that kind of works with only 65 parts. Also, I figured out how to do ascents in 1.0! here you go, the fruits of my labor so you tame SSTOs in 1.0 faster:

Turns out the key is to follow the Mach effects, without blowing up. Basically, the closer you are to Mach effect territory, the more air you will have for your engines and the higher their thrust will get (the effect is quite dramatic, actually). If you go too slow, they won't give you enough oomph, so pull down AoA again until you get mach effects and a decent acceleration, then go up basically as fast as you can. But, once you get close to the thermal barrier (about 1km/s at 20kms, less if lower) you have to pull up to go higher, faster and thus avoid burning up.

Also, regarding that "get Mach effects" comment, that is highly dependent on your TWR. And there is a lower bound that won't let you accelerate above Mach 1 and will probably make you drop out of the sky at 10kms, so take that into consideration. But once you can speed up over 400m/s at about 10kms, you can make orbit, so stop adding engines and fiddle with your ascent path instead, making it shallower at about 10kms until you get into that virtuous cycle of accelerating more the faster you go because the engines get more air to burn. Once you get that going, then pull up to build vertical speed and avoid burning up, and you will get about the same cutoff speed irrespective of your ground TWR.

So in the end, SSTOs are even more sensitive to piloting now that basically you get more performance the closer you get to blowing stuff up. I am doing most rocket takeovers now at about 750~850m/s at around 20-25kms, when the RAPIERS get to 50kN thrust in airbreathing mode, just by following mach effects to about 12-15kms and 400~500m/s, then pulling up as I accelerate to avoid burning up the leading edge of the wing when I close to takeover speed.

That, and you need serious rocket delta-v and TWR in rocket mode to do those ~1.5km/s to orbit from airbreather cutoff, so don't expect great payload fractions to LKO on any SSTO, but refueled in orbit they will all be able of going cismunar.

Edits:

Ascent profile is pretty much 30 degrees till ~10km, level out to let speed build up to 450m/s, start climbing as hard as the control surfaces let you, switch rapier mode when engine thrust drops below 170kN due to altitude (~20-21km) and turn on the poodle.

Glad to see I am getting things right, that is pretty much the exact same ascent I do on my 10mT shuttle, so we must have similar TWR ratios, tough I burn my mass to LKO in payload and crew cabins. Also, congrats on a LKO+1km/s plane under 1.0, and with payload to boot! Also:

Impressive range, that may be the first one I've seen that goes beyond LKO in 1.0

Be interested to know if you can eek out a little more dv by kicking the poodle in before the rapier's change to CC mode; it's the more efficient rocket, and might just buy another couple of km on air

Once you kick things into gear above 10kms and Mach 1 and get into the supersonic speed run, the final speed is more limited by the thermal limit of stuff blowing up, so you will flame out the airbreathers at pretty much the same final speed, regardless of TWR. What will change is your angle of ascent (i.e: how long it takes you to run into the thermal barrier and blowing yourself up).

Rune. I hope that made sense for you guys. It's hard to explain these things!

Edited April 29, 2015 by Rune

[Teutooni]

Impressive range, that may be the first one I've seen that goes beyond LKO in 1.0

Be interested to know if you can eek out a little more dv by kicking the poodle in before the rapier's change to CC mode; it's the more efficient rocket, and might just buy another couple of km on air

Well it's not a very refined design yet (threw it together in 30 mins). That was the profile I used on the first test flight (which succesfully ended up on the surface of minmus). It might be beneficial to turn on the poodle much earlier, as low as 7km to give the extra bit of thrust so the rapiers can be pushed to optimal operating range of mach 2-4 earlier. Should probably turn off the poodle once rapiers output over 200kN and turn back on when switching rapier modes.

The purpose of the upload was not by any means to give the ultimate spaceplane, just an early proof of concept plane that shows beyond LKO performance is still very much possible.

EDIT: I don't have hard numbers but it seems your suggestion is indeed an improvement. Updated the ascent profile. Also updated the design file with improvements to aerodynamics for easier landing.

EDIT2: It seems there are rather complex ascent profiles that are close to optimal and don't use any rockets until 1300m/s and 21km altitude. Managed to get this thing up to 75x75 orbit with 1490m/s dv left. The problem is it's pushing the plane to the limits and I melted some control surfaces in the process.

Edited April 29, 2015 by Teutooni

[Yorz]

Nice design, and well done for making it with turbojets and a low tier rocket! Your next challenge; carry a cargo - with only turbojets and a low tier rocket

I think your fuel flow problems would go away if you remove the fuel lines that are aiming out from centre. Circular pipes tend to confuse things. You can always manually pump fuel back to the nacelles after your deorbit burn, so I'd be inclined to have the lines running towards the rocket only.

Fuel problems have been solved, just put in a crossfeed.

Also challenge completed

[soulreaver1981]

i'm working on something.

i thing where gonna need rocket engine to make a hard push straight up after the first 20000m

[eddiew]

Fuel problems have been solved, just put in a crossfeed.

Also challenge completed

Lol! That is... extraordinary xD I would not have considered putting jet engines in that configuration... a whole new world has been opened to me

Has anyone managed a plane with small canards that don't explode on the way up? I could do with some more pitch authority...

Edited April 29, 2015 by eddiew

[sumrex]

Well I make it to space without a nosecone. It drives me nuts. The nosecone and crew cab on any reentry vehicle is the toughest part and can take the most heat etc. But NOOOOOO!!! That does not count in KSP and they blow up while the lesser protected and unaerodynamic fuel tanks survives just fine as a nosecone. I think Ill just slap a docking port on the the front and call it a day.

https://dl.dropboxusercontent.com/u/...20Burner.craft

[NFUN]

Just wondering if anyone's accomplished this yet.

A streamer accomplished it before 1.0 released...

[Yorz]

Lol! That is... extraordinary xD I would not have considered putting jet engines in that configuration... a whole new world has been opened to me

Has anyone managed a plane with small canards that don't explode on the way up? I could do with some more pitch authority...

Biggest problem I have with it, I just don't like the looks of it hehe.

[eddiew]

Turns out the key is to follow the Mach effects, without blowing up. Basically, the closer you are to Mach effect territory, the more air you will have for your engines and the higher their thrust will get (the effect is quite dramatic, actually). If you go too slow, they won't give you enough oomph, so pull down AoA again until you get mach effects and a decent acceleration, then go up basically as fast as you can. But, once you get close to the thermal barrier (about 1km/s at 20kms, less if lower) you have to pull up to go higher, faster and thus avoid burning up.

follow the Mach effects

follow the Mach effects

That... that, sir; I think that right there is the hidden tip that the devs have been forgetting to tell us. And it certainly would make sense that something that's usually as intuitive as KSP would have a visual indicator of when to go up and when to speed up!

Following this reactive flight plan and totally ignoring the numbers, I now have a light lifter that's capable of getting an FL-T200 based satellite to LKO. Nothing got much past 1200 kelvin on the way up, so loads of safety headroom

Kick the nuke about 24km, rapiers to CC once they fizzle about 26-27. Annoyingly this was about 870m/s, i.e. well short of what SSTOs used to be able to do in 0.9.0 under FAR; but it was good enough.

Nice gentle landing. Overshot, but enough fuel to turn around, and the quadruple airbrakes make it a cinch to drop out of the sky wherever you choose. Note the parachutes were never deployed

Will probably play with this airframe a bit and try to lower the tail, since it's a bit high, but still, very pleased with it as a starting point

In other news, does anyone else find it really hard to keep their planes flying straight? Mine love to wander off to one side under nuStock, and every roll correction comes with a massive dip of direction and speed :<

Edited April 29, 2015 by eddiew

[Rune]

That... that, sir; I think that right there is the hidden tip that the devs have been forgetting to tell us. And it certainly would make sense that something that's usually as intuitive as KSP would have a visual indicator of when to go up and when to speed up!

Glad to be of help!

Regarding your roll/yaw stability issues... well, they are roll/yaw stability issues. xD But seriously, mind your tails. Make sure they are straight, and that when you deviate form your desired position, the resulting torque tries to get you back to the initial position. In the pics you give, for example, the vertical tails are angled outwards for roll stability, which may seem good (when you roll to one side, the tail on that side lifts more and thus tries to correct), but their control surfaces will mess yaw inputs, since they give a roll torque in the wrong direction when you try yawing. Probably that's it, try angling them inwards (and the wings upwards for roll stability) or just leaving them straight (neutral, which usually works best in KSP).

Rune. We have very nice fly-by-wire controls, compared to the real plane guys that worked this stuff out.

[eddiew]

Regarding your roll/yaw stability issues... well, they are roll/yaw stability issues. xD But seriously, mind your tails. Make sure they are straight, and that when you deviate form your desired position, the resulting torque tries to get you back to the initial position. In the pics you give, for example, the vertical tails are angled outwards for roll stability, which may seem good (when you roll to one side, the tail on that side lifts more and thus tries to correct), but their control surfaces will mess yaw inputs, since they give a roll torque in the wrong direction when you try yawing. Probably that's it, try angling them inwards (and the wings upwards for roll stability) or just leaving them straight (neutral, which usually works best in KSP).

I'll give it a bash tonight, cheers. Tbh the angle was just for aesthetics - I was going for a look that I suspect FAR wouldn't have been happy about and wanted to see if it worked in nuStock. The only thing that'll stop me from going to nuFAR will be if I can persuade it to make fun and exotic shapes. I feel that FAR (and I hope nuFAR) flies better than nuStock, but I'm a little worn out on realism and the limits that come with it. Being able to be a bit more free in the aesthetics would please me

Might try to find some vertical pieces that are a bit shallower too, that tail's definitely higher than I'd have liked.

[Teutooni]

Some stability issues can be solved by dedicating control surfaces to one kind of movement. Tail fins yaw only, wingtips roll, big wing elevons/canards pitch, for example. Love how the plane looks though eddiew!

[Findthepin1]

A spaceplane is a vehicle that can reach space/orbit using only one stage, and has at least one wing.

I have an idea. MWAHAHAHAHA. You'll see soon enough.

[eddiew]

Some stability issues can be solved by dedicating control surfaces to one kind of movement. Tail fins yaw only, wingtips roll, big wing elevons/canards pitch, for example. Love how the plane looks though eddiew!

Thank you And I already do assign specific axes to control surfaces - tis a habit that FAR gets you into, cos you won't get very far if you don't! *baddumtish!*

[eddiew]

Slingshot class light lifter. Low tech parts; 2x turbojets and 2x LV-45s. Although I forgot to check if the elevons are all available by that point...

Some dodgy clipping required, and barely enough fuel to de-orbit... but I guess that's only to be expected for this tier of tech. Pretty happy to have made it at all with a 36 ton plane!

And the Onager B, about the lightest thing I can get to orbit with turbojets and a scanning satellite. Insanely slow falling speed for absolutely no reason I can fathom. Any parachute at all would guarantee a safe landing ASL.

The third intake is probably pointless, since the jets give up about 19km whatever you do. Just barely enough fuel to de-orbit, but given the nature of the beast, again I'm happy with the result.

Edited April 30, 2015 by eddiew