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1.0.2 - Any hope left for SSTOs?


panzer1b
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I'm pretty sure you can do it in less than 3886 if you drop your pe down to just above eve's orbit, and then burn from there... a bi-eliptic transfer would be more efficient in this case. You just need to have gilly in the right lace at the right time for a moho transfer window.

Still, you likely won't be SSTOing there and back....

I'm thinking I'll try and make a mk3 SSTO design that will go to laythe and back when I get back today- witha 1.25 m diameter laythe SSTO in a mk3 cargo bay.

If I can send 2 kerbals to the surface of laythe and back, and recover everything, that should also settle this idea that there's no hope left for SSTOs.

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If I can send 2 kerbals to the surface of laythe and back, and recover everything, that should also settle this idea that there's no hope left for SSTOs.

I'm reasonably certain we'll see a traditional SSTO Laythe with return soon. It's going to be like the 3 minute mile, once someone proves it can be done, tons of people will be pulling it off.

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Yea... I think he means a 4 minute mile.

I don't think one *should* be able to do a SSTLAB (Single Stage To Laythe And Back).

Staging should be a thing that one needs to do.

Staging doesn't mean disposing parts.

I've always been in favor of a system where a SSTO brings the cargo to LKO

Then a nuclear tug (possibly refeuled by the same SSTO, possibly the same as the SSTO if it had its own nuclear engines and significant fuel stores left over) pushes the Apoapsis way out, and undocks to aerobrake back down to LKO for another payload

Then the transfer stage turns the eliptical orbit into an escape trajectory.

Then you do orbital rendevous with a dedicated lander at the destination

(you can even leave part of your craft in a highly eliptical orbit at the destination, so you circularize less mass and save fuel)

The nuclear tug is reusable, the transfer stages are reused, the landers are re-used... but you need to do a lot of orbital rendevous, and you don't take everything everywhere.

Its a spaceflight game... orbital rendevous... staging, etc... should be a part of it.

Sure the missions take more gameplay time and are more complicated, but that is where the fun is for me.

As a simpler example:

This SSTO can take kerbals to the Mun and back... it just doesn't have everything go to the mun and back.

11205152_10103548408288173_5405657931943816741_n.jpg?oh=7bff57b1435c0c04bae949e0be3e5dd7&oe=55DE75B6&__gda__=1439780323_f5fa0ddde63b7ef1e9deccd23d576d6d

Although I need to modify the payload and cargo bay a little to have 100% recovery, to allow everything to dock in the cargo bay - or I can leave the lander in mun orbit, and just have the next mission use it.

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- - - Updated - - -

Yea... I think he means a 4 minute mile.

I don't think one *should* be able to do a SSTLAB (Single Stage To Laythe And Back).

I did! And whether it should be doable or not, I believe it can be done. I also think this aero model will allow for a SSTO planet-hopping ISRU craft that has a more manageable part count than my design.

EDIT:

Its a spaceflight game... orbital rendevous... staging, etc... should be a part of it.

Sure the missions take more gameplay time and are more complicated, but that is where the fun is for me.

Well doing what's fun for you is definitely what counts :)

I think I'd really enjoy setting up a series of ISRU outposts such that a SSTO to Laythe could easily refuel and return, though I also enjoy the engineering challenge of dragging every last drop of dV out of a single-stage craft.

Edited by Sattorin
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100km orbit with a 2 ton fuel tank in the cargo bay, I need to play around with it a bit, I don't think the turbojets are getting enough air and the fuel is not flowing properly. 3 stage engines. Full throttle turbojet take off, pitch up to 45 degrees kick in the rapiers, you can wait a bit on these depends how toasty you like to get, but from my experience nothing explodes. Once the airspeed acceleration starts to tail off at around 800+ (you will notice it start to slow down) before it reverses hit the nukes. Then just hold on for apoapsis. The rapiers will run out of oxygen before you finish circularising but you can finish the last bit with the nukes. Enough juice left for a deorbit and short flight to KSC.

O7zYxkO.png

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Yup, but don't feel bad about it. We may be in the same weight/powerplant category, but yours is a comfortable family car with all the extras and niceties [...]

...and it gets in orbit with 1400m/s to spare now, with a more optimal ascent profile :D

Like you I am also getting lots of ideas on this thread! I do think I have room to get heavier on 2x LV-N, I am at 0.74 TWR now and could easily add a few tons. However the 2x jet engines are having trouble pushing anything above 24t beyond mach 2, so I will experiment with adding a third engine "727-style" as Wanderfound did.

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100km orbit with a 2 ton fuel tank in the cargo bay, I need to play around with it a bit, I don't think the turbojets are getting enough air and the fuel is not flowing properly. 3 stage engines. Full throttle turbojet take off, pitch up to 45 degrees kick in the rapiers, you can wait a bit on these depends how toasty you like to get, but from my experience nothing explodes. Once the airspeed acceleration starts to tail off at around 800+ (you will notice it start to slow down) before it reverses hit the nukes. Then just hold on for apoapsis. The rapiers will run out of oxygen before you finish circularising but you can finish the last bit with the nukes. Enough juice left for a deorbit and short flight to KSC.

http://i.imgur.com/O7zYxkO.png

Is the nukes cost effective over having 6 ton more fuel for the rapiers?

I'm not interested in taking an spaceplane much outside of LKO, if I want I can top the tanks in LKO,

Edited by magnemoe
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Is the nukes cost effective over having 6 ton more fuel for the rapiers?

I'm not interested in taking an spaceplane much outside of LKO, if I want I can top the tanks in LKO,

If you want to bring cargo to LEO, and you will assemble your expeditions there? Sure, it probably is very inefficient and having the high TWR of chemical engines to minimize gravity losses with good mass ratios is probably more important. Especially to get the barely 1,500m/s you need to go to low orbit. Nukes really shine when you can use them for long, low TWR interplanetary burns (or at least transfers to Mun/Minmus). However, if you want the spaceplane to go places, this is certainly the way to go.

Rune. But they are sure good fun!

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Is the nukes cost effective over having 6 ton more fuel for the rapiers?

I'm not interested in taking an spaceplane much outside of LKO, if I want I can top the tanks in LKO,

If I wasn't going anywhere else eventually I would drop the nukes and add rapiers or lvt-30's or something.

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If I wasn't going anywhere else eventually I would drop the nukes and add rapiers or lvt-30's or something.

Yes, I only use spaceplanes to go to LKO, other ships to go elsewhere, Mun and Minmus orbit might be an exception but would need another lander anyway.

One use might be rescue missions as they don't require landings and spaceplanes are easy to land at spaceport.

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Yes, I only use spaceplanes to go to LKO, other ships to go elsewhere, Mun and Minmus orbit might be an exception but would need another lander anyway.

One use might be rescue missions as they don't require landings and spaceplanes are easy to land at spaceport.

Easy to do a budget bulk passenger hauler, too; stick a dozen command chairs in a cargo bay. They'll only be in there for a short flight anyway, no point in shelling out for luxuries. :)

Or put a Klaw in the bay, and rescue the whole capsule. Free √ when you recover it.

Edited by Wanderfound
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Right, I'm in the camp that really never expected single stage to go anywhere outside the Kerbin system. I do like to use my plane fleet to serve stations around Mun an Minmus, so will be tweaking my designs to achieve that. I don't necessarily expect the ship's make a round trip back to Kerbin on one tank, as I will be able to refuel the stations locally with mining.

So, Kerbfleet's designs are converging on a liquid fuel only, ~28t, two seater with modest cargo capability and ~1500 dV remaining in LKO. That serves my needs and my vision of a realistic space transport infrastructure.

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Is the nukes cost effective over having 6 ton more fuel for the rapiers?

I'm not interested in taking an spaceplane much outside of LKO, if I want I can top the tanks in LKO,

I just ran the numbers on this. If you're staying in LKO, then no; the LV-N is neither cost effective nor mass efficient.

The LV-909 is preferable in every situation where .8G or more acceleration is desired. At 0.5G acceleration, the LV-N is only preferable for ships that weigh more than 7 tonnes per engine *and* have a DV budget of 1,500m/sec or more.

So in all instances, the LV-N should not be used in anything that's just going to LKO and back.

HTHs,

-Slashy

Edited by GoSlash27
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I just ran the numbers on this. If you're staying in LKO, then no; the LV-N is neither cost effective nor mass efficient.

The LV-909 is preferable in every situation where .8G or more acceleration is desired. At 0.5G acceleration, the LV-N is only preferable for ships that weigh more than 7 tonnes per engine *and* have a DV budget of 1,500m/sec or more.

So in all instances, the LV-N should not be used in anything that's just going to LKO and back.

HTHs,

-Slashy

Slashy is wise, listen to the slashy.

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The exception of course is to Slashy's wise wisdom is if you just don't want to carry oxidant anymore, then LV-Ns and turbojets are the only way to fly :)

I did add the 727-style third jet and here we are in LKO with 1900 dV to spare! ~28t at liftoff, no O2. Have not tested cargo carrying yet but am confident I could bring at least a few tons in that Mk2 bay abaft the cockpit.

JUQWiCL.png

CXYNRWC.png

ETA: I do generally fly pure stock, but if I were to mod one part it would be to make that bicouple liquid fuel-only.

Edited by Kuzzter
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The exception of course is to Slashy's wise wisdom is if you just don't want to carry oxidant anymore, then LV-Ns and turbojets are the only way to fly :)

I did add the 727-style third jet and here we are in LKO with 1900 dV to spare! ~28t at liftoff, no O2. Have not tested cargo carrying yet but am confident I could bring at least a few tons in that Mk2 bay abaft the cockpit.

http://i.imgur.com/JUQWiCL.png

http://i.imgur.com/CXYNRWC.png

ETA: I do generally fly pure stock, but if I were to mod one part it would be to make that bicouple liquid fuel-only.

Kuzzter,

The lv-n isn't the better option in your case, it's the only option. ;)

Best,

-Slashy

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The exception of course is to Slashy's wise wisdom is if you just don't want to carry oxidant anymore, then LV-Ns and turbojets are the only way to fly :)

I did add the 727-style third jet and here we are in LKO with 1900 dV to spare! ~28t at liftoff, no O2. Have not tested cargo carrying yet but am confident I could bring at least a few tons in that Mk2 bay abaft the cockpit.

pictures were here

ETA: I do generally fly pure stock, but if I were to mod one part it would be to make that bicouple liquid fuel-only.

Would you be a darling, and share your ascent profile? Because I'm trying to do pretty much the same, just with two turbos... Is it I need another Turbo or do I need to learn how to fly the Turbonuke combo?

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I did add the 727-style third jet and here we are in LKO with 1900 dV to spare! ~28t at liftoff, no O2. Have not tested cargo carrying yet but am confident I could bring at least a few tons in that Mk2 bay abaft the cockpit.

You've given me quite a bit of inspiration with that plane! Gorgeous!

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SSTO's aren't a problem in 1.0.2

This is my take for LKO satellites. The cargo bay is easily switchable with 2 crew compartments instead, making it able to ferry 11 Kerbals. I managed to get an orbit of 210x210 in the crew transport version.

http://imgur.com/a/b8cG8

Aye... except it's not an SSTO.

"Single Stage" means you're not decoupling parts.

Best,

-Slashy

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ETA: I do generally fly pure stock, but if I were to mod one part it would be to make that bicouple liquid fuel-only.

Make the best of it: stick some VTOL Vernors on the underside for low-G landings, use the bicoupler to carry a smidge of oxidiser just for them.

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Would you be a darling, and share your ascent profile? Because I'm trying to do pretty much the same, just with two turbos... Is it I need another Turbo or do I need to learn how to fly the Turbonuke combo?

Happy to share! What I've learned so far is that there appears to be a "tipping point" of getting enough velocity for the ramjets to develop ludicrous thrust. For my designs to date, I find I need to keep it under about 9.5 tons per jet engine and about 14 tons per nuke. The 28t craft shown above works great on 3 jets and 2 nukes; at 30t is doesn't make it.

Ascent profile for the Nooxie 6:

--Start on full throttle jet engines 1 and 2.

--Fly off end of runway, retract gear.

--Start jet engine 3 and pull up to 25-30 degrees

--Keep full throttle all three engines. Velocity should rise steadily as thrust compounds, beginning to spike around 10km

--At 18-20km you should see your velocity approaching 1200 m/s, climb rate 400 m/s or better, and jet thrust decreasing.

--Start the LV-Ns when you begin losing velocity. You may have to start early, around 18km, if TWR is low.

--When jets flame out, close your intakes.

--Depending on your TWR you will need to climb at 30-45 degrees. Watch your time to apoapsis; nose up to always keep it >30 seconds out as your apoapsis increases and your periapsis becomes less negative

--As you approach orbital velocity you can nose down to prograde, and circularize.

Good luck! There may certainly be room for improvement in the above and I would love to hear how you make out.

- - - Updated - - -

Make the best of it: stick some VTOL Vernors on the underside for low-G landings, use the bicoupler to carry a smidge of oxidiser just for them.

You know, that's not a bad idea. I did use vernors on a similar design in 0.90, for Duna.

- - - Updated - - -

You've given me quite a bit of inspiration with that plane! Gorgeous!

Thank you!

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