1.0.5, harder to make spaceplanes?

[tewpie]

That plane is not exactly useable for anything beyond what you did with it there, but I’ll admit that before saying the sorts of dV we got 1.0.4 aren’t possible, I should have investigated the Mk3 parts more. Of course that plane probably would have had 9km/s in the old aero system. Nonetheless, if I mentally put 4 more nukes on that plane to make it have a somewhat flyable TWR of 0.2 instead of a preposterous 0.067, hold my nose at the flagrant abuse of the cargo bay, put an actual Kerbal-containing cockpit on it, andgive it some solar panels, some reaction wheels, and some rcs, I expect you’ll end up with somewhere close to 6km/s on orbit with that monster. Still no landing legs though, so forget about any airless bodies with more gravity than Minmus. Anyway, I will now experiment with Mk3 some more before I pronounce the things I wanted to do before impossible. And thank you for at least offering something constructive to go with your "quit whining!".

What would you do if I made a 9kms ssto? Like I said this is far from optimal

If you're going to argue on practicality, ANY SSTO with 3kms in orbit, an ISRU, and sufficient TWR can go ANYWHERE, so this dv in orbit measure you keep talking about is moot.

[herbal space program]

I would say show me, but it has to have at least 0.2 TWR on orbit or it's useless for what I wanted to do. And the challenge I was working on specifically forbade ISRU, so THAT is moot as well. The point is how far can you go, where can you land and return from, with no refueling. And personally, I'd say also with no abuse of massive cargo bays to cheat the drag model either, but I guess that's debatable.

[tseitsei]

Why is it that you don't feel others are entitled to express their opinions? Does this thread need your policing? All you are doing is antagonizing people with this type of comment.

You are most certainly entitled to your opinion but you shouldnt go around telling how game is stupid because "its impossible to make an ssto with 6000dv on lko".

Or at least you should stop whining when someone specifically demonstrates with example craft how to make an ssto with 7600dv on lko.

Making crafts like that should be hard. And if you cant do it it doesnt mean it's impossible. You now have proof that the way you want to play the game (apparently high dv ssto planes is your way and that's totally cool) is still doable. So now you just need to get designing/testing... If it would be easy it wouldnt be nearly as fun now would it?

[Vanamonde]

Please keep things civil, guys.

[Ozzallos]

Was harder for me at first, but the new atmo modeling just means you need to tweak your build a bit more. None of my previous single stage direct launch vehicles survived the atmospheric revision, so I asked the boys and girls over at Twerkstar to throw it all away and start from scratch. They came up with a 17 engine vertical launch beast. 8 Whiplashes & 8 rapiers for the ascent and a spike for economic orbital maneuvers. Still need to even out the liquid fuel/ox ratio, but overall, we're good to go.

Jeb likes.

[herbal space program]

You are most certainly entitled to your opinion but you shouldnt go around telling how game is stupid because "its impossible to make an ssto with 6000dv on lko".

Or at least you should stop whining when someone specifically demonstrates with example craft how to make an ssto with 7600dv on lko.

Making crafts like that should be hard. And if you cant do it it doesnt mean it's impossible. You now have proof that the way you want to play the game (apparently high dv ssto planes is your way and that's totally cool) is still doable. So now you just need to get designing/testing... If it would be easy it wouldnt be nearly as fun now would it?

First of all, I never, EVER said “the game is stupidâ€Â. Where on Earth are you getting that from? I expressed some disappointment that Space planes have now taken a significant haircut and some irritation that changes to the air have now broken all my designs six times in the last year. I think I am well within the bounds of civil discourse to express those opinions. There was no “rantingâ€Â, as Pecan dismissively pronounced, or any other invective against the game or the Devs.

Secondly, I also never said it was now impossible to build any SSTO with >6km/s deltaV. If you’re willing to put up with monstrous, totally impractical, ugly, and/or exploitative designs it’s of course still possible. So what? Nobody has yet shown me a ship that can do what I was trying to do that has the same range. And truthfully, I’m far, far less irritated by the changes to the game than I am by the army of gremlins that comes out of the woodwork to attack if I dare to say anything that can at all be interpreted as negative. Don’t you guys have anything better to do?

- - - Updated - - -

Was harder for me at first, but the new atmo modeling just means you need to tweak your build a bit more. None of my previous single stage direct launch vehicles survived the atmospheric revision, so I asked the boys and girls over at Twerkstar to throw it all away and start from scratch. They came up with a 17 engine vertical launch beast. 8 Whiplashes & 8 rapiers for the ascent and a spike for economic orbital maneuvers. Still need to even out the liquid fuel/ox ratio, but overall, we're good to go.

Jeb likes.

https://www.dropbox.com/s/of8vt2buv0po8kk/screenshot0.png?raw=1

Zomg. What is the TWR of that thing when it takes off?

Edited November 14, 2015 by herbal space program

[Pecan]

...There was no “rantingâ€Â, as Pecan dismissively pronounced...

(& @ panzer1b, of course)

Sorry, didn't mean to be dismissive and 'ranting' was the wrong word.

It was meant to be an "I understand, but remember, the fun's in the hard" (even if having to re-do hard every release might be wearing thin)

[herbal space program]

(& @ panzer1b, of course)

Sorry, didn't mean to be dismissive and 'ranting' was the wrong word.

It was meant to be an "I understand, but remember, the fun's in the hard" (even if having to re-do hard every release might be wearing thin)

Thank you for that Pecan. I was feeling just a bit ill-used there, and I really appreciate the gesture. What you said was actually much more measured than some of the other “quit whining†comments. And as you said, the fun is in doing the hard stuff. I think I will just wait until they settle on their aero model before committing to any more 100-hour missions that are completely dependent on the design functioning exacttly as expected.

[Ozzallos]

Zomg. What is the TWR of that thing when it takes off?

Now that I'm home, I can make the calculations

Rapiers (stationary) 105kN*8 = 840kN

Whiplash (stationary) 130kN*8 = 1040kN

Total at launch: 1880kN

Weight at launch: 81t (180 parts)

1880kN / 81t * 9.81 = TWR of 2.4

Not horrible. She'll crank out 1,300m/s through a 35 degree ascent before finally losing acceleration at about 22-23km. Switch the Rapiers over, light the Cone and let the Whiplash array stall out naturally. Only takes about 10 seconds of burn after that to give you enough juice to coast up to 85km with about 200units to spare after circularizing. Kill the Rapiers and maneuver on the cone. Granted, that's not a lot for anything but orbital maneuvers, but the idea was to refuel her in space and send it on it's way.

Unfortunately, I'm running into a problem when it comes to the re-usability aspect. Those whiplashes don't handle re-entry too well and I lost every nozzle on the way down to heat in the last test.

Still has bugs to iron out, but she makes orbit and that's a win in itself

[herbal space program]

Now that I'm home, I can make the calculations

Rapiers (stationary) 105kN*8 = 840kN

Whiplash (stationary) 130kN*8 = 1040kN

Total at launch: 1880kN

Weight at launch: 81t (180 parts)

1880kN / 81t * 9.81 = TWR of 2.4

Not horrible. She'll crank out 1,300m/s through a 35 degree ascent before finally losing acceleration at about 22-23km. Switch the Rapiers over, light the Cone and let the Whiplash array stall out naturally. Only takes about 10 seconds of burn after that to give you enough juice to coast up to 85km with about 200units to spare after circularizing. Kill the Rapiers and maneuver on the cone. Granted, that's not a lot for anything but orbital maneuvers, but the idea was to refuel her in space and send it on it's way.

Unfortunately, I'm running into a problem when it comes to the re-usability aspect. Those whiplashes don't handle re-entry too well and I lost every nozzle on the way down to heat in the last test.

Still has bugs to iron out, but she makes orbit and that's a win in itself

Wow! Not sure what your application for this thing is, but with that kind of TWR at takeoff, you could either boost a whole lot more fuel or drop half of those engines. At the TWR you have, I think a somewhat steeper ascent profile might prove more economical as well. You are speeding up so fast that your drag losses that low are going to become significant. But I must say it sure looks cool! There’s a thread in Challenges titled “lowest dV SSTM†where optimizing really high TWR ascents is discussed (disclaimer: the air was the Vulcan atmosphere of 1.0.4 ). The big impression I came away with from participating in that discussion is that the Mammoth engine cluster is OP! With its very high TWR and good ISP (for a rocket anyway), it can boost the most gigantic payloads. This ship, with a Mammoth and 6 Nervs, can make orbit with 4.4 km/s dV and a TWR of 0.3-0.6, depending on fuel remaining. That means I should easily be able to fly it to the Mun surface and back, although landing it would be challenging!

Javascript is disabled. View full album

[Ozzallos]

You're probably right about the steeper ascent. Will have to try it out.

The excess engines, on the other hand, seem necessary. 8 Rapiers by themselves will stall out at only 3km (or at least they did in 1.0.4) in a vertical launch. I'm guessing since they behave more like real ramjets, they don't have the initial velocity to self-sustain. I had to burn them as rockets to get enough seed velocity for the ramjets to function-- Literally launch as a rocket to about 200m/s then back to air breathing. It was hideously fuel expensive down at sea level. The whiplashes seem to solve this; both clusters giving enough kick to the other to self sustain through the initial launch with 4-5g of acceleration.

The application *was* a fully reusable vertical launch single stage lander without the drama of a spaceplane. Launch vertically, refuel in space, go to a planet, touch down, parachute back into kerbin atmo, repack and take off again. It worked marvelously before atmospheric friction was enabled

[for my use later]

https://www.dropbox.com/s/7tx0mjo41dpja6c/screenshot6.png?raw=1 --Engine cluster

https://www.dropbox.com/s/2ueoba7e1klfm2f/screenshot7.png?raw=1 --Shock zone

https://www.dropbox.com/s/0ucnsjmuzamihjb/screenshot11.png?raw=1 --Death of the Whiplash

Edited November 15, 2015 by Ozzallos

[ManEatingApe]

Spent this week going through the 5 stages of grief over the demise of 1.0.4's aerodynamic model, finally reached acceptance (helped by a nice glass of Yamazaki)

Anyway time to roll up the sleeves...

After some testing, it's not all bad news:

* Breaking through the sound barrier is much much easier, no more diving, simply levelling off will do.

* Increase in Oxidizer somewhat offset by savings in LF

* Between 15000 to 20000 metres is the new danger zone, had several shock cones explode.

Here's some photos of the progress so far:

Tweaked my baseline Mk3 design and achieved 7,093 dV in LKO. Not as much as Tewpie's nifty mass fraction entry but still respectable.

Has enough TWR to land on medium/low gravity bodies (e.g. Eeloo) and forgiving flight characteristics, so easy to land/take off on Laythe/Kerbin.

Interestingly this design actually performed *worse* under 1.0.4, only got 6,500 dV once in orbit.

Also redid the ion entry from the Laythe challenge. 9,075 dV in orbit (however only enough TWR to land on Gilly, Pol, Minimus or Bop). This was a fairly sloppy ascent so some room for improvement.

The ascent under the new aero model was much easier and saved me 1 ton of LF but cost 0.5 tons of LF/Oxidizer for a net savings of 0.5 tons in initial mass.

Still struggling with very small (< 15 ton) designs, but perhaps that's an unavoidable consequence of the new model.

[OgreMagi]

I just updated my KPS, I tend to play with lighter sstos, less than 20 tons. The lifting profile is a little different.

where I usually pulled max thrust and 45 to 50 degree, until I reached 15 to 17 k meters, I now have to lower my angle to get the additional thrust, the engines lose thrust at higher angles and each space plane has a sweet spot of angle, lift, and airspeed to make the transition to high altitude and high speed.
You have to test/play with it to keep it from overheating and burning up took my several tries to get it in orbit without losing a solar panel.

My lighter sstos don't have as much DV as before, the Nerva fuel change nerfed its DV when compaired to the old fuel/oxidizer but they are still acceptable for my needs.

[tewpie]

A more practical example (this is my workhorse SSTO for career mode; [URL="http://pastebin.com/8QJGxrJ8"].craft[/URL]):

Features: 6 kerbal capacity, science lab, full science suite, large ISRU + 2 drills, enough RTGs and fuel cells to run everything indefinitely. Oh and a lift engine in the front for vacuum VTOL. And a docking port so it can act as a tanker or tug.

3.4k dv to 90x90 orbit. (In 1.0.4 this was 3.6k dv, I basically made no changes except take off 2 intakes and replace the big drill with 2 jr. drills).

6.7k dv @ 0.15 - 0.2 TWR for interplanetary transfer (4x LVN)

3.5k dv @ 0.9 - 3.0 TWR for landings (4x LVN + 8x RAPIER + 1x Rhino)

Basically it can go anywhere, land anywhere, and take off from anywhere except Eve.

[IMG]http://i.imgur.com/0v1Srv8.jpg[/IMG]

ISRUs are cheating you say? I don't care :P

[Fire-Dragon-DoL]

[quote name='Alshain']Way way way way way better than 1.0.4. (way... way way). I thought my plane building days were over, but I just tried it in 1.0.5 and I love it.

Introducing the Shrike Mk2 ([URL="http://i.imgur.com/mwK9xXs.png"]click here[/URL] if you want to compare to the Mk1 from 0.90/FAR)
[URL]http://i.imgur.com/WFkvXdF.png[/URL][/QUOTE]

Can you please tell me what mod you use in 1.0.5 to obtain that screenshot? I tried looking for some, but either they are broken I fail at something badly, no clouds and no good looking sky in my KSP :(

[jbakes]

Ever since 1.0.5 my cockpit explodes on re-entry. it heats extremely fast and it never did that before. I mean I'm not entering steep or anything. I use to be able to set my Pe to 30km and be fine. I'm usually not one to complain but its ridiculous how hard it is to re-enter a space plane now. I mean what I am supposed to do make 5 low passes around Kerbin to re-enter?

[Red Iron Crown]

[quote name='jbakes']Ever since 1.0.5 my cockpit explodes on re-entry. it heats extremely fast and it never did that before. I mean I'm not entering steep or anything. I use to be able to set my Pe to 30km and be fine. I'm usually not one to complain but its ridiculous how hard it is to re-enter a space plane now. I mean what I am supposed to do make 5 low passes around Kerbin to re-enter?[/QUOTE]
Try going steeper. Somewhat counterintuitively, a shallow reentry can cause more heating than a steeper one.

[Rune]

[quote name='jbakes']Ever since 1.0.5 my cockpit explodes on re-entry. it heats extremely fast and it never did that before. I mean I'm not entering steep or anything. I use to be able to set my Pe to 30km and be fine. I'm usually not one to complain but its ridiculous how hard it is to re-enter a space plane now. I mean what I am supposed to do make 5 low passes around Kerbin to re-enter?[/QUOTE]

You just have to learn how to [I]fly[/I] your spaceplane during reentry. Let's give you some hints! :)

Bet you do some sleek aerodynamic designs, right? Well, those knife through the atmosphere too fast, getting you into the dense lower atmosphere before you can get enough G's to decelerate. So are you going to have to design your SSTO intentionally draggier than it could be? Hell no, you just need a good airbrake that you can turn on and off. And guess what, you already have a huge one built into you ship... the main wing! Wing lift can give you a bejeesus of G's (that's the technical term ;)), way before you get any kind of measurable deceleration due to drag while pointing perfectly prograde. And yeah, I know, you can perfectly well skip back to orbit and ruin your reentry accuracy... unless you know this little trick:

[img]http://i.imgur.com/gIzUuv0.png[/img]
[img]http://i.imgur.com/vBLOsWE.png[/img]

Notice the difference in vectors in the two images. In the first one, I am in what I call the "full stop ohboopohboop I'm going to overshoot" mode. Basically, I pitch up as much as I can, up to 90º, stalling the whole wing and creating big drag vector that point directly backwards. That effectively brakes me very high in the atmosphere without bouncing me back up, and in fact build vertical speed towards the ground quite rapidly starting at about 40kms. Then I usually go into "crap now I'm going to undershoot" mode, falling somewhere west of the mountains at 30 kms and with a speed that is actually less than what I have going up at this altitude. This consists in letting the bird pitch down so the wing no longer stalls out, generating even more lift than it did drag, flattening out my trajectory to near horizontal and somewhere in the vicinity of 1000m/s with a decent glide slope back to KSC. I might need to do a couple more "Kobras" to stall out in order to slow down if I pick up too much speed when falling, but yeah, pretty much the same principle of pitching up and down to create aerodynamic forces that take away energy before it can be invested in compressing air into high temperatures. :)

Of course to do this you need a SSTO with a lot of manoeuvrability to sustain the high angles of attack and remain controllable, I.E: a CoM CoL that lay very close to each other on reentry, and ample control surfaces with good lever arms. Check them out with empty tanks in the SPH!


Rune. Hope that helps you! Edited November 22, 2015 by Rune

[Majorjim!]

[quote name='Rune']You just have to learn how to [I]fly[/I] your spaceplane during reentry. Let's give you some hints! :)

Bet you do some sleek aerodynamic designs, right? Well, those knife through the atmosphere too fast, getting you into the dense lower atmosphere before you can get enough G's to decelerate. So are you going to have to design your SSTO intentionally draggier than it could be? Hell no, you just need a good airbrake that you can turn on and off. And guess what, you already have a huge one built into you ship... the main wing! Wing lift can give you a bejeesus of G's (that's the technical term ;)), way before you get any kind of measurable deceleration due to drag while pointing perfectly prograde. And yeah, I know, you can perfectly well skip back to orbit and ruin your reentry accuracy... unless you know this little trick:

[url]http://i.imgur.com/gIzUuv0.png[/url]
[url]http://i.imgur.com/vBLOsWE.png[/url]

Notice the difference in vectors in the two images. In the first one, I am in what I call the "full stop ohboopohboop I'm going to overshoot" mode. Basically, I pitch up as much as I can, up to 90º, stalling the whole wing and creating big drag vector that point directly backwards. That effectively brakes me very high in the atmosphere without bouncing me back up, and in fact build vertical speed towards the ground quite rapidly starting at about 40kms. Then I usually go into "crap now I'm going to undershoot" mode, falling somewhere west of the mountains at 30 kms and with a speed that is actually less than what I have going up at this altitude. This consists in letting the bird pitch down so the wing no longer stalls out, generating even more lift than it did drag, flattening out my trajectory to near horizontal and somewhere in the vicinity of 1000m/s with a decent glide slope back to KSC. I might need to do a couple more "Kobras" to stall out in order to slow down if I pick up too much speed when falling, but yeah, pretty much the same principle of pitching up and down to create aerodynamic forces that take away energy before it can be invested in compressing air into high temperatures. :)

Of course to do this you need a SSTO with a lot of manoeuvrability to sustain the high angles of attack and remain controllable, I.E: a CoM CoL that lay very close to each other on reentry, and ample control surfaces with good lever arms. Check them out with empty tanks in the SPH!


Rune. Hope that helps you![/QUOTE]

That's a nice post Rune. I am confused why people are burning up though. All the cockpits are rated to at least 2000. I have been re-entering at random and and never even come close to burning up. Ever..

I think he might have a mod conflict of something like that as kerbin orbit re-entering is super forgiving. Unless he is entering at interplanetary speed but I highly doubt that.

[Fire-Dragon-DoL]

[quote name='jbakes']Ever since 1.0.5 my cockpit explodes on re-entry. it heats extremely fast and it never did that before. I mean I'm not entering steep or anything. I use to be able to set my Pe to 30km and be fine. I'm usually not one to complain but its ridiculous how hard it is to re-enter a space plane now. I mean what I am supposed to do make 5 low passes around Kerbin to re-enter?[/QUOTE]

Uhm, it's true the cockpit heats extremely fast, much faster than the other parts (you can clearly see it turning red when there is no reentry heat yet), so I definitely believe it's bugged in some way.

That being said, I can safely reenter: Periapsis at 50k (notice that atmosphere is much higher now!), 30° angle, and you keep passing near Kerbin until you are around ~2300 m/s orbital speed. Then you are free to go down.

I also fixed my mods, I can finally see clouds! ;)

[Pecan]

[quote name='Majorjim']...I am confused why people are burning up though. All the cockpits are rated to at least 2000. I have been re-entering at random and and never even come close to burning up. Ever..[/QUOTE]

You, me and the cognoscenti. There are a lot more new players now the game's getting ever more popular though.
For the record, mutatis mutandis, I'm having no re-entry issues whatsoever.

[Tourist]

I've had no problem with any of my existing spaceplanes, either going up, or coming back. My ascent profile has changed bit, in that going for 1600 m/s before switching to rocket engines now appears suicidal. But I've had no problem getting to orbit, with enough juice to complete the mission by going to rockets at 1400 and pitching up a bit.

Now, my spaceplanes admittedly are not as large as some of the monstrosities that I've seen posted around here, none of them are reaching Laythe. But they are no slouches in the cargo carrying capacity. I deliver all my landers for atmosphereless moons into space via spaceplane... key spacestation parts. I've noticed no difference when they reenter at all. Edited November 23, 2015 by Tourist

[Gaarst]

No, 1.0.5 is the easiest version for spaceplanes since 0.15, considering it is the only version in which I have managed to make a working SSTO spaceplane. :P

[tewpie]

[quote name='Tourist']I've had no problem with any of my existing spaceplanes, either going up, or coming back. My ascent profile has changed bit, in that going for 1600 m/s before switching to rocket engines now appears suicidal. But I've had no problem getting to orbit, with enough juice to complete the mission by going to rockets at 1400 and pitching up a bit. [/QUOTE]

You can still go that fast (and even faster) on air breathing rapiers. I hear heatshields are now more aerodynamic than before *hint hint* :wink:

[KerikBalm]

I managed to get that fast on laythe though... and close to it with the same craft on kerbin. it did have some fixed radiators that were normally occluded from heating effects, and it was a VTOL craft with a very high TWR