How to Make a Big and Efficient SSTO Space Plane (KSP 1.8.1)
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- เผยแพร่เมื่อ 12 ก.ย. 2024
- F00FlGTHER's ultimate SSTO guide! Learn how to make and fly very efficient SSTO spaceplanes in Kerbal Space Program.
This guide will start with concepts then walk through the design of a very large cargo SSTO, capable of delivering 90t to Low Kerbin Orbit. Then end with a full flight from runway to orbit and a safe landing back on the runway.
Please leave your thoughts in the comments below!
So good. Formulas, numbers, rationales. None of this "just try some stuff, you've gotta get a feel for it" handwaving.
30-35 tons per Rapier, 5-6 tons per m^2 wing, 10% LF by weight to get to altitude, 15% LOx by weight to get to orbit, 50% cargo (which should be fuel while learning the ascent, efficient AoA is huge), 5% wing angle. Sweet, now I've got a guideline. Made a variation of this design (with slightly less tech -- rather than 6 rapiers and Big S delta wings, instead I used 6 Whiplash + 6 Dart and airliner wings), got it working in a couple hours. Scaled down to Mk2 (60 tons, 2 Whiplash + 2 Dart), got to orbit on the first try.
As a total beginner doing career mode, it's a huge help to finally have a functional Mk2 spaceplane as a taxi and small cargo hauler, and a functional Mk3 spaceplane as a large cargo hauler.
the amount of information i learned from this video was tremendous. thank you!
You're very welcome, I'm glad you enjoyed it. I think I already told you this on reddit haha.
Great work. Detailed and well explained, this is a tremendous contribution to the community.
Thanks! High praise coming from you sir!
I learned so much from this video, probably watched it 100 times over two years. Still hoping for an other one :)
notes to myself, ignore this
10:57 weight optimization
15:29 shock cone intake
19:34 cool main wings
21:53 cool tail
22:50 lifty wings
23:35 control surface bits
32:55 quick action group tip
29:45 R.A.P.I.E.R attachment
34:13 center of mass/thrust/lift alignment
35:59 landing gear adjustments
37:25 extra liq. fuel
38:56 autostrutting
44:00 aero-gooey and takeoff
I will not ignore,in fact I will pay close attention,use,appreciate,and thank you! Nothing you can do to stop me. Thank you for posting this.
This is a really impressive video. It might lack the sex appeal of a Scott Manley vid and the self-aggrandizing "Look what I can do" of a Matt Lowne video, but this video makes up for all that with SCIENCE! I'll be breaking out the nerd calculator with this and have my SSTOs up and about in no time!
I know making videos is a pain in the butt, but it would be good to have one where you do calculations for other engines and early tech tree SSTOs.
"Lacks the sex appeal of Scott Manly" LMFAO!!!! I pee'ed a lil when I read that.
When you're having trouble snapping parts with camera angles you can hold alt to force snap to nodes
Indeed! I was holding alt on pretty much every node placement in this video ;)
The problem was sometimes the part wants to be way behind the craft when you have long fuselages like this so it takes some creative camera angles to get the part there even when you hold alt.
FINALLY THANK YOU I KNEW I HEARDT THIS BUT FORGOT THE KEY THANK YOU
Oh wicked cheers
I think this is the best kerbal space program video I’ve ever watched
Hey, sir.
Im the guy on reddit we argued about Nerv and rapiers
I was trying to piss you off. I knew you were correct in your field.
Very informative video.
Thank you so much for this. There's a few people in the KSP community who obviously know their stuff, so I'm always on the lookout for them to share their knowledge. You of course are one of them. Some of this stuff can be tough to grasp at first when new to the game. Thankfully your way of teaching promotes understanding, which is much more valuable in the long run. Thanks again. Looking forward to more content as long as you're willing to make it.
You're very welcome, thanks for the kind words ;)
This made so much sense, I got out a notepad and started jotting notes! Thank you!
He's breaking out MS Paint folks, this just got serious lol. Great vid man, good info to get me started with space planes.
Paint ftw :P glad you enjoyed it!
Wow, such a good video. Played KSP for years and not really done planes, this has inspired me!
Glad to hear it, good luck!
Wow I was making several mistakes this is the best SSTO tutorial ever thank you so much
wow dude, thanks. Your stuff works, i just made a 1600 ton SSTO with over 6K m/s once in orbit, and also lots of cargo. Unbelievable
Thanks. I've built a lot of SSTOLs, but always gone by the "feel". This info will be a great help!
The math at the beginning was a big help
Excellent, glad it could help!
This is the best general guide for SSTOs that I've seen, would love to see more videos from you
amazing tutorial. Please make more like this!
Soon! ;)
That was comprehensive, thank you. Is it okay to say I love you lol
This is cool and I learned several new things that I will be able to use to improve my sstos. So thanks for that! I do have to take issue with your claim that 66 m s-1 dv is "plenty enough" to rendevous with a space station though. For Kerbin, I've never done that with less than ~500-1000 m s-1, so I'm not sure what voodoo you'd have to pull to do it on 66 m s-1. And really, overall, such a bare bones ssto as this wouldn't let you do very much of anything when you got to orbit, other than just land again (assuming you got the descent EXACTLY right and didn't overshoot). For me personally, when I build sstos I build them with an eye to going somewhere and doing something, so I'm less concerned with efficiency than I am with functionality. I don't want to have to worry about getting the ascent profile exactly right every time. So I tend to overpower/overengineer my sstos intentionally (and let's just be honest and admit that there is really no reason to be obsessed with maximizing efficiency in this game, unless it's just something you enjoy doing). But I guess it just depends what you're designing the craft to do.
Transfer windows, transfer windows. With a bit of practice, 60 m/s sounds completely reasonable to dock with a station.
I love the work, man
dang this man smart
First video I’ve watched of yours -
Subbed
Shit only 1 video on your channel 😅
This is very helpful, and taught me many things i used to be confused upon
Excellent, I'm glad it helped you!
Awesome video, I love your practicality
making it look easy :)
Very well explained and helpful video!
I’d very much like to see efficient SSTOs for various mission profiles through the stars! Thank you
So good please make more.
from a french : THX a lot! the perfect vidéo i was looking for from 6 mounth! sooooo, i sub! If you don't mind, any help for VTLO is welcom .. :D
Merci! I'll add VTOL to my list of things to do for a future video! :)
Thanks for sharing. Really good insight into SSTO's, especially a large cargo capable SSTO. Before now I have really struggled to build them.
When it comes to small passenger SSTO's, do you think the same principles apply? Would you be able to demonstrate or describe a design and profile of a small Mk1 or Mk2 passenger SSTO?
Yeah same principles. You want to make your plane as streamlined as reasonably possible in the hangar and then fly it as fast and as low as you can without it blowing up :D
For sure I'll make small passenger one in the next video. Someone else asked for a lower tech SSTO so I'll plan on making it a passenger SSTO without RAPIERs.
F00FlGHTER I just started playing again and running career mode. Currently unlocked the first mk2 parts and have been fiddling around with a low tech ssto for tourists and rescues without much luck.
I’d love to see some designs with lower tech stuff, even if you don’t get to more videos you’ve inspired me to keep working on it! I’ll do some experiments to see if I can establish some numbers like you have here for the rapier and keep working on it.
@@f00flghter29 what happened to that
Amazing. Thanks so much!
What if we are using the mark 2, or even mark 1 fuselages where we can't angle wings, or can only angle them very little
I learned a lot but I’m still crashing into the water every time when i try to copy this… I dropped my payload weight then i just started doing a circle… I’m so stuck…
Will such a scheme work without autostruts?
Yeah it's big but not big enough that it's completely unstable without autostruts. As long as you use the same attachment hierarchy you should be fine, it'll be more wobbly and difficult to fly but it shouldn't fall apart unless you do some crazy high angle of attack maneuvers.
Only just over 6000 m/s DeltaV at launch? How, did you get into orbit with that? I find my SSTO's require around 10000 m/s to orbit. I must be doing something wrong with my designs. I frequently create SSTO's with over 20000 m/s from the runway to get around 4000 m/s left in orbit (due to the extra weight of NERVs and extra fuel).
Delta-v at launch can be misleading or even meaningless with jet engine SSTOs. But it could be because I used much less rocket fuel tanks than most during the ascent so there's less oxidizer as just dead weight after it assumes the jet engines use up all the liquid fuel, or it could be because you've got extra liquid fuel dedicated to your Nerv engines. If you put that liquid fuel towards the RAPIER's 3200s Isp then yeah you're gunna have a lot more delta-v at launch. The way the game calculates delta-v it consumes all available fuel in the stage. Since we only have one stage, it assumes your jet engines with their much higher Isp consume all the liquid fuel. Does that make sense?
@@f00flghter29 Yes it's possible. It could be that also be that I'm not that great at this game yet. In fact, the SSTOs I build are far more capable than I am :) I believe some of my creations could reach Laythe, but I can't get a ship to the Mun yet due to my bad piloting and not getting to grips with manoeuvre nodes . I could do with someone to really check out one of my ships to see how good they are; someone who can actually play the game
@@DavstrWrexham I could give em a spin if you want. You can share the craft file through kerbalx.com, googledrive, pastebin, etc.
@@f00flghter29 Thank you. I have put 2 up. At the moment there are no pics, since I'm new to that site, here are the links: kerbalx.com/DavstrWrexham/Grand-Explorer
and kerbalx.com/DavstrWrexham/Duna-Flyer
@DavstrWrexham Your grand explorer is definitely capable of landing on Mun. Here it is in orbit (i.imgur.com/YC2ksfO.png) with almost 4km/s remaining, and here it is on Mun (i.imgur.com/FoVQslW.png). I'm guessing your problem with landing on Mun is the low TWR, as you can see in that last image we landed with a TWR of 1.3 and I believe we started the deorbit with a TWR of 1.1. The trick to landing with a TWR
do we still have to angle the wings if using FAR?
You still working on other videos?
Damn. I made an SSTO with 12K deltaV but i think ive got an issue with drag.
I'll repost the same response I made above:
Sorry to hear it's not working for you. If you want I can take a look at the craft file or you can post some images. When my designs, that follow all the principles and characteristics in this video, struggle to break the sound barrier it's almost always a drag issue. Sometimes the cargo bays can be buggy, make sure that your cargo isn't creating any drag by using the aero overlay (F12) or by turning on aero data in action windows (alt+F12-->physics-->aero-->check the action window box). To try to avoid cargo bay bugs try not to use the smaller bays with bigger parts; do not start with them open, or open them before getting to orbit; and always load from the hangar, don't revert to runway.
Still working on the other videos?
Yeah I don't get it. I tried to replicate this. I made several different versions of planes following the principals/characteristics you've explained here and none of them work. I can't get over 315m/s and every time I get anywhere near ~10,000m in altitude, the plane starts to stall. I get NO WHERE near the speeds you achieve.
Sorry to hear it's not working for you. If you want I can take a look at the craft file or you can post some images. When my designs, that follow all the principles and characteristics in this video, struggle to break the sound barrier it's almost always a drag issue. Sometimes the cargo bays can be buggy, make sure that your cargo isn't creating any drag by using the aero overlay (F12) or by turning on aero data in action windows (alt+F12-->physics-->aero-->check the action window box). To try to avoid cargo bay bugs try not to use the smaller bays with bigger parts; do not start with them open, or open them before getting to orbit; and always load from the hangar, don't revert to runway.
Im in the same boat. Not getting anywhere near the speeds or lift using the same calculations in the video of 1 rapier/30 tonnes and 5 tonnes per meter sq of wing area. 4 rapiers at 93 tonnes isnt even enough to get me off the runway with 4 Big S dv's.
@@Kinaek What speeds are you hitting by the end of the runway? If you can get to 110m/s or so you should be able to takeoff. If you can't get to 110m/s with 4 RAPIERs and 93t then you've got some crazy drag going on. Do you have any images or a craft file?
low tech SSTO when?
How did you come up with the 30-35t/rapier, how would I translate that to another engine?
Mainly through trial and error. For turboramjet style engines like the Whiplash and RAPIER you're mostly limited by how much you can get into the air off the end of the runway since they're at their worst at subsonic speeds. While it is possible to get 40t+/RAPIER into the air if you have enough wing area and you give yourself a longer runway, you use a whole lot more fuel accelerating up to speed due to the ascent taking longer and from the extra drag on the wings. At some point you break even where the difference between adding more fuel and wings vs another engine results in the same performance. If you're just going to low Kerbin orbit that point is around 35t/RAPIER.
However, if you want to make a longer range SSTO the benefits of being able to burn off fuel mass compared to hauling around another engine become much more apparent. You can load your RAPIER down with 45t and it'll take an extra 6t of fuel or so to get to orbit but that's 6t you can burn off as opposed to a 2t RAPIER engine that you have to drag around with you. Most fuel tanks have a mass ratio of 9, so up until the point where it takes 18t of extra fuel to get to orbit it is theoretically more efficient to cut engines and load up on fuel. In practice however, you're approaching the point where you're hurting the maximum speed you can get out of the airbreathing mode by loading it down so much so you're losing out on that ultra efficient open cycle Δv. It's a delicate balance and a lot more complicated than just going to LKO which is why I didn't talk about it in this introduction video. However, I plan on doing a long range mission after the next video which will be a lower tech SSTO, so I'll be talking about different engines there as well.
I did try to get a plane like this into a working state but I stuck at 20 KM height. The plane just stops rising after switching to closed and pointing Prograde.
Maybe the problem is the really bad frame rate of my game, feels like 5 fps and physic is reduced to 2 - 3 seconds per tick. This results in a 7 minute test flight needing around 15-20 minutes.
Yikes, those low frame rates can really try my patience :/ What speed are you going when you switch to closed and what is your wing area to mass ratio? Are you using wing incidence?
Could someone help me? He mentions that he would use 1 rapier engine every 30-35 tons. How many tons would you use one nuclear engine for? If that makes sense...
It depends on what you want to be doing. If you want to land on Mun for example, you're going to want to have a TWR of around 1.5 or so on Mun in order to land safely. So about 1 Nerv for every 27 tons. However, that's after you've already spent all the fuel getting to Kerbin orbit and transferring to a Munar orbit. So if you take that fuel mass into account it comes to about 1 Nerv for every 40-50 tons or so. Keep in mind that you can use the Nervs to help you circularize so you don't need as much oxidizer as you see in this video, so you can make things more efficient and err towards that 50 tons mark. I'm currently working on a low tech SSTO video and after that I'll tackle a long range SSTO with RAPIERs and Nervs ;)
It was not the first of many…
I followed these instructions as well as I could, but I can't break 350 m/s at sea level! I even tried with slightly more engine and slightly more wing and I _still_ can't break past this point. I have no surface attachments, just the shock cone at the front, 2 rapiers + nosecone tanks on the side, 1 rapier at the back and the wings. I have no idea what the problem is.
Forgot to put this in the comment, I have 4 rapiers and 16 m^2 of wing for an 80 ton craft including the 36 ton orange tank payload. No matter what I do to uprate the craft I cannot get it faster than this.
@@ryanspence5831 It sounds like you've got drag in your cargo bay. Cargo bays can be kind of buggy so make sure you always revert back to the hangar and launch from there instead of reverting to the runway and never open your bay until you're in space. To confirm this is the problem, use the "aero data in action windows" by going to alt+F12-->physics-->aero and then check that action window box. Then you can right click on parts inside your cargo bay during the flight to see if they're generating any drag. If it's non-zero then revert back to the hangar and try again. If it's always creating drag then you've probably got a part that's too big, e.g. using the 36t orange tank with the small or medium mk3 cargo bays.
@@f00flghter29 Thank you so much! Will report on results.
@@ryanspence5831 legend has it, he still hasnt reported on results to this day... fr tho did it work? i wanna be sure to avoid that problem since its my first time building a heavy ssto
@@chocotriscuit4917 i forgor 💀
How do you move the parts so far away from their roots?
Hold down shift while offsetting
OMG Life Saver!
how is 66m/s enough to dock with a space station?!
I suppose with rcs, a skilled pilot, and a very low space station its certainly possible
@@Commentsnotvideos Not really. Unless you pretty much match the station orbit exactly on your ascent. And even then you'd be lucky to pull it off with 66 m s-1.
Too much downtime in the video. It should be 28 min long. Otherwise a big fat +
Needs some work mate. Am glad it worked to dump a tank into orbit. But try a more practical mission. IE to Duna and back carrying a starter base. That's a good test I think. I know I learnt allot doing it. You will find it much harder to stay with what you said in the presentation and you will have to make allot of adjustments to it. You will need solar, chutes, comm, RCS, etc that will create parasitic drag. No way around it. And it will get really bad if you have to use a resource scanner. Plus you would have to add nucs to it as those trashy rapiers are really not that great but all we have for the transition part of the flight. Anyhow, I learnt off of Mark Thrimm and Matt Lowne designs before I started building my own. Lots of pain and grief in that six months of learning where I had to abandon my knowledge of aerodynamics as some of it didn't work in KSP.
Putting 90t into orbit was the purpose of this space plane. I mentioned at the start of the video that I'll be doing other things, including long range SSTOs in the future, which will undoubtedly use Nervs. However, lets not kid ourselves, there's nothing "practical" about SSTOs beyond delivering payload to LKO. There's no reason beyond bragging rights to drag a bunch of air breathing engines and wings around in space. Don't get me wrong, I love the challenge of not staging, but it's certainly not practical. The goal here was to show how to make and fly an efficient SSTO, while correcting many of the common misconceptions I've seen in SSTO design. Mark Thrimm and Matt Lowne make great, fun videos, but their SSTO designs and flight profiles are not efficient, they routinely use excessive engines and make unnecessary, large AoA maneuvers. If you want to be inspired by ultra efficiency, check out Bradley Whistance's SSTOs. There's also no reason why the concepts and techniques I demonstrate in this video can't be used on SSTOs for any application. You can hide anything you want in cargo bays or fairings to very easily "get around" the drag they create. I will certainly take your request for a Duna expedition SSTO video. I'm currently working an a low-tech passenger SSTO, among other things, so it'll probably be til March or even April before a Duna video comes out ;)