eloquentJane

Spacecraft Design Evolution in KSP

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Posted (edited)
On 16 March 2017 at 2:36 PM, eloquentJane said:

The obvious alternative is making biplane-like designs where you have two layers of the same wing shape because one wasn't lifty enough (I've gotten into that habit recently and I have noticed other people doing it as well).

Banging my usual drum, you don't need a lot of wing for heavy lift or long range:

JFYj7ID.png

 

NOYwtKP.jpg

 

QMfaLse.png

 

oJQB7re.jpg

 

All single-layer wings, nothing but big deltas on the Mk2's, two pairs of mostly unclipped strakes added on the Mk3's.

Canards and tailplanes help, but as you can see in picture #2 they aren't compulsory. Wing incidence plays a large role; you want that draggy fuselage pointing dead into the wind while you accelerate.

Edited by Wanderfound

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On 15 March 2017 at 6:16 AM, A_name said:

Asparagus monstrosities.

nJEdzOQ.png

 

duTxW3X.png

 

:)

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The thing I find particularly odd about asparagus staging in KSP is that it's almost never necessary unless you're ascending from Eve. If you know how to do a gravity turn well, you can fly a rocket to orbit efficiently enough that there's never a need for asparagus staging.

@Wanderfound That's quite an interesting design because of the outer layer of boosters. Having drop tanks on top of SRBs probably doesn't fall under the usual definition of asparagus staging (since they don't feed the engines they're connected to) but it's definitely an interesting design that makes more sense when compared to real engineering than normal asparagus staging does (basing things off of what's doable with current technology). It's a pain to work with if you want to minimize wasted fuel though.

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21 minutes ago, eloquentJane said:

The thing I find particularly odd about asparagus staging in KSP is that it's almost never necessary unless you're ascending from Eve. If you know how to do a gravity turn well, you can fly a rocket to orbit efficiently enough that there's never a need for asparagus staging.

Asparagus staging did make more sense in earlier versions, and old habit are hard to kill.

The addition of more varied SRB's, the concept of cost and a more refined aeromodel has changed the table quite a bit.

But it's not just habits, it's also the dreaded 'internet history persistence'. Searching the net for help/guidance/tutorials for 'KSP launch' (or j.random other thing) and you'll get a pile of suggestions, some of them several years old and totally wrong (some of them totally wrong even when posted).

 

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15 hours ago, nascarlaser1 said:

I have only a few things I ever care about in my ships.

1: They keep the Kerbal alive. This is a must. Whether or not I'm playing with LS installed (which I do a lot) the Kerbals must NOT DIE. This can range from having elaborate and overpowered escape pods on my stations that will never be used, or having a simple yet effective ejector seat on my test shuttles that will always be used :P.

My spaceplanes tend not to have launch escape systems etc.,  but I do have a crash test program I'm considering formalising into an N-CAP rating.   It's a combination of putting expendable structure around the crew areas and also keeping stalling speeds low and safe.

Gear up landing test -

 

 

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On 2017-03-17 at 4:29 PM, nascarlaser1 said:

keep the Kerbal alive. This is a must.

This.

I'm almost vegetarian, except for bacon, but for Kerbals there's no exceptions :wink:

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I started to test rovers, kerbin rovers , utility rovers JUST NOT THESE DARN MUNAR-JOOLIAN-EVIAN MONSTROSITIES.

And created a new design bureau for myself!

Introduce you my brand new "Carbon" design bureau!

(awkward voice)

xHascku.png

So, i wanted to mess with rover designs, that are not very well suited for KSP. And here is the results for now:

1. "Defender''

Er5Vtud.png

"Defender" is a compact rover for transporting personel across the KSC. It has normal stats, and has a very simple and modular design.

2."Lynx"

4uyyavZ.png

It is a sport class vehicle for a long trips to the forests or a very quick drive around modern cities. Has a good speed and very nice impact tolerance.

3. "Warranteer"

bSNRaY6.png

Great rover for personal needs! It has a great speed, turns well and  it is very compact.

 

Hmmm, i think i need to improve my designs(25m/s is not enough), or make an entire new vehicles.. What do you think?

 

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Posted (edited)
15 hours ago, eloquentJane said:

The thing I find particularly odd about asparagus staging in KSP is that it's almost never necessary unless you're ascending from Eve. If you know how to do a gravity turn well, you can fly a rocket to orbit efficiently enough that there's never a need for asparagus staging.

@Wanderfound That's quite an interesting design because of the outer layer of boosters. Having drop tanks on top of SRBs probably doesn't fall under the usual definition of asparagus staging (since they don't feed the engines they're connected to) but it's definitely an interesting design that makes more sense when compared to real engineering than normal asparagus staging does (basing things off of what's doable with current technology). It's a pain to work with if you want to minimize wasted fuel though.

Asparagus adds a few hundred m/s per booster ring compared to onion staging, which adds up when you're trying for extreme range. And although you can usually just substitute bigger boosters, the big rockets are expensive compared to a cluster of low-tech boosters (the one in the pic was built for a career game, so I was trying to keep cost down).

SRB droptanks are tricky if you want to absolutely maximise it, but if you're willing to undershoot on maximum tank capacity it isn't too hard; just build so that the tanks run dry well before SRB separation. I nearly always stick at least a small tank on top of any SRBs these days; no fuel hoses required, just activate crossfeed on the decouplers.

The pictured ship only has the mess of hoses because the inner liquid boosters are properly asparagused (i.e. dropping in pairs instead of quads), so all of the SRB droptanks need to feed into the first-dropped set of LFBs. Even that could be avoided these days if you want to take the time to fiddle with advanced tweakables and fuel priority.

Edited by Wanderfound

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I find that my designs usually tend to function rather than looks, although I begin every design with an aesthetic already in mind based on my earlier experiences with the kind of vehicle I'm building. So, when I'm building landers, I already start thinking of a more vacuum-based design, or maybe when designing a SSTO I think of a more pointy sleek shape, etc. I also try to base the design based off of what the mission is, so I rarely re-use a design.

 

That being said, I always try to push the aesthetics as far as I can before performance is impacted. Here are some examples:

 

3QH0Rnc.png

Spoiler

8vdM8Ga.pngRcCRVTB.pngryW1EbV.png

Spoiler

3QH0Rnc.png

LhubZX1.pnggLdguoO.pngUk78eW6.png

 

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On 3/14/2017 at 9:02 AM, eloquentJane said:

Something I find quite interesting is how spacecraft evolve to suit certain requirements. Some players, such as myself, try to make our spacecraft look quite realistic, but this often ends up not being optimal for the game (most of the time adding extra parts to make a design look realistic makes it less efficient).

Real spacecraft designs, at least those operating beyond LEO, have to contend with realities that are entirely absent within the game, such as engine radiation, waste heat (face it, it's not a concern beyond ISRU or maybe, maybe a Moho trip), cosmic radiation, fuel boil-off, crew life support and comfort, etc... They are also designed to keep the structural element to a minimum in order to extend delta-V, efficiency is one of the highest concerns.

On 3/14/2017 at 9:02 AM, eloquentJane said:

Other players, however, design spacecraft to work well in the unique environment of KSP.

Conversely, KSP craft tend towards being squat, compact, and/or fanciful due to game engine constraints, orbital construction of a coherent starship being a serious challenge in more ways than one, lack of dangerous considerations, simplified physics model, reduced delta-V requirements, and so on.

Plus, it is incredibly easy to get anything to orbit in KSP, and not just because of delta-V requirements. Even in RO you could potentially launch a satellite without a fairing because there is no consideration towards protecting the payload from vibration or heating or failure of the electronics.

For me, while I enjoy building "realistic" looking craft I find I can't really achieve that goal because of the peculiarities of the building system and the failures of orbital construction. Procedural parts help but mainly with launch vehicles. End-game craft are, as you have stated, massive nuclear-engine monstrosities composed of the largest Mk3 tanks (because we can't have huge, round LF tanks for some reason, mods obviously change that) but I don't bother with the smaller pods because the large round can will fit within a Mk3 cargo bay just fine (and my docking skills are up to scratch). I don't build with an eye towards cost efficiency because I don't play career mode and I find that, quite frankly, incredibly boring (in fact, I maintain that mainstream designs have become very cookie-cutter because of career mode).

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On 3/17/2017 at 0:42 PM, nascarlaser1 said:

wait... a converatron can refill greenhouses?? YAAYYYY!!!

Slightly modded, in that it outputs some CO2/Waste/Wastewater along with with other resources.

I also changed the small convertotron to just have an on/off switch so you can't control what you get out; instead of losing a straight 80% by mass, I instead get a dribble of everything and all the stuff I can't use goes to waste.

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My Kerbals construct silly things when nobody is looking at them. Maybe better so...

Spoiler

sM4bUY6.png

The lack of seriousness in my Space program concerns me more and more. Jeb should also be concerned about the fact that personal parachutes are still in shipping...

But when i do look at my Kerbals at work it seems as they have become quite nifty at space things:

Spoiler

xIdjssD.png

:D

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On 3/14/2017 at 7:19 PM, Long Finger said:

Personally I really hate the designs I see where things are attached in such a way that they could never realistically function. For example you can stick things over the doors of a service bay (like some disgraceful youtubers) and still open those doors as if the things weren't there!

I have had to come to terms with the idea of Kerbals living inside of a full fuel tank with a docking port stuck on it however, and I quite like the magic strutting feature because attaching struts nicely is sooo hard.

That is something I try to avoid.  I hate bay door clipping.  However, I am grateful for the ability to limit the range of motion on some bay doors.  Sometimes a fully-opened bay will clip through things mounted on its sides, so limiting the door authority can allow things to enter and exit without the doors smacking through geometry.  As for crew mobility, I try to apply clipping rules there too and avoid situations where Kerbals would have to crawl through other objects that have non-crew functional purpose, like fuel tanks.  I make an exception if there is no way to make something aerodynamic and aesthetic without that, but I try to minimize that and keep it plausible (an LF/O tank that only carries LF on a splaceplane I can pretend has a crew tube since not all the internal volume is being occupied.)  I tend to assume that hollow structural components are Kerbal-permeable (or can be made so by our dedicated VAB construction teams.)

 

On 3/16/2017 at 5:03 AM, Rune said:

jwiggjr.png

I have to say, I love that Dragon-style module.

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On 3/18/2017 at 10:03 AM, eloquentJane said:

@Wanderfound That's quite an interesting design because of the outer layer of boosters. Having drop tanks on top of SRBs probably doesn't fall under the usual definition of asparagus staging (since they don't feed the engines they're connected to) but it's definitely an interesting design that makes more sense when compared to real engineering than normal asparagus staging does (basing things off of what's doable with current technology). It's a pain to work with if you want to minimize wasted fuel though.

I used to do the drop-tank-on-top-of-solid-booster style quite a lot, but not so much anymore these days.  Felt like too much effort trying to balance the fuel consumption to the actually gain in performance.  After a certain point, adding more complexity in the name of efficiency becomes counter-productive.  Drop tanks that can drop independently of the boosters served me better because I can alter the point that they drop depending on how much I need to open the throttle during ascent.  Dropping the SRBs before the tanks are empty wastes that fuel, holding onto the empty tanks because the SRBs are still burning wastes mass, and trying to balance that for every different payload takes too much trial and error.

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30 minutes ago, Fearless Son said:

Dropping the SRBs before the tanks are empty wastes that fuel, holding onto the empty tanks because the SRBs are still burning wastes mass, and trying to balance that for every different payload takes too much trial and error.

If you assume that your lifter will be at full throttle until the SRBs burn out and the tanks on top of the SRBs are empty, you don't need to balance it for each different payload since the burn time will be the same. Balancing it initially is still a pain, but you don't need to rebalance it each time. Obviously a design that has to remain at full throttle all the time isn't always ideal, but it's the easiest way to make drop tanks on top of SRBs work.

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2 hours ago, luizopiloto said:

SSTO:

3sFRNn9.jpg >> eLadUUo.jpg

I had never considered using fairings in an SSTO like that (mostly mine have been limited to heat-resistant aerodynamic nosecone replacements.)

Thank you, this represents an innovation I am going to have to steal.  

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2 hours ago, Fearless Son said:

I have to say, I love that Dragon-style module.

That's actually the Heinlein, a Kerbin-capable SSTO... you can grab it here if you want to take a closer look.

0mQwnaS.png

My "Dwagon" is quite smaller:

CMPgH8G.png

 

Rune. I love the new "fore by throttle" function.

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On 3/14/2017 at 3:16 PM, A_name said:

Other examples of design choices that would only show up in KSP:

...

Asparagus monstrosities.

 

Actually, asparagus staging was something that was planned to be implemented on the Falcon Heavy, but became too complicated. http://www.spaceref.com/news/viewpr.html?pid=33185 Of course, we are nowhere near ten-stage asparagus monsters, but the Falcon Heavy was close to using it.

In fact, I remember reading that in later iterations of the Falcon Heavy in the future they may use asparagus.

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Posted (edited)

The Falcon Heavy uses two side boosters, so onion staging, but what is the difference between onion staging or asparagus staging. 

Edited by Alpha 360
"Kouston, we have several problems, but that doesn't matter so we want to continue on with the mission."

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28 minutes ago, Alpha 360 said:

The Falcon Heavy uses two side boosters, so onion staging, but what is the difference between onion staging or asparagus staging. 

The biggest difference is using outer stages to feed inner stages. With just two side boosters, the Falcon Heavy on the outside would look like normal onion staging, but internally, it wouldn't if it cross-feed the fuel from those boosters into the main booster. They'd empty and be dropped sooner while the main booster would continue on with a full tank. Onion staging would have the strap-ons drop later and the main having only a partial tank afterwards.

Onion vs asparagus is just as much about how the fuel flows as the apparent staging.

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21 hours ago, eloquentJane said:

If you assume that your lifter will be at full throttle until the SRBs burn out and the tanks on top of the SRBs are empty, you don't need to balance it for each different payload since the burn time will be the same. Balancing it initially is still a pain, but you don't need to rebalance it each time. Obviously a design that has to remain at full throttle all the time isn't always ideal, but it's the easiest way to make drop tanks on top of SRBs work.

Yeah, even then its pretty easy to do if you have MJ or KER installed. I just put on the decouplers, the SRB's and a tank (as a guess)  I set the staging to go SRB, LF, Decoupler, and it will tell you the burn time for the SRB and for the main engine using the fuel from the boosters. Add tanks until the LF time is close, but not more than the SRB time.  Merge the bottom two stages and you are done.

I also have a premade bottom stack of TwinBoar + 4 Thumpers + Tankage.  I end up putting that on most of my medium sized launches anyway. It works out nice. I use GravityTurn and the Thumpers burn out just as the time to Ap hits 50s, and GT wants to throttle down. 

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On 3/20/2017 at 1:03 PM, luizopiloto said:

SSTO:

3sFRNn9.jpg >> eLadUUo.jpg

I like how the one on the right kinda looks like a squid.

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it always ends up asparagus... 

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SSTO, droptanks, asparagus, heatshield...this mission has an identity crisis.

 

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