Nao

That's quite good idea! It does nerf nuclear engines quite a bit thou, since mech jeb can't use them to their full potential. (burning at an ~30deg angle to set flight path just after last normal engine separation). But i'll try it later

Ohh that clears that out 100% correct... but! The more engine mass you take with you the less dV you will get by burning fixed amount of fuel. On airless body, using nuclear engines, the most Mass efficient launch TWR is only ~1,25.

Studiowałem co prawda na polibudzie ale nie mam żadnych koneksji z biblioteką pwr. Powodzenia!

I use Bi-elliptic orbits for: Getting faster planet (and other ships) intercepts at smaller fuel cost than forcing one burn transfer. Making big inclination changes (above 38,94 deg inclination change its more efficient to make bi-elliptic 3 burn plane change) (KSP Orbit Mechanic has a chart of terminal radius ratios for different angles) Also while not pure bi-elliptic there are some transfers that use more than one burn to get some dV for free from other bodies like: Going to Dres and Eeloo using Jool aerobrake can save some dV sometimes Going to Moho or low kerbol orbit through gravity slingshot off Jool (never tried it thou)

That means you didn't push the your designs to the limit. Of course its possible to make SSTO that use as much dV as even most sophisticated asparagus staged performance rocket, but it wou't go much further after reaching orbit. I have done rocket only SSTKE (single stage to kerbol escape) that require more than 16000m/s dV and to ascent with that much energy left, my ship needed more than 5000m/s to get to LKO. This happens because of two things: 1) Low TWR (1,1-1,2) will make you suffer bigger gravity losses no matter what, while giving more dV. 2) Switching to only nuclear engines as fast as possible at high altitude. Because it's more fuel efficient to burn at an angle with LN-N's than using other engines in the velocity vector direction, and burning at an angle "wastes" dV.

Congratulations! Since the Duna orbit is elliptic, during earlier testing i could get transfer Pe below Kerbin orbit with lower deltaV of around 540m/s. When trying actually to get a real transfer window in my testing save, it ended up little more: 610m/s from 50km orbit. It is important that when exiting Duna SOI your trajectory should be as parallel to Kerbol orbit as possible. Ideally you should be at transfer orbit Ap right as you exit Duna SOI. And that's probably what costs you more dV than needed.

Welp, nie wiem czy ci się przyda ale skoro obydwoje we Wrocu siedzimy to mogę udostępnić troche starych czasopism. Głównie "Technika wojskowa", której mam pewnie z 60+ numerów zprzed 2000roku i troche mniej "Lotnictwa" z podobnych lat. Miałem też troche naukowych czasopism ale pooddawałem

Też się przywitam, a co. Nie zauważyłem nawet, że sie to międzynarodowe forum tak rozrosło . Kerbaluję od wersji 8.3 chyba (z forum Dwarf Fortress sie do Kerbalach dowiedziałem). Ostatnio tylko czytam angielskie forum, ale miło widzieć że jest postęp w polskiej części

Kilka tygodni to byłby horror w Toi Toiu (albo Apollo), ale myślę, że wraz z postępem technologii dało by rade! Na przykład juz teraz można wygenerować obraz który zaspokoilibyśmy głód przestrzeni naszego mózgu na czymś takim jak Occulus Rift. (coś jak okulary VR). Właściwie to tak pewnie się będzie odbywać tranzyt długoterminowy: malutka kapsuła, załoga podpięta pod matrixa, "wychodzisz" do klaustrofobicznych realiów tylko na jedzenie, kibel i zdięcia. Może być całkiem przyjemne!

@SRV Ron, Yes but the bigger the speed, the harder is for the moon/planet to alter your trajectory, and the amount of dV gained from slingshot is proportional to the trajectory change angle. That's why you can get 400m/s+ slingshot from Mun when going to Eve (going to Eve actually cost's almost the same as just going to Mun that way). But when trying to get Mun slingshot to Jool it is 100 m/s gain at best. edit: Did a simple ingame test, it takes around 600m/s dV to get from low Duna orbit to Kerbin, and at that speed Ike slingshot will give around 60-70m/s, 10% savings, not bad.

Yes and no, if your TWR at its lowest point during flight (not counting the last 500m/s when you are almost in orbit) is above 1,7 then you can expect 4500m/s dV to orbit. 1,5 TWR rocket can expect ~4900m/s dV, and 1,2 TWR (would be ok for SSTO, and pretty bad for staged rocket) and probably burns around 5300+m/s dV. edit: ninjaed

Lol, no offence, but you tell him to not use "cheats" while providing one yourself. I would consider using external tools that give knowledge you can't normally find in the game more "cheaty" than just extending the standard UI usability by modifying original options file. edit: actually more OnTopic, Slingshot around should work, but due to its small gravity you would probably lose more speed correcting your ship for proper flyby than you gain from slingshot. Also for reference best case scenario slingshot from Mun can net you 400+m/s. Ike would probably give less than 50m/s

For career mode i use a satellite left in High Kerbin orbit. Set up a maneuver node for it to just escape Kerbin, then another maneuver to transfer to desired planet's orbit. By rotating the second node i around the Kerbol orbit I find the position for intercept. The angle between the node and destination planet is (roughly) the phase angle. You need some experience to do transfers like that but its quite natural. And also that way you can plan more complicated transfers that require more than one burn, like bi-elliptic etc.

I would add one more important element that is ofter overlooked in this kinds of discussions. The engine mass. High TWR means high engine mass. During burns fuel is used to accelerate itself, payload and engines. If we increase TWR, we allocate more energy from fuel to accelerate the engines themselves. This is why while mathematically the best speed to ascent is at terminal velocity (TWR~ 2) the least fuel will be spent by using ship with TWR~ 1.8, and the smallest liftoff mass will be achieved at TWR~1.6. The deltaV required to achieve orbit will increase but with less engine mass the fuel mass fraction will increase, giving the ship more deltaV than it looses to the gravity drag using lower TWR.

@Spyritdragon I believe the image is wrong, the game prioritizes fuel lines first so in the second part both engines will draw from the light gray tank. After separation the main stage will be full. You can check it in game.

Welcome to the forums , nicely done. The 48-7S are indeed ridiculous, I'm not touching them unless i really have to, but 20% is doable. I could be wrong but i think some versions ago (0.16-0.18?) we got well into the twenties with similar challenge.

Glad to help. I guess in real rockets there are some things that may make the rocket spin, like the bell nozzle cooling exhaust or something like drains etc. The newest Falcon 9 did suffer uncontrollable rotation problem when returning to earth... But i guess thats all out of the scope of the game.

...and then the high speed liquid hits a bend in a tube that tells it to move downward toward combustion chamber, we get back all the rotational momentum and we even get some thrust out of the moving fluid!

It's true that the rocket was designed to work without asparagus first. But I don't think number of stages changes much here, especially when it is the asparagus that gains advantage of lower number of stages. (low number of stages, more Dv per stage, more fuel tank mass to tow for the non asparagus version). The idea behind my design is just exploiting each of the different propulsion system to its full potential. Engines are decoupled before their fuel tank mass becomes too bit to affect performance in a big way. This chart (idk who made it so can't give credit ) shows correlation of fuel mass to Dv for each engine. If we want to use the engine over long burns for maximum Dv gain then yes, asparagus delivers great performance. But for engines with very high ISP or designs with low burn time (low Dv requirement) does not benefit from asparagus as much. I dont think of this as gimmicky or thinking out of the box but just using the tools available to their greatest potential. That's why i used the term lazy - as you can't go wrong strapping another stage on asparagus ship, but designing similar non asparagus one is much harder, but doable half of the time. Going further, in my opinion, one of the reasons fo Falcon Heavy to use fuel cross-feed is because they use low ISP engines (much lower than for example Space Shuttle's engines). So even thou they have super light fuel tank, the mass fraction of it becomes big enough to warrant investment into cross-feed to increase performance. Also, for this challenge: Payload Fraction Challenge, I've just created an ascent rocket, that delivers payload to orbit at 18% mass fraction and uses 4 stages, i would call that efficient, and it doesn't use any fuel transfer method.

So.. an unusual entry. Academia 2, no-asparagus rocket. 4 stages and zero fuel lines: 18,02% payload fraction 1) On launch pad 123,83t 2) In 75x75km orbit with 14kg propellant left 3) Payload decoupled 22,32t There is a lot to improve, and of course using asparagus staging would help a lot, but the design idea was to remain simple and efficient while not using fuel lines (like they do on normal rockets).

Of course you can make asparagus in such way that i would be impossible for similar no cross-feed rocket to compete. But it would be possible to design a reasonable asparagus launcher first and get similar efficiency out of no-asparagus modification. In the end what matters are particular TWR of stages so the flight profile is efficient and engines are doing similar job (only real difference is fuel tank mass that gets accelerated further on no asparagus rocket), that's why i moved the fuel around and end up with fractions seen on the first stage of asparagus rocket (it's hard to divide a tank into three parts while moving fuel from center stack into the outers). If done the other way it would mean that the fractions would be on the no-asparagus one instead. Also I'm currently designing no-asparagus ship for the Payload Fraction Challenge and I'm already at 17% mass efficiency at only 3 stages. Which is very close with other ships that use fuel lines. //Edit: got an entry with 4 stages and 18% payload efficiency, tied for the lead as of writing this// Not all asparaguses are lazy of course , but there are some designs where people blindly go "i need to add asparagus to my rockets to increase efficiency" but due to bigger errors in rocket design they don't make good use of the system.I think it's easier to design efficient asparagus rocket just because each stage starts from full state, so we just add stage after stage to existing rocket keeping the same TWR and the whole thing flies well. But then if you look closely we end up with something like stock Kerbal X (not saying it's bad, its great for what it is supposed to be) with first 3 stages burning only 15-20s and next flying for 100s. And as we know, for engines with similar ISP the most effective use of staging is when each stage has very similar burn time. Also since this thread is about why we don't see asparagus IRL while we often do in KSP, i wanted to point out that while asparagus can increase performance of any launch system, similar performance can be achieved by careful design. And since in IRL it's more costly to use those fuel lines we see efficient use of no cross-feed staging instead.

Don't remember the exact numbers but In one of the test's on the bug I used 1 circular intake and 50 closed ram intakes to go ~2230m/s and above 30km altitude on 100% throttle. The circular intake provided less 0,8 (or was it 0,65?) units of air when the flameout occurred (normally it takes 3,36). The engine fuel flow was smaller than normal (it looks like automatic flameout control, when below minimal air flow, the engine starts to drop fuel flow and thrust by itself), but the thrust was somewhat higher than expected from the speed and fuel flow values too (also thrust go down if you throttle down even thou it looks like engine is limiting thrust by avilable air so theoretically it shouldn't ). Idk what is actually going on there. Having 1-2 closed radial intakes per ram intake gives lesser but still noticeable boost in performance If you are using lots of radial intakes, try adding one ram and close all the radials, it should have much better performance. @ tavert's craft, at first I thought about gimbals too, but then I remembered that its KSPhysics, and it probably can wobble itself to death with out player even touching it at that length. Maybe using MJ to throttle down, putting the flight on rails for one frame then throttle up one every other second it could finish it's burn .

Send a probe first! Imitating the landing of manned craft. There are several things that can go wrong on a Duna misson that aren't apparent from tests on Kerbin. Oh and if you are not sure if you will have enough fuel, then just by using the lander (without interplanetary stage) starting from low kerbin orbit try landing and returning from Mun, if it manages it, it should have enough for Duna.

@numerobis If you don't spam ram intakes, you could try adding some closed radial intakes to increase performance with minimal partcount impact. There are some shenanigans going on with them, i was able to get up to 55% more performance out of the engine by adding closed radials. In one test the engine not only worked at 100% thrust at 1/4 of normal flameout air, but also had more thrust than it should at that fuel flow/speed. (Didn't manage to use this bug with large amounts of intakes so no new Maching bird record but it definitely can be useful). I think they provide "ghost" air even when closed and mess up some calculations.

Adding some flames to the discussion Asparagus staging in KSP is so good because people are lazy and design their rockets more by visuals rather than actual mission requirements. Even in KSP it's possible to make no fuel cross feed rocket to be almost as good as asparagus one. (For standard designs of course. For the ones stretching engine efficiency as hard as possible, cross feed will be much better.) For example this rocket that was designed to as a Tylo land and return mission: Last three stages are the same, both rockets have the same engines and the same amount of fuel. There are no fuel lines in firsts pic, and there is asparagus staging on the first 3 stages in the second pic. The difference is only 8146m/s to 8327m/s and the asparagus has 0,01 more TWR on second stage. 8146m/s No fuel lines8327m/s asparagus with the same engines, launch mass and TWR.