EPT![[image loading]](http://puu.sh/hTJwv.png)
fuck my life
what the fuck am i doing
Kerbal Space Program - Page 37
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Cyro
United Kingdom20333 Posts
fuck my life what the fuck am i doing | ||
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Cyro
United Kingdom20333 Posts
lets forget this ever happened *deletes ships* i can't think of a more painful way to do a first orbital rendezvous | ||
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nimbim
Germany985 Posts
How did that situation even come up? | ||
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Cyro
United Kingdom20333 Posts
edit: This mod that i'm using actually has decoupler-sepratrons, it's really nice. It holds stuff a little distance away then when you activate, it kicks them away and then stays attached with a mini-SRB in it. Feels pretty balanced in the stock game, but just bigger. When you have engines twice as powerful and fuel tanks twice as big as the stock game max, it's much easier to get a payload of a certain size to X orbit/location, because the % of the craft that is fuel/engines can be much larger without lagging the game. Also, this probably costs a fortune  yay sandbox | ||
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Cyro
United Kingdom20333 Posts
With his test rocket (5.17km/s delta V) it cost only ~3.4km/s to get to orbit - but that's in 1.0.2 and carrying the extra fuel. Without that increased drag and payload (reducing fuel until it only has enough fuel to get to orbit, and doesn't arrive there with useless fuel weight) i can see getting ~3km/s to orbit with that kind of ascent profile. Have to test myself, it's pretty wildly different from what i've been doing so far. He also used a launch TWR of ~1.5, so i guess 1.7-ish would be equivalent in 1.0? Though there was evidence of higher TWR increasing efficiency - the only time that's really in question is when you're creating excessive drag that's enough to cost even more than the losses to gravity would cost you during a slower ascent (not a problem past low atmosphere, especially in 1.0) or adding engine weight to achieve it Really, you only need ~2.1km/s. The rest of the delta-v is just how much you're losing to gravity and drag on the way up there, which is non-zero but highly variable. With a very very thin and fast rocket, like with a 1m design, nosecone and a single modified engine for huge thrust - it could allow for TWR's much higher so that you lose almost no energy to gravity and drag and probably make orbit with some silly amount like 2.6km/s of delta V ~ i'm not sure of the math really and how much energy is lost to one vs the other with a typical ascent | ||
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stenole
Norway869 Posts
On May 21 2015 13:18 Cyro wrote: This guy did some testing in the 1.0.2 atmosphere with ascent profiles for rockets. It actually seems extremely powerful to pitch over very sharply and quickly - he got improving results with sharper and faster turns, down to as sharp as 80 degrees (so only 10 off the horizon) at 500 meters. I'd like to see the source of that. You would think that drag would eat up a lot of speed with such an ascent profile. Really, you only need ~2.1km/s. The rest of the delta-v is just how much you're losing to gravity and drag on the way up there, which is non-zero but highly variable. With an atmosphereless Kerbin, you would need to at least reach the orbital speed at 0m altitude which is about 2426m/s. The initial planetary rotation only gets you a 174 m/s head start. Lets pretend you still want to reach a 70 000m altitude orbit. The Hohman transfer would add 130 m/s of delta v. So you would need a minimum of 2.4km/s of deltaV. Because you don't have infinite TWR, it would be reasonable to add at least 100 m/s of delta v lost to gravity drag for a high TWR engine. | ||
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Cyro
United Kingdom20333 Posts
With an atmosphereless Kerbin, you would need to at least reach the orbital speed at 0m altitude which is about 2426m/s I'm in a stable orbit atm as low as i can realistically get (70.1km to 70.2km) at under 2300m/s. That's a little higher than i thought but still not 2426, unless the rotation speed is not counted there but still makes the orbit work it's a trade off between gravity loss vs air drag when choosing TWR, he took a low TWR and flew mostly sideways through the atmosphere http://www.reddit.com/r/KerbalSpaceProgram/comments/36k47k/gathered_data_for_some_10_ascent_profiles/ | ||
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Simberto
Germany11875 Posts
He was talking about a theoretical orbit at height 0 on Kerbin, which can be easily calculated for spherical orbits if you do know the gravitational constant in KSP (which i do not, but it is really easy to find out) or based on already known higher orbital velocities. Equating the centripetal force and the gravitational force leads to m1v²/r=G(m1*m2)/r², with m1 being the orbiting mass, v the orbital velocity, r the orbitalradius (including radius of Kerbin, not the height above ground), m2 being the mass of Kerbin This leads to v²=G*m2/r v²=G*m2/(Rk + h) G and m2 being constants let you easily calculate the necessary speed of any orbit with the information that Kerbin's radius Rk is 600km. h being your height above Kerbins surface here. As can be seen, the kinetic energy necessary for such an orbital speed = m v²/2 increases antiproportionally with a single radius, while the energy you need to spend to escape the gravitational potential to that height from Kerbins surface is Epot(Rk)-Epot(r) G*m2*m1/Rk-G*m2*m1/r =G*m2*m1*(r-Rk)/(r*Rk) Thus, the total energy needed to achieve a certain orbital radius from 0 velocity at Kerbin surface height = dEkin+dEpot =0.5G m1m2 / r+Gm1m2(r-Rk)/r*Rk =(r-0.5Rk) * Gm1m2/(r*Rk) = (1/Rk - 1/2r) G m1 m2 Which still increases with increasing r, to a maximum of Gm1m2 * 1/Rk at an infinite r, which is the energy needed to escape Kerbin completely. | ||
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Cyro
United Kingdom20333 Posts
wanted to test that anyway orbital speed at 0m altitude Didn't catch this part :0 Thanks for corrections, i guess that all makes sense. I was off on the speed @ low orbit by >100ms as well (i usually establish orbit @ like 80km) | ||
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stenole
Norway869 Posts
I think this new atmosphere doesn't have the cutoff it used to have in 0.90. So if you are timewarping, you will be on rails, but if you are flying or using physics timewarp, you will experience some drag even if it is very small. I'm not 100% sure, but I've seen the cutoff values in the wiki are marked "deprecated". The Atmosphere-without-Kerbin-scenario is what you have to deal with on Tylo. Landing there makes you appreciate that Kerbin has an atmosphere. | ||
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felisconcolori
United States6168 Posts
On May 22 2015 22:17 stenole wrote: It seems like the guy in the reddit post uses angles relative to the horizon, not relative to straight up. That being said, figuring out this new atmosphere is quite a challenge. It's not something you can easily plug into an equation like most other things in this game. It's a good thing there are grunts out there willing to run tests so the rest of us don't have to. I think this new atmosphere doesn't have the cutoff it used to have in 0.90. So if you are timewarping, you will be on rails, but if you are flying or using physics timewarp, you will experience some drag even if it is very small. I'm not 100% sure, but I've seen the cutoff values in the wiki are marked "deprecated". The Atmosphere-without-Kerbin-scenario is what you have to deal with on Tylo. Landing there makes you appreciate that Kerbin has an atmosphere. It would be interesting to see, although if there is drag acting beyond or just on the fringe of the atmosphere, I haven't seen it utilizing the aerodynamic forces overlay. To the debug data.... | ||
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Cyro
United Kingdom20333 Posts
It seems like the guy in the reddit post uses angles relative to the horizon, not relative to straight up That's what i thought at first too, but idk how he's getting to orbit with those angles. Wouldn't that depend highly on how much your rocket flops over? That would require reducing your thrust and making yourself less aerodynamically stable. None of my designs would reach anything even remotely resembling a circular 75km orbit if i flew like that, but they fly surprisingly well if i pitch over sharply as soon as i've got a bit of speed going. It would be interesting to see, although if there is drag acting beyond or just on the fringe of the atmosphere, I haven't seen it utilizing the aerodynamic forces overlay. To the debug data.... I don't think it's that, i'd guess the calculation to estimate your path is just slightly less exact than the actual flying, or something weird with time warp. I came out of a small warp at below 72km and then my periapsis started falling, it dipped below 70km and then i lost like 100 meters in 1 orbital revolution after hitting the atmosphere so it would have de-orbited after that | ||
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Cyro
United Kingdom20333 Posts
edit:~ I'm having a lot more success treating them like rockets with wings rather than planes with rocket engines. I have moved a bit away from single stage designs though - drop tanks are quite useful. Overall i'm probably doing silly things with no cost benefit. If you truly want to carry something to orbit and get back with no cost aside from fuel expenditure, mk.3 is the way to do it | ||
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Cyro
United Kingdom20333 Posts
this is one of the best KSP vids that i've seen :D (pre-1.0) What are aerospike engines actually used for? I mean the rocket engines with "good" efficiency in and outside of atmosphere. SSTO's that need more TWR than nukes? edit: i guess they probably weigh waaaaaaaaay less than nukes. That could be a huge factor. --------------- ![[image loading]](http://i.imgur.com/rEt5dht.jpg) Recent trip to minmus~ even with poor and unplanned flying i was able to pick an awkward landing site and hit it very accurately~ This is how my recent spaceplanes look (mostly because i didn't find a better way to keep the center of mass where i want it while spending fuel, probably due to lack of creativity). I used some drop-tanks for more delta-v there. Guess i'l try a landing on duna or eve next? :D Maybe even aerobreaking and a visit to Gilly ^that thing in the background of that pic is a previous plane, not a rock That same plane i was flying earlier, a slightly earlier revision of it when i mistimed an orbital insertion burn and messed up the orbit, eventually being forced to completely re-enter or waste like 1k delta v. I went from almost orbit (150km apoapsis with lots of horizontal speed)to 5km off the ground and 250m/s (on purpose) and then i throttled to full and tabbed out~ i tabbed back in and my plane was actually like 15km up at a good angle, so i took a shot at getting it back up. It made it no problem to a stable orbit :D pretty impressive and resilient beast nukes are very effective even at like 7km, they just can't get off the ground. They have like 1/4 thrust at 0km, 3/4 thrust at 7km but they are so heavy. With basic plane shell, adding a second nuke increased wet mass by ~18% but dry mass by like 45%. I didn't really realize that in the past, i would look at the mass numbers before and after adding the engine with all of my tanks full - having 1.18x as much mass with 2 engines didn't mentally add up to "single engine has >1.3x as much delta-v" at first playing a singleplayer game for hours without ranting about a bunch of mostly useless crap is haaaaardd | ||
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Daumen
Germany1073 Posts
![[image loading]](http://i.gyazo.com/81790553624322f895e18a86bc845ffa.png) used that Orbital Scanner thingy, planet is lighting up: ![[image loading]](http://i.gyazo.com/cb3efbbc51630df69329beb190cafa8c.png) landed right on a highlighted spot but it feels really slow. Am i doing something wrong? should i have landed somewhere thats NOT highlighted? | ||
Epoxide
Magic Woods9326 Posts
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Daumen
Germany1073 Posts
Forgot that Engineers make the mining process faster. edit: Now Im mining from another place, one that was lit up brighter by my scanner, now my mining rate is lower °_° ![[image loading]](http://i.gyazo.com/471f72644cf4c21c3697bad411d6863f.png) so the lit up areas are actually areas with less ore? thats kind of unintuitive :o | ||
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Cyro
United Kingdom20333 Posts
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stenole
Norway869 Posts
There is another scanner that looks like a hexagon which lets you see the ore on the surface underneath your craft. This only works after using the big scanner. It also tells you your coordinates and which biome you are over. You get a better resolution image of where the ore is. I have no idea if there is a lower or higher altitude limit the scanner, but I've never had any problems with it, so I'm guessing not. The last one is a surface scanner which works up to an altitude of 1000m. This tells you exactly how much ore is on the surface under you and works in real time, so you can hover or drive around until you find a number you like. My own impression is that as long as you get to somewhere that has some ore, regardless of quantity, you have access to unlimited fuel. You might have to time warp for quite a bit of time. It's important to bring enough solar panels though because both the drills and converter use a lot of power. Having an engineer on board makes the process go a lot faster. Also remember to have a tank for the ore otherwise you won't be mining anything. I haven't done it too much yet because my missions can usually be done without needing to refuel along the way. But the little I have done has made me learn better how to land next to things that are already on the ground. I'll probably mine more when I finally decide to do a return mission from Eve or if I decide to fully conquer Laythe. | ||
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Cyro
United Kingdom20333 Posts
But the little I have done has made me learn better how to land next to things that are already on the ground. I'd kinda like a minmus mining base, but i'm dreading trying to actually dock useful craft to it :D I just opened game and went from launchpad to mun landing and back to kerbin using craft i built for a newbie friend easy with no worries or even being close to needing a quickload, that was nice. I took off a bunch of mods to make a few stock craft, but i'm immediately missing the SpaceY radial decouplers. They're really useful, adding a bit of room between the two parts you are attaching and then acting as both a decoupler and sepratron | ||
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