EPTKerbal Engineer doesn't like my ship either... at some points it's just given up and said 0 TWR when I'm flying normally.
Ah well, still have things to figure out. On the plus side of things, infiniglide is dead.
Kerbal Space Program - Page 35
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felisconcolori
United States6168 Posts
Kerbal Engineer doesn't like my ship either... at some points it's just given up and said 0 TWR when I'm flying normally. Ah well, still have things to figure out. On the plus side of things, infiniglide is dead. | ||
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Cyro
United Kingdom20322 Posts
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Cyro
United Kingdom20322 Posts
+ Show Spoiler + ![[image loading]](http://i.imgur.com/wK64aNB.jpg) ![[image loading]](http://i.imgur.com/JCsu5ik.png) ![[image loading]](http://i.imgur.com/zjSX4zh.png) ![[image loading]](http://i.imgur.com/wnhGFbo.png) center of lift is too far forward when fuel is low, i will keep that in mind for edits and future designs. My plane with COM that falls forward onto the center of lift @0% fuel flies a lot better | ||
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felisconcolori
United States6168 Posts
How large of a payload can it lift? And is there a reason why I'm not seeing a lot of Mk3 parts in successful spaceplanes? (I know that EJ_sa's not flying his shuttle currently, as it appears it no longer functions well.) | ||
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Cyro
United Kingdom20322 Posts
To a 75km circular orbit.. maybe a mk.2 fuel tank or two (regular size, like the two in the middle of the plane) so not much at all. The engines stopping working well at so low heights really hurts. If you make an orbital trajectory, your engines will cut off and then you have to drag through the atmosphere from ~15km-30km and lose hundreds of meters per second. Going too steeply gave me worse results than going up more sharply, but if you go up too sharply you need like 1km/s of delta-v to circularize entirely from oxidizer and it's all a mess. If i took off the side wing engines, i don't think it'd be able to easily break through mach 1. I saw a graph recently, the drag there is actually drastically higher than at mach 1.1 and if you can't get some more airspeed, your engines won't give more thrust and you're stuck at mach 0.95 all day instead of 3.5x faster ^that craft does have ZERO staging though. | ||
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felisconcolori
United States6168 Posts
I think I'll try a ridiculous pancake rocket to see if they have actually become totally useless. | ||
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Cyro
United Kingdom20322 Posts
I think I'll try a ridiculous pancake rocket to see if they have actually become totally useless. Not useless, but less efficient - especially if you have a decent TWR (like 2.5) You can watch the atmospheric efficiency display in kerbal engineer. It gives you your speed as a % of terminal velocity. The moment you stage, you can see it jump - so it might say 150% then drop to 30% when you remove some huge stuff sticking out of the sides of your rocket. For fuel-efficient ascent, you'd vary your thrust to keep it above 85% but below 100% at all times AFAIK. A kick to get off the launchpad is nice (some rt-5 clusters that burn and detach almost immediately are good, you don't need to worry about them being aerodynamic as there's little air resistance going from 0m/s to ~250m/s) and then it's fairly reasonably easy to stay at >90% of terminal velocity for ~2km-15km, but after that the more thrust, the better. The faster you're going, the less energy you are wasting to gravity and the more effective your thrust will be due to the oberth effect and they actually has a fairly huge impact on your ability to set an orbit - it's visible when comparing 0.5 TWR to 2.0 TWR to 6.0 TWR  (in-flight TWR is higher than initial because of fuel consumption, check it out on kerbal engineer display)Since terminal velocity is much higher with a thinner rocket, it's probably best if possible to have a fairing (or nose cone) and then have it go down in a stack, i think, with nothing huge (like big size fuel tanks) sticking out of the sides. That does limit your ability to do stuff like asparagus staging though, which is still extremely powerful. If you stack straight down, there's nowhere to put more engines so you can easily have less thrust than desired | ||
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felisconcolori
United States6168 Posts
On May 10 2015 11:24 Cyro wrote: Since terminal velocity is much higher with a thinner rocket, it's probably best if possible to have a fairing (or nose cone) and then have it go down in a stack, i think, with nothing huge (like big size fuel tanks) sticking out of the sides. That does limit your ability to do stuff like asparagus staging though, which is still extremely powerful. If you stack straight down, there's nowhere to put more engines so you can easily have less thrust than desired Well. I can get three orange tanks to orbit full with only a little effort. This one is being a little more difficult, but I think if I can solve the spent boosters slamming into other portions of the rocket on the tricky stage 4, it could get much more to orbit. Also, launching is touchy - light the engines, then must QUICKLY release the launch clamps (I could stage the engines and clamps at the same time, I guess) or my rocket launches out of the flames of my exploding launch pad. + Show Spoiler + ![[image loading]](http://i.imgur.com/V4WN5iX.png) This is a night launch. The launchpad did not survive. ![[image loading]](http://i.imgur.com/xjD7ZhK.png) ![[image loading]](http://i.imgur.com/wdEdEba.png) The view from below - the asparagus staging is tricky to get that circle, because there is one unmatched stack that has to feed into the next stage and then across a small gap to the stack on its right - not enough space for another stack in there to keep it "even" and fully symmetrical. ![[image loading]](http://i.imgur.com/btkggvG.png) Post-launch in the daylight. Viewed from above, with data. The current issue comes in when the "T" at the end of the main six spokes releases both side tanks at the same time. Inevitably there's an unbalanced collision of the dropped spent stacks into one of the arms. Oh, and SAS? That's turned off pretty quickly as the "gyrating" to keep it in one spot induces lots of wobble I can avoid by manually nudging it. Why build this? No reason - putting fuel into orbit. | ||
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Cyro
United Kingdom20322 Posts
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stenole
Norway869 Posts
On May 10 2015 08:48 Cyro wrote: I made a new plane today. Can carry a payload to a stable orbit, i'm not sure how high - but not a very big one. Parts count is too high to fly comfortably, the game runs ok but the physics get more and more wonky as you add more stuff. Cool plane. On May 10 2015 09:11 felisconcolori wrote: And is there a reason why I'm not seeing a lot of Mk3 parts in successful spaceplanes I think it's mostly a problem of scale and how they will fit awkwardly with other parts. Mk3 parts are so much heavier than mk2 but only really offer twice as much area real estate for engines. So you are forced to be more creative when placing the extra engines you need. In the same way you need more wings, but the old 0.90 wings are a little flimsy and the new mk3 wings make for bad building blocks for building bigger wings. If you want things to look pretty you also need to use the adapter parts which are also bulky and parts don't clip on nicely to them. In order to keep the large plane from flexing too much and breaking apart when landing you need lots of struts. The end result is that you get a high part count which can cause the game to run slowly. What I've seen from other people's spaceplanes is they don't make planes that deliver cargo to orbit, but instead fly to other worlds. So if you don't need the mk3 cargo bay, why not use parts that are easier to build with. Personally, I don't think it makes a lot of sense to carry around air breathing engines and wings in space. On the plus side, mk3 parts hold the most fuel per ton of the tanks in the entire game (mk2 almost holds the least per ton being almost as bad as the oscar and donut tanks). On May 10 2015 12:39 felisconcolori wrote: Why build this? No reason - putting fuel into orbit. Seems like a great reason to me. Sometimes, you want to refuel in space instead of sending a giant craft into space with its own fuel. | ||
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felisconcolori
United States6168 Posts
On May 11 2015 01:17 stenole wrote: I think it's mostly a problem of scale and how they will fit awkwardly with other parts. Mk3 parts are so much heavier than mk2 but only really offer twice as much area real estate for engines. So you are forced to be more creative when placing the extra engines you need. In the same way you need more wings, but the old 0.90 wings are a little flimsy and the new mk3 wings make for bad building blocks for building bigger wings. If you want things to look pretty you also need to use the adapter parts which are also bulky and parts don't clip on nicely to them. In order to keep the large plane from flexing too much and breaking apart when landing you need lots of struts. The end result is that you get a high part count which can cause the game to run slowly. What I've seen from other people's spaceplanes is they don't make planes that deliver cargo to orbit, but instead fly to other worlds. So if you don't need the mk3 cargo bay, why not use parts that are easier to build with. Personally, I don't think it makes a lot of sense to carry around air breathing engines and wings in space. On the plus side, mk3 parts hold the most fuel per ton of the tanks in the entire game (mk2 almost holds the least per ton being almost as bad as the oscar and donut tanks). Seems like a great reason to me. Sometimes, you want to refuel in space instead of sending a giant craft into space with its own fuel. That's what you can't see underneath the fairing at the top. It's got a probe core, Sr. Docking port, some RCS, and solar panels. I put it into orbit, then leave it there with all the fuel available for future missions or emergency topping up. Also makes for a cheap refueling station or interplanetary propulsion section. I'm thinking, with the amount of dV that's still in orbit, I could make a pretty sloppy transition to Moho and still manage to get into orbit. The strength of the Mk3 part node attach (or lack of it) seems like a pretty significant thing. But the Mk3 wet wings and the cargo bay are pretty important to the shuttle enthusiasts out there. You're right, they don't really scale well when you're looking at larger craft - and making large wings from wing parts can be all kinds of pain, as the stock Stearjet shows so painfully. | ||
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nimbim
Germany985 Posts
+ Show Spoiler + ![[image loading]](http://i.imgur.com/SAxtK7a.png) | ||
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Cyro
United Kingdom20322 Posts
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Epoxide
Magic Woods9326 Posts
On May 11 2015 06:45 Cyro wrote: So~ how do you actually get to asteroids and fly them around? Do they have much mass? You need to upgrade tracking station twice, track an asteroid, and yeah the biggest ones are extremely heavy. | ||
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Cyro
United Kingdom20322 Posts
I kinda took a break from building rockets for a while, now i'm having an issue with side-attached engines smashing into the rest of the rocket after detaching. The hydraulic detachment manifold seems to have insufficient force for big parts in atmosphere. I was looking to make a reasonably big (but simple) rocket using parts just bigger than mk.1 with ~5km/s (ish) of delta-v for someone new to the game. Maybe more vertical staging | ||
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Epoxide
Magic Woods9326 Posts
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nimbim
Germany985 Posts
On May 11 2015 07:52 Cyro wrote: Would it be worth dragging one to orbit to mine for fuel or is it easier to just dump huge fuel tanks with docking ports up there? I kinda took a break from building rockets for a while, now i'm having an issue with side-attached engines smashing into the rest of the rocket after detaching. The hydraulic detachment manifold seems to have insufficient force for big parts in atmosphere. I was looking to make a reasonably big (but simple) rocket using parts just bigger than mk.1 with ~5km/s (ish) of delta-v for someone new to the game. Maybe more vertical staging Launching some orange tanks to orbit is significantly easier. Getting a big asteroid (they have only limited ressources, so you'd want a type-E for a refueling station) into a precise orbit is a real pain, turning them is a struggle, getting the camera in the direction you want is annoying because the center of mass will be inside the asteroid while you are attached to it. It's just a question of would you rather launch fuel tanks again and again or combine an asteroid redirection contract with building a refueling station. Something to keep in mind is how laggy it gets once you combine something heavy like a station with multiple ports and some stocked fuel with a heavy asteroid. I built this station when asteroids first came out, but it got eaten by the kraken shortly after I finished construction and I made no quicksave after I attached the type-D (which took about 40minutes from a 500m rendezvous to docking)  + Show Spoiler + ![[image loading]](http://i.imgur.com/ZByPqPB.png) ![[image loading]](http://i.imgur.com/K6FLsBi.png) total mass: 3200t For your staging problem, I'd try sepatrons, but don't point their exhaust at your rocket, rather shoot them off sideways. Also, you can try to attach the decoupler directly at the center of mass of the empty fuel tank, otherwise it may flip in one direction or the other and destroy the rocket. | ||
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Cyro
United Kingdom20322 Posts
For your staging problem, I'd try sepatrons Ahh yes. Fuck, those things exist | ||
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Cyro
United Kingdom20322 Posts
I made a rocket with rapiers and put 16 of them on - but the TWR was too low to get anywhere near breaking the mach 1.0 air resistance cliff. I couldn't add more, because there was nowhere to put them - the entire cross section of the rocket was just rapier exhausts. If i stuck more out the sides, i'd be increasing resistance and maybe not actually helping?~ (perhaps it's doable if you build a rocket and then use an adapter to get the base of the rocket bigger than the fuel tanks you're using above, but that would still drag a lot) Everything cool generally seems to be small (with like 3-5 rapiers) or big (with like 20+) and i'd just like a version that's like four times as big with eight times more kick | ||
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felisconcolori
United States6168 Posts
I think using an asteroid to refuel might be workable but it'd have to be pretty situational - in a lot of cases, you can just as easily land on the body you're going to find them around and mine that for fuel. The fuel mining capability should make it a little bit easier to land on and take back off of places like Tylo and Laythe, though. The landers I had built in the past for those planets were monster rockets capable of getting orbit from Kerbin unassisted. | ||
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