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06-25-15, 03:02 PM | #1 |
Ocean Warrior
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I would look at two things (though slapping on some SRB's can't hurt either). How you are getting into orbit (your flight path), and your rocket's design.
Your flight path should follow what is called a gravity turn. http://wiki.kerbalspaceprogram.com/wiki/Gravity_turn Basically what you want to be doing is flying almost straight up for about the first 5,000-10,000 meters, then start to pitch over and gain horizontal speed. by about 25,000 meter you should be flying almost horizontally (make sure your flightpath marker stays at least 5-10 degrees above the horizon). The reason why you fly up first before turning is you want to get through the thickest part of the atmosphere as directly as possible. Flying too fast is also not a good thing (well design rockets have a starting thrust to weight ratio of about 1.2-1.4) as the faster you go the more air resistance becomes a problem. Getting that perfect launch takes a lot of practice. Now for rocket designs, I would suggest sticking to conventional designs. Be sure to use nose caps on the main section+any boosters. Also having multiple stages makes a huge difference. You do not want one big rocket going all the way to orbit as you will be wasting a lot of fuel hauling up empty tanks. If you want to see what i mean, try building two small rockets. one using 2 of the same fuel tank with one engine, launch it straight up, see how high it gets. then take the rocket you built and put a secondary stage in between the two tanks and fly the mission again. Even though the second rocket is much heavier because of the decouple and 2nd engine, it is capable of going a lot higher than the first rocket. This is what i mean by multiple stages http://www.subsim.com/radioroom/show...79&postcount=6 They really do make a huge difference. Scott Manley also has some great video tutorials. https://www.youtube.com/playlist?lis...-O2ak6mBYXWPAL As for the suggestion to use mechjeb... I wouldn't, at least not yet. Learn how to fly first before using mechjeb to automate things. Though in theory mechjeb can teach you how to do some things, it also can teach you a lot of bad habits (there are a number of things that mechjeb does poorly or needs a lot of tweaking to do properly) and it can become a crutch where one can become dependent on it. Plus I think it really detracts from the early fun of first learning how to do things. |
06-25-15, 11:01 PM | #2 | |||
Airplane Nerd
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I haven't quite got the gravity turn downpat yet. I don't know how to figure my thrust to weight ratio. I'm not familiar with any of these equations mainly because my high school dropped Physics in favor of Anatomy and Physiology. I know. Terrible. MIT offers physics courses for free online...i may read through some of that stuff. Quote:
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06-26-15, 06:14 AM | #3 |
Lucky Jack
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Mods wise, this early in the game I'd suggest three things.
Kerbal Engineer - Doesn't automate anything but it does provide lots of information about your craft in both the VAB and during launch (providing certain criteria are met). Kerbal Chatterer - Purely cosmetic, adds random Kerbal voices to the game along with communication beeps and the like. Gives a bit of life to it. Alarm Clock - Think of it as an upgraded 'warp to' function. Can be very useful in later missions when you're planning to head for Duna and the like and you need to fast forward the game to a specific launch window. In regards to finding that launch window, I suggest: http://alexmoon.github.io/ksp/ Which will give you information in order to find the best time to head off to Duna with the least amount of Delta-V. Happy Lithobrakings! |
06-26-15, 08:58 AM | #4 | |
Navy Seal
Join Date: Jul 2007
Location: Stavka
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TWR = (Thrust) / (Mass * 9.81) If you're under a TWR of 1 then your rocket cannot counteract the gravity pulling it down and it'll stay on the launch pad forever (or topple over and explode), so more boosters are clearly needed. As long as you're above 1 you should be able to achieve liftoff. If you're just barely above that then your acceleration might be too low and you'll lose energy because your ship spends more time pushing against gravity, but if you're much above it then you will accelerate too fast and lose energy on atmospheric drag. IIRC the point where extra gravitational drag because of a slow ascent and atmospheric drag balance out is your terminal velocity, but that's a bit hard to figure out. Anyway, you can throttle down liquid fuel rockets or limit the thrust on SRBs until you've found the optimal ascent profile. The other thing that you should know if you want to plan out missions is Konstantin Tsiolkovsky's famous rocket equation, which is something like this: Delta-V = (Exhaust Velocity) * In[Mass Ratio] Your exhaust velocity is the engine's specific impulse times 9.81 and is the basic measure of efficiency when it comes to rockets (a higher exhaust velocity will mean you can accelerate while consuming less propellant). Your mass ratio is the mass of the ship with fuel tanks full divided by the mass of the ship while empty (you can set the amount of fuel in the tanks by right-clicking on them in the VAB, at which point the Engineer's Report should reflect the new mass). Delta-V is the measure of your rocket's total ability to change velocity, which basically amounts to your fuel budget for the mission (unless you re-fuel at a station or something). If your rocket has enough delta-V for a specific mission then under ideal circumstances it would be able to perform it. For example, I believe getting to Kerbin orbit requires a delta-V of 3,500m/s nowadays, so if your rocket is capable of that (and has TWR > 1) then it should be able to make orbit. If it had less than that it would never make orbit, and if it has more to spare then it can go on to do other missions or de-orbit. Calculating the delta-V of multi-stage rockets is unfortunately a bit of a pain, but if you want to do it then you basically need to calculate the delta-V of the entire rocket until the first stage's fuel tanks are dry, then calculate the delta-V of the rocket with the first stage jettisoned until the second stage's fuel is out and so forth until you reach the last stage, at which point you add the results together. Like this: Δv = (Ve1 * In[M / M1e]) + (Ve2 * In[(M - M1) / M2e]) + ... Or something... Anyway, there are probably places that explain all this much better than I do, and naturally Kerbal Engineer would also calculate all this stuff for you as well. But if you don't want to mod the game then knowing how to calculate your TWR and delta-V along with how to execute basic orbital maneuvers should allow you to complete most types of missions without too much trouble.
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Current Eastern Front status: Probable Victory Last edited by Raptor1; 06-26-15 at 09:03 AM. |
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06-26-15, 09:02 AM | #5 |
Navy Seal
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I thought delta v was just the change in velocity required to perform a maneouver
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06-26-15, 09:07 AM | #6 |
Navy Seal
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It is as well. The rocket equation calculates the total delta-V the rocket is capable of. Maybe I got the terminology off somewhere...
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06-26-15, 12:19 PM | #7 |
Silent Hunter
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Not really. It's just a matter of bringing the entire thing up in the air and let it free-fall nose down unpowered. Then just record the velocity on the way down as a function of altitude. That's terminal velocity. So, not hard, but 'costly'. During ascent in the lower atmosphere you should stay under that speed as you rise
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06-26-15, 05:07 PM | #8 | ||||
Airplane Nerd
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Now, for installing these mods, do I use JSGME or just straight up copy them. And will game updates screw with my mods? ------ In other news, I DID IT! Returned from orbit around 0115 this morning. Toyed with a few designs until I decided to build a rocket similar in design to one I saw in the training scenarios. Sure enough, with a gravity turn, I made it into orbit with oodles of fuel. I'm very satisfied. Next mission is a fly by of the "Mun" and I haven't thought much about it at all but i'm wondering how I go about that. Since I don't have maneuver nodes yet....
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06-26-15, 06:19 PM | #9 | ||||
Ocean Warrior
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I don't use CKAN myself though as I tend to mod many of the mods I use, so the last thing I want is some program auto updating everything. Quote:
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06-26-15, 11:55 PM | #10 | ||
Airplane Nerd
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06-26-15, 09:15 AM | #11 | ||||||
Ocean Warrior
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I agree with Oberon's recomendations (other than chatterer, I find chatterer annoying after a while). A while ago I made a post about recommended mods http://www.subsim.com/radioroom/show...&postcount=379 It still more or less applies, though some mods are not updated any more, or there are newer better versions. Anyhow the places to find mods are: http://kerbalstuff.com http://kerbal.curseforge.com http://forum.kerbalspaceprogram.com/...lugins-Library My key mod recommendations are: Active Texture Management Module Manager Toolbar Distant Object Better Atmospheres Kerbal Engineer Redux KSP Alternate Resource Panel Protractor Continued NavHud Docking Port Alignment Indicator Kerbal Alarm Clock Kerbal Inventory System Kerbal Attachment System Ferram Joint Reinforcement TweakableEverything Editor Extensions SCANsat Deadly Reentry Infernal Robotics RealChute Atmospheric Trajectories Landing Height Display NavUtilities RCS Build Aid Transfer Window Planner Precise Node KW Rocketry B9 Aerospace (when ever the heck it gets updated, I would avoid the large ship parts though) All of these mods build on the KSP experience, either by adding new parts, or new features. Its also a fraction of the mods list that I tend to use Quote:
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This is the more accurate definition. Last edited by NeonSamurai; 06-26-15 at 09:26 AM. |
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06-30-15, 08:53 PM | #12 |
Lucky Sailor
Join Date: Oct 2010
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Returning from orbit is easy. Burn retro till your orbit drops below like 50k. Then eventually you land. Some practice runs will add precision.
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06-30-15, 09:06 PM | #13 |
Lucky Sailor
Join Date: Oct 2010
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By pure coincidence....
The other day, I made my first rendezvous with a shuttle to a space station. I've been using the shuttle for satellite insertion and repairs and other utilities. But since I'm using a orbital refueling station around Minmus for interplanetary missions, I needed a way to get kerbals up to the reusable craft. This version of the shuttle has a crew capacity of 20. The small service/escape vehicle also docked can only hold 7, or 3 with cargo. There is a Minmus-LKO shuttle that will transfer kerbals between the two stations. As it turns out, it was on the same day, the anniversary of Atlantis docking with Mir. STS-71 was not only the first Shuttle mission to dock with a space station, but was also the 100th manned flight by the US. Last edited by Gargamel; 06-30-15 at 09:11 PM. |
07-03-15, 11:12 AM | #14 | |
Ocean Warrior
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I think you mean burn prograde against the mun's orbit (ie burn in the direction opposite from the mun's orbital path). |
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07-03-15, 09:11 PM | #15 | |
Lucky Sailor
Join Date: Oct 2010
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Err... ummm... I must have missed a good portion of the discussion. I thought he was having trouble landing from LKO. |
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