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Found 18 results

  1. I understand the dV map to get from Kerbin to LKO is 3400, another 950 gets me to the sun and then 90 more will get me to a fly-by Eve with another 80 to get into orbit and 1350 to circularize just over the atmo. So to get into orbit of Eve I would need 5850 (plus margin) to simply get to the orbit of Eve. If I want to return from Eve to Kerbin what parts of that do I need to account for? Do I need to add the whole thing back or can I forget that 1330 that was used to circularize?
  2. I usually don't mind calculating Delta-v for missions on my own, but this seems to be a really useful tool. In my opinion would be a great addition to the enhanced edition for new and old players. Hope @SQUAD is considering adding this to a future update. Here is the discussion posted by @UomoCapra
  3. Hello! Firstly, I know questions like this one have already been made both in and out of the forums before, yet every thread I found and read do not fix my problem or give me an idea of what I'm doing wrong. Also, sorry if this ends up a bit too long and technical, I want to try and make it as clear and detailed as possible, especially when explaining the math I did, so it doesn't confuse or give the reader a headache. So... I finally decided to play KSP [more] seriously, disabling "revert flight" and trying to calculate the rocket performance and everything else before launch to minimize failures. I'm playing the Enhanced Version for the Xbox, which should be pretty much a 1.2 stock for PC. The rocket I have is comprised of two stages: the first one has 3 engines, a center Swivel one (with 2 FL-T800s on top), and two radially mounted Reliant engines in an asparagus setting (so they have one FL-T800 on top each, with both of these fuel tanks feeding into the center one directly above the Swivel - this way, once the radial tanks are expended, they will be jettisoned with the Reliant engines). The second stage is the orbital stage, having a single LV-909 Terrier with a FL-T400 on top (will talk about it later on). The goal of this rocket is to carry scientific equipment to a space station at a 200km circular orbit over Kerbin, where it's currently being assembled for a mission to Minmus. The problem I initially has is that the Delta-V calculation I done for the first stage gave me a result of ~1899m/s², which theoretically should not have been enough to allow me to leave Kerbin's atmosphere (as "Delta-V out" of Kerbin is 2500m/s²). Yet, I managed to dock with the intended station with about 60% of fuel remaining in the second stage (no cheats involved, I swear). I've done all the calculations based on what's available at wiki.kerbalspaceprogram, making use of the "Advanced Rocket Design" and "Cheat Sheet" topics. Will go over the math now: Starting up, I calculated the average Isp of the three engines at sea Level, which was pretty much: (F1+F2+F3/(F1/Isp1)+(F2/Isp2)+(F3/Isp3) being F=Thrust at sea level. This gave me an AvgIsp of 261 (which I called Isp1). Right after, I got the total mass of the craft (M0=28556t) and the first dry mass (aka: the mass with empty radial tanks before dropping them and the Reliants; which I called M1=20556). I also calculated the new mass right after dropping the radial tanks and with full center tanks and swivel engine (M2=16646); and dry mass for empty center tanks (M3=8646). Based on this, I calculated 2 delta-Vs for the first stage: Delta-V1, while both the Reliants and Swivel were firing; and Delta-V2, after the Reliants were dropped and only the Swivel was firing and taking fuel from it's own tanks now. So, Delta-V1 = Isp1(261)*g[9,81]*ln(M0/M1)[0,32] obtaining a value of ~819m/s². Did the same for Delta-V2, calculating the Isp2 for the Swivel only part of the flight, for which I got an Isp2 of ~167.9; then Delta-V2 of 1070m/s² I then made the sum between both Delta-Vs, obtaining that nasty odd value of ~1889m/s². As for the second stage, it gave me a Delta-V value of 276.6m/s², adding the whole sum to 2175m/s² (which shouldn't even be enough to take me out of Kerbin's atmosphere, let alone docking. The whole flight from Launch to a circular 200km orbit should require ~4844.88m/s², more than twice what I had! Some thought and considerations (and questions): 1. I know the Delta-V I calculated is lower than the real Delta-V, since, for all the first stage engines, I only accounted for the Sea Level Isp and ignored the Vacuum Isp - while in reality the higher I went, the more Isp I'd have, thus increasing my Delta-V - although I don't believe it would have such an impact on the Delta-V. 2. I tried being efficient during the atmospheric flight, avoiding overspeed and unnecessary drag, which caused me to lower the throttle quite a bit (especially while the 3 engines were firing) and in turn increase the engine-on time, resulting in more Isp since I was ever higher with the engines on. This goes back to point 1, since I only considered Isp for Sea Level even though half of my fight happened at high altitude / low pressure / higher Isp environments. Could this also justify the Delta-V discrepancy? 3. Is there a way I can calculate Isp at an specific altitude so I can be more accurate (instead of only taking into account the Vacuum Isp for the 2nd/orbital stage and ASL Isp for the first stage)? 4. I tried repeating the math but assuming I'd not fire the Swivel until the Reliants were dropped. In the end it gave me a noticeably higher Isp and Delta-V, although still not as high as theoretically necessary. This is kinda odd though, shouldn't firing all engines together but feeding only from the radial tanks be more effective? Thanks. Would love to hear what I've been doing wrong and hope I didn't give too much headache to people trying to read this. (And yes, I'm super jealous of you PC players with all the fancy Kerbal Engineer calculating stuff!) Cheers.
  4. I have decided that after spending almost 600 hours in the game (595, should be 600 by the time I'm done tonight) it's finally time. I have never learned ∆v. All I know (and this could even be wrong, i'm really quite clueless) is that ∆v is the amount of acceleration/deceleration (although deceleration is acceleration technically) a ship or stage of a ship (or anything really) is capable of with it's current mass, fuel, fuel efficiency, and thrust. please, if I am wrong, correct me. what I would like to know is how to properly calculate the ∆v needed to make it into a specific orbit, how ∆v can be calculated for any given ship you may make, and anything else important to know about ∆v. I am by no means a noob at KSP, but also by no means an expert, to give you a feel for where I'm at in terms of ability, in career mode I have landed Kerbals on Duna and Eve, crashed a probe into Eeloo, done single ship return missions to both Minmus and Mun, I have landed a class C asteroid on Kerban using only 1 ship, and in terms of aircraft, i have flown around Kerban using a single drone without refueling, and landed back at KSC (technically I plowed into the hangar at about 450 m/s as a celebration, but i've landed that exact drone 4 other times out of 5 attempts, so I could have landed it if I wanted to). I never really bothered with ∆v because I was usually able to ignore it, and just build the ship so that it looked like it would be good enough to make the trip, then I would launch under the personal decision that regardless of the failure or success of the mission, I would revert the flight after (I called these flights my simulator flights, and I considered them to not be real, that way it was a test, to see if my ship could do what it needed to do) then after a successful simulator flight I would launch for real, and regardless of success or failure, I would not revert after the flight. using that method ∆v wasn't ever NEEDED. With the addition of certain ∆v based aspects of the game in the latest update, I decided the time had come for me to finally learn how it works, and start applying it to my space program. Many thanks, -Water
  5. Here are images from the first time I played KSP 1.6.1, which I started playing today! (I previously had played 1.2.2 and 1.4.2)
  6. Hello everyone, after a few months I have recently started playing KSP again and for the first time I have now decided to deal with interplanetary spaceflight that goes beyond Eve and Duna. For that I now first used the Nerv engines as they are so efficient. I have built a few in my opinion quite nice spacecrafts after watching many videos on youtube and I successfully landed on Dres and even Moho already (without returning though). However during these missions and also my current mission to Moho with a new or modified spacecraft I ran into a problem that didn't seem to occur in the videos I've seen. I don't know if it's somehow caused by the Nerv engines or whatever but whenever I set a maneuver, no matter how big it is, the curved Delta v bar to the right of the navball is completely or half red and the estimated burn time is completely wrong aswell. When I start my burns at about half the time to the maneuver as the estimated burn time so that the burn splits into 2 equal sections before and after the maneuver node, my resulting orbit is quickly WAY off the planned one. I didn't find out how to add screenshots but my burn is about 600 delta v and I have about 7000 with my current spacecraft. Does anyone know what's the reason for this .... bug? This way I can't go to Moho or at least it's never as efficient as in the videos I've watched.... annoying
  7. Is there a ΔV map of the Kerbol System with the OPM planets at 6.4x scale? I was able to find them seperatly (IE OPM ΔV map and a 6.4x ΔV map) but none with both. If there is not does anyone know how I would determine the change in ΔV for a scale factor of 6.4?
  8. the idea came into mind when i saw tons of different kopernicus mods that replace kerbin system, here is what i wondered, isn't there a way to calculate those nasty delta V numbers based on the info "In game" and produce a kerbal in game wiki like system for them? why not? knowing enough about unity programming, i know that if you do smart job, you can instantiate different prefabs (including GUI stuff) on the fly, why not being able to make the ingame wiki more flexible for these type of things? ok, maybe ingame's already existing one is a bit bad idea simply because it may need tons of reflection in programming and more... but a mod that behaves just like ingame wiki? dedicated to get different info from the configs and ingame and calculate and show all the available info "procedurally"? this way, the mod developers wouldn't need to sit and do all the nasty calculactions for the delta v map and many more stuff like geosync orbits and lots of other things
  9. Maybe I'm missing something obvious here, or maybe it's not possible for some reason, but can anyone tell me how to get Mechjeb to show the amount of delta v per stage independent of other stages in the VAB? What I mean is, let's say I have my main payload stage, which has 1000 delta-v. Mechjeb shows this correctly in the VAB. But when I add a booster stage, let's say it has delta-v of 2000, the delta v of my first stage will be lower (ie, as if it was trying to push the full weight of the craft, including the booster stage), maybe 750. Likewise if I add another booster stage, let's say solid rockets, with a delta-v of 1500, both previous stages will show lower delta v values again. It makes it quite difficult to calculate how much total DV I have, because rather than telling me I have the 3500 total for my booster stages, and 1000 for my main craft, it may show 1500 for stage 1, 1000 for stage 2, and 300 for my main craft... Am I making sense? As I say, maybe I'm missing something obvious, but if anyone could clue me up, I'd appreciate it...
  10. Hello! I have recently gotten into calculating the delta V of all my rockets, just for fun , and have come across a problem. I have some rockets where the first stage is a liquid fueled engine and 2 SRB's. The basic equation assumes that all of the boosters burn out at the same time. However, in this case, the SRB's burn out first, while the liquid-fueled portion of the stage continues burning. Is there any perfect equation for this calculation?
  11. Hi Guys, I'm having some issues with mechjeb. I have the majority of features that are available, but as of a few days ago the delta V calculator has disappeared. This has significantly affected gameplay and I'm wondering what the cause would be. I'll link to a list of my mods - http://imgur.com/gallery/dDAJB. Thanks Daniel
  12. Just a quick one for you guys, is there a mod to calculate a vessel's current delta V in flight? Previously I uses Kerbal Engineer, I did install it under 1.2.1 but it seems it doesn't take account of the new way fuel is handled in 1.2 - my spaceplane has nukes but they are not part of the same stack as my liquid fuel tanks, as there are no fuel ducts, kerbal engineer doesn't seem to realise that fuel can get to those nukes, so assigns me a very low delta V value. I'm in a career game and just flew this Whiplash/Dart/Nerv contraption to orbit. I was hoping to go to Gilly as it's Bill's first trip to space. I've developed an aversion to docking maneuvers and was hoping i wouldn't need to refuel the thing. We got 2709 LF remaining and are currently massing at 36.86T.
  13. How much does a kerbal EVA suit have delta v?
  14. Alright. Let me make on thing clear. I know how to calculate delta v. I have the math done and burned into my head. But I cam across a problem, how do I get the ISP, for different engines on the same stage? So say if I have a "MainSail" and a "Thud" sharing the same fuel on the same stage, how to I get the ISP to put into my formula?
  15. How much Delta-V is needed in Keribn orbit (100km) in order to arrive at the Jool system with a reasonable amount of delta-v for navigation? Every time I send a craft to Jool, I get there and either shoot right out of the system, crash into Jool or a moon, or end up stranded in a ridiculously useless orbit. At the moment I have some frogs stranded on/around Pol and it seems like getting there was a fluke. Appreciate any assistance! (PS- It doesn't help that once you enter the Jool system, Jool itself becomes untargetable)
  16. So, I looked up delta V and apparently its basically synonymous with acceleration. So what is all the fuss with Delta V readouts etc? Why are Delta V readouts necessary?
  17. The calculation is dv = ln(MStart / MEnd) * ISP * 9.81 But why is that 9.81 in there? I assume that it is the acceleration due to gravity on Kerbin and Earth (or it could just be a 1-in-100 coincidence). Is the calculation different on Jool (or Mars?) where the acceleration due to gravity is completely different? Is there a reason that the specific impulse isn't just quoted as 9.81 times higher and then we just drop the "* 9.81" from the equation?
  18. Given a payload of: 1 Mk1 Command Pod (with 10 units of mono propellant) 1 Mk16 Parachute 1 TR-18A Stack Decoupler Create a working, multi-stage rocket by adding up to 100 more parts (for a total of up to 103 parts) to generate the most (vacuum) delta-V possible, with these restrictions: You must use stock parts. You may not use mods that alter the physics of the game or augment the abilities of stock parts. Things like KER and Mech Jeb are fine. You must be able to achieve stable Kerbin orbit, launched from KSC. My expectation is that you can achieve this orbit with 3200-4500 dV. Designs that fall outside of this range may be disqualified. You may not use jet engines. Use of ion drives is OK, but you must meet the power requirements for continuous burn. The total burn time for the entire vehicle must be 2 hours or less, but feel free to use multiple engines to lower your burn times. You may use the FTX-2 External Fuel Duct, but may not transfer fuel by hand.