SHaFT7 Posted January 9, 2014 Share Posted January 9, 2014 (edited) Perhaps you can also post the exact settings you entered into the calculator (or just a screenshot ).the checkbox says KW rocketry, but it was done with NovaPunch and Stock Parts Edited January 9, 2014 by SHaFT7 Link to comment Share on other sites More sharing options...
blizzy78 Posted January 9, 2014 Author Share Posted January 9, 2014 (edited) This seems to work fine for me (click for full image). Perhaps you didn't set up fuel lines or stages correctly?MechJeb must have gotten confused, so I did it again. Now I have the correct amount of engines, and the dV is a bit lower. But everything seems to be correct. Edited January 9, 2014 by blizzy78 Link to comment Share on other sites More sharing options...
SHaFT7 Posted January 9, 2014 Share Posted January 9, 2014 odd. I know the fuel is correct. My payload is is 334t. that goes into making the 2333ton total right? or is the 2333t supposed to be without the payload? Link to comment Share on other sites More sharing options...
blizzy78 Posted January 9, 2014 Author Share Posted January 9, 2014 (edited) My payload is is 334t. that goes into making the 2333ton total right?Yes. With the settings you entered into the calculator, it would be350 t payload + 1983 t lifter = 2333 t total Edited January 9, 2014 by blizzy78 edited the quote so that my answer actually answers the question it was intended to Link to comment Share on other sites More sharing options...
SHaFT7 Posted January 9, 2014 Share Posted January 9, 2014 (edited) then can you tell me what's up with this .craft? I must be missing something simple...https://dl.dropboxusercontent.com/u/5421261/KSP/350t%20Lifter%20NP%20stretchy.craftI found one thing strange. As I am working with stretchy tanks, the fuel to oxidizer ratio moves from 0.818181 to other values, causing an inbalanced burn during take off. tanks don't drop as they should. I'm trying to edit it via the action groups, but it's still not getting the dV anywhere close to yours. I even redid my payload as a single stretchy tank weighing 350t. I completely redid the stacks again just to make sure I had it right. It still doesn't come out correct.here's a copy of the craft file with the fuels edited to the proper 0.8181 ratio: https://dl.dropboxusercontent.com/u/5421261/KSP/350t%20Lifter%20NP%20stretchy2.craft Edited January 9, 2014 by SHaFT7 Link to comment Share on other sites More sharing options...
blizzy78 Posted January 9, 2014 Author Share Posted January 9, 2014 then can you tell me what's up with this .craft?I can't load that because it uses some parts I don't seem to have. Link to comment Share on other sites More sharing options...
SHaFT7 Posted January 9, 2014 Share Posted January 9, 2014 (edited) I can't load that because it uses some parts I don't seem to have.the second craft should just use mechjeb, stretchy tanks (the v8 continuation), novapunch, and stock parts. the first one also uses TAL's spherical tanks.EDIT: I forgot that it also uses the radial super decouplers from mobius rocket works: http://forum.kerbalspaceprogram.com/threads/39049-Mobius-RocketWorks-Engine-Mounts-and-Parts?highlight=mobius Edited January 9, 2014 by SHaFT7 Link to comment Share on other sites More sharing options...
blizzy78 Posted January 9, 2014 Author Share Posted January 9, 2014 I'll post my craft tonight when I get back from work. I can't comment on the LF/OX ratio in StretchyTanks, I still use the original release 1.2.2, not the StretchySRB continuation by NathanKell. Link to comment Share on other sites More sharing options...
blizzy78 Posted January 9, 2014 Author Share Posted January 9, 2014 This is the craft I had been building: https://www.dropbox.com/s/fi4a9jmij9jnsbz/350%20t.craftIt uses only MechJeb, StretchyTanks, and the NovaPunch engines as suggested by the calculator. Link to comment Share on other sites More sharing options...
SHaFT7 Posted January 9, 2014 Share Posted January 9, 2014 (edited) thanks i'll try it out.EDIT: Now this is weird. I loaded up your craft and immediately got this:also the staging was all screwed up. After fixing it, and touching nothing else, I still only got ~3500dV, which is pretty close to my craft.hmmmmmEDIT2: I tried loading up the other stretchy tank mod I found, 0.2.2, but it was worse and missing several parts. no idea what's going on.EDIT3: I went back and added a whole second ring of the same booster segments and got the dV up to 4570m/s. while this is enough (barely) for orbit, i'd still love to know why my setup shows such different numbers than yours. Edited January 11, 2014 by SHaFT7 Link to comment Share on other sites More sharing options...
SHaFT7 Posted January 11, 2014 Share Posted January 11, 2014 here's another one, completely stock except + mechjeb.dV is still WAY off. Link to comment Share on other sites More sharing options...
blizzy78 Posted January 11, 2014 Author Share Posted January 11, 2014 here's another one, completely stock except + mechjeb.Please post the craft file. Also, is your MJ up to date? Link to comment Share on other sites More sharing options...
SHaFT7 Posted January 11, 2014 Share Posted January 11, 2014 (edited) running v 2.1.1.0-161. updated yesterday.www.lancekeltneronline.com/ksp/Fail%20Lifter.craftUPDATE: I started a new game with only MJ as an addon.same ship, less mass, more dV. something is wrong with my addons...UPDATE2: my ModularFuelTanks v4pre10 was causing the issue. updating to 4.1 put the dVs back where they should be.sorry for the bother, it was me all along! Edited January 11, 2014 by SHaFT7 Link to comment Share on other sites More sharing options...
Michael_ Posted January 16, 2014 Share Posted January 16, 2014 This is one of the best improvements to KSP I've ever used. Thank you so much for putting it together. How difficult would it be to let users specify a dV? I am working backwards toward the number by just lowering the payload fraction and trying the setup, but that takes much longer than just going with something reasonable. The design phase is my favorite aspect though, so I enjoy it nonetheless.I would also love to see additional optimization strategies than those you've got--or to have a better understanding of what they mean. Right now, if I calculate for best TWR, does that mean closest to the top of the range I specified? If so, why is that important since any value inside that range must be acceptable? Would it be difficult to add a calculate for isp in a vacuum option? Or average isp over all stages within the model (i.e. all stages described by the app, so ignoring payload stages). Also, is the center stack size a drop down to avoid calculation time complications? I always wonder whether I ought to jump up to a 3.75 and end up re-running calculations in any case. Again, thank you so much for this tool! Link to comment Share on other sites More sharing options...
Michael_ Posted January 16, 2014 Share Posted January 16, 2014 This is one of the best tools for KSP I've ever used. Thank you so much for putting it together. How difficult would it be to let users specify a dV instead of a payload and payload fraction? I am working backwards toward the number by just lowering the payload fraction and trying the setup, but that takes much longer than just trying something reasonable to start with, but I want to use what you've put together. The design phase is my favorite aspect though, so I enjoy it nonetheless.I would also love to see additional optimization strategies than those you've got--or to have a better understanding of what they mean. Right now, if I calculate for best TWR, does that mean closest to the top of the range I specified? If so, why is that important since any value inside that range must be acceptable? Would it be difficult to add a calculate for isp in a vacuum option? Or average isp over all stages within the model (i.e. all stages described by the app, so ignoring payload stages)?Also, is the center stack size a drop down to avoid calculation time complications? I always wonder whether I ought to jump up to a 3.75 and end up re-running calculations in any case. Again, thank you so much for this tool! Link to comment Share on other sites More sharing options...
blizzy78 Posted January 16, 2014 Author Share Posted January 16, 2014 How difficult would it be to let users specify a dV instead of a payload and payload fraction?The calculator is only intended to produce lifter setups. I take it you don't want to go into low Kerbin orbit, but go higher up. In that case it might be easier to just add an additional transfer stage that takes you from LKO to a higher orbit. As far as the calculator is concerned, that transfer stage would factor into the payload.Right now, if I calculate for best TWR, does that mean closest to the top of the range I specified?Yes. "Best TWR" will give you the result of all possible combinations that has the best TWR, while all other parameters must still be met.If so, why is that important since any value inside that range must be acceptable?Of course "best TWR" doesn't have much use, since the specified range must still be met. I just put it in there regardless. The other options are more interesting.Would it be difficult to add a calculate for isp in a vacuum option? Or average isp over all stages within the model (i.e. all stages described by the app, so ignoring payload stages)?I don't think I will add anything complicated. Perhaps an interesting choice would be something like "best Isp @10 km" or something like that, but not averaged over the entire ascent.Also, is the center stack size a drop down to avoid calculation time complications?Yes, for one, widening the restriction for a specific center stack size opens up alot of engine combinations, so calculation time is definitely an issue here. Second, you may want to impose such a restriction for whatever reason. Link to comment Share on other sites More sharing options...
Michael_ Posted January 16, 2014 Share Posted January 16, 2014 This is much more helpful than other attempts (which seem...too similar) but I'll watch for any updates. Thanks again. Link to comment Share on other sites More sharing options...
Surefoot Posted January 29, 2014 Share Posted January 29, 2014 What is the "true radial engines" checkbox for ? Link to comment Share on other sites More sharing options...
blizzy78 Posted January 29, 2014 Author Share Posted January 29, 2014 This checkbox will restrict calculations to only consider radially mounted engines for the "radial" spot. If you don't check it, it will also consider smaller regular engines, like the LV-T30. Link to comment Share on other sites More sharing options...
Surefoot Posted February 1, 2014 Share Posted February 1, 2014 Thanks. Played with it a bit, found a problem with one design:payload 126tpayload fraction 30%twr 1.8 to 3.0 (that's for an Eve upper stage)center stack size 3.75mboosters 2 - 6max center outer engines 4center radials 0 0max booster outer engines 4booster radial engines 0 4only "true radial engines" checkedi calculate for best ISP, with stock, KW and NovapunchResult ends with center stack having a Bearcat with 3x 48-7S, which is quite not enough to propel its own weight along the top payload - TWR is maybe 0.8 at best and of course way under the 1.8 that i need for Eve. Once i drop the side boosters the craft drops like a stone.Shouldnt the center stack respect the min. TWR ? (i went around that by replacing that cluster with a KW Titan, but that's maybe not optimal) Link to comment Share on other sites More sharing options...
blizzy78 Posted February 1, 2014 Author Share Posted February 1, 2014 Your payload fraction is way too high. You will get a result that should work much better with a payload fraction around 15%.Shouldnt the center stack respect the min. TWR ?No. The TWR constraint is only for the complete vessel, ie. at liftoff. As you get further out of the atmosphere, the TWR doesn't matter as much, since there is less drag. In space, it is essentially irrelevant as long as it is >0. Link to comment Share on other sites More sharing options...
Surefoot Posted February 1, 2014 Share Posted February 1, 2014 (edited) Yeah i know, right. This was just for one of the upper stages of my Eve lander-lifter. 126t is actually 2 other stages above that one. With your tool i tackle multi-stage by considering the stages above as payload - that's why i dont need to have 15% payload fraction (also i use FAR, i can get around 21% payload fraction on Kerbin and get to orbit.. and for Eve it's more like 3%).That's why the middle stage not respecting the min. TWR is a problem here, and i suspect for other lower stage calculations. With 15% fraction my stage would be too heavy (i am trying to balance the whole thing, it has to be able to land.. also FAR punishes unwieldy designs) Edited February 1, 2014 by Surefoot Link to comment Share on other sites More sharing options...
Streetwind Posted March 31, 2014 Share Posted March 31, 2014 (edited) I just found this today. I like it! I'm a bit confused though - in a quick test, it is giving me a booster configuration with clipped engines, even though I have unchecked the "allow part clipping" box. The center stack is properly un-clipped, just the boosters are.payload 10tpayload fraction 15%twr 1.6 to 1.7center stack size 2.5mboosters 4 - 6max center outer engines 8center radials 0 - 0max booster outer engines 8booster radial engines 0 - 3true radial engines = TRUEallow part clipping = FALSEallow thrust limiting = TRUEcenter stack thrust 20 - 30Only stock parts allowed.This gives me a center stack with 9 Rockomax 48-7S, and four 1.25m boosters with 7 Rockomax 48-7S each. And as you can imagine, seven 0.625 engines on one 1.25m tank clip quite heavily. Edited March 31, 2014 by Streetwind Link to comment Share on other sites More sharing options...
blizzy78 Posted March 31, 2014 Author Share Posted March 31, 2014 It does not check if the number of engines at a spot (outer or radial) will clip into each other. So as a workaround, you should reduce the maximum number of engines at that spot. Link to comment Share on other sites More sharing options...
Streetwind Posted March 31, 2014 Share Posted March 31, 2014 Ah. So you mean that only by setting the booster to a maximum of 3 engines assures that I will not get a clipped result? Got it. Doesn't make much sense anyway to allow more than that, considering there exists no engine small enough Just wanted to make sure this wasn't a potential bug. Link to comment Share on other sites More sharing options...
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