Jump to content

Hetsin

Members
  • Posts

    10
  • Joined

  • Last visited

Reputation

0 Neutral

Profile Information

  • About me
    Bottle Rocketeer

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. I'm having a similar issue with NEAR, except that during lower reentry (~20km to 30km) -for some reason- the Mk I Pod intregal shield, the DRE 1.25 m shield and the 1.25 m conical Oblivion shield stop using ablative shielding for a few seconds (~3 to 5) before resuming to use it. That repeats 3 or 4 times per reentry. Higher up (~30km to 35km) the ablative shield will rapidly switch between not being used and having minor usage (~0.03/sec). This is on the Normal DRE setting. Overall, from a 85x30 reentry I'm using ~60 to 80 ablative shield units. Incidentally, a Mk1-2 pod with the included 1000 unit heat shield nearly burned up from a 120x30 decent with ~0.7T extra. In short, DRE is behaving oddly with NEAR since the update to .90. The only things I think it could be is that DRE is 'cooling' the shield as is ablates or NEAR has messed with something that DRE assumed to be true. As far as I know, both DRE and NEAR are updated on my system. I'll probably switch back to FAR if it isn't having this issue. If more info is needed, I can provide it.
  2. Thank you for this mod. It makes finding thing in my overstuffed sea of parts actually manageable.
  3. This mod is awesome and it makes flying in NEAR/FAR a pleasure rather than a chore. I do have a question on what other people's setups are on twin-stick controllers. Currently I have it setup that (On a PS2 controller) Right stick is pitch/roll Left stick is yaw R2/L2 is throttle control Square is SAS toggle Triangle is Gear toggle Circle is Brake toggle Everything else is unbound and I can't figure out what to make them, other than L1/R1 cycling through presets. I tried looking up controller setups for console flight game/sims with limited success and would love some suggestions, especially on what to do about the vertical axis on the left stick. Hmm, maybe make it vertical translation and the D-pad the other translations? That might cause issues during docking. =\
  4. I'm having an issue with the toolbar integration. If KER is disabled through the toolbar in the VAB, the area that KER uses in the VAB isn't 'freed'. As in it behaves as if it wasn't disabled, not letting parts move through that area and dimming the function buttons (Parts, AG, Crew, New Craft, Load Craft, Save and Launch) when mousing over the area. Is there a workaround for this?
  5. @Trueborn I took a look through the source for 1.4b1, and I was wondering why you did the suicide burn calculations the way you did (in orders of magnitude of precision, I think)? I'm only asking because it seems inefficient to me and I've recently had an interest in suicide burns. I've worked out some equations that might be useful (some basic physics), unless your method does something I'm not realizing?
  6. First off I love this mod, sort of wish the text wouldn't be unreadable at the scales I'd like to have, but that's fine. I having an issue with the mod's calculated burn time and LV-N engines, in that it's not calculating and I have to switch to the stock burn time to get any sort of figure. For example my 11t Duna Science Lander had the 1070 dv transfer burn calculated for 33 s in 33 s, when switching over to stock gave me a ~4:30 burn in 12 m. On other vessels with LV-N's it's similarly refused to calculate. I'm currently running v1.3, so that may have something to do with it. Does anyone have a fix for this?
  7. I hope this is not necro-ing, but I have some clarifications regarding this, due to testing and maths I did. This assumes you have access to an information mod and are landing on a body with no atmosphere. I'd recommend having the landing engine(s) on a toggle action group instead of staging like OP suggests. Assuming any given orbit: The vertical dv is ~ sqrt(2*g*h + v0^2). Where: g is gravity at the surface. (This will be obviously less at higher altitudes, but to be conservative aka not make kerbal paste, I figure it best to use surface g. Conversely, you can probably do some maths to figure out the average g, but this is the quick and dirty version) h is the craft's radar height. v0 is the craft's vertical velocity at a given moment. (If you are in a circular orbit this is effectively 0) The burn altitude comes to the OP's calculation, restructured a bit. Altitude fraction = (Vertical dv ^2) / (2 * 1000 * Thrust (kN)) Note: I put the thrust in kN, mostly for ease of reference You may ask, where'd the mass go? The reason I didn't multiply the mass is because, at this point you should kill your horizontal velocity, which uses fuel, which decreases mass. After completing the horizontal burn : Suicide burn altitude ~ Altitude fraction * mass (kg) This should, when your vertical velocity gets to 0, leave you a few hundred m above the surface. If you were skilled enough, or had the automated aid, to keep your Thrust to Mass ratio (TMR) constant it -should- leave you a few m above surface (because of the conservative g value). That's how I figured out how to calculate suicide burns, now on to clarifications. Suicide burns are not particularly efficient. We all know that hovering is as inefficient as you can get (using the highest possible dv to go nowhere) and can be defined as having a TMR equal to g. A suicide burn is TMR - g (a) for t seconds to equal the vertical dv, so your 'gravity waste' dv is equal to g*t. That isn't even the biggest offender of dv usage, which is the suicide burn itself. The higher from the surface you are, the more vertical dv you need to burn. Therefore minimize the dv needed, you need to minimize the vertical dv (reduce height) and decrease burn time (increase TMR and reduce vertical dv). The increase to TMR has to be tempered with mass and fuel usage which is beyond my scope of understanding to figure out. Example (Mun suicide burns, total values include the dv used to bring it down after the suicide burn thus breakdown values are approximate, using a ~ 3.8t lander with 50kN engine): 28.8k x 28.6k : 900 dv (530 h dv, 285 v dv, 75 gw dv) 10.2k x 8.8k : 760 dv (540 h dv, 166 v dv, 60 gw dv) The transfer orbit between them: ~23 dv So the lower orbit saved about 115 total dv on the suicide burn. The main points are suicide burns are not as efficient as most people think, however they do allow a certain amount of ease for determining landing sites. Also, the burn should be done from as low an orbit as possible (mainly within limits of maneuverability and terrain). And as always make sure to buffer your dv budget, in case fun things happen. ADDENDUM (theory crafting aka untested): That was the quick and dirty way, now to increase accuracy! The biggest way to increase the accuracy of the burn (lower the height when vertical velocity is 0), it to keep a constant TMR. You can adjust the throttle (or presumably thrust in 0.23) to match the mass lost with the burn, but this is ... difficult to do manually. You can also plan around average mass of the craft while burning, but to do this you need to know how much fuel is used. This gets us: The quick and dirty method: First we need to know the fuel flow rate (m-dot) for the stage (thanks Advanced Rocket Design tutorial). m-dot = thrust / (Isp * 9.82) // This is a constant for the stage (unless you turn off/on engine(s)) then m-avg = m0 - (dv / (2 * m-dot * (TMR - g))) The accurate method (based off of the Tsiolkovsky Rocket Equation): m-avg = (m0 + (m0 / e ^ (dv / (Isp * 9.82)))) / 2 Where: m-avg is the average mass to plug in to the altitude fraction m0 is the starting mass TMR is the starting Thrust Mass ratio // Hey, I did say quick and dirty e is, of course, Napier's constant. ~2.71828 So now you're finishing your burn closer to the surface. Which may or may not be a good thing. Next step, how do we use less dv on the burn? Easy! Basic trigonometry. Now I nearly failed my trig class all those years ago, so there is undoubtedly a more efficient way, but I figure this will do as a start. This also requires a relatively flat stretch of area, so kilometerage may vary. So you've calculated your vertical dv. Good. Now look at your horizontal speed. Figure out the dv needed to reduce your horizonal velocity to your vertical dv. You see where I'm going with this, right? So to calculate your mass after the horizonal burn. This will be: Quick and Dirty: m1 = m0 - (hdv / (m-dot * (TMR - g))) Accurate: m1 = m0 / e ^ (hdv / (Isp * 9.82)) Where: m1 is the final mass after the burn m0 is the starting mass hdv is the horizontal delta v TMR is the starting Thrust Mass ratio e is, of course, Napier's constant. ~2.71828 You plug m1 into the m-avg formula as m0, and multiply the dv in that formula by sqrt(2) (~1.4142). Instead of rad+, you put the pitch to 45 deg retrograde, wait for the altitude it spits out and burn. This should save about 1/4 of the vertical dv that you initially calculated, which may or may not be worth the effort.
  8. I don't suppose there is a way for non-radial parts to be used inside the compartment? My issue is that I want to put a probe core inside the compartment (with a Fuel Tank as the root part), but it uses the spare attach node so the compartment can't be capped. Is there a way around this that I can't find, or could this be a future feature? Love the part regardless. =)
  9. Well, color me impressed. I run B9 + some other mods (without the relevant debloaters) and went from 2.25Gig to 1.4Gig as reported in Task Manager. For this subpar rig that I'm running (3Gig RAM) that's a mighty big chunk of change. To be honest I was skeptical before, but, just wow. Thank you.
×
×
  • Create New...