J_Davis

Please don't oversell me. XD Edit: If you use engines other than KW and Stock, please note me your perceptions of each engine and what kind of engine it is. I am guessing right now for making the stockalike file, and I really don't know what types of engines I'm looking at in most cases. Also, I want to share how I'm setting up the fuels. I'm using a system since the stockalikes are for gameplay, not realism. Please comment on the system I am using: Type Primary Alternate Tertiary Mixture L Kerolox NTO+MMH NTO+Aerozine Lean Mix KL MMH AZ L+ Kerolox Hydrolox NTO+MMH Balanced KL HL MMH U Hydrolox NTO+MMH UDMH+Nitric Rich HL MMH UDA U+ Hydrolox NTO+MMH UDMH+Nitric Very Rich HL MMH UDA O NTO+MMH Hydrolox FOOF+H2S* Extremely Rich MMH HL SHOES A Kerolox Hydrolox Kerosene+HTP Balanced KL HL KHP N LH2 LCH4 LNH3 NH NM NA N/A

Handy to know.

That part's intentional.

There's three solutions that are generally used. 1 - Use RCS to ullage the tank; 2 - Use a special SRB to ullage the tank; 3 - Ignite a stage right before a previous one is done. Once you're in space, like on an Apollo CM or LEM, you use solution 1, a few seconds of RCS to settle the tanks before the main burn. During launch 2 and 3 are common. Generally, 3 is a Soviet solution and 2 is an American one, though the Soviets invented 2 - at least as far as I can gather from the history. (There's a 4 - very kerbal - spin the craft on yaw or pitch axis using reaction wheels, let the centrifugal effect settle the tanks before the burn.) Now, Mechjeb doesn't like 3 much as far as I can tell, but once you have SRBs you can use proper staging and 0 stage delay to make 2 work just fine during launches. What would need to change is the flying of manoeuvre nodes in space and the reentry/landing burn. Once the craft is in space it needs to do that ullaging process. I would think that a short RCS burn wouldn't hurt a non-ullage modded game, it'd just look strange. Those of us with the mod would certainly appreciate it, however. I tried looking at the Mechjeb source and seeing if it would be possible to add such a burn easily with my lack of programming knowledge, but I didn't know what was going on inside there at all. Startup and shutdown would be nice as well, though I can see why determining what engine to turn on-and-off would be much harder than just turning on RCS and using it for a few moments.

That would be quite useful, yes. Perhaps though, if all flight operations need different behaviour for ullage, engine thrust, and ignition concerns, a different mechjeb would be needed in general, one that would do the necessary steps for a more realistically modded KSP.

Hey, I'm sure you get a lot of requests, but would it be possible to create a module for mechjeb that would use a few seconds of RCS to ullage the tanks prior to a burn? That would make mechjeb reliable in the game game where I'm using the engine ignition mod: http://forum.kerbalspaceprogram.com/threads/51880-0-23-Engine-Ignitor-%28V3-1-Released-Dec-27-2013%29 . As it is, I have to manually ullage right before each automatically programmed burn, sometimes resulting in a loss of accuracy (not much, but I'm a perfectionist with stubby finger motions).

I can imagine it now: String FOOF.hypergolicWith = "Kerosene, RP-1, N2O4, MMH, H2S, Water, Oxygen, Food, LH2, LOX, SolidFuel, RocketParts, Ore, Kethane, Kerbals";

Okay, I'm putting the RF configs for the Ignitor mod in my dropbox and putting it up at https://www.dropbox.com/sh/33cwz5b1y480low/9tpVtmMrlF . Basically, every engine uses a little bit of an internal supply of MMH+NTO to kick off each burn. Engines burning MMH+NTO have, obviously, as many ignitions as ullage and ignitors will allow. I also changed the hypergolic fuel canister to contain a little bit of MMH+NTO. Hope this is useful!

I've done this for KW and Stock. (I don't use the other packs so I didn't change them). Would these configs be distributable and useful?

Is this related to the NaN bug from engines having tweakable electric charges?

If you're willing to stomach making all the changes, you can switch the resources in the igniter configs into realfuels. I suggest MMH+N2O4. Some engines may need to be gifted a small supply.

Yeah, I realized that after I wrote the post. dV is right, just not the twr. Thanks for letting me know about that!

Could we get an option to change TWR and deltaV calculations based on Isp depending on whether we've modded the game to have Isp changing fuel consumption rate or Isp changing the engine thrust? This is important for realistic engine builds.

Does anyone know if this functionality can be toggled? Perhaps a setting that switches between "Isp changes Thrust"/"Isp changes Burn Rate"? This seems to have odd effects on the deltaV calculations as well.

That's the thing, I'm not a modder myself, and I feel pretty uncomfortable when I'm in the files editing them. So such an API doesn't do much for me.

This makes it much more difficult to use Kethane while doing other mods, I'll note~

One would hope it would be, but who knows?

This is a good pack, and I look forward to future updates. I'm sure it's fun trying to allow for every single flag under the sun!

You are probably right on the 24 s basis. That's very likely for such an ultimately complex system such as Kerbal time. We'll have to make some "cultural assumptions". I'm glad my numbers were helpful!

I have an alternate setup I like to use. I assume that Kerbals would end up treating Mun as a week marker, given it's low orbital period. Longer lengths of partial-year time are based on Minmus. ('Munths' and 'Minmuths' to contrast the two?) I also like a more accurate and less drift-prone day ('Ked'). From the wiki: Sidereal Year: 9 203 545 s (Since there appears to be no inclination for Kerbin, this will be the same as the tropical year, or 'Kyr') Sidereal Day: 21 600.000 s Kyr = 426.0900 Sidereal Days = 425.0900 Solar Days (Ked) This gives us: 1 Ked = 21 650.813 s 1 Ked = 12 'Keh' [Hours Analogue] 1 Keh = 30 'Kem' [Minutes Analogue] 1 Kem = 30 'Kes' [second Analogue] For months, I use Minmus, as I noted. (I also change the length to get a 'familiarish' number of months.) 1 Minmuth = 1 220 401 s / 2 1 Kyr = 15.08282 Minmuths And 1 Minmuth = 28.18372 Ked This seems a reasonable interpretation of how Kerbals would tell time: a downside is that there is a conversion factor between their seconds and ours. Still, I prefer to think of things in terms of Kerbal Time, as then the time length on interplanetary missions looks much like our own. -------- By the way, if this mod were to convert the time outputs to kerbal-centric units, I would find that absolutely awesome. But I'm no programmer so I don't even know if it's possible.

It's a modpack. With a list of my common mods. Why, thank you!

I believe so. It has a configuration file therefor.

I love this, but there exist one tiny bug that is nonetheless very frustrating. While the engine seems to be using the proper thrust and ISP, it's reporting the stock value for ISP to the GUI and (worse still) to Engineer and MechJeb, making the deltaV calculations totally wrong (at best). This makes it hard to plan out complicated missions. I suspect the problem is not entirely yours. -- Edit: Manual Calculations using your given ISPs is more accurate, so it's usable. It's just very frustrating.