[0.25] Engine Ignitor (Workaround for some bugs V3.4.1: Aug.31)

[Guest]

I've got a problem with the largest KW Griffon engine. It's supposed to ignite from launch clamps, but when actually trying to fire it, it fails. I'm using Modular Fuel System, could you check it out?

Also, I have a feeling that fuel flow destabilizes way too slowly. In reality, once there's no force acting on the fuel, there's no reason for it to go into the turbopump. An unpressurized tank would have problems igniting even after a short period in 0G.

[HoneyFox]

I've got a problem with the largest KW Griffon engine. It's supposed to ignite from launch clamps, but when actually trying to fire it, it fails. I'm using Modular Fuel System, could you check it out?

Also, I have a feeling that fuel flow destabilizes way too slowly. In reality, once there's no force acting on the fuel, there's no reason for it to go into the turbopump. An unpressurized tank would have problems igniting even after a short period in 0G.

1. KW Griffon XX? I will take a look. maybe there's something wrong in the config files. Do you have similar issues when using other engines that require launch-clamp ignition assistance?

2. That's what I was asking for information about before.

So normally how long is "a short period"? half a minute or even just several seconds? or does it depend on anything else?

Edited October 29, 2013 by HoneyFox

[HoneyFox]

Ah, i guess the reason may be another one: the igniteRange for launchClamp is 3.0 meters IIRC, for KW Griffon XX or some other engines that have big size, this may cause issue.

I will change the logic of external igntior range-checking later. Like checking if: any external ignitor is in range OR any external ignitor is attached to the engine (either surf-attach or node-attach). That way, as long as you have surf-attached the clamp to the engine, you won't need to worry about that igniteRange any more.

[HoneyFox]

OK, I've just published V3.0.1.

Add an attach logic for external ignitors.

Adjusted some incorrect configs in IgnitorKOSMOS.cfg, add IgnitorRLA.cfg in the pack.

[Guest]

2. That's what I was asking for information about before.

So normally how long is "a short period"? half a minute or even just several seconds? or does it depend on anything else?

Sorry for lack of response, you've fallen off the front page. By "short period" I thought about a few (1-2) seconds, no more. Right now, "normal" KSP staging is usually possible, using the still stable flow from the boost to ignite the next stage. Meanwhile, IRL, the next stage is activated before the previous one is done running. If this was neglected, the next stage would probably fail to ignite.

Also, how about interaction with Modular Fuel Tanks mod? You could talk to NathanKell about this, it'd really benefit both mods.

Edited November 6, 2013 by Guest

[NathanKell]

We did talk. As soon as I get a chance we'll do integration.

[Guest]

That's awesome. The next release of MFT will be really great.

[HoneyFox]

Sorry for lack of response, you've fallen off the front page. By "short period" I thought about a few (1-2) seconds, no more. Right now, "normal" KSP staging is usually possible, using the still stable flow from the boost to ignite the next stage. Meanwhile, IRL, the next stage is activated before the previous one is done running. If this was neglected, the next stage would probably fail to ignite.

Oh my... only 1~2 seconds? I thought the diffusion would be slow (like 10~20 seconds or so) due to liquid's surface tension(surface tension actually may cause the liquid to leave the boundary and allow gas to get into that place i guess) adsorption to the boundary of fuel tank even if it's under zero-G. And you mentioned activating next stage while the previous one still running, I thought that kind of staging is mainly used only on Russia's rockets, right?

Edited November 7, 2013 by HoneyFox

[rhoark]

Venting could be done with a little "engine" (linear RCS model perhaps) that can be shut down but not throttled (so it can be action grouped independently of the throttle)

[Guest]

Oh my... only 1~2 seconds? I thought the diffusion would be slow (like 10~20 seconds or so) due to liquid's surface tension(surface tension actually may cause the liquid to leave the boundary and allow gas to get into that place i guess) adsorption to the boundary of fuel tank even if it's under zero-G. And you mentioned activating next stage while the previous one still running, I thought that kind of staging is mainly used only on Russia's rockets, right?

Yes, it's mostly a Russian thing, but I think that Titan from II up might've used it too, judging by it's open interstage. Americans generally used ullage motors. Unless they're very small (and thus can afford pressurized tanks), rockets rarely run without any ullage system. Currently you can afford doing that in KSP, as long as you don't dawdle for too long with igniting the stage.

[HoneyFox]

Yes, it's mostly a Russian thing, but I think that Titan from II up might've used it too, judging by it's open interstage. Americans generally used ullage motors. Unless they're very small (and thus can afford pressurized tanks), rockets rarely run without any ullage system. Currently you can afford doing that in KSP, as long as you don't dawdle for too long with igniting the stage.

hmm, perhaps I will increase the rate of diffusion a bit in the next minor version so that it will take less time to destablize the fuel flow.

As for ullage system, now we already have:

1. pressurized tank if the stage is small (though this is decided by engine ignitor module right now, NathanKell may need to integrate this with MFS, I remember that there's indication of pressurized tanks in TANK definitions... should be useful here). <-- should only be used by probes' own propellant system or small upper stages i guess.

2. use a dedicated engine as venting device (with performance similar to that stock Ant Engine but with even lower Isp, and uses the same types of fuel of the main engine). <-- a simple solution, but wastes lots of fuel.

3. use a set of dedicated motors which use hypergolic fuel stored in its own built-in pressurized tanks. <-- best solution IMO, but have limited ignition times depends on how much fuel it brings.

4. use RCS thrusters to ullage. <-- found that quite handy in some emergency situations but TWR is low and need to press RCS FWD for several seconds.

5. solid ullage motors, apparently one time use. <-- i seldom use this unless i'm quite sure the upper stage only needs two burns (normally one for circularization and another for KTO/TMO...

[HoneyFox]

Venting could be done with a little "engine" (linear RCS model perhaps) that can be shut down but not throttled (so it can be action grouped independently of the throttle)

I was considering if i need to implement a special PartModule for this or just use a little "engine" to emulate that.

Perhaps the latter solution is good enough, with the help of action group settings.

[CoriW]

I was considering if i need to implement a special PartModule for this or just use a little "engine" to emulate that.

Perhaps the latter solution is good enough, with the help of action group settings.

Hey HoneyFox, I've made a "Ullage Engine" part that you can use for this mod if you'd like, (In fact I made it specifically for this mod), sent you a PM about it.

EDIT: Hurray for my 300th post!

EDIT: Right so I've talked to to HoneyFox a bit and we've arranged for me to make a few parts for this mod.

Edited November 14, 2013 by CoriW

[rpayne88]

Where are the igniters? I can't find them anywhere.

[HoneyFox]

Where are the igniters? I can't find them anywhere.

hmm... it's just a built-in module in an engine to simulate several kinds of conditions of a successful ignition. but you can create a part with the ModuleExternalIgnitor module yourself, and surf-attach that part onto your engine. That will work, too.

[HoneyFox]

Hey HoneyFox, I've made a "Ullage Engine" part that you can use for this mod if you'd like, (In fact I made it specifically for this mod), sent you a PM about it.

EDIT: Hurray for my 300th post!

EDIT: Right so I've talked to to HoneyFox a bit and we've arranged for me to make a few parts for this mod.

Yeah, thanks for these wonderful parts. they will fit into this nicely:

3. use a set of dedicated motors which use hypergolic fuel stored in its own built-in pressurized tanks. <-- best solution IMO, but have limited ignition times depends on how much fuel it brings.

[CoriW]

Alright so until HoneyFox get's the link into the first post I'll put it here for now.

Rocket Power Industries

The download for the Ullage Pack is the first one in the "Individual Downloads" section, and if you scroll down a bit there's a picture of the parts and their stats.

[HoneyFox]

Alright so until HoneyFox get's the link into the first post I'll put it here for now.

Rocket Power Industries

The download for the Ullage Pack is the first one in the "Individual Downloads" section, and if you scroll down a bit there's a picture of the parts and their stats.

Ok, just updated the OP with information of that ullage engine pack.

[Guest]

Could you update the plugin to 0.23. There were quite some changes done, and I'm not sure if it's still working. Also, that ullage simulation config would be really nice.

[HoneyFox]

Could you update the plugin to 0.23. There were quite some changes done, and I'm not sure if it's still working. Also, that ullage simulation config would be really nice.

Yep. 0.23 is just coming out and i'm still downloading it.

it seems to have some nice features like tweakable fuel amount/thrust limiter etc.

Guess there's no need to re-invent the wheel again for these functionalities which i was planning to integrate into MFS. So the schedule will change and i will first check EI and several of my plugins to see if they work in 0.23.

Will take some time though, and you can also try to test EI plugin in 0.23, there's quite some changes about engines (like RAPIER) in 0.23 so, yeah it's very probably that my plugin needs tweaking.

Also i'm considering if EI needs to provide something as tweakables.

[firstpirlo]

Yep. 0.23 is just coming out and i'm still downloading it.

it seems to have some nice features like tweakable fuel amount/thrust limiter etc.

Guess there's no need to re-invent the wheel again for these functionalities which i was planning to integrate into MFS. So the schedule will change and i will first check EI and several of my plugins to see if they work in 0.23.

Will take some time though, and you can also try to test EI plugin in 0.23, there's quite some changes about engines (like RAPIER) in 0.23 so, yeah it's very probably that my plugin needs tweaking.

Also i'm considering if EI needs to provide something as tweakables.

too young too slow,sometimes naive:D

[Guest]

Ignitor loading would be perfect. Essentially, each ignitor would have mass, and you could vary their load to shave off a few kilos off your ascent stage. Also, some kind of MFS-integrated ignitor resource addition would be great, too. Consider that many larger engines need to be purged before re-ignition, usually with helium. It'd be nice if this functionality was modeled. Usually, that'd mean a helium tank attached to the stage (either inline or radial) or an MFS-based addition to the main fuel tank. It'd be nice if the autoconfig could handle that, too. For instance, you'd set "ignitions" number in the window, and it'll automatically add necessary helium along with the fuel. Helium usage would vary by engine, of course.

Also, config changes would be nice, too. Some smaller engines should have unlimited (or near-unlimited) restarts, only requiring ElectricCharge. Hypergolics shouldn't have this problem at all, being usually rated for hundreds of restarts and only using their own fuel to ignite. Ignitors should also respect engine configs. The same engine configured for hypergolic propellants should work without the usual igniter load for a keroLOX config. It could still have finite ignitions, but a much higher, fixed number reflecting the number of restarts engine was rated for.

Oh, and could you rename "Hypergolic fluid" to "Hypergol"? It's what it's usually called IRL.

Edited December 18, 2013 by Guest

[HoneyFox]

too young too slow,sometimes naive:D

everytime there's an update of KSP, there comes the busy hours of all modders.

[HoneyFox]

Ignitor loading would be perfect. Essentially, each ignitor would have mass, and you could vary their load to shave off a few kilos off your ascent stage. Also, some kind of MFS-integrated ignitor resource addition would be great, too. Consider that many larger engines need to be purged before re-ignition, usually with helium. It'd be nice if this functionality was modeled. Usually, that'd mean a helium tank attached to the stage (either inline or radial) or an MFS-based addition to the main fuel tank. It'd be nice if the autoconfig could handle that, too. For instance, you'd set "ignitions" number in the window, and it'll automatically add necessary helium along with the fuel. Helium usage would vary by engine, of course.

Also, config changes would be nice, too. Some smaller engines should have unlimited (or near-unlimited) restarts, only requiring ElectricCharge. Hypergolics shouldn't have this problem at all, being usually rated for hundreds of restarts and only using their own fuel to ignite. Ignitors should also respect engine configs. The same engine configured for hypergolic propellants should work without the usual igniter load for a keroLOX config. It could still have finite ignitions, but a much higher, fixed number reflecting the number of restarts engine was rated for.

Oh, and could you rename "Hypergolic fluid" to "Hypergol"? It's what it's usually called IRL.

So you mean, you want the ignitor count to be tweakable? Currently ignitors don't have mass and i don't know how to adjust weight to the part correctly.

For helium purging engine, will it be acceptable to you by making helium as one of IGNITOR_RESOURCEs(guess this should belong to NathaneKell if he's writing auto-config for EI), yes the ignition sequence will be a simplified one compared to the one in RL but i think that's ok.

Right now those ModuleManager configs in the plugin pack have setup several small engines to have nearly unlimited ignitions (~200 or so) already, they usually use EC or LiquidFuel+Oxidizer(to emulate engines that use hypergolic fuel), this will also become better once NathaneKell finished the auto-config: e.g. if you choose MMH+N2O4 as the fuel used, the ignitor will be automatically adjusted to use MMH+N2O4 as IGNITOR_RESOURCEs.

About the name of "HypergolicFluid", it just works as a "placeholder" and it will no longer be used when used with MFS which completes integration with EI. Something like MMH+N2O4, UDMH+N2O4, etc. will replace it I hope.

P.S.: Great. I've just tested EI in 0.23 and it works well (even with the new thrustLimiter feature).

I haven't tested it on RAPIER (guess that it won't work because it uses a different class "ModuleEnginesFX" instead of "ModuleEngines") but perhaps i can just ignore this engine since it's a very special type. plus, i haven't give any ignition limitation to other jet engines before, so...

Edited December 18, 2013 by HoneyFox

[HoneyFox]

Oh almost forget... the latest version which contains a config.xml for ullage simulation will be released once i finished checking bugs and preparing plugin package.