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

[Amazingteknique]

What would be the best fix for using real fuels with the engines that ignite off the igniter combined with a small amount of liquid fuel and oxidizer. Ive seen it possibly only on the KW engines, Im really new to this addon though. Should I just switch it into hypergolic fuel resource instead of this or is there a way to use the real fuel mixes?

[HoneyFox]

What would be the best fix for using real fuels with the engines that ignite off the igniter combined with a small amount of liquid fuel and oxidizer. Ive seen it possibly only on the KW engines, Im really new to this addon though. Should I just switch it into hypergolic fuel resource instead of this or is there a way to use the real fuel mixes?

Ah, currently using it with MFS Real Fuel may bring some issues because i used LiquidFuel+Oxidizer as ignitor resources to emulate engines using hypergolic fuel. which apparently doesn't match with RealFuel well. Currently SFJackBauer is working on a better (and more realistic) combination of the two, you can check it here.

Right now you might need to add some small amount of LiquidFuel+Oxidizer in the fuel tank if the ignitor does need them.

And soon i'll release a new version, with which you can see in VAB/SPH what resource(s) & their amount is/are needed by the engine's ignitor, thus helping you to know what additional resource(s) should be added into the fuel tank.

I've finished all these WIP features stated in OP and it's now in testing phase. The release date should be just very close, perhaps tomorrow or so if everything is OK.

[HoneyFox]

OK, V3.1.0 has released. Just want to bump the thread.

[DennyTX]

***

Add ignitor resource display in VAB/SPH so that users are clear what additional resources are needed.

***

where it should be? cant found...

[HoneyFox]

where it should be? cant found...

Mouse hover on the engine installed on your rocket, there should be some text displayed in red if the engine requires any ignitor resource.

[Galane]

This is interesting. http://forum.nasaspaceflight.com/index.php?topic=15312.0

From the Space Shuttle Main Engine Orientation Presentation (105 pages) on L2:

"ASI SPARK IGNITER

The spark igniter generates sparks at a rate and energy level sufficient to ignite the propellants in the

ASI chamber.

Six igniters are used on the SSME, two each (for redundancy) in the MCC and both preburners. The

spark igniter is completely self-contained in that a 26-VDC input as provided by the controller, results in

a 10-kilovolt, 50 sparks per second output. The igniter is hermetically sealed and welded."

Something else to consider are monopropellants that ignite when contact is made with a solid, non-consumable, catalyst. Hydrogen Peroxide is commonly used with a catalyst containing silver, though any sufficiently rough surface can work if the concentration is high enough. It'll even combust with organic matter like leather or human flesh. The ME-163 pilots probably didn't like to think about what would happen if the tanks of T-Stoff and Z-Stoff they sat between sprung leaks.

I suppose the Z-Stoff catalyst would be not so nasty. The T-Stoff, being 80~85% pure hydrogen peroxide would be an extreme grade of nasty.

Hydrazine is quite a versatile chemical. It can be a monopropellant by itself for low thrust uses or mixed with other things it can be a rocket propellant, a liquid fuel for artillery guns and many other things.

I'd love to see an engine in KSP that runs on FOOF.

Edited December 28, 2013 by Galane

[Zander]

Just a question. This mod limits the number of restarts to some amount. But is that realistic? From what I have read (not very much) it seems like rocket engines are either capable of restarting an indeterminate number of times or not capable of restarting at all. I have never heard of one that can do 5 restarts exactly and after that can't restart. So shouldn't the mod just disable restarting for some engines and allow unlimited restarting for others while possibly simulating some random wear and tear that might result in a failure or explosion on a restart.

[HoneyFox]

Just a question. This mod limits the number of restarts to some amount. But is that realistic? From what I have read (not very much) it seems like rocket engines are either capable of restarting an indeterminate number of times or not capable of restarting at all. I have never heard of one that can do 5 restarts exactly and after that can't restart. So shouldn't the mod just disable restarting for some engines and allow unlimited restarting for others while possibly simulating some random wear and tear that might result in a failure or explosion on a restart.

As for whether in RL there's a certain number an engine can restart, TBH i don't know, but i've seen some reference saying some engine has ... as its ignition system and is capable of 5 restarts...

Perhaps wear and tear is a good point, i.e. the ignitor may randomly break especially after many ignitions. But such random accidents will make people very frustrated so we really need to think over about this kind of "simulation" (I even don't know if it's realistic enough).

Anyway, this plugin itself didn't limit you much. You can adjust the config files (i know that's quite a lot to edit) so that engines are either having unlimited restart capability or can only be ignited once. Whether you still want ullage simulation is up to you, and if you have checked the config.xml brought with V3.1 package you can see there are options that will make engines fail or explode when restarting if fuel flow is unstable.

[LameLefty]

Just a question. This mod limits the number of restarts to some amount. But is that realistic? From what I have read (not very much) it seems like rocket engines are either capable of restarting an indeterminate number of times or not capable of restarting at all. I have never heard of one that can do 5 restarts exactly and after that can't restart. So shouldn't the mod just disable restarting for some engines and allow unlimited restarting for others while possibly simulating some random wear and tear that might result in a failure or explosion on a restart.

Yes, it's realistic. Generally speaking, first stage engines are not capable of starting themselves and rely on ground systems to do so: they have ground-supplied pressurants to pressurize fuel and oxidizer tanks, and some also require ground systems to begin spinning turbo pumps. This is not universally true but it's very common. Others still require ground-supplied fuel and oxidizer tank pressure but spin up turbo pumps with helium, which is a limited resource. Still others, such as SpaceX Merlin engines, use a number of "charges" of a set of hypergolic compounds called TEA-TEB (Google it) to start (they're responsible for the characteristic green/yellow flash on Falcon engine start; check YouTube for videos).

Air-starting an engine in flight is another problematic issue; LH2/LOX engines can use spark igniters but you still have to be able to spin up turbopumps and/or pressurize the flowing propellants. Here is how the J-2 engine did it. http://en.wikipedia.org/wiki/Rocketdyne_J-2#Start_sequence Note the time limit between starts; wait longer than about 6 hours and you couldn't restart it again even if you have the fuel.

For kerosene/LOX or other fuels, air starting has its own issues. Kerosene can't get TOO cold or it starts to gel and won't flow properly. It also subjects engine parts to fouling and sooting from combustion products. Again, you need a way to get the turbopumps spinning good and fast. Unlike LH2 which will warm and expand into gas very easily, thus starting to flow naturally, kerosene is a liquid and has to be pumped. The best way to get the pumps spinning quickly, and thus fuel flowing quickly at flight pressure into the combustion chamber, is hypergolic start cartridges.

[Zander]

As for whether in RL there's a certain number an engine can restart, TBH i don't know, but i've seen some reference saying some engine has ... as its ignition system and is capable of 5 restarts...

Perhaps wear and tear is a good point, i.e. the ignitor may randomly break especially after many ignitions. But such random accidents will make people very frustrated so we really need to think over about this kind of "simulation" (I even don't know if it's realistic enough).

Anyway, this plugin itself didn't limit you much. You can adjust the config files (i know that's quite a lot to edit) so that engines are either having unlimited restart capability or can only be ignited once. Whether you still want ullage simulation is up to you, and if you have checked the config.xml brought with V3.1 package you can see there are options that will make engines fail or explode when restarting if fuel flow is unstable.

Sounds good btw how does ullage simulation work? Does it check if there is downward gforce along the long axis of the rocket?

[HoneyFox]

Sounds good btw how does ullage simulation work? Does it check if there is downward gforce along the long axis of the rocket?

Yes, so any measure you can find to push the ship forward will help. (decoupler might not help because the push is not long enough, separatron solid boosters work well though)

if you pull the ship backward instead, things will become worse. Remember this when you are in atmosphere. (Pay attention to the direction of aero-drag I mean...)

it also checks side acceleration and rotate rate. Remember the recent Falcon 9 first stage not being able to ignite after reentry due to exceeded roll? it is somehow simulated (though not physically) also.

Side acceleration can make your fuel shift to the side, pitch/yaw rate can centrifuge the fuel to the top & bottom. In such cases the fuel might reach the fuel inlet (the display will show "Very Stable"), but it's not truly stable. when you want to ignite the engine in such situation, you'd better use small throttle first, so that all the fuel can move down to the bottom of the tank slowly and steadily. Otherwise the fuel will get down quickly and probably with lots of air pocket produced, the fuel flow might then turn back to unstable soon and result to flame-out.

Edited December 28, 2013 by HoneyFox

[J_Davis]

What would be the best fix for using real fuels with the engines that ignite off the igniter combined with a small amount of liquid fuel and oxidizer. Ive seen it possibly only on the KW engines, Im really new to this addon though. Should I just switch it into hypergolic fuel resource instead of this or is there a way to use the real fuel mixes?

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.

[J_Davis]

If you're willing to stomach making all the changes, you can switch the resources in the igniter configs into realfuels.

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?

[NathanKell]

Yes. Do want.

[HoneyFox]

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?

That would be useful and i think it's distributable. The real fuels config should be under the license CC-BY-SA IIRC.

[HoneyFox]

Oops, i guess i've packaged the previous version (V3.0.1) into the latest package...

So you'd better download it again (dropbox link).

[J_Davis]

Yes. Do want.

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!

[NathanKell]

J_Davis: cool, thanks!

HoneyFox, for a forthcoming update, I'll add a tag for each resource definition hypergolicWith, and its value will be a comma-delimited string of other resources it's hypergolic with. Can you then, for each propellant, grab that, and check if the string contains each other propellant's name? That will determine if the fuel mixture is hypergolic.

(Or just grab the first propellant's string and check against all others, stopping when having a match. I'll guarantee the listings are symmetric.)

[J_Davis]

I'll add a tag for each resource definition hypergolicWith, and its value will be a comma-delimited string of other resources it's hypergolic with.

I can imagine it now:

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

Edited December 31, 2013 by J_Davis

[NathanKell]

The first rule of rocket club is don't discuss FOOF.

The second rule of rocket club is pack a good pair of running shoes.

[HoneyFox]

J_Davis: cool, thanks!

HoneyFox, for a forthcoming update, I'll add a tag for each resource definition hypergolicWith, and its value will be a comma-delimited string of other resources it's hypergolic with. Can you then, for each propellant, grab that, and check if the string contains each other propellant's name? That will determine if the fuel mixture is hypergolic.

(Or just grab the first propellant's string and check against all others, stopping when having a match. I'll guarantee the listings are symmetric.)

So if i check that it's a hypergolic pair, i just ignore the ignition checklist about resource requirement? Should be easy. but it seems a bit too hacky to do this.

[NathanKell]

Why hacky? I thought you proposed it a ways back, asking whether we could add tags to resource definitions.

You should probably make a static dictionary pairing resourcenames with those strings, filled on first module awake/start/whatever. Look at what I used to do for TLTIsps etc in MFS before v4.

Though...best not to ignore the resource requirement. What if you added a resource requirement for just fuel, and it draws 1 second of burn from the engine's PROPELLANTs?

I guess at that point it's on the module-adder to ensure the propellants are hypergolic, rather than you.

I guess really all this could just be done on my end, by using the appropriate config per CONFIG.

Edited December 31, 2013 by NathanKell

[HoneyFox]

Why hacky? I thought you proposed it a ways back, asking whether we could add tags to resource definitions.

You should probably make a static dictionary pairing resourcenames with those strings, filled on first module awake/start/whatever. Look at what I used to do for TLTIsps etc in MFS before v4.

Though...best not to ignore the resource requirement. What if you added a resource requirement for just fuel, and it draws 1 second of burn from the engine's PROPELLANTs?

I guess at that point it's on the module-adder to ensure the propellants are hypergolic, rather than you.

I guess really all this could just be done on my end, by using the appropriate config per CONFIG.

Well i did remember that it was proposed sometime earlier (perhaps by me or by some other guy?) But consider that i've got IGNITORE_RESOURCE implemented, such way of skipping resource consumption would be hacky, IMO.

It would be easy if you can write a config file to list all hypergolic pairs, and EI can automatically reset IGNITOR_RESOURCE requirements to that pair (thus keeping the resource requirement while making it depend on no additional resources) The amount of requirement needs some calculation though...

Talking about the config, i haven't make much progress on your spreadsheet. There are lots of information there and it takes me quite some time to even just add one new column into it. There might be different number of CONFIGs for each engine, that makes things more complex.

And i'm a bit confused about the three engine config packs. One from MFS 3.3, one from SFJackBauer and another one from RO, right?

I keep using the first one because the rest two rescale parts' sizes quite a lot and i dislike that (no offense). So i would like to ask, how is the progress of the config from MFS 3.3? have you been working on it since that version?

Edited December 31, 2013 by HoneyFox

[NathanKell]

HoneyFox, first: was showing KSP to a friend and just had an engine fail to ignite due to ullage issues. SO COOL.

I really should just make my sheet output proper configs. Got lazy. Sorry. I'll do that in the next couple days, automate it, etc.

Re: the engine packs. I haven't touched the stockalike pack in a loooong time; Chestburster was maintaining it but RL has been not so good lately. And, honestly, I have very little motivation because I never use it. :]

But I recognize that some people do, so...it'll get updated.

FYI the RealEngines pack from SFJackBauer (just the pack alone, not Realism Overhaul), here, you can just delete everything except RealEngines_stats and not have any rescaling.

[dlrk]

The ullage simulation is pretty cool. I'm looking forward to hypergolic mixtures being implemented, should be nice too.