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

[TeeGee]

Seems pretty weird for an electric ignitor to be good only once, but that seems to be what the majority of engines have with stockalike Real Fuels configs.

OHHHH! I have this exact same issue! OK, it's due to stockalike real fuels then. How can we reignite these engines multiple times then? I don't see an electric ignitor part in the VAB only the universal one.

[TeeGee]

How about hypergolic fuels? I noteced using real fuels and the like that engine ignition is still dependent on the engine and not on the fuel type. Is there a mod or script that accounts for this with regards to engine ignition?

[NathanKell]

Just because an engine uses hypergolic fuels doesn't mean you can ignite it any more (or fewer) times than anything else, it just means the ignition method is different.

[Raptor831]

OHHHH! I have this exact same issue! OK, it's due to stockalike real fuels then. How can we reignite these engines multiple times then? I don't see an electric ignitor part in the VAB only the universal one.

With regards to the RF Stockalike engine config, the ignitions are all dependent on what type of engine it is. Launch engines are one-time only, Upper stage have a few ignitions, and orbital ones a lot. In the XLS file I use, it fills out those parts automatically. You can grab the XLS and check it out yourself.

That said, I don't use EI myself, so if you have better ideas for what those numbers should be, you can certainly drop a note with your reasoning on the stockalike engines thread (link in my sig).

EDIT: So, I was partially correct about ignitions. By default the configs give multiple ignitions with hypergolics only, with a few exceptions.

Edited June 7, 2014 by Raptor831
Fact checking

[TeeGee]

Just because an engine uses hypergolic fuels doesn't mean you can ignite it any more (or fewer) times than anything else, it just means the ignition method is different.

But I thought that as long as fuel pumps into the combustion chamber with hypergolic propellant, they will always ignite because they react on contact.

If that's true, then that means hypergolic fuels don't need ignitors... right?

If so, then that means when I use hypergolics, I should be able to ignite my engines as long as I have fuel. This means that I don't need ignitors anymore, but that's not what I am seeing for real fuels/stockalike/engine ignitor.

[HoneyFox]

But I thought that as long as fuel pumps into the combustion chamber with hypergolic propellant, they will always ignite because they react on contact.

If that's true, then that means hypergolic fuels don't need ignitors... right?

If so, then that means when I use hypergolics, I should be able to ignite my engines as long as I have fuel. This means that I don't need ignitors anymore, but that's not what I am seeing for real fuels/stockalike/engine ignitor.

For small thrust ones (RCS thrusters for example) this might be true. For larger ones, you might still need to give some initial "push" to spin up the fuel pump before trying to ignite the engine, yeah i know this is not ignitor thing, perhaps i should try changing "Ignitor" to "Restarts" or perhaps not if this doesn't matter...

Edited June 7, 2014 by HoneyFox

[SpacedInvader]

So in the last week or so I found an interesting little chart showing how different tank and engine combinations work together (pressurized vs. non-pressurized and pressure-fed vs. non-pressure fed). I found this very useful for picking out an engine at the time, but now I can't find it again for the life of me. I wonder if someone knows where I can find it or perhaps could repost something similar here.

Thanks.

[NathanKell]

TeeGee: just because the fuel and oxidizer doesn't require ignition doesn't mean the engine doesn't. As HoneyFox says, for non-pressure-fed engines you'll need to kickstart the turbopump. Also, the combustion chamber or nozzle may be burnt through by the end of the burn (engines are only rated to fire for so long...) and they might break/explode if ignited again. Or in the most severe case, the valves themselves might be so melted by the first ignition as to be useless (not only can you not relight, you can't even stop!)

[TeeGee]

TeeGee: just because the fuel and oxidizer doesn't require ignition doesn't mean the engine doesn't. As HoneyFox says, for non-pressure-fed engines you'll need to kickstart the turbopump. Also, the combustion chamber or nozzle may be burnt through by the end of the burn (engines are only rated to fire for so long...) and they might break/explode if ignited again. Or in the most severe case, the valves themselves might be so melted by the first ignition as to be useless (not only can you not relight, you can't even stop!)

So even if we use hypergolic fuels, the chamber has an ignitor to get the engine started?

Could you post a link explaining how hypergolic fuels ignite in an engine? In engine ignitor it says my hypergolic rocket using mnh/n2o2 has 24 electric ignitors available for ignition. If a fuel ignites on contact with eachother, why do we still need an ignitor?

I'm missing something..

[Dinokin]

i'm have a problem here if i use this mod with real fuels the engine state is always invalid... (i tried with and without rf stocklike cfg... took me few hours to discover which mod was causing this problem...)

[NathanKell]

As HoneyFox just said, "Ignitor" is a misnomer. It's not how many cigaratte lighters are strapped to the engines, it's a way to keep track of how many ignitions the engine can handle. In this case, it takes a certain amount of electricity to spin up the turbopump or open the feed valves, and the combustion chamber, nozzle, etc. are only rated for a certain number of restarts (example: GATV used a pump-fed hypergolic engine and was rated for 15 restarts, IIRC).

[CjStaal]

I'm a bit confused on how to install this. Do I install "Hyomoto's MFD mod for RPM", then the "Vessel Viewer RPM plugin", then "Engine Ignitor", and then the "Incremental update for RPM v0.16"?

[TeeGee]

As HoneyFox just said, "Ignitor" is a misnomer. It's not how many cigaratte lighters are strapped to the engines, it's a way to keep track of how many ignitions the engine can handle. In this case, it takes a certain amount of electricity to spin up the turbopump or open the feed valves, and the combustion chamber, nozzle, etc. are only rated for a certain number of restarts (example: GATV used a pump-fed hypergolic engine and was rated for 15 restarts, IIRC).

OHH!!! Cool. But....

http://www.orbiterwiki.org/wiki/Space_Transportation_System_(STS)

long story short, shuttle OMS engines are good for 1,000 ignitions.

Edited June 8, 2014 by TeeGee

[NathanKell]

Yes, yes they are. And you'll note that in my engine pack, equivalent engines (small pressure-fed hypergolic "orbital maneuvering" engines) get essentially unlimited ignitions.

[Dinokin]

i'm have a problem here if i use this mod with real fuels the engine state is always invalid... (i tried with and without rf stocklike cfg... took me few hours to discover which mod was causing this problem...)

[TeeGee]

Yes, yes they are. And you'll note that in my engine pack, equivalent engines (small pressure-fed hypergolic "orbital maneuvering" engines) get essentially unlimited ignitions.

Which pack did you create? I'm using this mod, real fuels and stockalike engines. I only get 24 ignitions on oms engines even when I use MNH/N2O2. Does your engine pack take hypergolics into account with engine igntion as well as ISP?

If so, please direct me to it!!

[NathanKell]

Reaching for the Stars engine pack.

[HoneyFox]

http://puu.sh/9jYdo/73e782d05d.jpg

Can you post some output_log.txt?

To do this, you simply start the game, go directly to launch that simple rocket, after the first ignition check if the state is INVALID, then close the game and grab that log file.

[HoneyFox]

Which pack did you create? I'm using this mod, real fuels and stockalike engines. I only get 24 ignitions on oms engines even when I use MNH/N2O2. Does your engine pack take hypergolics into account with engine igntion as well as ISP?

If so, please direct me to it!!

The "stock-alike engines" has some simplified ignitor configs: it judge if it's hypergolic and set 24 for all of them, then set 1 for all those L type engines (IIRC), and sort of these things. So some of these engines are not accurately matching their counterparts in RL.

[Dinokin]

Can you post some output_log.txt?

To do this, you simply start the game, go directly to launch that simple rocket, after the first ignition check if the state is INVALID, then close the game and grab that log file.

https://www.dropbox.com/s/etjks78mhns0o8x/output_log.txt

[TeeGee]

Reaching for the Stars engine pack.

Yeah I tried the engine pack, it's pretty good but your orbital engines have unlimited ignitions regardless of fuel type. I was hoping that it detected what kind of fuel I was using and would ignite accordingly.

The fuel types for each engine are a little confusing. Why are some rockets limited to only hydrolox and not kerolox? Why can't the lv50 use mnh/n202? Things like that.

Also the thrust on some of the engines seems a little unbalanced. I'd always assumed that the heavier the engine bell, the greater the intended thrust.

[NathanKell]

Look up the RL-10. It's sure as heck not hypergolic, and yet is designed for many ignitions.

Regarding nozzle size, I get asked that about twice a week. The tl;dr is "look up expansion ratio" but here's something I just posted to the RPL thread.

Regarding sizes: you understand that sea level and vacuum require different nozzle sizes, right? Apollo SPS is ~3m diameter and produces 90kN thrust, and it absolutely doesn't have the largest expansion ratio even! By contrast the XLR11 had four chambers, each about 0.2m in diameter, and each produced 9kN of thrust; another example would be the LR-83 used on the Navaho cruise missile (and, modified slightly, as the booster engines for Atlas). It produced 602kN thrust and was 0.88m in diameter.

It all depends on your expansion ratio (nozzle exit diameter : throat diameter), and you want a relatively low ratio for sea level, and near-infinite for vacuum.

Regarding fuel mixtures: in RftS, each of the major spacefaring nations has some mixtures they prefer, and some that everyone uses (kerolox, hydrolox). The British use kerosene and HTP, for example, and amines / nitrous oxide; the Germans Nitric Acid (later NTO) and UDMH; the Americans Nitric Acid and aniline, then NTO/AZ50 or NTO/MMH.

As to why limited: understand that, besides the LANTR, AFAIK *no* rocket engines are actually designed to run on different fuel mixtures. So as it stands we're already breaking credulity by this idea you can switch fuel modes. The LR-87 is the only engine that has operated with all three classes (kerolox, hypergolics, hydrolox) although there were obviously extensive modifications to the engine each change.

This, frankly, is why the stockalikes configs exists: to give (unrealistic) freedom for people who just want MOAR FUEL MODES without realistic sizes or constraints.

[guto8797]

Can anyone help me? I dont know what is going on

Engine ignitor is correctly installed, parts show up, engine tooltips and etc correct, but its almost like it doesnt work at all! No hypergolic fuel is consumed on hypergolic engines and no ignitors are consumed on regular engines! What could be wrong?

I also have RPM (with MFD) and Vessel viewer. I installed the Engine ignitor main file, along with RPM, vessel viewer compatible version (in a different folder, as provided in the zip: My gamedaya has EngineIgnitor and RPMEngine Ignitor)

EDIT: Hummm... i noticed now, on flight, engine status are duplicate. odd. there are two sets of engine stability etc

EDIT2 : Got rid of duplicates, had duplicate configs. Problem persists. NO hypergolic fuel nor ignitors consumed. Shows Engine State INVALID

Edited June 9, 2014 by guto8797

[TeeGee]

Look up the RL-10. It's sure as heck not hypergolic, and yet is designed for many ignitions.

Regarding nozzle size, I get asked that about twice a week. The tl;dr is "look up expansion ratio" but here's something I just posted to the RPL thread.

Regarding fuel mixtures: in RftS, each of the major spacefaring nations has some mixtures they prefer, and some that everyone uses (kerolox, hydrolox). The British use kerosene and HTP, for example, and amines / nitrous oxide; the Germans Nitric Acid (later NTO) and UDMH; the Americans Nitric Acid and aniline, then NTO/AZ50 or NTO/MMH.

As to why limited: understand that, besides the LANTR, AFAIK *no* rocket engines are actually designed to run on different fuel mixtures. So as it stands we're already breaking credulity by this idea you can switch fuel modes. The LR-87 is the only engine that has operated with all three classes (kerolox, hypergolics, hydrolox) although there were obviously extensive modifications to the engine each change.

This, frankly, is why the stockalikes configs exists: to give (unrealistic) freedom for people who just want MOAR FUEL MODES without realistic sizes or constraints.

So when you determined to have the stock orbit engines (LV 909) only use amines and NO... what was that based on? The LV T30 has higher thrust than the heavier skipper engine. Radial engines has 1 time ignitions. Things like that confuse me and render some engines useless for any task.

I just wanted to find a configuration set that is the most realistic interpretation of stock engines, fuels and ignitions. Stockalike is not realistic, I know that, but I need to know where you got these engines stats from and why you chose to implement them as you did.

If you claim that of all the engine configs you have in your rft pack are the most realistic interpretations of fuel, ignition and stats on this site, then I will gladly use it. The problem is that I don't understand why certain stock engines have been given the stats you've given them.

I'm not planning on using country specific fuels, I play the game without pretending it's Earth. All I wanted was to use an engine cfg, that incorporates ignition, real fuels etc into one file.

[RedAV8R]

Can anyone help me? I dont know what is going on

Engine ignitor is correctly installed, parts show up, engine tooltips and etc correct, but its almost like it doesnt work at all! No hypergolic fuel is consumed on hypergolic engines and no ignitors are consumed on regular engines! What could be wrong?

I also have RPM (with MFD) and Vessel viewer. I installed the Engine ignitor main file, along with RPM, vessel viewer compatible version (in a different folder, as provided in the zip: My gamedaya has EngineIgnitor and RPMEngine Ignitor)

EDIT: Hummm... i noticed now, on flight, engine status are duplicate. odd. there are two sets of engine stability etc

EDIT2 : Got rid of duplicates, had duplicate configs. Problem persists. NO hypergolic fuel nor ignitors consumed. Shows Engine State INVALID

I don't believe this isn't an Engine Ignitor issue. Did you just recently update RealFuels to v6+. That is my guess, the new RealFuel's update broke it and a couple other things.