Jump to content

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


HoneyFox

Recommended Posts

There was mention in the OP of rotation affecting fuel flow, does this mean the mod will model the "centrifuge effect"; if the rocket is spinning too fast my engines won't light?

:P Right, the actual reason that drived me to model this was of that Falcon 9's 1st stage re-ignition failure after reentry several months ago, that's a pity.

Edited by HoneyFox
Link to comment
Share on other sites

:P Right, the actual reason that drived me to model this was of that Falcon 9's 1st stage re-ignition failure after reentry several months ago, that's a pity.

Heh that's funny, that is same event that prompted me to ask the question.

Link to comment
Share on other sites

Could you add some way to make Dtobi's sparkers work as external ignitors for non-hypergolic engines? Preferably as a separate integration config. If installed, instead of only having to stick a launch clamp near the engine, you'd actually have to place a sparker under each of them so that they could ignite. A very neat feature IMO, though probably should be optional.

But those aren't actually used to ignite anything. They just burn off the excess hydrogen before ignition. The ignitors themselves on the SSMEs are located inside the engine housing - you can't see them at all.

Link to comment
Share on other sites

On the other hand, I've seen an Ariane 5 launch video, which clearly showed burning pilot flames (not exactly like the Shuttle sparkers, but similar) igniting a Vulcain engine. I guess this differs from engine to engine.

Link to comment
Share on other sites

On the other hand, I've seen an Ariane 5 launch video, which clearly showed burning pilot flames (not exactly like the Shuttle sparkers, but similar) igniting a Vulcain engine. I guess this differs from engine to engine.

The Vulcain does use an external blowtorch as its ignition source. I didn't mean to say that the sparker couldn't be used in the game as an ignition source, only that it wasn't it's real world fuction.

And on another note, I'm having some serious difficulty with Bobcat's Soviet Engines; namely, they won't ignite. Ive got adequate power supply from the launch clamps, as well as hypergolic fluid (those are the only two ignition resources for non-nuclear engines, yes?), but when I launch, my rocket just flops over on the tower. Right clicking shows that I've used up my ignition, but my engine isn't burning. Also, there are a bunch of buttons that say jettison(?) so I'm a bit stumped.

Link to comment
Share on other sites

The Vulcain does use an external blowtorch as its ignition source. I didn't mean to say that the sparker couldn't be used in the game as an ignition source, only that it wasn't it's real world fuction.

And on another note, I'm having some serious difficulty with Bobcat's Soviet Engines; namely, they won't ignite. Ive got adequate power supply from the launch clamps, as well as hypergolic fluid (those are the only two ignition resources for non-nuclear engines, yes?), but when I launch, my rocket just flops over on the tower. Right clicking shows that I've used up my ignition, but my engine isn't burning. Also, there are a bunch of buttons that say jettison(?) so I'm a bit stumped.

Are your launch clamps close enough to the engines? if not, those engines that need external ignition sources cannot be ignited.

Link to comment
Share on other sites

Its pretty inconvinient to have just few pressurized tanks...

We shoudl have ability to put Hellium, or whatever gas is used to stabilise fuel, in all tanks using modular fuel tanks functionality.

By the way, external ignitor mentioned in OP post - are there gone in newest version? Are there still some engines without self ignition capability?

Edited by kiwiak
Link to comment
Share on other sites

Are your launch clamps close enough to the engines? if not, those engines that need external ignition sources cannot be ignited.

I've got launch clamps directly attached to the engine bell, and, to the to fuel tank right above. Also, most of them aren't external ignition. the cfg says Internal_(Small, Medium, Large)

Link to comment
Share on other sites

On the other hand, I've seen an Ariane 5 launch video, which clearly showed burning pilot flames (not exactly like the Shuttle sparkers, but similar) igniting a Vulcain engine. I guess this differs from engine to engine.

Those items do not ignite the engines. They are only meant to burn off excess hydrogen that has not been ignited internally inside either the combustion chamber or the gas generator. Ariane 5 does a pretty good job at it while the Delta IV does a modest job at best (hence the charred blackness on the sides of the cores that you see after it has lifted off). A nice view of this is on the most recent GPS launch. If you have not checked it out there is a picture on the Spaceflight Now website that is a good example.

http://spaceflightnow.com/delta/d365/launch/

But then the amount of hydrogen the RS-68 pumping out is a lot more than the Vulcan, not to mention the SSME had all the gas generator exhaust going through the combustion chamber so all the excess was pretty much burning at engine start.

Link to comment
Share on other sites

Its pretty inconvinient to have just few pressurized tanks...

We shoudl have ability to put Hellium, or whatever gas is used to stabilise fuel, in all tanks using modular fuel tanks functionality.

By the way, external ignitor mentioned in OP post - are there gone in newest version? Are there still some engines without self ignition capability?

Yup. I've heard that NathanKell (or whoever is responsible of MFS/RF) has plan to implement some kind of FuelTankTypeSwitcher in game so that we can change a tank to be normal one, cryogenic one, service-module one, etc. but I don't know when will that feature come.

For external ignitor, I haven't changed anything related. So you should still have at least Mainsail, KW's Griffon series and NP's Bearcat series that need external ignition sources.

But if you're using any engine configs provided with RF (which might override the ignitor settings), perhaps these external ignitor requirements are gone.

Link to comment
Share on other sites

I've got launch clamps directly attached to the engine bell, and, to the to fuel tank right above. Also, most of them aren't external ignition. the cfg says Internal_(Small, Medium, Large)

That's quite strange... what specific type(s) of engines are you using? If it's from Bobcat's soviet engine pack, most engines in that pack should use HypergolicFluid and is self-ignite-able, with one exception that requires a bunch of ElectricCharge and another exception that requires external ignitor.

Link to comment
Share on other sites

That's quite strange... what specific type(s) of engines are you using? If it's from Bobcat's soviet engine pack, most engines in that pack should use HypergolicFluid and is self-ignite-able, with one exception that requires a bunch of ElectricCharge and another exception that requires external ignitor.

It's all of the engines from Bobcat's soviet pack, but the one I use most often is the RD-180. I'm using RF and Nathan's RftSEngines. There's nothing in the cfgs that should be causing a conflict, but I'll test it without them just to be sure.

Link to comment
Share on other sites

It's all of the engines from Bobcat's soviet pack, but the one I use most often is the RD-180. I'm using RF and Nathan's RftSEngines. There's nothing in the cfgs that should be causing a conflict, but I'll test it without them just to be sure.

Did you ever extracted the IgnitorCfg pack in my latest EI 3.2.0? It contains some configs for Soviet Engine Pack. If you're using RF+Nathan's RftsEngines, you'd better delete the extracted files according to Nathan's advice, otherwise it might cause some conflicts (though frankly speaking I don't know why there's conflict).

Link to comment
Share on other sites

  • 3 weeks later...

Out of no where I lost all of my engine ignitors and my real fuels options for most of my engines. Not sure what did it haven't added or changed a mod since I started using the RSS realism overhaul.

Link to comment
Share on other sites

Out of no where I lost all of my engine ignitors and my real fuels options for most of my engines. Not sure what did it haven't added or changed a mod since I started using the RSS realism overhaul.

I'm not sure if Realism Overhaul's engine config has EI config built-in. If not, you might need to extract the config-pack provided by EI itself. you'd better confirm this with RO's author.

Link to comment
Share on other sites

Is there a method for getting fuel to stabilize before igniting in zero-g?

As stated in above posts, you can use ullage motors (either small SRBs, high-thrust RCS or pressure-fed engines that don't need ullage) to accelerate the rocket for a while to stabilize the fuel.

As a last resort, you can pitch/yaw your vessel quickly. and due to centrifugal effect, some part of fuel will fall to the bottom of the tank. You then should throttle up *gently* and burn for a while to make the upper part of the fuel fall to the bottom as well, then later you can throttle up to full power. DO *NOT* throttle up too quickly or the fuel will get unstable again in this case.

Link to comment
Share on other sites

HoneyFox, I'm wondering if the numbers need to be tweaked some, maybe? I know Apollo used a "few second" RCS burn to settle fuel prior to SPS ignition, and that's 4x490N thrusters settling ~18 tons of fuel (out of 29 tons of craft, or 44 counting LM) in a few seconds. That certainly doesn't happen with EI. On the other hand, if we make propellants *too* susceptible to acceleration, then drag will make it very hard to light lower-altitude upper stages.

Link to comment
Share on other sites

HoneyFox, I'm wondering if the numbers need to be tweaked some, maybe? I know Apollo used a "few second" RCS burn to settle fuel prior to SPS ignition, and that's 4x490N thrusters settling ~18 tons of fuel (out of 29 tons of craft, or 44 counting LM) in a few seconds. That certainly doesn't happen with EI. On the other hand, if we make propellants *too* susceptible to acceleration, then drag will make it very hard to light lower-altitude upper stages.

True, I've made an attempt to tweak these values but it seems like the propellants are still not susceptible enough

For the drag during ascent, i don't think it's a big issue, we can always install ullage motors to counteract the drag and still provide slightly positive acceleration during stage separation (in fact, rockets like Saturn V do have such design for their 2nd stage), but it's true that this will be more tricky about how much thrust we need for ullage during our design phase (i.e. when in VAB) because we cannot easily know how much drag force there will be...

Edited by HoneyFox
Link to comment
Share on other sites

For larger things that's fine (I always automatically add ullage rockets...); I was thinking of, for example, the WAC Corporal, the Aerobee, and other sounding rockets of that ilk. (220kN for .75 seconds booster, then a pressure-fed RFNA/Aniline sustainer in the second stage.)

Which reminds me: does the ullage simulation take into account how full a tank is? When a tank is very full it should require much less work to ullage it (the tank is much more propellant by volume when there's more propellant in it...). This would also solve the above problem, I think: since the RFNA/Aniline tanks are full on separation/ignition, then even massive drag shouldn't disturb the tanks much.

Link to comment
Share on other sites

Firstly, thanks for this great mod. Super realistic. I'm very new to this mod and struggling to learn the science.

I am having real beginners problems so I'm hoping someone can advise me. I have Realism Overhaul, Real Fuels, Race for the Stars pack, FAR and Engineer (I think they are the relevant ones). I have a really simple rocket with a stayputnik and a small stretchy tank and an A4 engine. The tank is filled with the recommended proportions of Kerelox.

When attached to the launch clamp, it ignites and burns. I usually let it burn for a few seconds and then release the clamp. About 1s after I release the clamp the engine turns off, the rocket gets to about 30 m. Why is this happening and what can I do to correct it?

I tried looking for information earlier in the thread but to no avail. Thanks.

EDIT: Tried using thrust limiter on the engine but still shuts off the engine after maybe a second.

Edited by TimeforAction
Link to comment
Share on other sites

For larger things that's fine (I always automatically add ullage rockets...); I was thinking of, for example, the WAC Corporal, the Aerobee, and other sounding rockets of that ilk. (220kN for .75 seconds booster, then a pressure-fed RFNA/Aniline sustainer in the second stage.)

Which reminds me: does the ullage simulation take into account how full a tank is? When a tank is very full it should require much less work to ullage it (the tank is much more propellant by volume when there's more propellant in it...). This would also solve the above problem, I think: since the RFNA/Aniline tanks are full on separation/ignition, then even massive drag shouldn't disturb the tanks much.

Currently it doesn't. It shouldn't be too hard to add that factor though (if not by using realistic way to simulate that). but i guess that will make it even harder, perhaps coefficient tweaking should be done before adding this.

Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...