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

[HoneyFox]

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.

That sounds strange, is your rocket spinning fast? And please check the fuel flow status in the engine's context menu. It should be Very Stable or Pressurized normally.

[TimeforAction]

I am certain that I am doing something really basic to screw this up. SRB works fine BTW. I also have Remote Tech 2. Could it be something to do with the no connection signal I get from RT which appears as soon as the clamp is released?

No spin on the rocket at launch. No problem with ignition on the launch clamp. It will burn forever on the clamp. I watched the temp rise (on the clamp) to about 700C.

On clamp release it lasts for about 1.5s then the engine shuts off. Fuel flow is Very Stable, even over the 1.5s before shutdown.

Edited March 22, 2014 by TimeforAction

[rifter]

TimeforAction: Add some batteries?

[TimeforAction]

No batteries available at this stage in the RPL tree

[Guest]

I am certain that I am doing something really basic to screw this up. SRB works fine BTW. I also have Remote Tech 2. Could it be something to do with the no connection signal I get from RT which appears as soon as the clamp is released?

Ah, in that case, add a basic RT antenna. The Tracking Station in RSS is misplaced, and because of that, actually out of range of the basic probe core antennas on the pad.

[TimeforAction]

WOW. That works and solves the engine cut out problem to boot. Why would the engine cut out if it loses communications with mission control?

Regardless, thanks LOADS. It's been taking many hours out of my life to try to figure out that relatively simple problem. Most of those hours are reading through forums trying to find a solution so thanks again.

[HoneyFox]

WOW. That works and solves the engine cut out problem to boot. Why would the engine cut out if it loses communications with mission control?

Regardless, thanks LOADS. It's been taking many hours out of my life to try to figure out that relatively simple problem. Most of those hours are reading through forums trying to find a solution so thanks again.

That's Cilph's design for RT2, go and check his release thread, in which many people have discussed about this design before.

[NathanKell]

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.

Should make it easier, though, surely? Well, easier when tanks are full and harder when tanks are empty. But generally you can use RCS to ullage your OMS tank supply, so the harder-when-nearly-empty should be survivable.

[xZise]

WOW. That works and solves the engine cut out problem to boot. Why would the engine cut out if it loses communications with mission control?[...]

I would guess there are two arguments for having the thrust cut:

1.) You can't communicate with the rocket so it doesn't matter if it is running or not (okay maybe it would have risen above the horizon but that is not a given). I had for example forgotten an antenna so I did notice that problem and tired to figure it out. So you get immediately an notification that no connection is established.

2.) Cutting power is (I guess) in most cases the safest way. You should be in orbit when it happens and then it doesn't really matter. And as I said in the first argument, when you can't control it, it doesn't matter if the engines are running, because you will most likely overshoot.

Fabian

[NathanKell]

3. Easier to force throttle to 0 than to lock throttle to "what it currently is"

[HoneyFox]

3. Easier to force throttle to 0 than to lock throttle to "what it currently is"

Well perhaps not if the plugin simply records and then changes the "throttleLocked" to true for engines on board... then set them back when communication is re-established.

Anyway... that's why I love SRB kick engine for the last stage, with careful calculation, they can send the payload to an orbit that's not too far away from what I want, but I won't need to worry about whether it can burn-out before the communication gets lost. It's especially useful when no communication network has been established yet.

[NathanKell]

Yup, same here! Also no need to worry about needing to loft super-high so you don't reenter during kick.

[pingopete]

I just installed this hoping to get slightly more immersive launches of my shuttle and like the challenges it presents However, I can't see any launch clamp sparks? I have them either side of my SSME's but see nothing when I action group trigger their 'activate' function :/ My engines will start with the clamps present either side but no visuals

[HoneyFox]

I just installed this hoping to get slightly more immersive launches of my shuttle and like the challenges it presents However, I can't see any launch clamp sparks? I have them either side of my SSME's but see nothing when I action group trigger their 'activate' function :/ My engines will start with the clamps present either side but no visuals

No there's no special eye candy for the ignitors... plus, these sparks are not to ignite the engine in RL, but to burn the vented propellant before launch.

[theSpeare]

How's the compatibility for this plugin? I consider this to be essential and can't wait for it to be available

[HoneyFox]

How's the compatibility for this plugin? I consider this to be essential and can't wait for it to be available

If Squad hasn't made big changes to engines (I think they haven't, they basically are focusing on new vessel type & claw related things IMO), it should be still compatible I think. You can always make a try.

Edited April 2, 2014 by HoneyFox

[theSpeare]

Sweet! Will you quickly add the ignition requirements etc for the new engines?

[HoneyFox]

Sweet! Will you quickly add the ignition requirements etc for the new engines?

Until i get back home and finish the download of 0.23.5 of course.

[theSpeare]

No problemo! Cheers for your work

[HoneyFox]

No problemo! Cheers for your work

Ok Tested. So far everything works well.

EDIT: here is a modified config.xml which makes ullage much easier via small acceleration.

Replace the file in "GameData\EngineIgnitor\Plugins\PluginData\EngineIgnitor\" folder with it.

https://www.dropbox.com/s/12g16cz9yf2hvpy/config.xml

Edited April 6, 2014 by HoneyFox

[Oksbad]

Is it intentional that full tanks still require ullage motors to settle the fuel? I assumed they wouldn't but then my upper stage failed to ignite.

[Guest]

Yes, it's intentional. All tanks require an ullage burn, except of pressurized ones.

[coldblade2000]

Do any of you know where I could find information about the ingitor/# of ignitions real engines have? I'm making a config for Realism Overhaul but I haven't found ****.

[HoneyFox]

Do any of you know where I could find information about the ingitor/# of ignitions real engines have? I'm making a config for Realism Overhaul but I haven't found ****.

It's quite limited as I've been trying to find some information for those engines in KOSMOS/SovietEnginePack/etc which have counterparts in RL. Most of them will at most tell you the type of ignitor, very few will tell you how many times it can ignite in ground tests, even fewer will tell you its capability when in actual launches.

[HoneyFox]

Is it intentional that full tanks still require ullage motors to settle the fuel? I assumed they wouldn't but then my upper stage failed to ignite.

For most of these rigid fuel tanks, I think there should be always ullage inside, even a very small portion.

Anyway, i'm working on this, so that in next release, If a tank has more fuel inside, the ullage will be simpler and you *might* need shorter time for ullage burns.

* because the vessel will be much heavier when it has more fuel, the acceleration provided by ullage burn will be smaller. Hence the final ullage burn time might be still slightly longer than when it's nearly empty.