[0.20.2] Project Arcturus: Thrust Corrector, Remission and Range Safety

[The Lone Wolfling]

Does anybody have any better ideas what might be going on, or what tests I could do to figure out what's going on? It's not the end of the world if I can't get these engines working, but they did look like they'd be fun for good-looking SSTOs. Thanks for reading, and extra thanks if you've got any ideas!

I know exactly what's going on.

The way that the SABRE engine works is that it swaps moduleengines on-the-fly. Thrust corrector currently assumes the the moduleengines in a part doesn't change.

The way the thrust corrector works is that on flight start it records the true maximum thrust of the engine into a variable, and then adjusts the maximum thrust every frame to get the mass flow right. As such, what happens is that on flight start, it records the maximum thrust in a vacuum of the moduleengines in the SABRE. Then, when you switch to the rocket, the engine is switched, but the thrust corrector doesn't know that and keeps changing the maximum thrust based on the original maximum thrust (of the other engine module)

It should be relatively simple to check if the Isp curve has changed, and if so recalculate everything. It's not perfect (it would fail if both engines have the same Isp curve but different maximum thrusts), but it should work for the SABRE at least.

[CaptainArbitrary]

The way that the SABRE engine works is that it swaps moduleengines on-the-fly. Thrust corrector currently assumes the the moduleengines in a part doesn't change.

This is correct. Since I don't use anything like that in my game, it never occurred to me to check for it in the plugin.

[Commander Zoom]

Even though I probably won't bother installing these myself (but Range Safety tempts me), they're all neat little mods and I thank you for making and sharing them.

[rryy]

After playing around with the Thrust Corrector, I feel that it makes jets quite overpowered. Turbojets normally barely get up to 225 kN at higher altitudes, but this makes it peak at nearly double that at 450 kN, which is great!

Edited July 21, 2013 by rryy

[CoriW]

The download for Thrust Corrector seems to be broken at the moment, would anyone happen to have a copy of it they could link temporarily until it's fixed?

EDIT: Nevermind, it appears the download site was under maintenance, it's back up now.

EDIT: Since nobody else has posted I'll avoid double posting by editing this post, does anybody know if Thrust Corrector is compatible with the Modular Fuel System plugin?

Freely given. If you wanna write a GUI and make the thing work in the VAB, I know at least a few people will be very happy.

I don't know if I've mentioned lately, by the way, just how dependent I've become on Modular Fuel System. It's completely changed the way I play the game. Even my capsules use the mod, so I can configure their consumables (hydrazine, Oâ‚‚ and the like) in the VAB. Thanks so much for it.

Wait a second, is this pretty much confirmation that Thrust Corrector works with Modular Fuel System?

Edited July 24, 2013 by CoriW

[rryy]

Does anyone know if the Thrust Corrector is working for 0.21?

[sephirotic]

Great simple realism mod fix. I love this kind of simple plugin mods that bumps realism with tweaks that works with virtually every mod.

Another interesting realism mod plugin/feature that would go very nicely with this and modular tanks would be a mod that actually limits minimum throttle on the engines. Large lifter/1st stages engines usually can´t be throttle at all while upper stage and modern orbital engines can only be throttle at best on the range of 30~100%, even so, smaller throttle-speeds means less than optimal pressure and lower efficiency per thrust. A mod that could simulate this depending of engine size and fuel types would be awesome, even in a simplified way.

In this topic of throttle control, i would love to see someone making a "throttle steering" mod compatible with 0.2x. (controls throttle of rocket similar to RCS fashion but to help steering and rovering/landing) I miss that mod and the great possibilities regarding vtols that thing could give...

Edited July 25, 2013 by sephirotic
spelling fixes

[mizo]

So far thrust corrector is working fine on 0.21 for me.

[BigFatStupidHead]

Wow! I'm glad to find thrust corrector; I've always had to handwave the weirdness in fuel-flow rate as alternate-universe laws of physics.

[Jong]

Bug report: This mod seems to ramp up the power of engines that have higher Isp at sea level than in vacuum beyond their rated maximum thrust. When I used it with firespitter's helicopter rotor, which has a Isp of 2000 at sea level and 1 in vacuum, touching the throttle slightly gives the engine some ungodly high thrust just before the helicopter hilariously flings itself into the sky and rips itself apart.

[drtedastro]

just downloaded and installed down range.

Great, just great....

have been looking for something like this....

many thanks.

EDIT: works fine with 0.20.?? but I am unable to get it to work with 0.21.1. Any ideas? has the .cfg format or method changed for .21???

any help will be appreciated.

EDIT: oops, silly me. Does not work when using a Pod with Kerbals..... Only for other pods. Ok, so I will have to deal with Bill K. some other way.....

Edited August 5, 2013 by drtedastro

[Van Disaster]

ThrustCorrector really should not work with turbines, should it? ( or any engine that makes use of atmosphere. ) Unfortunately they also use ModuleEngines, so I can't think of an easy way to avoid it.

[Jong]

maxMdot = e.maxThrust / (Math.Max(this.ispAtSeaLevel, this.ispInVacuum) * engineModule.G);
maxThrustInVacuum = this.maxMdot * this.ispInVacuum * engineModule.G;

This should get the thrust corrector to work properly on engines with max Isp at sea level as well.

EDIT: I've just discovered that jet engines have maximum Isp at pressures between sea level and vacuum.

			ConfigNode ispCurve = new ConfigNode ();
			e.atmosphereCurve.Save (ispCurve);
			string[] ispValues = ispCurve.GetValues ("key");
			int vCount = ispValues.Length;
			float maxIsp = float.MinValue;
			char[] delimiters = new char[] { ' ', ',', ';', '\t' };
			for (int i = 0; i < vCount; i++)
			{
				string[] valueSplit = ispValues[i].Split(delimiters, System.StringSplitOptions.RemoveEmptyEntries);
				maxIsp = Mathf.Max(maxIsp, float.Parse(valueSplit[1]));
			}

			maxMdot = e.maxThrust / (maxIsp * engineModule.G);
			maxThrustInVacuum = this.maxMdot * this.ispInVacuum * engineModule.G;

These changes appear to work, although I'm a complete n00b at modding so I can't guarantee 100% that it won't screw anything up.

I've attached a link to the patched plugin and source.

Link

EDIT: I've just discovered that it also doesn't work on engines that switch modes in flight, like the B9 SABRE engines

Edited August 10, 2013 by Jong

[Hyratel]

any love for this? especially on two-mode engines, it locks at the current-thrust and breaks usability

[pina_coladas]

So does this totally throw off thrust to weight calculations in kerbal engineer and mechjeb? I feel sure that it does, which is the only thing stopping me from grabbing this badly-needed fix.

[Hyratel]

it does but only in the VAB. eventually you'll get a feel for how severe the thrust handicap is at sea level, and learn to build to compensate

[Starwaster]

it does but only in the VAB. eventually you'll get a feel for how severe the thrust handicap is at sea level, and learn to build to compensate

It becomes a lot less severe if you use Modular Fuel Tanks + Real Fuels and build rockets the way they're built IRL: Use LH2/LO2 for lighter upper stages so your lower stages don't labor so much.

[mrluckypants96]

Tried this out with some other mods and got... interesting... results. It seems that the thrust from jets was scaled up highly (350Kn from a 200Kn jet (LLL Radial Jet) at sea level) and that rocket thrust was highly decreased (150Kn from a 960Kn engine (B9 Sabre) at the edge of atmo). I can't get into orbit anymore, but, on the bright side, my jet fighters are a lot faster.

[KerbMav]

Has anyone picked up this mod and dealt with the problems?

Seems that way!

Edited November 7, 2013 by KerbMav

[Absolute Human]

Has anyone picked up this mod and dealt with the problems?

Seems that way!

This is not entirelly honest...

That mod works the opposite way.

It encreases thrust above 100%...

Not much realism in that

And it seems that the new thrust limiting function or something other in 0.23 breaks it

Maybe someone could make a hotfix?

[a.g.]

That mod works the opposite way.

It encreases thrust above 100%...

Not much realism in that

I'm pretty sure I know exactly why that bug happens (and just wrote to Ferram about it). As a workaround, you should enable and set both cutoff sliders - note here that setting the ISP cutoff to 0 effectively means no cutoff (i.e. what you want), because there are no engines with <0 isp.

[Starwaster]

I suggest Modular Fuel Systems Continued.

http://forum.kerbalspaceprogram.com/threads/52780-Modular-Fuel-System-Continued-v3-3

It has thrust correction built in.

If you have no interest in the modular aspects of MFS, just install it and ignore those parts. Don't install Real Fuels, the thrust correction will work just fine.

[Absolute Human]

It has thrust correction built in.

I can see only "modularFuelTanks.dll" there, but I will try and see if it works as a thrust corrector.

[NathanKell]

MFS thrust correction only works on an engine that has a MFS engine module. It doesn't work globally. If you want non-MFS thrust correction in .23, get KIDS.

[Starwaster]

MFS thrust correction only works on an engine that has a MFS engine module. It doesn't work globally. If you want non-MFS thrust correction in .23, get KIDS.

crap your right. dunno what I was thinking.

So it pretty much only works with Real Fuels option installed with it.