Add ability to set thrust limiter thresholds in action groups

[Fearless Son]

Okay, so the ability to set thrust limiters on engines is great, and with the exception of solid fuel engines, those thrust limits can be adjusted while in-flight.  This is quite handy for things like reducing thrust output to make fine maneuvers without overshooting, or when using a VTOL craft with downward facing nozzles that need to be adjusted to balance the thrust across the mass.  

However, it does come with the limitation that trying to do this while in flight and (especially) under thrust is incredibly difficult.  On a single engine craft this is kind of possible, on multi-engine craft this is a nightmare.  Try limiting the thrust of four engines, one at a time, while also under power and you will see what I mean.  Thus, I would like a way to adjust maximum thrust on-the-fly (ha!) using action groups, if I can previously specify some thrust limits in the VAB/SPH.  

This would allow things like an efficient transition from a VTOL mode to a forward-thrust mode, or the ability to steer a craft by controllably making the thrust asymmetric.  Or even just having a multi-purpose lander that can switch modes to best suit the gravity of the body it is trying to land on.  And (I hope) this would be a relatively easy thing to add.  

Edited July 8, 2016 by Fearless Son

[Blaarkies]

I have a Twin-boar SSTO rocket, that also has a Poodle on the bottom(between the Twin-boar nozzles). At 9km altitude I activate the Poodle, and would like to throttle down only the Twin-Boar(because it is less efficient than the Poodle)...but at the moment all I can do is toggle the Boar on/off, because if I throttle down then the poodle also throttles down

This suggestion is the perfect solution

[Alshain]

I don't really get the need for this.  I mean, why would you carry dead weight like that?  In space, it is irrelevant because you typically have plenty of time to adjust manually.  When launching in atmosphere, having an engine that isn't performing at it's maximum is dead weight and should be designed better or discarded via decoupler.  It makes absolutely no sense to change the thrust limit as you ascend, if your TWR is too high then the rocket should be designed with a lower TWR or designed to stage away the extra mass.  In fact, I don't recommend thrust limiting liquid engines on launch at all, that is what the throttle is for.

As for VTOL, in theory it could be useful but in practice, it won't be fast enough or versatile enough to be able to balance out the engines even with action groups so... well I'm positive it won't work the way you want in the end.

Regardless this would take a UI overhaul.  Action Groups are inherently boolean and I wouldn't count on that changing any time soon.

Edited July 8, 2016 by Alshain

[Blaarkies]

1 hour ago, Alshain said:

I don't really get the need for this.  I mean, why would you carry dead weight like that?  In space, it is irrelevant because you typically have plenty of time to adjust manually.  When launching in atmosphere, having an engine that isn't performing at it's maximum is dead weight and should be designed better or discarded via decoupler.  It makes absolutely no sense to change the thrust limit as you ascend, if your TWR is too high then the rocket should be designed with a lower TWR or designed to stage away the extra mass.  In fact, I don't recommend thrust limiting liquid engines on launch at all, that is what the throttle is for.

As for VTOL, in theory it could be useful but in practice, it won't be fast enough or versatile enough to be able to balance out the engines even with action groups so... well I'm positive it won't work the way you want in the end.

Regardless this would take a UI overhaul.  Action Groups are inherently boolean and I wouldn't count on that changing any time soon.

I get about 1.5 TWR at launch when lifting the 14t payload...any less and I am wasting dv on gravity drag(maybe i am already losing out on gravity drag...but we have to balance dead engine weight vs drag). 30seconds after launch, the vessel is way lighter and the Boar tries to crush the poor payload under a few g's. Remember, this is an SSTO, I cant drop the Boar. Now with that in mind, the Poodle has like 50 Isp more than the Boar, thus using the Poodle as much as possible has increased my payload by 2t(even though the Poodle itself added another 1.5t to the craft).

So this is the problem: 
-I need the Boar for liftoff
-I need the Poodle for squeezing extra efficiency.
-I need to use the Poodle as much as possible for this, else I am "...having an engine that isn't performing at it's maximum is dead weight..."
x- discarding isn't an option for SSTO

As for the VTOL:
-Take of from a bumpy place
-10m-50m in the air, we want to use the wings -> activate forward engines
-at 50m/s we might have half the aerodynamic lift we need to stay aloft...but the vtol engines are pushing up at 1.2 TWR(we are at full throttle because we want to get wing ling as quick as possible, that uses less fuel than hovering)
x-Now we drop throttle so that the wing lift+vtol lift equal 1 TWR upwards? But now it takes longer to reach flight speed.
x-We could cut the vtol engines and keep max throttle...hoping that we could pull out of the dive.
►If we could somehow keep the throttle at max, but slash the vtol throttles all at once to 50%, then we would just start falling slowly for a few seconds until enough speed is attained for more winglift, at which point we could finally cut the vtol engines, and again fall the last few seconds until flight speed is reached
* I use "fall" to mean "rate of decent is increasing"...not tumbeling through the air, although that is very kerbal-like.

What if we could set it the same way that Flap/Spoiler limits are set on FAR? 
An extra "show advanced" button(like the RCS thrusters have for actuation toggles). In that extra piece is "Alternative throttle", which you then set, but in the Action Groups is a "toggle alternative throttle" event to add to an action group.
*A linear timer function would be cool, so that the throttle slowly transitions from current->alternative over 10seconds(or "x" seconds)

[Van Disaster]

This is actually not a bad idea, if you gave the limiter discrete steps like flap deployment. One of the throttle balancer mods might already do this, of course.

It'd be quite convenient if you needed to thrust limit a whole group of engines too, especially if you're using some autopilot mod that doesn't throttle limit itself.

Edited July 8, 2016 by Van Disaster

[Alshain]

12 hours ago, Blaarkies said:

I get about 1.5 TWR at launch when lifting the 14t payload...any less and I am wasting dv on gravity drag(maybe i am already losing out on gravity drag...but we have to balance dead engine weight vs drag). 30seconds after launch, the vessel is way lighter and the Boar tries to crush the poor payload under a few g's. Remember, this is an SSTO, I cant drop the Boar. Now with that in mind, the Poodle has like 50 Isp more than the Boar, thus using the Poodle as much as possible has increased my payload by 2t(even though the Poodle itself added another 1.5t to the craft).

So this is the problem: 
-I need the Boar for liftoff
-I need the Poodle for squeezing extra efficiency.
-I need to use the Poodle as much as possible for this, else I am "...having an engine that isn't performing at it's maximum is dead weight..."
x- discarding isn't an option for SSTO

As for the VTOL:
-Take of from a bumpy place
-10m-50m in the air, we want to use the wings -> activate forward engines
-at 50m/s we might have half the aerodynamic lift we need to stay aloft...but the vtol engines are pushing up at 1.2 TWR(we are at full throttle because we want to get wing ling as quick as possible, that uses less fuel than hovering)
x-Now we drop throttle so that the wing lift+vtol lift equal 1 TWR upwards? But now it takes longer to reach flight speed.
x-We could cut the vtol engines and keep max throttle...hoping that we could pull out of the dive.
►If we could somehow keep the throttle at max, but slash the vtol throttles all at once to 50%, then we would just start falling slowly for a few seconds until enough speed is attained for more winglift, at which point we could finally cut the vtol engines, and again fall the last few seconds until flight speed is reached
* I use "fall" to mean "rate of decent is increasing"...not tumbeling through the air, although that is very kerbal-like.

What if we could set it the same way that Flap/Spoiler limits are set on FAR? 
An extra "show advanced" button(like the RCS thrusters have for actuation toggles). In that extra piece is "Alternative throttle", which you then set, but in the Action Groups is a "toggle alternative throttle" event to add to an action group.
*A linear timer function would be cool, so that the throttle slowly transitions from current->alternative over 10seconds(or "x" seconds)

For the SSTO, I would suggest... don't use SSTO.  You aren't saving anything.  SSTO's are way overrated, and they aren't very cost effective.  As for the VTOL, it won't work that way, you will never get it to be so precise.  I really don't care if they add it or not, I just don't see the need for the effort and I doubt they will add such a thing anyway.  There is no precedent for it in game and the system of configuring it that you propose is very complicated and goes against the simplicity that Squad tries to maintain with the UI.  I wouldn't get your hopes up at this happening.

[Blaarkies]

11 hours ago, Alshain said:

For the SSTO, I would suggest... don't use SSTO.  You aren't saving anything.  SSTO's are way overrated, and they aren't very cost effective.  As for the VTOL, it won't work that way, you will never get it to be so precise.  I really don't care if they add it or not, I just don't see the need for the effort and I doubt they will add such a thing anyway.  There is no precedent for it in game and the system of configuring it that you propose is very complicated and goes against the simplicity that Squad tries to maintain with the UI.  I wouldn't get your hopes up at this happening.

I would say you are doing SSTOs wrong then...try playing around with them, stick to basic designs until you get the hang of it and remember to minimize complexity(cost and mass is irrelevant once you land it back at KSC). My SSTO gets payloads to LKO at less than 700funds per ton at excellent reliability, i have yet to crash one after the 16th launch. Playing on Hard settings and funds/sci/rep turned down to 30% i need to squeeze all funds out of every launch. I know the Cheap & Cheerful rocket challenge shows disposable lifters that does this even cheaper, but reliability is a serious concern for me since I cannot really afford a failed launch or click a revert button because of the chosen difficulty...hence I love using this SSTO that saves me roughly 2000funds per ton it puts into SSTO.

As for VTOL, I have done exactly that and got it to be so precise, but I had to use two sets of engines: 2 engines burning gives 100% thrust, but only one engine burning gives 50% thrust(now just position these groups as pods around the craft where necessary). But this hogs down a lot of action groups just for the takeoff part. It isn't really more complicated than the extra "advanced" buttons added to the RCS thrusters...players don't have to use it if they don't want to, but still squad went ahead and added 7+ more buttons to RCS ports, despite that going against the simplicity of the ui.

VTOLs are some of the top 10 cool stuff the game can brag about, even though it is really never needed to "finish" career mode...kind of like spaceplanes, rovers, mining bases or ion probes. But the parts for all those still exist because enough players consider them fun.

I agree that almost any amount of effort from SQUAD to implement this might not be worth the feature, since the VTOL player base is quite small...so ill just stick to Davon Throttle Control Systems to do VTOL craft

[Red Iron Crown]

For the SSTO, perhaps you could swap out each Twin Boar for a pair of Vectors (better TWR and Isp with similar thrust, and the higher cost is unimportant if you're recovering it well). That way you could use an action group to turn off half of them when the TWR gets excessive.

[Blaarkies]

2 hours ago, Red Iron Crown said:

For the SSTO, perhaps you could swap out each Twin Boar for a pair of Vectors (better TWR and Isp with similar thrust, and the higher cost is unimportant if you're recovering it well). That way you could use an action group to turn off half of them when the TWR gets excessive.

Great idea! But I am afraid I haven't reached that far into the techtree on this save yet(still haven't upgraded the SPH, so the 140t limit makes unlocking the 3.75m parts useless at the moment).
How would I position the pair of Vectors so as to not induce torque as I turn off one of them?

[Red Iron Crown]

You use a pair of them to replace each Twin Boar (I'm assuming you have more than one Twin Boar as the suggestion doesn't make sense other wise). Turn off one in each pair and it should avoid thrust torque while delivering half the thrust.

[Alshain]

9 hours ago, Blaarkies said:

I would say you are doing SSTOs wrong then...try playing around with them, stick to basic designs until you get the hang of it and remember to minimize complexity(cost and mass is irrelevant once you land it back at KSC). My SSTO gets payloads to LKO at less than 700funds per ton at excellent reliability, i have yet to crash one after the 16th launch. Playing on Hard settings and funds/sci/rep turned down to 30% i need to squeeze all funds out of every launch. I know the Cheap & Cheerful rocket challenge shows disposable lifters that does this even cheaper, but reliability is a serious concern for me since I cannot really afford a failed launch or click a revert button because of the chosen difficulty...hence I love using this SSTO that saves me roughly 2000funds per ton it puts into SSTO.

It's not that I do SSTO wrong, it's that I do standard lifters very right.  My standard lifters, can compete quite well with SSTOs, to the point that the SSTO's benefits become not worth the time spent recovering them.

Edited July 9, 2016 by Alshain

[Blaarkies]

16 hours ago, Red Iron Crown said:

You use a pair of them to replace each Twin Boar (I'm assuming you have more than one Twin Boar as the suggestion doesn't make sense other wise). Turn off one in each pair and it should avoid thrust torque while delivering half the thrust.

Oh yes that would work beautiful!
Sorry i should have mentioned the SSTO: It is a single Boar(with a Poodle on the bottom of the boar) with 2 orange tanks stacked on top. At the very top is the 2.5m faring structure with a docking port(and all the probe, RCS, Reaction wheel, parachute, stuff on top). On the top docking port is a 2.5m heatshield(bottom side facing down towards the Boar), but there is another docking port on the heatshield(on which the final payload is mounted). After payload delivery, i can still dock to spacestaions to transfer left over fuel. Once all is done, i detatch the heatshield-docking port combo, and redock to that...now the SSTO has a heatshield nosecone(re-entry happens nose first)
 

13 hours ago, Alshain said:

It's not that I do SSTO wrong, it's that I do standard lifters very right.  My standard lifters, can compete quite well with SSTOs, to the point that the SSTO's benefits become not worth the time spent recovering them.

Oh yes of course, i do realize disposable launchers can get very cheap AND they only take like half the mission time(since SSTO missions are over until it is back at KSC). At normal difficulty I would never even look at SSTOs, because by the time I have that kind of tech I am already drowning in funds...running two disposable missions in about the same amount of time as a single SSTO mission is definitely more profitable, but for my 30% settings the profit margin on disposables get really low, to the point where SSTOs are more profit per effort. But mostly what I like is that SSTOs can take up anything with them, no matter the price, like multiple RTGs, massive RCS/Reaction wheel controls, best probe cores and even lots of those super expensive fins. This all helps to make my missions a lot easier while not costing anything extra(once I have that kind of tech someday)

* I took another look at disposables again(i dismissed them back when the SRB nerf came in), but I am struggling to get below 1800funds/ton without resorting to hundreds of the small basic fins. Gimbaling on engines keep it upright, but if I have to throttle down it starts tumbling. How do I avoid this?

[Norcalplanner]

5 minutes ago, Blaarkies said:

* I took another look at disposables again(i dismissed them back when the SRB nerf came in), but I am struggling to get below 1800funds/ton without resorting to hundreds of the small basic fins. Gimbaling on engines keep it upright, but if I have to throttle down it starts tumbling. How do I avoid this?

Check out the Cheap and Cheerful Rocket Payload Challenge I ran back in 1.0.5 for cheap disposable lifter ideas.  Many of the entries were below 700 funds per ton of payload; a couple even got below 600 funds/ton.  You can also find a lot of good ideas for cheap lifters in the tutorial linked in my signature.

[Rodyle]

On 7/8/2016 at 9:51 PM, Alshain said:

For the SSTO, I would suggest... don't use SSTO.  You aren't saving anything.  SSTO's are way overrated, and they aren't very cost effective.  As for the VTOL, it won't work that way, you will never get it to be so precise.  I really don't care if they add it or not, I just don't see the need for the effort and I doubt they will add such a thing anyway. 

IE: Stop liking things I don't like.

[Azimech]

Perfect for building advanced engines and electronics. I vote yes!

[pandaman]

As an idea I like it and I can see it's uses, even though I don't know how much I would use it myself.

 That said I have no idea how easy or difficult it could be to implement.

[wumpus]

On 7/8/2016 at 1:29 AM, Alshain said:

I don't really get the need for this.  I mean, why would you carry dead weight like that?  In space, it is irrelevant because you typically have plenty of time to adjust manually.  When launching in atmosphere, having an engine that isn't performing at it's maximum is dead weight and should be designed better or discarded via decoupler.  It makes absolutely no sense to change the thrust limit as you ascend, if your TWR is too high then the rocket should be designed with a lower TWR or designed to stage away the extra mass.  In fact, I don't recommend thrust limiting liquid engines on launch at all, that is what the throttle is for.

I see two places where I really want this.  The problem is I doubt the same UI would work for both of them.  I'm guessing that being able to adjust max thrust in flight would help for landing, but it wouldn't help for the orbital insertion at all.

Orbital insertion via nukes and chemical rockets (let the nukes run full blast for the duration and feather the chemicals as needed).  The current method tends to use action groups to fire the chemicals full bore and shut them down as needed (which is likely optimal anyway).

Landers: Do a near-suicide burn to some point above the surface with max thrust, then reduce thrust for better control (this might even take the poodle off the "useless engine" list).  I suspect that allowing you to change max thrust in flight would help (and also allow you to crash while fiddling with the change).

[Fearless Son]

On 7/10/2016 at 0:57 PM, wumpus said:

Landers: Do a near-suicide burn to some point above the surface with max thrust, then reduce thrust for better control (this might even take the poodle off the "useless engine" list).  I suspect that allowing you to change max thrust in flight would help (and also allow you to crash while fiddling with the change).

That is actually one of the exact situations I had in mind for this kind of thing.  If you are using a single-engine landing craft you can kind of manage it by right-clicking and manually setting the slider, but you have to be quick.  However, if you are using a multiple-engine lander (like the kind you might if you have a docking port on the bottom or a package you intend to drop on the surface to reduce ascent mass) then not only do you have to be quick with the right-click menu adjustments, you also need to be precise to get everything to the same thrust level lest you end up with asymmetric thrust and corkscrew in a way to make your suicide-burn literal.  

There might be something to be said for having multiple symmetric engines and disabling them in pairs while allowing the remaining ones to go full thrust, but that introduces its own problems.  For example, you would need at least four engines (two to disable and two to keep on,) which might be a bit overkill for many landers.  Not to mention that it introduces additional complications about trying to balance the fuel quantity per engine (if each is fed from its own tank.)  

[TheDestroyer111]

I vote no! It would be too complex. It is much more effective to just make the thrust limiter "symmetrified". Currently, when you have engines on a symmetry axis, you adjust thrust limiter on only one of them. But when you deploy aero surfaces or adjust their authority limiters, you do it for all surfaces that were placed in symmetry at the same time. Thrust limiter should also follow this rule. It won't be a problem for VTOL planes, as the CoM shift when attaching payload or changing fuel levels is almost always in the forward/backward axis and if you want to adjust it on roll axis, just attach the 2 engines separately.

[Alshain]

41 minutes ago, TheDestroyer111 said:

I vote no! It would be too complex. It is much more effective to just make the thrust limiter "symmetrified". Currently, when you have engines on a symmetry axis, you adjust thrust limiter on only one of them. But when you deploy aero surfaces or adjust their authority limiters, you do it for all surfaces that were placed in symmetry at the same time. Thrust limiter should also follow this rule. It won't be a problem for VTOL planes, as the CoM shift when attaching payload or changing fuel levels is almost always in the forward/backward axis and if you want to adjust it on roll axis, just attach the 2 engines separately.

See, now this makes much more sense to me.

[Blaarkies]

Found it!
modactions-control-your-vessel-including-other-mods-via-actiongroups

@Fearless Son, you wanted a mod for this, right? It seems like it has all the features mentioned, and the interface looks real simple and sleek too!