An unexpected benefit of tweakables

[Kerbart]

Not sure if this has been posted before, and if so you can throw custard pie in my face... But it's great that COM in the VAB reacts immediately to fuel changes. That way you can put the RCS ports where the COM really will be when it's docking time, not where it is when the tanks are fully loaded.

[leax256]

I have thought about doing this but haven't really played enough to need to test it. now, how does it react to changes in thrust limiting?

[ripvanlemon]

...COM in the VAB reacts immediately to fuel changes...

That actually is really cool! I didn't realize you could do that. I usually use RCS and SAS together when docking (SAS to hold my orientation and RCS to translate) so it's not really VITAL to have the thrusters right on COM, but it does help.

Now, if you have thruster groups on either side of COM, aren't they supposed to work "smart" -- i.e. they thrust proportional to their distance from COM? So this would really just help you cut out a set.

[LethalDose]

I have thought about doing this but haven't really played enough to need to test it. now, how does it react to changes in thrust limiting?

I think CoT reacts immediately, same as the fuel/CoM. I haven't tried it, but thrust-limiting was used in the VAB to point the thrust thru the CoM on several different asymmetric craft during one of the KerbalKon events.

[Commissioner Tadpole]

Well, you still have to predict how much fuel there will be when you begin to dock.

[Cashen]

I would find this useful for placing separation motors on radially attached boosters. You could find where their empty center of mass is and place the separation motors there, instead of guessing. That way they'll be properly pushed to the side instead of flipping out.

[Sof]

Well, you still have to predict how much fuel there will be when you begin to dock.

Yes, but chances are you know what it will be roughly and set accordingly, and if its a refuelling station you're docking to, then you can assume your tanks should be more or less empty.

Either way, using the COM when the fuel tanks are set to empty is going to be a closer to the actual value than a full tank.

I never thought of doing this if I'm honest. Glad to pick up tips from this thread.

[Sirine]

I can open FULL parachute while entering DUNA. At high altitude.

and check the illumination (light) position while at VAB or SPH.

[nimbim]

It's neat, but I think with the new SAS it almost doesn't matter where your RCS thrusters are.

[I_Killed_Jeb]

i've been using this to great help in the SPH

[Loerelau]

I can open FULL parachute while entering DUNA. At high altitude.

Yeah!! This is a real benifit! Also set the burning rate on SRB's.

[goldenpeach]

Another use for the tweekables: VTOL!

I remember, in 0.16 or 0.17, that I have tried to make a VTOL but I couldn't for the simple reason that I couldn't know the thrust vector whem the horizontal engine was inactive.

Now, I just have to set the thrust limiter to 0!

[bonyetty]

BTW Docking controls automatically balance the RCS from 0.20 from memory me thinks, so no need to worry about the CoM when placing them. Handy for aircraft though, thanks.

[bonyetty]

Well, you still have to predict how much fuel there will be when you begin to dock.

Not if you use Docking controls. Globe button bottom left of screen, near the green rocket button.

[JackleOfSparta]

I thought RCS was most effective the further it is away from the center of mass?

[SkyHook]

You can't even imagine the progress that my shuttle program has made as a result!

[numerobis]

I thought RCS was most effective the further it is away from the center of mass?

It has the more torque the further it is away from the center of mass. Whether this is effective or not depends on your goal: if you want to rotate, it's good. If you want to translate, torque is the enemy (it makes you rotate).

[Aragosnat]

That you can make rocket / jet powered rovers easier now that their wheels can rotate. =^.^=

Like this baby:

[zxczxczbfg]

I thought RCS was most effective the further it is away from the center of mass?

Well, sort of. It provides more torque, as someone above me said (i.e. more "leverage). However, it used to be that RCS thrusters were literally more powerful the closer to the CoM you put them. This would allow you to make absurdly fast SSTOs powered solely by RCS, an obviously untenable situation in realism terms, so Squad changed the thrusters to have fixed thrust.

[Superfluous J]

Very cool and I never thought of it.

And what you do is set up thrusters at one end of your craft (where the fuel will be). Then set up a second set for when the tanks are about 3/4 full to balance it out. Note where you put them, then delete them. Set up another set for 1/2 full, note wehre you put them and delete them. Then finally set up a 3rd set for 1/4 full. Then put the other 2 sets back and set up action groups to enable the correct ones.

[Rastaman]

SRBs can be fine tuned and are much more useful now. Singular primary ascend stages can just be solid now, powering you for minutes into very thin atmosphere.

[koshelenkovv]

Not sure if this has been posted before, and if so you can throw custard pie in my face... But it's great that COM in the VAB reacts immediately to fuel changes. That way you can put the RCS ports where the COM really will be when it's docking time, not where it is when the tanks are fully loaded.

Also it's incredibly useful for planes.

Another very useful tweakable is fine throttle - landing with overpowered engine is much easier now - just limit throttle to TWR 1.5

[Superfluous J]

Also it's incredibly useful for planes.

Another very useful tweakable is fine throttle - landing with overpowered engine is much easier now - just limit throttle to TWR 1.5

I JUST did this in probably the most extreme way. I put a radial parachute on 5 probes that I sent in one package to Minmus, so I could land them each in a biome, then return to Kerbin with the science for full credit. The probes were so small that the parachutes pulled their COM way from the COT, and the 30kN thrust from the 48-7S was enough to send them spinning. I found that 1.5kN was about all I could accomplish. So, I thrust-limited the engine to 5 percent (5.5 actually, I couldn't get it to 5 for some reason) and then used it like a really tiny regular engine.

Thankfully this mission was to Minmus and not Mun. With these small probes 1.5kN was enough to land and take off with not too much difficulty.