[1.8+] Real Fuels

[Agathorn]

Thanks!

I just downloaded your latest version, and i'm going to try Ferram's code with a surface area of like 1 or something since I don't know what it should be.

[Agathorn]

So i'm still getting major amounts of roll, and the space craft seems incapable of rolling through either thrusters or RCS to counteract it.

It was a more smooth path though, if I ignored the roll. Just had to be good on the ball.

[HoneyFox]

So i'm still getting major amounts of roll, and the space craft seems incapable of rolling through either thrusters or RCS to counteract it.

It was a more smooth path though, if I ignored the roll. Just had to be good on the ball.

Are you using procedural fairings? or do you have some boosters that are not 'strut'ed well enough?

[Scripto23]

I haven't gotten a chance to test anything yet, but the roll may due to the way the mod arranges the 9 Merlin engines. They're symmetrically placed 3 along each side for a total of 6 on the main cluster, then 3 individual ones in a row through the center (picture). This was done so that certain engines could be shut down independently, which is the way SpaceX plans to land the first stage. After first staging, shut down the cluster of 6, supersonic retrograde burn with 3 engines to set a ballistic trajectory back to the landing pad, then shut down 2 of those and use the final remaining engine in the center to land.

Anyway, it's possible that the gimbaling on those separate engines are acting like boosters and if the gimbals are disabled it might kill the roll. So I'll give that a try tomorrow and report back.

[Agathorn]

I haven't gotten a chance to test anything yet, but the roll may due to the way the mod arranges the 9 Merlin engines. They're symmetrically placed 3 along each side for a total of 6 on the main cluster, then 3 individual ones in a row through the center (picture). This was done so that certain engines could be shut down independently, which is the way SpaceX plans to land the first stage. After first staging, shut down the cluster of 6, supersonic retrograde burn with 3 engines to set a ballistic trajectory back to the landing pad, then shut down 2 of those and use the final remaining engine in the center to land.

Anyway, it's possible that the gimbaling on those separate engines are acting like boosters and if the gimbals are disabled it might kill the roll. So I'll give that a try tomorrow and report back.

I'll play around with it some more. Thanks for the info on how it is intended to be flown. I want to do some research into the SpaceX flight profiles.

Thing is though the craft doesn't seem capable of rolling on its own. So even if you fix the problem causing the roll, it still leaves the craft unable to roll on demand. Is this correct for the Falcon 9?

[HoneyFox]

I'll play around with it some more. Thanks for the info on how it is intended to be flown. I want to do some research into the SpaceX flight profiles.

Thing is though the craft doesn't seem capable of rolling on its own. So even if you fix the problem causing the roll, it still leaves the craft unable to roll on demand. Is this correct for the Falcon 9?

For this i will try my gimbal plugin with it to see if roll control can be achieved, if these nine engines are independent 9 parts instead of one, it should work.

[Agathorn]

For this i will try my gimbal plugin with it to see if roll control can be achieved, if these nine engines are independent 9 parts instead of one, it should work.

Well I don't know if it can be different internally, but as far as the parts you place in the VAB, it is one part that has 6 engines in a pack, and it has holes for you to add 3 individual engines in a line in there. I'm not sure why it was designed that way in KSP to be honest.

Wouldn't be hard to make a part with no engines though and then you would mount all 9 in it.

EDIT: Going to try your plugin as well. As I understand it since you do have 3 engines in a line, you should be able to roll by gimballing the two outboard engines.

[HoneyFox]

Well I don't know if it can be different internally, but as far as the parts you place in the VAB, it is one part that has 6 engines in a pack, and it has holes for you to add 3 individual engines in a line in there. I'm not sure why it was designed that way in KSP to be honest.

Wouldn't be hard to make a part with no engines though and then you would mount all 9 in it.

EDIT: Going to try your plugin as well. As I understand it since you do have 3 engines in a line, you should be able to roll by gimballing the two outboard engines.

Ah... that's still acceptable... so it will have two of these three engines to do roll control and for the rest (6+1), everything remains unchanged.

[Agathorn]

Ah... that's still acceptable... so it will have two of these three engines to do roll control and for the rest (6+1), everything remains unchanged.

Doesn't seem to work for me. On the full launch vehicle I get no roll control at all. If I just put the engine cluster on the bottom of the smaller tank, thus making a much smaller launch vehicle, then roll input actually causes yaw for me.

I think the way the engine cluster is designed in KSP might need some work?

EDIT: Yeah I need to go back to stock and verify it isn't something in RO causing it, but from what i'm seeing the 6 engines in the pack do NOT gimbal, which is against the design of the real rocket where the SpaceX literature clearly says all 9 engines gimbal.

Edited January 22, 2014 by Agathorn

[ssgavin1250]

Elokaynu: Ok. Now, load KSP, try to scroll the RF window (by dragging the bar downards), and then quit. Then upload your ksp/KSP_Data/output_log.txt file.

I followed the instructions that you gave him to do, however, there is no RealFuels.dll anywhere in the GameData folder. Once the ModularFuelTanks.dll all the tanks are once again stock. The menu does not even show up in the action groups window.

[NathanKell]

HoneyFox, have you considered manually gimbaling the thrust transforms themselves, rather than gimballing the gimbal transform name? That way engines with multiple thrust transforms could provide gimballed roll control, which would be _excellent_. Useful for any multiple engine mount.

[NathanKell]

ssgavin1250: for ease of cross-work with MFT, the realfuels dll is once again named ModularFuelTanks.dll.

So yes, you should have one, and only one, ModularFuelTanks.dll and it should be in the RealFuels/Plugins folder.

[HoneyFox]

Doesn't seem to work for me. On the full launch vehicle I get no roll control at all. If I just put the engine cluster on the bottom of the smaller tank, thus making a much smaller launch vehicle, then roll input actually causes yaw for me.

I think the way the engine cluster is designed in KSP might need some work?

EDIT: Yeah I need to go back to stock and verify it isn't something in RO causing it, but from what i'm seeing the 6 engines in the pack do NOT gimbal, which is against the design of the real rocket where the SpaceX literature clearly says all 9 engines gimbal.

KSP's stock gimbal module doesn't support roll control at all... but you talked about RO, i don't know if RO has implanted any 3rd-party gimbal module into these Falcon 9's rocket engines though.

You might need to check what gimbal module these engines are using, whether it's the stock one or the one in the Space Shuttle Engines pack, or SmartGimbal in EE or something else.

[AbeS]

I followed the instructions that you gave him to do, however, there is no RealFuels.dll anywhere in the GameData folder. Once the ModularFuelTanks.dll all the tanks are once again stock. The menu does not even show up in the action groups window.

Delete the RealFuels folder and redownload, the plugin is still called modularFuelTanks

[Agathorn]

I followed the instructions that you gave him to do, however, there is no RealFuels.dll anywhere in the GameData folder. Once the ModularFuelTanks.dll all the tanks are once again stock. The menu does not even show up in the action groups window.

What I see in my install, which works:

In GameData there should be a "RealFuels" directory. In that there should be a "Plugins" directory, and in that is a file oddly called "modularFuelTanks.dll", but despite the name it must be the correct file because I NEVER had the Modular Fuel Tanks mod installed. Ever.

[HoneyFox]

HoneyFox, have you considered manually gimbaling the thrust transforms themselves, rather than gimballing the gimbal transform name? That way engines with multiple thrust transforms could provide gimballed roll control, which would be _excellent_. Useful for any multiple engine mount.

The gimbal transform name is exactly the same as the thrust transform actually.

If the modeler can give each nozzle a transform with correct orientation, i mean each of them needs to be rotated along the thrust vector axis for some angle so that its z axis will pointing towards/away from the center y axis of the engine), my plugin should be able to provide proper roll control (i.e. each engine will rotate along its *local* x axis, just like these vernier thrusters, to provide roll moment).

[Agathorn]

KSP's stock gimbal module doesn't support roll control at all... but you talked about RO, i don't know if RO has implanted any 3rd-party gimbal module into these Falcon 9's rocket engines though.

You might need to check what gimbal module these engines are using, whether it's the stock one or the one in the Space Shuttle Engines pack, or SmartGimbal in EE or something else.

Nathan would know best, but I couldn't find any other plugins that looked to control Gimbals installed in my RO copy of KSP. I know one is used with the RftS engines, but i'm not using those so don't have it installed.

[ssgavin1250]

NathanKell, I actually found that I am only having the scrolling issue on any of the tanks from the StretchyTanks mod, it seems to work on all the tanks that have a fixed volume. On the stretch tanks it seems to be giving the window too many decimal places to deal with causing it to word wrap, thus moving the buttons farther down than the plugin thinks there should be options. Because of this maybe the plugin does not realize I should be able to scroll down.

[NathanKell]

Agathorn, HoneyFox: it uses (or doesn't use) whatever LazarasLuan originally assigned, and/or Scripto23 changed in the realism patch for it.

HoneyFox: why use the transform's local axes, other than "down"? And note the thrust transform *isn't* always the same as the gimbal transform--sometimes there's a separate thrust transform from the model used to represent the gimbaling part of the engine.

Re: local axes. This is exactly the issue with dtobi's mod: some engines have flipped local axes for the gimbal. So why not use *vessel* axes as the basis for the non-down axes? That would avoid any issues in exporting.

[NathanKell]

ssgavin1250: interesting find! I'll fix the display.

EDIT: try reinstalling. They *should* round in the latest RF. Still getting the issue?

Edited January 22, 2014 by NathanKell

[HoneyFox]

Agathorn, HoneyFox: it uses (or doesn't use) whatever LazarasLuan originally assigned, and/or Scripto23 changed in the realism patch for it.

HoneyFox: why use the transform's local axes, other than "down"? And note the thrust transform *isn't* always the same as the gimbal transform--sometimes there's a separate thrust transform from the model used to represent the gimbaling part of the engine.

Re: local axes. This is exactly the issue with dtobi's mod: some engines have flipped local axes for the gimbal. So why not use *vessel* axes as the basis for the non-down axes? That would avoid any issues in exporting.

Ok, there is possibility that these are different transforms. So let's just talk about the transform specified in gimbal module.

Rotating gimbals based on vessel's reference transform is the original way the stock gimbal module uses.

This works well with yaw/pitch control coefficients in my plugin, but gives bad results when dealing with roll controls when we have symmetric counterparts sharing same roll coefficient value of tweakables. (because inverted pitch/yaw commands should be generated in order to achieve roll control)

Also, in order to constrain the gimbal (in order to implement the single-axis gimbal feature), it is needed to convert the control (based on vessel's reference transform) into gimbal transform first, then calculate the local rotation (constraints get involved here) and convert it back to vessel's reference transform because my module is not replacing the stock gimbal module but more like "parasitizing" on it.

Edited January 22, 2014 by HoneyFox

[Agathorn]

Agathorn, HoneyFox: it uses (or doesn't use) whatever LazarasLuan originally assigned, and/or Scripto23 changed in the realism patch for it.

As far as I can tell Laz's original uses no gimballing, no plugins at all.

Scripto does add this:

    MODULE
    {
        name = ModuleGimbal
        gimbalTransformName  = thrustTransform
        gimbalRange = 0.8
    }

But I don't know if that is something special or just stock.

[ssgavin1250]

so yeah... I have like 6 different installs of KSP, but this is the only instance in which i use both of these two mods at the same time... then i realized I apparently still had v6 of Stretchy installed in this one...

so yeah... it works now

[Agathorn]

so yeah... I have like 6 different installs of KSP, but this is the only instance in which i use both of these two mods at the same time... then i realized I apparently still had v6 of Stretchy installed in this one...

so yeah... it works now

Glad you got it working.

I find the best thing when having problems other's are not, is just nuke your GameData (except Squad of course) and just reinstall all the latest versions of all the mods. Almost every time someone is having weird problems its because they have old or outdated versions mixing with newer ones, or even old mods that aren't even supported anymore (like MFT vs RF).

[HoneyFox]

As far as I can tell Laz's original uses no gimballing, no plugins at all.

Scripto does add this:

    MODULE
    {
        name = ModuleGimbal
        gimbalTransformName  = thrustTransform
        gimbalRange = 0.8
    }

But I don't know if that is something special or just stock.

It means: Scripto assumed that there's a transform named "thrustTransform" in the engine model...

Usually this name is used for engine's gimbal but there might be exceptions. There might be one more hierarchy out there with a different name... who knows? (the modeler of course)