Reaction Wheels Don't Feel Realistic

[Krazy_Kerbal]

One thing I've always valued about KSP is how it opened the door to all these topics and motivated me to learn all about orbital mechanics. It does its best to give an introduction to all these concepts, but either because of its engine limitations or out of fear of scaring away its customers, it can't do everything accurately.  Now, I understand that the game is simpler than how real life rocketry works in some ways, and I feel like reaction wheels are no exception to one of the shortcuts they've taken when cheating the laws of physics. 

After some Googling, there doesn't seem to be much offered in the way of mods that have been updated to the latest version. Is that because the authors have moved on or because the latest version has only been recently released? They don't make sense to me, for the little I understand about reaction wheels, I still paid a little attention in physics class. I know there is a lot of complexity to them that's missing here, like how they become saturated and where the torque gets dumped and how, etc. 

What I've done in my current vanilla game is just lower the wheel authority to 10% to better simulate how they'd function. Do you have any recommendations on any other quick changes I could make? Should they stay as they are because they function as intended in the Kerbal environment. I tend to forget the scale of things in 1/10th of real life, so maybe they're fine, and I'm just not used to it... thoughts?

From a long time KSP fan, thanks for the community input.

Edited October 26, 2021 by Krazy_Kerbal

[OHara]

True, KSP reaction wheels are not realistic.  I think the reason they are so powerful is to make the game playable by more people.   I find it fun to play with them weakened, as you have done, using fins to steer the rocket in the atmosphere, and then RCS thrusters outside the atmosphere.

There are mods, saturable reaction wheels and  mandatory RCS, which I have not tried, but which you might like.

I have also used the 'Breaking Ground' mod from Squad to build craft that use the robotic parts to build realistic reaction wheels, which is fun for the building part, but awkward to do all the time.

The past several revisions of KSP1 have allowed many mods to work without no change, so it is worth trying your mods with later versions than they advertise, maybe after checking the mod-thread to see what other users have tested already. 

Also, you might decide that your favourite version of KSP1 is not the latest, but maybe 1.8.1 or 1.10.1 or something.

[Krazy_Kerbal]

Thank you so much. I only recently started playing again, and my goal is to play a career game without mods that influenced it (aesthetic mods like EVE are fine). I checked out your link on Kerbalx. This is definitely the way I'm gonna start building things.  Feels way more satisfying to me knowing how things work and why.

That being said, I also wish the game could add some grid fins like the SpaceX Falcon uses.

Edited October 26, 2021 by Krazy_Kerbal

[jastrone]

well the reaction wheels in ksp are quite big and seem to have a lot of space to turn in. also it doesnt really ad that much fun to make them realistic your ship would just loose controll easier thats all

[Krazy_Kerbal]

2 hours ago, jastrone said:

well the reaction wheels in ksp are quite big and seem to have a lot of space to turn in. also it doesnt really ad that much fun to make them realistic your ship would just loose controll easier thats all

Having fun in a simulation-type game is creating a ship that works realistically and accomplishing the same goals that someone else needed 16 SRBs and whatever number of RWs to cheese something. Of course, there is fun is goofing around too, but I am focused on close-to-realistic simulation at the moment.

Edited October 26, 2021 by Krazy_Kerbal

[Gotmachine]

They are indeed extremely cheaty.
Not because they don't have saturation mechanics, but because compared to real world reaction wheels, for an equal mass, the torque they provide is about 100 times higher.

For example, you can compare the KSP 0.625m small reaction wheel that weight 50 kg and provide 5 kNm of torque to that real CMG assembly  that provide only 0.075 kNm of torque, weight 70 kg and is roughly a 0.6m cube.
The figures for the much larger ISS CMG assembly are identical : 280 kg, 1.2m, only 0.26 kNm.

Said otherwise, to be realistic from a mass POV, the KSP 0.625m reaction wheel should be weighting about 5 tons.

If you want a quick and dirty fix, you can use the following ModuleManager patch (put that in a *.cfg file anywhere in your gamedata folder)

@PART[*]:HAS[@MODULE[ModuleReactionWheel]]:FINAL
{
  @MODULE[ModuleReactionWheel]
  {
    @PitchTorque *= 0.01
    @YawTorque *= 0.01
    @RollTorque *= 0.01
  }
}

Edited October 28, 2021 by Gotmachine

[theJesuit]

7 hours ago, Gotmachine said:

They are indeed extremely cheaty.
Not because they don't have saturation mechanics, but because compared to real world reaction wheels, for an equal mass, the torque they provide is about 100 times higher.

For example, you can compare the KSP 0.625m small reaction wheel that weight 50 kg and provide 5 kNm of torque to that real CMG assembly  that provide only 0.075 kNm of torque, weight 70 kg and is roughly a 0.6m cube.
The figures for the much larger ISS CMG assembly are identical : 280 kg, 1.2m, only 0.26 kNm.

Said otherwise, to be realistic from a mass POV, the KSP 0.625m reaction wheel should be weighting about 5 tons.

If you want a quick and dirty fix, you can use the following ModuleManager patch (put that in a *.cfg file anywhere in your gamedata folder)

@PART[*]:HAS[@MODULE[ModuleReactionWheel]]:FINAL
{
  @MODULE[ModuleReactionWheel]
  {
    @PitchTorque *= 0.01
    @YawTorque *= 0.01
    @RollTorque *= 0.01
  }
}

Disappointed the dirty fix wasn't increased the tonnage to 5.

But otherwise it is a very stockalike fix

I'll see myself out.

[ColdJ]

On 10/28/2021 at 10:30 PM, Gotmachine said:

If you want a quick and dirty fix, you can use the following ModuleManager patch (put that in a *.cfg file anywhere in your gamedata folder)

Playing around with game mechanics globally is a bad idea and will come back to bite you. KSP gives the player to the ability adjust things how they want in game with the advanced tweakables turned on. Just do what you were doing to start with and adjust to what feels right for you. If you can think up and build a craft then adjusting a craft how you want before saving it is not that much of a chore.