Reaction Wheel Placement

[Spaced Out]

Does it matter where in the stack I put a reaction wheel?

[Starman4308]

In the limit of a completely rigid vehicle, no. All that matters for reaction wheels in rigid vehicles is how much torque they output and the craft's moment of inertia.

Since KSP vessels are not completely rigid, I would avoid placing them anywhere too wobbly, but it's generally not an issue.

[bewing]

Just so long as your rocket is not very bendy, then not really, no. If you calculate out the torque equations then it takes the same torque, no matter the location. It takes more force if you put the reaction wheel way out on the end, but a reaction wheel produces constant torque -- and whatever amount of force is necessary to generate that constant torque.

 

[Silverwood]

I was wondering what exactly do the reaction wheels do? Now I now someone will say read the manual or whatever - but the in guide is not very helpful and the tutorials dont really tell you.

So i just wondered in simple terms what they do.

Keth

 

[tomf]

11 minutes ago, Silverwood said:

I was wondering what exactly do the reaction wheels do? Now I now someone will say read the manual or whatever - but the in guide is not very helpful and the tutorials dont really tell you.

So i just wondered in simple terms what they do.

Keth

 

They provide torque to turn a vehicle in space (or elsewhere) with out having to use reaction mass like RCS. Many probe cores and IIRC all pods include built in reaction wheels but if you use one that doesn't or the built in one isn't enough to turn your vehicle fast enough then you can add additional wheels.

Edited June 12, 2017 by tomf

[Starman4308]

34 minutes ago, Silverwood said:

I was wondering what exactly do the reaction wheels do? Now I now someone will say read the manual or whatever - but the in guide is not very helpful and the tutorials dont really tell you.

So i just wondered in simple terms what they do.

Keth

 

Real reaction wheels or KSP ones?

KSP wheels are magic torque machines that apply torque in the requested direction indefinitely.

Real reaction wheels* spin up a wheel rotating in the opposite direction as you want to turn; you spin the wheel, the wheel spins you back. They quickly saturate when the wheels are spinning as fast as they can go, and are best thought of as devices for storing and releasing angular momentum.

*There's another variant that deflects an already spinning wheel, but the net effect is similar.

[GluttonyReaper]

1 hour ago, Silverwood said:

I was wondering what exactly do the reaction wheels do? Now I now someone will say read the manual or whatever - but the in guide is not very helpful and the tutorials dont really tell you.

So i just wondered in simple terms what they do.

Keth

 

 

In simple terms, they let you turn your rockets around while they're in space. The more reaction wheels you have, the faster you can turn

[Silverwood]

Oh I see! Thank you all.

K

[Snark]

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