is there something like 'delta-omega'?

[JtPB]

I thought about that, if we have dV for linear movement, we could have d-omega(which is the angular velocity of an object). The calculation formula can be used for RCS and gimbal thrusters, dont you think?

[CalculusWarrior]

Interestingly, I believe there is a limit to how fast an object can turn in KSP (7 radians per second). This makes it hard to determine how much you can rotate an object.

[JtPB]

Interestingly, I believe there is a limit to how fast an object can turn in KSP (7 radians per second). This makes it hard to determine how much you can rotate an object.

Ok, so lets determine it just for theory. also the centrifugal force will rip apart a vessel quite fast if we will keep going to big rotation speeds...

[OrtwinS]

The rotational speed limit was mentioned in the new interview with the devs.

I'll be fixed in the next update.

[NovaSilisko]

Interestingly, I believe there is a limit to how fast an object can turn in KSP (7 radians per second). This makes it hard to determine how much you can rotate an object.

That's a unity setting, actually. Easily changeable in code:

http://docs.unity3d.com/Documentation/ScriptReference/Physics-maxAngularVelocity.html

Quick, somebody make a mod to increase it to something like 10,000!

edit: Missed post above mine. Good to hear.

Edited March 27, 2014 by NovaSilisko

[cantab]

Reaction wheels and control moment gyros have no limit on overall dw, though Real ones may have a net limit.

[Ralathon]

depends on how you make the attitude control work. If you turn purely on RCS then you have limited rotational impulse, not if you use reaction wheels. In real life reaction wheels do have some additional limits that affect rotational impulse. For example, you can't keep accelerating them ad infinitum. So they can get saturated, and need to be decharged. Either by flipping the spacecraft 180 degrees so the minute forces you're cancelling operate in the opposite direction, or with a puff of RCS.

[Doozler]

Ok, so lets determine it just for theory.

Just for fun then:

Neglecting reaction wheels and just using thrusters placed at a distance r_t from the axis of rotation:

We can do the calculation but it depends on how the moment of inertia changes with time. This will be different for different rockets (eg depending on how far the fuel tanks are from the axis of rotation.

If we assume that the moment of inertia decreases constantly with time, i.e: MI(t) = MI(0) - y t, we get a pretty similar formula to delta V:

(F= total thrust (identical thrusters), MIfull(empty) = Moment of interia when tanks full (empty), r_t = distance of thrusters from axis, y= rate of change of moment of intertia )

We can now look at some simple cases.

Fuel tanks and thrusters on arms of length r_t, MI(t)= MI_full - c* r²_t*t so y = -c*^rt, when c is fuel consumption rate.

For cylindrical tanks of radius rc along the axis I get:

For a heavy station with tanks in the middle y is very small, so

I don't know why I did that.

Edit: added nice maths from http://www.codecogs.com/latex/eqneditor.php

Edited March 27, 2014 by Doozler

[Nuke]

deltaX literally means change in X, or how much X has changed since last time you looked at it (which can be a second, an hour, a frame (of arbitrary duration), etc). any variable can have a delta.

[MarvinKitFox]

Interestingly, I believe there is a limit to how fast an object can turn in KSP (7 radians per second). This makes it hard to determine how much you can rotate an object.

7 radians per second, hard limit?

No wonder i could never get more than about 1.5km/s from my octopus satellite deployer!

[Starstrider42]

7 radians per second is a little over one revolution per second. Dare I ask why you'd need to turn a ship that fast...?

[RockoDyne]

In theory you could, if your center of mass was stationary. Since it probably won't be though, figures would end up all over the place.

[cantab]

Flinging stuff, it sounds like. Which is a good idea thanks to the aforementioned reaction wheels being able to keep making torque.

[lajoswinkler]

Anyone remember this?

http://forum.kerbalspaceprogram.com/threads/48269-Fuel-tank-rotational-damage

[Doozler]

Anyone remember this?

http://forum.kerbalspaceprogram.com/threads/48269-Fuel-tank-rotational-damage

Must... Not... Revive dead... Thread...

OP, did you have a particular reason for asking? Do you have some nefarious plans?

[lajoswinkler]

Must... Not... Revive dead... Thread...

OP, did you have a particular reason for asking? Do you have some nefarious plans?

Of course you can, provided that you have a valid reason for it. The worst thing is to create identical thread copies. It clutters the forums.