Flywheels have little to no effect for pitch and yaw.

[Sluttershy]

I haven't been playing this for too too long, so please forgive me if this is a noob question, but whenever I use my flywheels, they do basically nothing for my pitch and yaw unless my ship is really tiny. My roll works at pretty much any size (although massive ships do work noticeably but not horribly worse. That can always be solved with more flywheels if necessary). But when using large multistage rockets, my flywheels don't have any noticable effect on the orientation of my ship, even if I put like 10 of the ARWMs on. When exiting the atmosphere using solid fuel boosters, I basically have to keep my liquid engines running at around 20%-40% thrust just for the gimbals, which is a waste of liquid fuel. I'd really like to just be able to use flywheels and save my liquid fuel for changing velocity and not waste it on steering.

Does anyone know why this happens with pretty much all of my rockets, and is there anything that I can do to alleviate this issue?

[Ogre420]

SAS units are SPINNING around the ROLL axis, PITCH & YAW normally need control surfaces to affect the ship.

BUT you can try to SURFACE attach 2 more SAS units in a cross pattern (90 Deg.) to each other and the first SAS unit. (Use GIZMO'S to place/rotate them)
Imagine taking 1 SAS unit and attaching 2 more trying to make a BALL out of it.
Each SAS unit will be spinning along each of the 3 axis points.

I'm NOT sure what the game will do with this but it MIGHT help...

Also you MIGHT want to look into RCS units.

[[m00] insane_eon]

In short, it is intrinsic to a rocket's long shape that it's harder (that is, the same torque has less effect) to pitch and yaw than to roll. Since flywheels apply the same torque in every direction, they'll have less control effect in some directions.

[AlexMBrennan]

SAS units are SPINNING around the ROLL axis, PITCH & YAW normally need control surfaces to affect the ship.

Have you ever looked at KSP before giving such sage advice? Just launch a pod into space (or use hyperedit, or do the basic flight tutorial), and notice how it is perfectly responding to QE (roll) as well as WASD (pitch and yaw) once you are out of the atmosphere.

Worse, it would have taken you about 30s to find out that you are completely wrong about everything but I guess it's more fun to troll new players with bovine excrement advice.

[Washell]

Add some RCS thrusters for control.

[Ogre420]

AlexMBrennan lähetti viestin:

SAS units are SPINNING around the ROLL axis, PITCH & YAW normally need control surfaces to affect the ship.

Have you ever looked at KSP before giving such sage advice? Just launch a pod into space (or use hyperedit, or do the basic flight tutorial), and notice how it is perfectly responding to QE (roll) as well as WASD (pitch and yaw) once you are out of the atmosphere.

Worse, it would have taken you about 30s to find out that you are completely wrong about everything but I guess it's more fun to troll new players with bovine excrement advice.

Hope you have a FAN, because MOAR BOVINE EXCREMENT flying your way.

To Quote C7 one on the people that worked on KSP...

"The placement does matter for reaction wheels. Generally speaking they can cause some problems if placed far from the center of mass. Imagine you are grabbing that point and rotating it. That is what the reaction wheels will try to do. You'll get offcenter rotation anywhere other then near the COM.
— comment by C7, in his blog entry “Updated Information on SAS"

A SAS unit is USUALLY placed directly INLINE with the CoM, which means that the SAS unit has little problem ROTATING the ship.

As C7 stated, to have the same effect on PITCH & YAW, the SAS unit would have to be placed DIRECTLY at the CoM (Which changes as fuel is burned/stages are dropped.)

Because of this ROLL will always be easier to control.

To assist in affecting PITCH & YAW alternate methods are needed, See the first & last line of that post, add FINS for added control in atmo, and RCS for added control in space.
(Ok the stuff in the middle was a bit of a joke)

A capsule hyperedited into space will be rotating DIRECTLY around it's CoM, so you can go crazy with it in all 3 axes.

Maybe YOU are the one that should take 30 seconds to get an education before posting.

@fPeter | ВэЛосираптуре : Sorry for the joke in the middle.

The closer to BALL shaped the easier it will be for a SAS unit to control all 3 axes.
Once you start going LONG you will need to add some OTHER method of assisting in the control of the PITCH & YAW

In ATMO, FINS or ELEVONS are the best option (Although they will have no effect on the craft in space except as dead weight)

Monoprop and RCS thruster units placed around the craft will assist PITCH & YAW in BOTH atmo & space.

If you don't mind burning fuel & LOX, (And are far enough along in the Tech tree) you can add Vernors in place of monoprop & RCS thrusters. (They are 12x more powerfull then the RCS thruster blocks and 6x more powerful then the linear RCS port)

Oh and to kill off the GRANDMA NAZI'S before they start...

"AXES is the only word in English that can be the plural of three different singular noun forms- AX, AXE, and AXIS."

[Patriot03]

^ You don't understand the first quote at all, that has to do with physical leverage, not any lack of torque being applied to all directions as is the case in KSP.

For more torque add more/stronger reaction wheels (2 for say, equally spaced away from the COM) for best control on any axis. No 90degree rotations needed. I've never had a problem getting plenty of trouqe for attitude control in space, Simply use the larger SAS modules for massive ships, 2 is usually the max you'll ever need.

If that doesn't work you're doing something wrong.

PS: If you're trying to use what would be comparativly tiny reaction wheels for an ENTIRE launch vehicle it's not going to be strong at all, and your best bet would be to have them higher up to add leverage, but that shouldn't matter as you're going to want to use thrust vectoring mainly. (I don't know why you want such extreme control {On an entire launch vehicle} though, a proper gravity turn just takes a tiny tilt right after launch and after that you just point prograde)

PPS: Keep in mind Reaction wheels are best suited for space, because if you try and use them during atmospheric flight you'll have to fight aerodynamic drag (Rotating doesn't have to do this, which is another reason why rotation is so much easier during launch) - The Arrow shaped rocket will naturally tend to fly straight(Fighting YAW/PITCH). This is especially true if you use fins. (I don't but many do, they're the training wheels of rocketry)

[El Rushbo]

Is flywheel an actual term for reaction wheels? Because to me a flywheel is something that the clutch presses against to rotate the transmission.

[Washell]

El Rushbo lähetti viestin:

Is flywheel an actual term for reaction wheels?

A reaction wheel is a type of flywheel, but given that real life spacecraft use three different types (reaction wheel, momentum wheel and control moment gyroscope) which all contain a flywheel as part of their system, it's better to refer to the specific type used/intended.

[Langkard]

I think Ogre420 and Patriot03 are arguing past each other. They are both correct, for the most part, because in KSP reaction wheels are really a combination of the three types stated by Washell above. They are simplified and much more powerful versions of the real world analogues.

Reaction wheels in KSP function best when placed at the COM and in space (insert spherical cow in space physics joke here), but they can be used albeit less effectively in the atmosphere if they produce enough torque to overcome the atmospheric drag. However, RSC thrusters are most effective when placed in pairs as far from the COM as possible, but they can also be used less effectively placed closer. See moment of inertia.

The following two physics discussions on the stack exchange do a good job of explaining it:

http://space.stackexchange.com/questions/10622/how-powerful-are-reaction-control-wheels
http://space.stackexchange.com/questions/4091/what-factors-determine-whether-a-spacecraft-probe-satellite-uses-gyroscopes-or-p