SAS not working on prop craft

[Stalled Erection]

It works fine while not moving, but does nothing to control the plane once in motion...

Any tips?

Thanks in advance

[desrtfox071]

SAS doesn't control a plane. It helps stabilize it. SAS requires either a pilot, or a working antenna as well. Could you be more specific about what the issue is? Also, if you can, please post a screenshot of the craft.

[Stalled Erection]

Sorry, its my first time asking for design help didn't know what to add.

Craft: https://imgur.com/FfCQ8uT I know its a poor design, i'm just messing with the props

Its piloted by Jeb, when it is stationary with no power to the motors the SAS works fine, it corrects the direction no problem when it roles down the runway. When the motors are switched on the SAS symbol turns orange and has that refresh symbol and I have to fly manually.

I can't for the life of me figure out how/if I can fix it.

[desrtfox071]

Originally posted by Rocky Clench:

Sorry, its my first time asking for design help didn't know what to add.

Craft: https://imgur.com/FfCQ8uT I know its a poor design, i'm just messing with the props

Its piloted by Jeb, when it is stationary with no power to the motors the SAS works fine, it corrects the direction no problem when it roles down the runway. When the motors are switched on the SAS symbol turns orange and has that refresh symbol and I have to fly manually.

I can't for the life of me figure out how/if I can fix it.

I'm going to guess too little electricity perhaps? I'm not sure, but you will have to fly manually in any case. SAS just adds stability to aircraft, so you still have to manually steer, aside from things like prograde, retrograde etc. Is that what you mean? You can't select prograde?

You may also need to set the motors to spin in opposite directions if you haven't already. Maybe you are experiencing engine torque.

[Stalled Erection]

I understand how to use it and it works fine on jets. I have 3 batteries so power shouldn't be an issue, and when I select prograde it does nothing, it's as if it has no authority control.

I have edited the directions so it flies just fine

[desrtfox071]

Originally posted by Rocky Clench:

I understand how to use it and it works fine on jets. I have 3 batteries so power shouldn't be an issue, and when I select prograde it does nothing, it's as if it has no authority control.

I have edited the directions so it flies just fine

Ok, so maybe check to make sure it does have control authority. The ailerons should be set to roll, the elevators (assuming you have them I can't tell from the image) should work pitch, and the vertical tail surfaces should work Yaw. Is that all setup correctly?

[Stalled Erection]

Yep, that's all fine.

https://imgur.com/Rg1nKEW

Checked the SAS as well to make sure I hadn't disabled anything by accident.

[desrtfox071]

Originally posted by Rocky Clench:

Yep, that's all fine.

https://imgur.com/Rg1nKEW

Checked the SAS as well to make sure I hadn't disabled anything by accident.

Not sure then to be honest. maybe the whole thing just flexes.

I assume the aircraft is generally sound - center of lift behind of slightly behind center of mass. Engine thrust aligned with centerline, etc?

[XLjedi]

Post it to KerbalX... I'll take a look at it for you.

[「๖Vɪɴʏʟ」]

when you say it does nothing, then does the plane slowly roll over in flight? what does the plane do when you're not touching any controls?

[funkynutz]

Don't bunch up the modules all in one place. Spread them out so there is one on each fuselage instead, closer to the centre of gravity instead of right at the back. And I'm not seeing any batteries?

Better yet, ditch them entirely, you don't need SAS modules on a plane. The command pod has enough torque to fly a plane and keep it steady.

[Stalled Erection]

Sorry for not replying sooner, was at work.

The aircraft is setup as correctly as I can get it, centre of lift is slightly behind the centre of mass, turboshaft engines don't produce thrust so I can't see where it is, but it should be correct.

When I don't touch the controls, it pitches forward and rolls slightly to the right (even with SAS on)

The batteries are between the SAS units, they're at the end for counter balance (its only a test craft so i'm not too bothered about having them in the correct positions), also I added them so I could have more control when flying.

I've taken screen shots of the craft just rolling down the runway vs with power applied to the turboshaft engines:

https://imgur.com/kzcFWG3

https://imgur.com/TmZDsCs

I'm not touching the controls at all in either screenshot

[Stalled Erection]

Also, I would upload the craft file to KerbalX but its not in the game files for some reason

[「๖Vɪɴʏʟ」]

one last thing, are both the engines spinning in the same direction?

[Mandellorian]

SAS was never written with torque from prop engines in mind, so it does nothing about the Torque they generate, worse with the latest update the torque generated is the same for engines rotating in opposite directions so prop aircraft roll like a ♥♥♥♥♥. Welcome to the EA like world of "surprise mechanics"

[「๖Vɪɴʏʟ」]

here you go with a way to fix the problem, useful part starts at 4:33 if you dont care about the full plane build
http://www.youtube.com/watch?v=OC4HYBBqNec&t=4m33s