FAR nonsensical torque

[theend3r]

I've flown pretty much exclusively with spaceplanes lately so this really surprised me. I've made a completely 100% symmetrical not-totally-unaerodynamic mini asparagus but it keeps tumbling out of the sky before it even gets rid of the first pair of tanks. What's wrong with my design?

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[waterlubber]

Is your CoD behind your CoM? That's the only reason I could think of. This is a problem for the new, as I call it, "floppydynamics"

[Radam]

Seems like hes in 0.9 still. With FAR aero and like the new one, you have to stick closely to prograde. More reaction wheels if not. Also, aerospikes dont have gimbal.

[Jovus]

I would guess that if you stuck some fins at the bottom your problems would go away.

[theend3r]

I found the culprit. After changing the engines FAR no longer wants me to fly engines-first. It seems that the problem is with how far computes drag, i.e. node = drag, no node = less drag and aerospikes have no nodes. If that is indeed so then shame on FAR, changing engines that shouldn't influence the airflow at all shouldn't change how the craft flies.

[Leszek]

Just like Radam says you are going to far from prograde.

You do not need more fins or reaction wheels, at least nor normally. You have to stay inside the circle of your prograde vector until you get up to at least about 30 km high.

Where the torque comes from is the more you point away from the way you are going, the more the side of the rocket is hitting the airflow. If you go to far, the force on the side of the rocket is more than you can counter and you flip out.

Old stock style of go to 10 km and then turn 45 is horribly horribly wrong and dangerous. With new stock aero/FAR/NEAR you have to get used to kicking 5 degrees when low and slow and then following your prograde over as you go.

My commentary is a bit off at the end but here is how it is done.

[theend3r]

Just like Radam says you are going to far from prograde.

You do not need more fins or reaction wheels, at least nor normally. You have to stay inside the circle of your prograde vector until you get up to at least about 30 km high.

Where the torque comes from is the more you point away from the way you are going, the more the side of the rocket is hitting the airflow. If you go to far, the force on the side of the rocket is more than you can counter and you flip out.

Old stock style of go to 10 km and then turn 45 is horribly horribly wrong and dangerous. With new stock aero/FAR/NEAR you have to get used to kicking 5 degrees when low and slow and then following your prograde over as you go.

I'm flying straight up. Or I'm trying to at least.

[Leszek]

I'm flying straight up. Or I'm trying to at least.

Another possibility is that your asparagus isn't right and you are draining the tanks non symmetrically.

[theend3r]

Another possibility is that your asparagus isn't right and you are draining the tanks non symmetrically.

That's why I included TAC in the screens, the asparagus is good. I also tried it without asparagus - the result is the same.

[Leszek]

That's why I included TAC in the screens, the asparagus is good. I also tried it without asparagus - the result is the same.

Then I am afraid I don't know. The possibilities that are left don't seem that likely. They include, an engine is thottle limited differently. A Rapier is in a different mode (Or is that an aerospike, I don't use either that much). An Engine isn't lined up properly. The fuel tanks you are draining first aren't opposite each other. .... Do any of those engines have gimbal? If not you might not have enough control.

You can put fins and more SAS on but you really shouldn't have to.