"Large angle of attack" issue

On the attached sim, I get a green check with all motors except the I280. For the I280, the sim gives the warning "Large angle of attack encountered (180)" and other warnings. What does this mean, and why is it an issue only with the I280?
Thanks,
Bill

Looks like the stability is pretty low for the I287 selected in the configuration drop-down on the far right. If it’s any worse when you select the I280, that’s probably the reason. Maybe the I280 is heavier? The warning says the rocket starts to tumble under thrust, so I think you need a larger stability margin — more nose weight, or bigger fins.

The rocket flight path changes off course from launch rod angle. Imagine inverting a cone above pad. It is an issue because in AeroFinSim there will be large bending moments and side forces onto fins that may fail at certain large angle of attacks based on epoxy tensile strength and radius of fillet. This means at worse you could have a fin failure or the path of rocket is not desirable with predictions.

The I280 may not have an optimum CG while it burns compared to CP. Gusts and crosswinds will affect Overstable rockets into a angle of attack change into the wind direction. You may have to reduce allowable cross wind speeds when you launch that motor. Launched a multistage L-1 last year into 15mph gusts. It had a short launch rail four feet. 2.2 stability on booster and it tilted into wind slightly but angle of attack was less than fin failure angle of attack. We requested fin sim for that reason just to know when fins may fail. But hey I'm a noob too.

Longer motors will move CG forward. You can also add some nose weight to move CG if Stability margin isn't high enough or redo fin design to change CP.

Thanks for the replies. Yes, I failed to note that stability drops below 1.0 with the larger I motors, the addition of weight in the NV resolved the issue. Still a bit odd that I got a green check with the I287, I120, and I170 but not with the I280.

I280 weighs the most (although not by much) - you can plot stability margin vs time for each to see what's going on and see when OR thinks it will go unstable.

It would be easy to add nose weight to that NC. Two screws... Try adding a bit of nose weight in OR and see if that clears it up.
I get 4500' in my OR sim but that's fully loaded for DD and tracking. You will probably get a lot higher running single deploy.