ORIGINAL: da Rock
Jezmo, if you look at the aerodynamic formula for quantifying pitch stability it's clear that AOAs have no part whatsoever. It's a formula that's been the basis of design for many, many years and proven to be true. There are ways that screwing up the AOAs will screw up your first flight, but if the elevator is trimmed on that flight, you'll land an airplane that is less efficient but still has whatever pitch stability it was designed and built into it.
Pitch stability is a function of 6 things. CG location, wing chord, wing area, tail moment, horizontal tail area, and chord. That's it. No AOIs or AOAs.
So the post may have been abrupt, but it did have value. It's quite possible that both posters are pointing to the same cause.
On the other hand, posts that insult or embarrass should be reported. And that one was harsh enough to warrant editing.
Thanks for looking at my post Rock. I am not nor do I want to be an aerodynamicist (though I have been a licensed Airframe and Powerplant Technician for over 29yrs). I have been flying a pylon racer made by Great Planes called the Viper 500. Mine had a tendency, for whatever reason, to be flying along perfectly straight and level, full throttle running about 120 mph give or take a few, and without warning would just make an abrupt twitch toward the ground. Quite unnerving since pylon racers are generally within 15ft or so of the ground. Any twitch toward the ground will definitely get your attention very quick and make you follow through on finding a cure. As it happens, many Viper pilots have had this phenomenon occur to them. There are threads on this forum about the problem and through those posts, for which I am greatful, I learned the cure is to change the incidence angle of the tail stabilizer assy. After the change in angle the plane no longer has this undesired twitch for the ground. Again, I am no aerodynamicist, and have no clue why the change in stab angle fixes the problem on this particular aircraft but it does. Moving the CG forward helps but then the plane becomes significantly more difficult to land as too much pitch authority is lost to hold the nose up as the speed drops making the landing speeds unacceptably high. Not sure it is the same type of problem but it sure seems related to me so maybe there is some correlation between incidence and pitch stability.