Well written Oryx.

>As long as there's airflow over a cambered surface, there's a pitching moment.

Agreed

>It's not an acceleration, it's a constant force.

Agreed

>Its effect requires a down-load on the horizontal for level trimmed flight.


It requires an "incremental" down load. I usually do the lift on the tail with all symmetrical airfoils to remove the camber or flap pitching moment and have always said that they change the amount of lift the tail has to make. With a midly cambered airfoil there is an incremental lift needed at the tail to compensate. For a complete answer that increment plus the elevator increment is added to the basic lift at what ever the local angle of attack due to downwash is. But the final answer is usually up.

The reason my experiment with a pattern ship works is because there are no camber effects.

The other thing that messes up perceptions is when you look at a typical trainer. The tail is set negative to the wing so the assumption is that the tail is lifting down. But all that does is give you angle of attack stability. It hasn't given a down load on the tail.

>Lift in level flight is composed of both weight AND that increment needed to carry the download.

Agreed

I looked up naca report 792 on the internet. They put strain gages and pressure taps on a typical fighter and flew the beast. The tail loads were up during maneuvering except..... because of airplane moments of inertia if you give a small quick stick yank, the tail load is down initially. As the airplane accelerates in pitch the loads begin to decrease until the reverse and return to up at the new trimmed condition.