XPM
Even though the horizontal stabilizer may be level when the airplane is in level flight, there is a downwash of air from the wings. This downwash strikes the top of the stabilizer and produces a downward pressure, which at a certain speed will be just enough to balance the “lever.” The faster the airplane is flying, the greater this downwash and the greater the downward force on the horizontal stabilizer
Hmm - different definition of 'downwash' is causing a problem. In this FAA document they seem to be using downwash to describe a force where I am using it to describe an angle of flow.
Consider for example this extract from Richard Shevell's "Fundamentals of Flight"
The downwash at the tail comes almost entirely from the trailing vortex system of the wing ...... In practice one wing semispan behind the wing qualifies as "far behind", so that 2CL/(Pi*A.R) gives a rather good approximation to the downwash at the tail. The downwash actually varies both with distance behind the wing and height of the tail above the wake.
In that expression CL is the lift coefficient and AR is the wing aspect ratio. I hope we can agree that if airspeed is increased the lift coefficient is reduced, so that downwash, to my definition, would be decreased. This is just the opposite of what the FAA are saying, but Shevell (and I) are talking about the incident flow angle onto the tail not the force generated on the tail by the downwash, which varies with speed squared as well as flow angle.
I think that is the reason for our apparent difference of opinion
