Originally Posted by
Concours77
Trying to make a point here. Attitude is displayed as degrees above/below Horizon. FPV displays degrees above/below horizon. Consolidating both elicits AoA. No?
Yes, as long as long as you're clear about what you're adding/subtracting.
You brought up wind, I didn’t.
Yes I brought it up for clarity.
It is not installed to assist manual handling. It is installed to protect the aircraft from the crew, just as shaker/pusher does.
This protection
is the relevant assistance.
Originally Posted by
CHfour
@Vessbot
If only life were so simple! I think you need to factor in the angle on incidence. The 738 cruises at around 2 1/2 nose up but the AoA is more like 5-6 degrees?
True, but the difference between nose and wing chord is fixed, and small, and can therefore be disregarded when talking about understanding changes, i.e., if you do this with the AOA, the airplane will respond like that. The nose vs. wing difference is just the adjustment of a fixed datum, for which difference us pilots don't have any data to base on anyway. So nose symbol vs. FPV is good for a basic conception.
Plus (and I'm perfectly willing to be shown wrong about this) I'd put money on that the axis of the nose symbol is the datum in use by all the engineering anyway. Because, as you yourself pointed out, there are more components in addition to the wing that contribute to the overall AOA-dependent behavior.
Apparently the slightly nose up attitude was to allow the fuselage to contribute some lift. Airbus, by contrast, rig their products to cruise with level cabins for passenger comfort. I've never operated the Bus though so the last bit could be B/S?
I would be shocked if this is true. The performance value of note is not lift (we can easily get much more lift than we need by simply hauling back on the stick) but rather lift/drag ratio. And I cannot imagine why they would want to use any lift tied with the drag penalty of flying the tube askew to the air, as opposed to the wing, which is exquisitely designed specifically for the purpose of high L/D in the cruise condition.
If indeed the fuselage is pitched up (note I said the fuselage and not the nose symbol, which can be programmed to be displayed anywhere wrt. the fuselage axis) I would bet that it's because the planes are cruised slower than originally intended, or some other compromise reason... but not because the original designers wanted it.