Quote:
Originally Posted by horseback
That might be appropriate for a general aviation private plane with a maximum speed of 170 knots, but for a fighter capable of advanced acrobatics with an engine spinning twice as many blades three times as long (& at least five times as heavy) and hosting five to ten times as many horses? 
cheers
horseback |
Still the same only more so. Lift is by speed squared, AOA and constant factors aspect ratio and wing area. As speed increases, AOA must decrease to keep level flight.
However the tailplane part of the airplane balancing act also has a lift and it's own AOI relative to the main wings which must affect need for trim.
If the P-38 tailplane actually forces the nose down more with increasing speed then the COL moving back as critical mach is approached would turn that into a bad thing... which may or may not be part of the P-38 death dive phenomenon.
I would be very careful pulling text out of books and treating everything with a key word as if on an equal basis with every other. Those comments come from people with different backgrounds and if filtered through yet another party with another background and then evaluated by a reader with a completely different background it's all too easy to end up in a subjective mess especially if the last person tries to use unqualified statements as hard references.
Ie, stick with controlled test data or have your experts on hand to qualify and explain just what they mean.
Don't play at guessing to arrive at your own conclusions even when you have some facts to go with the guessing. I have facts about lift and balance but only questions and not conclusions about the FM to make from those.
If the P-38 didn't need trim then why is it there? Did that quote about not needing trim with power of speed changes apply to small changes or to the full safe operating range? We all know that at some speeds that use of trim and slowing down did become needed, don't we?
BTW, what do you think of using 2 pots for coarse and fine adjustment? I've never seen such but series resistances do add.