Playing with the cheap flat foam models - -the comments made by Matthews -are very easy to prove.
We (I have a mouse in my pocket) have tried all kinds of cg shifts -just to see what happens . This experimenting is what led me to my original flight theories -- one being
"if the thing is light enough- the cg does not matter ."
And I can prove that by doing it. (minor radio trim inputs corrected the problems)
Absurd -yeh- but whilst doing these experiments -I also saw a lot of other cherished fables go right down the dumper.
"Thick airfoils make more lift"--
Phooey-they can't-if you keep getting thicker - you soon have a vertical plate!
All of the careful streamlining could be shown to have little or no value on the lightly loaded, slow speed flyers.
The real puzzler is the old fable about how a flat bottomed wing makes a better trainer.
It does make a good free flight tho. My Seniorita can be instantly trimmed for a level wide circle -shut off the radio and it stays.
as any dive creates speed and lift and it simply self corrects . P. oscillations
I can do same thing with the flat wing foamies-- just a bit trickier to get the cg just right so trim is speed sensitive