Originally posted by banktoturn
According to Simons, when the roll input disappears ( aileron deflection, wind gust, etc. ), the dihedral results in a sideslip toward the lower wing, which raises the effective AoA of the lower wing, and lowers the AoA of the higher wing, which gives higher lift for the lower wing, which acts to correct the roll.
I would tend to disagree, as the sideslip is not a cause, but a result. Ok, I am in a bank, and release the control. The flight is assymetric. Because I have less lift (projected surface), the plane tend to dive and accelerate (this IS a sideslip) The lower wing "see" the relative airstream at a higher AOA ( of faster, it's the same), lift increase, it correct the roll, ok.
Now, make the same bank, but imagine we are in a perfectly symmetric flight. That is, once banked, I put aileron in neutral, and give just the correct rudder input to keep the ball centered (admit it's almost impossible on a model, talking full scale here). The plane will, by itself, go back to straight and level flight, and if there is no other input, i will be able to slowly release the pressure on the rudder, to keep symmetric all the time until I am out of the bank/turn. (Done that, more than once, on the wonderfully flying machine named ASK-13. The most delightfull harmony of controls I have ever flown. )
The sideslip theory is valid in only one case, assymetric flight, while the projected surface theory is always valid, so I still believe that the sideslip is a secondary effect.
Bernard