Thanks, guys, for the further reply but we we still haven't got to the bottom of why the cutaway in the flap vane prevents the severe pitch down discovered in testing (by Duncan Simpson and Jim Hawkins, I believe ) and give the hawk such benign and pleasant handling.
I can see that a reduction in stab. travel (and that SMURFs directs airflow onto the stab. root, I guess they work best at large negative stab. deflection.) could prevent stalling of the stab. (even though MacD increased travel and power of the F4 stab by adding an inverted slat to the stab. LE,) but for the life of me I just can't understand why removal of just 15 inches of flap vane, outboard of the stab. span, produced such a dramatic cure for the pitch down.
Its not a smart A--- question, perhaps just the curiosity of the QFI in me, but I just can't see how it works. Anyone put me out of my misery !?
If this fails perhaps I should call exam wing at CFS at Valley !!
Last edited by RetiredBA/BY; 22nd Mar 2013 at 21:01.