Was in a flat spin in the F4U-7. Everyone knows that the procedure to get out is cut power, neutral ailerons, opposite rudder to spin, and pitch down. This had the opposite effect and exacerbated the flat spin. Proceeded into a test flight and tried the opposite, with maximum power and rudder into the spin and it corrected almost instantly.
Unrelated but the F4U-7’s canopy has had bugged reflections for over a year.