Originally Posted by
Dan Winterland
It's type specific. On the Chipmunk and Bulldog, the recovery was to centrralize the controls only. The Tucano, centralize and idle thrust. As the Tucano prop does 2000rpm in flight regardless of the throttle position, there are no gyroscopic force changes to worry about.
The RAF defined an incipient spin as buffet with undemanded roll, the combination of the two should warn you that you need to centralise. As the training was to teach pilots who would fly aircraft where this combination was a bad thing (Harrier, Jaguar, Buccaneer, Phantom Lightning and to a lesser extent the Tornado) this was good advice and the main emphasis in the training. Trainee pilots would get lots and lots of practice so that the recovery would be instinctive.
The RAF define the change from the incipint spin to the full spin as when the aerodynamic and inertial forces balance each other out. That sounded like a good explanation to me.
Thanks for that correction - most of my military LOC work was with the Tucano, which would explain my slightly incomplete recollection.
Darrol Stinton, who was an instructor at ETPS and wrote a few rather good books on aircraft design and flight testing, used a similar definition for incipient then fully developed spin, but reckoned that was normally about the first 6 turns. By that definition (which holds some reasonable water when you look at instrumentation data from a few spinning-instrumented research aeroplanes) most of us have never seen a fully developed spin.
G