Snaps/Spins

[Ron Van Putte]

You can analyze the skin off maneuvers like snaps and spins and we've 
been doing a lot of that.  However, one thing I haven't heard in the 
latest series of discussions is that, like other maneuvers, the airplane 
characteristics do not instantly develop into the spin/snap rates we see 
in mid-maneuver.  Newton has something to say about that.  Forces and 
moments produce linear and angular accelerations, which are opposed 
countering forces and moments as the rates build, until the steady state 
(constant rate) condition is achieved.  It takes time to do that. 
Similarly, it takes time to stop a snap/spin.  So, what you should see 
in snaps/spins is an increase roll/yaw rate, a constant roll/yaw rate 
and a decrease in yaw/roll rate.   What I'm afraid that some judges are 
seeing the acceleration and deceleration in roll/yaw rates at the 
beginning and end of a snap/spin as downgradable, when the pilot can't 
do anything about  it - it's physics.   

Ron Van Putte

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