Snaps/Spins

[Dean Pappas]

Hi Ron,
Your point is well taken, but the simple reality is that lots of fliers are pushing the envelope of zero-ing the snap, just to be able to do something more consistent. I forget who wrote earlier to say that (almost quote) you can't go wrong watching the best fliers at the NATs as to what is and isn't a snap, but I'm afraid that man was dead wrong (my apologies for forgetting your name, again). Many of the best fliers are the worst perpetrators. Some even vary how hard they push that envelope, based upon who is in the judges' chairs. They are good, after all! Certain of us (ahem) have a reputation for being intolerant of snaps that break first in yaw, or unstall a full 90 degrees before rotation stops, or other transgressions.
Regards,
	Dean Pappas

-----Original Message-----
From: Ron Van Putte [mailto:vanputte at nuc.net]
Sent: Tuesday, June 24, 2003 3:19 PM
To: discussion at nsrca.org
Subject: Snaps/Spins


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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