[NSRCA-discussion] Judging Snaps & spins II

[Earl Haury]

Posted this as a reply yesterday but it got snagged as too long with the ongoing thread attached - started a new thread.

Jim

Don't think that'll work very well. Let's take the analogy of a car moving in a straight line slowly - turn the steering quickly and the car will turn - changing "track". Do the same thing at high speed and the car will skid - track stays mostly the same and only attitude changes. Entering a snap is similar - establish a "skid". In both cases there will be a minimal departure from the original line until "traction" is lost and the skid occurs. Consider that the faster the pitch input the less AOA increase will be needed before rudder application. This is where we get into trouble trying to define a "break" into a snap, some visualize this as needing to be huge while, in reality, it may only be a few degrees. 

Also - with regard to the departure from track before the "skid". F3A rules require a "separation from the flight path" and AMA rules allow it "track closely maintains the flight path". Numerous things will define the amount of "separation" including rapidity of pitch / yaw, mass of airplane, wing loading, etc. The separation may be a few inches to a couple of feet and is not to be downgraded as long as the aircraft "closely maintains" track. So - if the snap (skid) progresses more or less parallel to but slightly offset (maybe in both pitch & yaw) it's not only OK, but a pretty good indicator that the snap isn't an axial roll.

Use the description to think through set-up and control inputs. Recognize that a properly done snap entry takes only a fraction of a second (if you have time to see exactly what's going on you'll be getting downgrades for track changes). With the proper set-up and practice a snap entry can be perfect almost every time - that just leaves the exit to deal with. Finish wings level and enjoy the 10!

Earl
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