[NSRCA-discussion] Judging Snaps & spins II

[Glen Watson]

The analogy Earl presents by far is the clearest explanation I have heard to
date defining the break leading a snap. I nominate this should be
incorporated by presenters at future judging clinics when explaining "How to
Judge a Snap".

 

Following this logic in addition to understanding the judging criteria FAI
or AMA should increase the accuracy on how to evaluate the snap portion of a
maneuver.  Keep in mind the snap is generally a single element within a
multi element maneuver.  The snap may be a 10 although there are plenty of
other elements that may necessitate downgrades. 

 

As a competitor, thanks a bunch Earl for providing thoughtful setup tips.

 

Regards,

Glen Watson

http://www.geocities.com/rcprecision/pah.html

 

 

  _____  

From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Earl Haury
Sent: Tuesday, October 23, 2007 6:27 AM
To: Discussion List, NSRCA
Subject: [NSRCA-discussion] Judging Snaps & spins II

 

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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