[NSRCA-discussion] How I became an expert Snap Judge (TIC)

mjfrederick at cox.net mjfrederick at cox.net
Wed Oct 14 07:54:46 AKDT 2009


  Well, coming to a complete stop, turning, and taxiing back to the pits 
used to be a judged maneuver. I'd imagine not touching the model during 
the flight is probably a throwback to that... Kinda like one of those 
funny old laws that was just never removed from the books.

Matt

On Wed, Oct 14, 2009 at 8:19 AM, Atwood, Mark wrote:

  Not to fear…  We can use Nov and Dec to discuss the physical 
impossibility of maintaining constant roll rates for rolling circles in 
the wind, and then save Jan – March for finding center for the Snap, 
Opposite 4/8 and Snap, Opposite 4pt in F-11.

And if that doesn’t work, we can always rehash why were explicitly not 
allowed to touch the aircraft in flight…   Anyone? Anyone?  Bueller? 
Bueller???

Mark Atwood
President
Paragon Consulting
office ~ 440-684-3101 ext. 102
mark.atwood at paragon-inc.com

IT Solution Providers:  Custom Software Development. Staff Augmentation.

 From: nsrca-discussion-bounces at lists.nsrca.org 
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Chris 
Moon
Sent: Wednesday, October 14, 2009 9:19 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)

Hey Mark,

  I was going to add that it doesn't take a rocket scientist to have to 
explain all of this to us....then Jerry posted.  :)

You are right, we are making this much more difficult.  The real problem 
is - we are not going to have this discussion all winter long as usual 
since it was brought up in October!

Chris

Atwood, Mark wrote:
So at the end of the day, we don’t really do a snap…ever.   I think many 
have always known that but this (assuming Sir Budd’s math is correct) 
basically ends the debate.

So what we’re doing then in Pattern is trying to emulate the look of a 
snap…not actually snap.  As such, I have a VERY hard time with the 
zeroing of a poor attempt.  Downgrade yes, but not the spurious snap 
nazi zero.  (I’m pretty sure I just set myself up for a few of them)…

This suddenly because a lot easier.  It’s like judging a loop.  Instead 
of trying to draw a circle were trying to make the plane look like it 
snapped… and some will do a better job than others.  As with the loop 
there will be variances…  Loops big and small, snaps tight  or open, 
etc, but at the end of the day, if you recognize the maneuver, it should 
probably be scored.

My $0.02

Mark Atwood
President
Paragon Consulting
office ~ 440-684-3101 ext. 102
mark.atwood at paragon-inc.com <mailto:mark.atwood at paragon-inc.com>
    <mailto:mark.atwood at paragon-inc.com>
IT Solution Providers:  Custom Software Development. Staff Augmentation. 
<mailto:mark.atwood at paragon-inc.com>
    <mailto:mark.atwood at paragon-inc.com>
 From: nsrca-discussion-bounces at lists.nsrca.org 
<mailto:nsrca-discussion-bounces at lists.nsrca.org> [ 
mailto:nsrca-discussion-bounces at lists.nsrca.org 
<mailto:nsrca-discussion-bounces at lists.nsrca.org> ] On Behalf Of Budd 
Engineering
Sent: Wednesday, October 14, 2009 6:13 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC) 
<mailto:nsrca-discussion-bounces at lists.nsrca.org>
    <mailto:nsrca-discussion-bounces at lists.nsrca.org>
Chris, Vicente, et al., 
<mailto:nsrca-discussion-bounces at lists.nsrca.org>
    <mailto:nsrca-discussion-bounces at lists.nsrca.org>
Angle of attack, alpha or AOA, for the aircraft is the difference 
between the flight path angle, gamma, and the aircraft attitude, theta 
(assuming the airfoil zero lift angle is essentially aligned with the 
aircraft reference datum, which for all practical purposes on our 
designs, it is).  Reference: 
http://www.aerospaceweb.org/question/aerodynamics/q0165.shtml 
<http://www.aerospaceweb.org/question/aerodynamics/q0165.shtml> . 
Flight path angle is the aircraft trajectory, or in pattern speak, 
"track" but along the pitch axis, i.e. climbing or descending.  In 
level, steady state flight (~1-g), the flight path angle is zero.  Which 
means that the angle of attack is equal to the aircraft pitch attitude. 
If you run the numbers using a reasonable airfoil lift curve slope at a 
representative level flight speed for our planes you'll find that our 
planes trim out around ~ 0.5 degrees alpha (Lift = Weight = CL * Qbar * 
S where CL is the lift coefficient, Qbar is the dynamic pressure, and S 
is the reference wing area).  This is because of our extremely low wing 
loading, it simply doesn't take a lot of angle of attack to generate 1-g 
of lift when your airplane only weighs 10 or 11 lbs.  Here's the other 
part: with the exception of velocity (or airspeed), the equation is 
linear, which means that if you double the aircraft weight, for the same 
flight speed, you get twice the alpha (again, for 1-g trim).  Or if you 
kept the weight at say 10 lbs, but cut the wing area in half, the angle 
of attack would then double to ~ 1 degree (again, for level, steady, 1-g 
flight).  Velocity is a little trickier to account for because it's a 
non-linear second order function in the lift equation (remember Qbar? 
Reference: http://en.wikipedia.org/wiki/Dynamic_pressure 
<http://en.wikipedia.org/wiki/Dynamic_pressure> , Qbar = 1/2 * rho * 
V**2) where rho is air density and V is the velocity).  Essentially, the 
lift doubles every time we increase Qbar by 2, or velocity by the square 
root of 2 (or 1.414).  So if you're flying along in level flight at 60 
mph (88 feet per second), and you speed up to 85 mph mph (124.45 feet 
per second), you've doubled your dynamic pressure (Qbar) and to stay at 
level 1-g flight, you'd have to retrim your plane in pitch to 1/2 of 
what your AOA was before (or you'll start climbing).  In this case the 
AOA would be ~ 0.25 degrees (as would the pitch attitude).  One last bit 
of info for the point I'm about to make is that the lift curve slope for 
our airfoils at the Reynolds Numbers we are operating at is linear out 
to around ~15-16 degrees alpha, with separation of lift occurring above 
that, closer to 18-20 degrees alpha (Reference: 
http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml) 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29> . 
Note that the onset of separation is independent of airspeed, it's 
purely a flow angle phenomenon, i.e. you can stall an airfoil at any 
airspeed, or attitude (if you can get to a high enough angle of attack). 
That's essentially what Chris is saying below. 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
    <http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
So what does this all mean? 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
    <http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
If you look at the numbers, for our planes, you can't get to stall from 
steady level flight (at any reasonable cruise speed) without inducing a 
significant G-loading on the aircraft (which will cause a noticeable, 
and very observable, change in the flight path angle), BEFORE the 
airfoil stalls. 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
    <http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
Here's some more numbers to help you connect the dots:  from level 1-g 
trim flight at 1/2 degree AOA, you'd have to induce nearly 30 g's to get 
to ~ 15 alpha, not likely you'd be able to do that without seeing it. 
Even starting at 2 degrees AOA (which is a lot for our models), you have 
to generate nearly 5-6 g's to reach stall (think you'd notice that?). 
Don't believe me?  OK answer this: Have you ever quickly but smoothly 
from level upright 1-g flight at a normal cruise speed input full aft 
stick for a second or two and then release it but no lateral input? 
What happens?  Unless something is grossly wrong with your airplane 
you're likely to see a rapid pitch up and a corresponding change in 
flight path angle, probably to something approaching a near vertical 
attitude, but not much else.  Why?  Our planes are so lightly loaded 
that only at spin entry and landing speeds can we induce enough angle of 
attack to approach stall on the airfoil on the plane without inducing 
significant g's and grossly altering the flight path angle (and flight 
path angle is what we really see when we're flying at cruise speeds BTW, 
not so much the pitch attitude until we're at much lower speeds.  That's 
because we mentally integrate the velocity vector in our minds but 
that's a topic for another time/day).  Full scale aerobatic planes (and 
to a lessor degree IMAC planes) don't suffer this problem nearly so 
badly since their wing loadings and inertia's are much higher (dynamic 
stability is somewhat more complex than static stability so I'm not 
going to go much further than this on this topic).  The bottom line is 
this:  we're not stalling the wing when we do our snaps, not even a 
portion of it (unless you're VERY low on airspeed at entry such as a 
spin).  We're too lightly loaded to get to stall at any reasonable 
airspeed, the airplane will respond too quickly in the pitch axis 
resulting in a rapid change in flight path angle, effectively unloading 
the AOA during the response. 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
    <http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
So what are we doing to make the plane present what appears to be a snap 
roll when we can't actually be stalling the wing asymmetrically to 
induce autorotation like many claim?  Lots of control power in pitch and 
roll coupled with additional rolling moment induced by dihedral effect 
(sideslip driven by rudder input).  Pretty much everyone knows that at 
higher AOA you can command/control roll with rudder, well that's due to 
dihedral effect (roll with rudder), it gets more powerful with a little 
AOA.  That's where you get the part of the dynamic that visually 
emulates a full scale snap roll but physically is quite different (you 
can make it look like a full-scale snap, but it really isn't). 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
    <http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
So the bigger question is should emulating a full-scale snap roll be a 
pattern judging criterion or do we even care? (we know what the answer 
is for full scale aerobatics and probably IMAC too but we are neither of 
these).  Until we decide the answer to THAT question, we're really just 
debating "how many angels can dance on the head of a pin"... 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
    <http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
OK, it's really, really late out here on the left coast, I've gotta get 
to bed.  Shoot away. 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
    <http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
Thx, Jerry 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>

Budd Engineering 
<http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29>
jerry at buddengineering.com <mailto:jerry at buddengineering.com> 
<mailto:jerry at buddengineering.com>
http://www.buddengineering.com <http://www.buddengineering.com> 
<http://www.buddengineering.com>
    <http://www.buddengineering.com>
    <http://www.buddengineering.com>
On Oct 13, 2009, at 8:54 PM, Chris Moon wrote: 
<http://www.buddengineering.com>


  <http://www.buddengineering.com>
Ahhh. angle of attack is not the same as the aircraft attitude.Websters 
defines angle of attack as "the acute angle between the chord of an 
airfoil and the line of relative air flow".  The relative wind flows 
parallel and opposite the direction of the wing's movement through the 
air.The wing's attitude as we see it from the ground is NOT the same as 
angle of attack. If you are in a vertical climb is the wing stalled? 
After all it is 90 degrees ATTUIUDE from your perspective on the ground, 
right? But the wing is not stalled because the relative wind is coming 
parallel and opposite the direction of flight. You can be in a nose low 
descent and stall a wing.  Now take a straight and level pass and give 
it an instantaneous large amount of up elevator. What happens? First, 
the plane continues in the direction it was going (straight ahead) for a 
short time, but what is important is that the angle between the relative 
wind (straight ahead) and the wing which is now pivoting up increases 
until it reaches the critical angle of attack and it stalls.  Without 
knowing the specifics of that wing design, we can't know when exactly 
this will occur, but it can be extremely fast and at a relatively low 
ATTITUDE in relation to the ground.  Hence, you do not need a high nose 
ATTITUDE in order to have a high angle of attack. There are too many 
variables for one to say that they need to see a nose high attitude in 
order to define a high angle of attack and thus a stall.  Remember also, 
that different wings have a different critical angle of attack where a 
wing will stall.  How does anyone know where that angle is without a 
wind tunnel and testing? and who am I to say it did not pitch up enough 
to stall therefore I giveth the pilot a 5 or zero even though I cannot 
possibly know the particulars of the wing that I am watching.
My comment of the 1-2 degrees was to say that we do not know how closely 
any particular wing is flying from it's critical angle of attack.  If it 
is in fact close, a change of only 1-2 degrees can cause a stall.  We 
are trying to be aerodynamic engineers from the ground and deciding for 
ourselves what the angle "should" look like and downgrading accordingly. 
Now throw in the conceptual difference between angle of attack and 
aircraft attitude, and it is easy to come to the wrong conclusion about 
stall or no stall. Are we fling only 1-2 degrees from the critical angle 
most of the time, no but the point it that there is absolutely no 
aerodynamic requirement for a very nose high ATTITUDE to be a 
requirement in order to get a high angle of attack on the wing.

Chris

Vicente "Vince" Bortone wrote:  <http://www.buddengineering.com>
Chris,  <http://www.buddengineering.com>
    <http://www.buddengineering.com>
I am copying from the first sentence FAI rule book: "   A snap-roll (or 
flick roll/rudder roll) is a rapid autorotative roll where the model 
aircraft is in a stalled attitude,   with a continuous high angle of 
attack "  The question: Is 1-2 degrees consider a good amount to define 
a high angle of attack?    <http://www.buddengineering.com>
    <http://www.buddengineering.com>
Vicente "Vince" Bortone

----- Original Message -----
 From: "Chris Moon"   <cjm767driver at hotmail.com> 
<mailto:cjm767driver at hotmail.com>
To: "General pattern discussion"   <nsrca-discussion at lists.nsrca.org> 
<mailto:nsrca-discussion at lists.nsrca.org>
Sent: Tuesday, October 13, 2009 3:07:01 PM GMT -06:00 US/Canada Central
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)

I think what this goes back to is the erroneous belief that you need to 
see an exaggerated pitch departure or it should be severely downgraded. 
Keep reading the maneuver description.  It needs "A" pitch break, and 
depending on the current aoa (angle of attack) that can be a difference 
of just a degree or 2 if you are near the critical aoa.  Please don't 
tell me guys, you are looking for MORE than a simple exceeding of the 
critical aoa and resulting stall.  An exaggerated pitch break just to 
prove to naysayers that you make a break is wrong, wrong, wrong.  It 
says it needs "A" break.  Please keep re-reading it.  Same for spin 
entry.  It needs to stall, not go 30 degrees nose up to "prove" a stall. 
We are getting wound up over a misunderstanding of the mechanics of a 
stalled condition.  As Don and Verne are alluding to, it really is not 
that complicated.

Chris

verne at twmi.rr.com <mailto:verne at twmi.rr.com>   wrote: 
<mailto:verne at twmi.rr.com>
Or you could just write in "DNO".... I always seem to see the break as 
in, nose up, tail down, and my 56 year old eyes are lousy. Verne ---- 
"Vicente "Vince" Bortone" <vicenterc at comcast.net> 
<mailto:vicenterc at comcast.net> wrote:    Verne, Following AMA 
description: if we don't see the break is 5 points downgrade.  That is 
1/2 of the snap roll maneuver.  Therefore, if we see the snap roll but 
don't see the break the judge has the right to write down 5 points score 
assuming that all other components are perfect.  Therefore, base on the 
rule book the snap roll without a break has a value of 5 points. 
Vicente "Vince" Bortone ----- Original Message ----- From: verne @ twmi 
. rr .com To: "General pattern discussion" < nsrca -discussion at lists. 
nsrca .org> Cc: "Don Ramsey" <don. ramsey @ suddenlink .net> Sent: 
Tuesday, October 13, 2009 2:14:02 PM GMT -06:00 US/Canada Central 
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC) 
Is there anybody involved in this discussion that honestly can't 
recognize a snap when they see one? I'm just asking..... Verne ---- Don 
Ramsey <don. ramsey @ suddenlink .net> wrote:      Vince,   What about 
the next sentence in the FAI definition, “If the stall/break does not 
occur and the model aircraft barrel rolls around, the manoeuvre must be 
severely downgraded (more than 5 points).”   How about if the break does 
not show and the model does NOT barrel roll around.  Do you still 
downgrade by 5 or more points?  I don’t know what the intent of the rule 
was but I can tell you for a fact that the judges that only score FAI in 
Europe do not downgrade it by 5 or more points.  I believe they use the 
“If it’s not a barrel and not an axial roll then it’s probably a snap, 
so judge it that way” because they have been instructed in the past to 
do it that way.     Don     rom: nsrca -discussion-bounces at lists. nsrca 
.org [mailto: nsrca -discussion-bounces at lists. nsrca .org] On Behalf Of 
Vicente "Vince" Bortone Sent: Tuesday, October 13, 2009 12:10 PM To: 
General pattern discussion Subject: Re: [NSRCA-discussion] How I became 
an expe rt Snap Judge (TIC)   Matt,   I am copying the snap description 
from the current FAI and AMA manuals.  I don't see the AND you mention 
in the FAI rule book.   See the important portion in bold.  I see that 
the AMA description is better in this respect.  You are correct in 
regard the downgrade in FAI .  5 or more points if you don't see the 
break and the model barrel rolls. Therefore, what is the downgrade in 
FAI if the judge does not see the break and there is autorotation?  I 
will say 5 points since it says 5 or more points if the model barrel 
rolls.  Again, it appears that AMA down grad descriptions are better. 
FAI : SNAP-ROLLS A snap-roll (or flick roll/rudder roll) is a rapid 
autorotative roll where the model aircraft is in a stalled attitude, 
with a continuous high angle of attack Snap-rolls have the same judging 
criteria as axial rolls as far as start and stop of the rot ation, and 
constant flight path through the manoeuvre is concerned. At the start of 
a snap-roll, the fuselage attitude must show a definite break and 
separation from the flight path, before the rotation is started, since 
the model aircraft is supposed to be in a stalled condition throughout 
the manoeuvre, If the stall/break does not occur and the model aircraft 
barrelrolls around, the manoeuvre must be severely downgraded (more than 
5 points). Similarly, axial rolls disguised as snap-rolls must be 
severely downgraded (more than 5 points). Snap-rolls can be flown both 
positive and negative, and the same criteria apply. The attitude 
(positive or negative) is at the competitor’s discretion. If the model 
aircraft returns to an unstalled condition during the snap-roll, the 
manoeuvre is severely downgraded using the 1 point/15 degree rule. 
AMA: Snaps: A Snap roll is a simultaneous, rapid autorotation in the 
pitch, yaw and roll axes of flight in a stalled wing attitude. The 
following criteria apply: 1. Since the maneuver is defined as a stalled 
maneuver, initiat ed by a stall of the wing induced by a rapid change in 
pitch attitude, the nose of the fuselage must show a definite break in 
pitch attitude from the flight path in the direction of the snap 
(positive or negative) while the track closely maintains the flight 
path. The lack of a discernable pitch break is downgraded by 5 points. 
Large deviations from the flight path, indicative of a delayed stall, 
are to be downgraded using the 1 point per 15-degree rule for each axis 
of the excursion before stall. For example, it the model pitches 15 
degrees nose up and the wings rotate 15 degrees before the stall, the 
maneuver should be downgraded 1 point for pitch and 1 point for roll. 2. 
The track visualized as the path of the Center of Gravity (CG) should 
closely follow the geometric flight path of the maneuver while the nose 
and tail auto rotate through opposite helical arcs around the flight 
path. Lack of these helical arcs (or coning) is indica tive of an axial 
roll and is scored zero. 3. If a stall does not occur and the model 
barrel rolls, the score is zero. A barrel roll can be identified when 
the CG, the nose, and tails scribe the same helical path through the 
required rotation of the maneuver 4. Snap rolls have the same judging 
criteria as axial rolls as far as start and stop of rotation, constant 
flight path through the maneuver and centering on lines. 5. If the model 
returns to an unstalled condition during the maneuver, such that the 
autorotation is not visible and the model rolls or barrel rolls to 
complete the maneuver, it would be downgraded using the 1 point per 15 
degree rule. 6. Airspeed is not a criteria which should be used to judge 
this maneuver. The wing of the model is stalled during this maneuver; 
therefore a significant decrease in speed may occur and is not a cause 
for downgrade. Vicente "Vince" Bortone ----- Original Message ----- 
From: "Matthew Frederick" <mjfrederick at cox.net> 
<mailto:mjfrederick at cox.net> To: "General pattern discussion" < nsrca 
-discussion at lists. nsrca .org> Sent: Tuesday, October 13, 2009 9:47:30 
AM GMT -06:00 US/Canada Central Subject: Re: [NSRCA-discussion] How I 
became an expert Snap Judge (TIC) ? While speaking with Don Ramsey about 
the nuances of judging snaps at a recent contest I found that he agreed 
with my interpretation of the FAI snap rule. The severe downgrade should 
only be applied if there is no break AND there is no autorotation (this 
is exactly what the rule says). Basically, lack of a break is not 
substantial grounds for the severe downgrade in FAI . If the break is 
not seen and autorotation still occurs at some point during the roll the 
one point per 15 degree rule applies. Since the snaps happen so fast, 
for me it's usually not more than 1 or 2 points unless it was blatantly 
obvious that the plane rotated a while before the snap truly began. It's 
the same as if you stop the snap before comple ting the rotation and do 
an axial roll to finish. This nonsense of people being so quick to apply 
a severe downgrade has gone too far. One element of a maneuver (because 
I can't think of any sequence that has just a snap roll) should not ruin 
a whole flight, or eve n that one maneuver unless it just wasn't a snap. 
I like the idea of "if it's not a barrell roll and not an axial roll, 
it's probably a snap."   Matt ----- Original Message ----- From: Vicente 
<mailto:vicenterc at comcast.net> <mailto:vicenterc at comcast.net> "Vince" 
Bortone To: General pattern discussion <mailto: nsrca -discussion at lists. 
nsrca .org>   Sent: Monday, October 12, 2009 5:12 PM Subject: Re: 
[NSRCA-discussion] How I became an expert Snap Judge (TIC)   I believe 
that the current downgrade is severe.  AMA 5 points.   FAI 5 or more 
points if my memory is correct.     In local contest I have been using 3 
points downgrade.  I know that is wrong but it has been my best way for 
me to take into account the break issue.  It used to be zero and it was 
changed to 5 points (IMAC still a 10 points downgrade or nada). 
Therefore, Ron is correct.  Probably makes sense to go 2-3 points 
downgrade if the judge can not see the break before rotation. 
Vicente "Vince" Bortone ----- Original Message ----- From: "John Fuqua" 
<johnfuqua at embarqmail.com> <mailto:johnfuqua at embarqmail.com> To: 
"General pattern discussion" < nsrca -discussion at lists. nsrca .org> 
Sent: Monday, October 12, 2009 1:51:00 PM GMT -06:00 US/Canada Central 
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC) 
Ron makes valid observation which I came to many years ago at the TOC 
when Mr. Bill graciously funded for full scale pilots like Patty 
Wagstaff do demo flights to entertain us.   The one thing that I came 
away with in comparing full scale to our airplanes is the speed of the 
snap/rotation.  In the full size aerobatics types that I observed there 
was plenty of time to see the nose pitch and then after somewhat of a 
hesitation yaw and rotate.  In our pattern planes, especially when using 
a snap switch, it all gets to be a blur due to sheer speed.  I have no 
solution to this issue but to MAKE the pilots show a break by having 
severe downgrades.  Otherwise the concept of a snap will be ignored. &n 
bsp;Yes it's hard to see which makes it incumbent on the pilot to 
present it to the judges.   -----Original Message----- From: nsrca 
-discussion-bounces at lists. nsrca .org [mailto: nsrca 
-discussion-bounces at lists. nsrca .org] On Behalf Of ronlock at comcast.net 
<mailto:ronlock at comcast.net> Sent: Monday, October 12, 2009 1:26 PM To: 
General pattern discussion Subject: Re: [NSRCA-discussion] How I became 
an expert Snap Judge (TIC) Here is a description that shows technically 
correct snap execution, and valid, consistent judging is possible. 
(Half of the District One guy need not read this, they have already 
heard it)   <G>   At a small airport airshow, one of demos was an 
in-trail formation of four full scale AT-6 Texans.   As each plane got 
to stage center, it did a single positive snap roll. Spectators saw four 
snap rolls in a row, about 5 seconds apart.   The flight of four went 
around, and repeated the maneuver.  Some spectators are getting bored - 
even a pattern guy could get bored with a string of 8 nearly identical 
maneuvers.   And then, they did it yet again!!   What's in this for us? 
The snap maneuver by each AT-6 appeared to take a second or so, from 
initiat ion to completion. By the time the fourth plane did a snap, you 
could start s eeing.... -  there is a nose pitch up,   -  then a yaw, - 
then plane rolled in direction of yaw, -  plane returned to straight and 
level flight.   By the time the flight came around for another four 
snaps, you could see more details.. -  there is a nose pitch up, 
(somewhat sudden, at least sudden for an AT-6) -  then a large amount of 
yaw, -  then rapid roll in direction of yaw, (rolling faster than it 
could with ailerons) -  plane returned to fairly close straight and 
level, nose slightly high.   By the time the flight positioned for yet 
another four snaps, (Yawn, spectators headed for cotton candy) the four 
distinct elements of the snap roll maneuver were easy to see, and there 
was time to evaluate (judge) each element. 1.    there is a nose pitch 
up,  (somewhat sudden, at least sudden for an AT-6, with little rise in 
altitude) 2.   then large amount o f yaw, (the yaw proceeds the upcoming 
roll) 3.   then autorotation at rate faster than it could do an ail eron 
roll) 4.   plane returns to level flight track, with nose lowering to 
level flight attitude.   We can all be expert Snap Roll Judges!   Ahhh, 
at least for AT-6 snaps.   What I take from all of this-   The problem 
is not snap descriptions.   It's the application of them; observation, 
discrimination and judging of elements in the split second observation 
time we have.  Is the task beyond reasonable expectations of most of us 
as a judging community?   I suppose we will continue work started over 
10 years ago to improve in these areas.   In the meantime, shall we 
reduce the impact of inconsistent judging of snaps by limiting the 
downgrade of the snap portion of a maneuver to say..two points2?   Ron 
Lockhart   _______________________________________________ 
NSRCA-discussion mailing list NSRCA-discussion at lists. nsrca .org 
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-discussion   _____   _______________________________________________ 
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-discussion No virus found in this incoming message. Checked by AVG - 
www.avg.com <http://www.avg.com/> Version: 8.5.421 / Virus Database: 
270.14.9/2428 - Release Date: 10/13/09 06:35:00 
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Internal Virus Database is out of date.
Checked by AVG - www.avg.com <http://www.avg.com>
Version: 8.5.420 / Virus Database: 270.14.3/2415 - Release Date: 
10/05/09 06:19:00  <http://www.avg.com>
   ___________________________________ <http://www.avg.com>

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<http://lists.nsrca.org/mailman/listinfo/nsrca-discussion> Internal 
Virus Database is out of date.
Checked by AVG - www.avg.com
Version: 8.5.420 / Virus Database: 270.14.3/2415 - Release Date: 
10/05/09 06:19:00 
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