<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial, helvetica, sans-serif;font-size:12pt"><DIV>Thats my all time favorite movie....</DIV>
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<DIV>Really this just means snaps will be discussed twice this winter.</DIV>
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<DIV>Brian</DIV>
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<B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> "Atwood, Mark" <atwoodm@paragon-inc.com><BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> General pattern discussion <nsrca-discussion@lists.nsrca.org><BR><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B> Wed, October 14, 2009 8:19:58 AM<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)<BR></FONT><BR>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">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. </SPAN></P>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">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???</SPAN></P>
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<P class=MsoNormal><B><SPAN style="COLOR: #76923c; FONT-SIZE: 13.5pt">Mark Atwood</SPAN></B><SPAN style="COLOR: navy; FONT-SIZE: 13.5pt"><BR></SPAN><SPAN style="COLOR: #1f497d; FONT-SIZE: 10pt">President<BR></SPAN><B><I><SPAN style="COLOR: #1f497d; FONT-SIZE: 11pt">Paragon Consulting</SPAN></I></B><SPAN style="COLOR: #1f497d; FONT-SIZE: 10pt"><BR>office ~ 440-684-3101 ext. 102</SPAN></P>
<P class=MsoNormal><U><SPAN style="COLOR: #548dd4; FONT-SIZE: 10pt">mark.atwood@paragon-inc.com</SPAN></U><U><SPAN style="COLOR: #548dd4"></SPAN></U></P>
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<P class=MsoNormal><B><SPAN style="FONT-FAMILY: 'Tahoma', 'sans-serif'; COLOR: #76923c; FONT-SIZE: 10pt">IT Solution Providers: Custom Software Development. Staff Augmentation. </SPAN></B><SPAN style="COLOR: #76923c"></SPAN></P></DIV>
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<P class=MsoNormal><B><SPAN style="FONT-FAMILY: 'Tahoma', 'sans-serif'; COLOR: windowtext; FONT-SIZE: 10pt">From:</SPAN></B><SPAN style="FONT-FAMILY: 'Tahoma', 'sans-serif'; COLOR: windowtext; FONT-SIZE: 10pt"> nsrca-discussion-bounces@lists.nsrca.org [mailto:nsrca-discussion-bounces@lists.nsrca.org] <B>On Behalf Of </B>Chris Moon<BR><B>Sent:</B> Wednesday, October 14, 2009 9:19 AM<BR><B>To:</B> General pattern discussion<BR><B>Subject:</B> Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)</SPAN></P></DIV></DIV>
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<P class=MsoNormal>Hey Mark,<BR><BR> 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. :)<BR><BR>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!<BR><BR>Chris<BR><BR>Atwood, Mark wrote: </P>
<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">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.</SPAN></P>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">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)… </SPAN></P>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">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. </SPAN></P>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">My $0.02</SPAN></P>
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<P class=MsoNormal><B><SPAN style="COLOR: #76923c; FONT-SIZE: 13.5pt">Mark Atwood</SPAN></B><SPAN style="COLOR: navy; FONT-SIZE: 13.5pt"><BR></SPAN><SPAN style="COLOR: #1f497d; FONT-SIZE: 10pt">President<BR></SPAN><B><I><SPAN style="COLOR: #1f497d; FONT-SIZE: 11pt">Paragon Consulting</SPAN></I></B><SPAN style="COLOR: #1f497d; FONT-SIZE: 10pt"><BR>office ~ 440-684-3101 ext. 102</SPAN></P>
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<P class=MsoNormal><B><SPAN style="FONT-FAMILY: 'Tahoma', 'sans-serif'; COLOR: #76923c; FONT-SIZE: 10pt">IT Solution Providers: Custom Software Development. Staff Augmentation. </SPAN></B></P></DIV>
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<P class=MsoNormal><B><SPAN style="FONT-FAMILY: 'Tahoma', 'sans-serif'; FONT-SIZE: 10pt">From:</SPAN></B><SPAN style="FONT-FAMILY: 'Tahoma', 'sans-serif'; FONT-SIZE: 10pt"> <A href="mailto:nsrca-discussion-bounces@lists.nsrca.org" rel=nofollow target=_blank ymailto="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</A> [<A href="mailto:nsrca-discussion-bounces@lists.nsrca.org" rel=nofollow target=_blank ymailto="mailto:nsrca-discussion-bounces@lists.nsrca.org">mailto:nsrca-discussion-bounces@lists.nsrca.org</A>] <B>On Behalf Of </B>Budd Engineering<BR><B>Sent:</B> Wednesday, October 14, 2009 6:13 AM<BR><B>To:</B> General pattern discussion<BR><B>Subject:</B> Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)</SPAN></P></DIV></DIV>
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<P class=MsoNormal>Chris, Vicente, et al.,</P>
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<P class=MsoNormal>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: <A href="http://www.aerospaceweb.org/question/aerodynamics/q0165.shtml" rel=nofollow target=_blank>http://www.aerospaceweb.org/question/aerodynamics/q0165.shtml</A>. 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: <A href="http://en.wikipedia.org/wiki/Dynamic_pressure" rel=nofollow
target=_blank>http://en.wikipedia.org/wiki/Dynamic_pressure</A>, 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: <A
href="http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml%29" rel=nofollow target=_blank>http://www.aerospaceweb.org/question/aerodynamics/q0136.shtml)</A>. 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.</P>
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<P class=MsoNormal>So what does this all mean?</P></DIV>
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<P class=MsoNormal>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.</P></DIV>
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<P class=MsoNormal>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.</P></DIV>
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<P class=MsoNormal>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).</P></DIV>
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<P class=MsoNormal>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"...</P></DIV>
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<P class=MsoNormal>OK, it's really, really late out here on the left coast, I've gotta get to bed. Shoot away.</P></DIV>
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<P class=MsoNormal>Thx, Jerry</P></DIV>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Helvetica', 'sans-serif'; FONT-SIZE: 10.5pt"><BR>Budd Engineering</SPAN></P></DIV>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Helvetica', 'sans-serif'; FONT-SIZE: 10.5pt"><A href="mailto:jerry@buddengineering.com" rel=nofollow target=_blank ymailto="mailto:jerry@buddengineering.com">jerry@buddengineering.com</A></SPAN></P></DIV>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Helvetica', 'sans-serif'; FONT-SIZE: 10.5pt"><A href="http://www.buddengineering.com/" rel=nofollow target=_blank>http://www.buddengineering.com</A></SPAN></P></DIV></DIV>
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<P class=MsoNormal>On Oct 13, 2009, at 8:54 PM, Chris Moon wrote:</P></DIV>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Helvetica', 'sans-serif'; FONT-SIZE: 13.5pt">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.<BR>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.<BR><BR>Chris<BR><BR><BR>Vicente "Vince" Bortone wrote:</SPAN></P>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial', 'sans-serif'">Chris,</SPAN></P></DIV>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial', 'sans-serif'">I am copying from the first sentence FAI rule book: "</SPAN><SPAN class=apple-converted-space><SPAN style="FONT-FAMILY: 'Arial', 'sans-serif'; FONT-SIZE: 10pt"> </SPAN></SPAN><SPAN style="FONT-FAMILY: 'Arial', 'sans-serif'">A snap-roll (or flick roll/rudder roll) is a rapid autorotative roll where the model aircraft is in a stalled attitude,<SPAN class=apple-converted-space> </SPAN><STRONG><SPAN style="FONT-FAMILY: 'Arial', 'sans-serif'">with a continuous high angle of attack</SPAN></STRONG>" The question: Is 1-2 degrees consider a good amount to define a high angle of attack? </SPAN></P></DIV>
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<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial', 'sans-serif'">Vicente "Vince" Bortone<BR><BR>----- Original Message -----<BR>From: "Chris Moon"<SPAN class=apple-converted-space> </SPAN><A href="mailto:cjm767driver@hotmail.com" rel=nofollow target=_blank ymailto="mailto:cjm767driver@hotmail.com"><cjm767driver@hotmail.com></A><BR>To: "General pattern discussion"<SPAN class=apple-converted-space> </SPAN><A href="mailto:nsrca-discussion@lists.nsrca.org" rel=nofollow target=_blank ymailto="mailto:nsrca-discussion@lists.nsrca.org"><nsrca-discussion@lists.nsrca.org></A><BR>Sent: Tuesday, October 13, 2009 3:07:01 PM GMT -06:00 US/Canada Central<BR>Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)<BR><BR>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.<BR><BR>Chris<BR><BR><A href="mailto:verne@twmi.rr.com" rel=nofollow target=_blank ymailto="mailto:verne@twmi.rr.com">verne@twmi.rr.com</A><SPAN class=apple-converted-space> </SPAN>wrote:</SPAN></P></DIV>
<BLOCKQUOTE style="MARGIN-TOP: 5pt; MARGIN-BOTTOM: 5pt"><PRE>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" <A href="mailto:vicenterc@comcast.net" rel=nofollow target=_blank ymailto="mailto:vicenterc@comcast.net"><vicenterc@comcast.net></A> wrote: </PRE><PRE> </PRE>
<BLOCKQUOTE style="MARGIN-TOP: 5pt; MARGIN-BOTTOM: 5pt"><PRE>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@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> </PRE><PRE>wrote: </PRE><PRE> </PRE>
<BLOCKQUOTE style="MARGIN-TOP: 5pt; MARGIN-BOTTOM: 5pt"><PRE>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@lists. nsrca .org [mailto: nsrca -discussion-bounces@lists. nsrca .org] On Behalf Of Vicente "Vince" Bortone Sent: Tuesday,
October 13, 2009 </PRE><PRE>12:10 PM To: General pattern discussion Subject: Re: [NSRCA-discussion] How I became an expe</PRE><PRE>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</PRE><PRE>ation, and constant flight path through the manoeuvre is concerned. At the start of a </PRE><PRE>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 </PRE><PRE>maneuver is defined as a stalled maneuver, initiat</PRE><PRE>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</PRE><PRE>tive of an axial roll and is scored zero. </PRE><PRE>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" <A href="mailto:mjfrederick@cox.net" rel=nofollow target=_blank ymailto="mailto:mjfrederick@cox.net"><mjfrederick@cox.net></A> </PRE><PRE>To: "General pattern discussion" < nsrca -discussion@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</PRE><PRE>ting the rotation and do an axial roll to</PRE><PRE> 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 <A href="mailto:vicenterc@comcast.net" rel=nofollow target=_blank
ymailto="mailto:vicenterc@comcast.net"><mailto:vicenterc@comcast.net></A> "Vince" Bortone To: General pattern discussion <mailto: nsrca -discussion@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" <A href="mailto:johnfuqua@embarqmail.com"
rel=nofollow target=_blank ymailto="mailto:johnfuqua@embarqmail.com"><johnfuqua@embarqmail.com></A> </PRE><PRE>To: "General pattern discussion" < nsrca -discussion@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</PRE><PRE>bsp;Yes it's hard to see which makes it incumbent on the pilot to</PRE><PRE> present it to the judges. -----Original Message----- From: nsrca -discussion-bounces@lists. nsrca .org [mailto: nsrca -discussion-bounces@lists. nsrca .org] On Behalf Of </PRE><PRE><A href="mailto:ronlock@comcast.net" rel=nofollow target=_blank ymailto="mailto:ronlock@comcast.net">ronlock@comcast.net</A> </PRE><PRE>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</PRE><PRE>ion to completion. By the time the fourth plane did a snap, you could start s</PRE><PRE>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</PRE><PRE>f yaw, (the yaw proceeds the upcoming roll) 3. then autorotation at rate faster than it could do an ail</PRE><PRE>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@lists. nsrca .org </PRE><PRE><A href="http://lists/" rel=nofollow target=_blank>http://lists</A>. nsrca .org/mailman/listinfo/ nsrca -discussion _____ _______________________________________________ NSRCA-discussion mailing list NSRCA-discussion@lists. nsrca .org </PRE><PRE><A href="http://lists/" rel=nofollow
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