[NSRCA-discussion] Snap entry in FAI

Mon Jun 16 11:05:11 AKDT 2008

Hmmm, never tried it without elevator!  Of couse my CG is about right, so it probably wouldn't work.  You are right about the top 4 to 6 pilots being able to "fly to" any rule we can come up with!

Jon Lowe

-----Original Message-----
From: shinden1 at cox.net
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
Cc: Jon Lowe <jonlowe at aol.com>
Sent: Mon, 16 Jun 2008 1:39 pm
Subject: Re: [NSRCA-discussion] Snap entry in FAI

Assuming your airplane c/g is set correctly ,,
here will be a displacement during the Snap ,, but it will enter and exit ,,on 
he same line  I.E.,,Pitch and Yaw will happen at the same time ..you will get a 
one at the tail ,,,the airplane will displace during the input . and recovery 
ill be a solid lock exit 
f the airplane is "not stalled" during the snap ,,usually because your  tail 
eavy,,,the airplane will exit on a different line than it entered,, Yaw ,and or 
itch 
his includes up,down and 45`s,and 
f you have to lead with any input ,,,your tail heavy
I hate to see the scores issued on the 1.5 knife snap :) 
o judge will know what inputs are being applied .
f the airplane is tail heavy you don`t need elevator ,,, {most are not using 
his input} But I bet you can`t tell me who.

he harder we try to define and rewrite the rules ,,,the easier it will be for 
uys Like Jason to receive the 10`s
ortals like us will not be able to complete the definition. 
nd Andrew, Chip and Jason will laugh all the way to the top 4
ryan
---- Jon Lowe <jonlowe at aol.com> wrote: 
 Jim,

 I have no clue how you think all three axes can be initiated at the same 
ime.  You keep forgetting the part of the RULE, quoted verbatim below,  that 
ays the "fuselage break and separation from the flight path" must happen 
BEFORE THE ROTATION IS STARTED".  I'm NOT equating fueselage break to pitch 
reak, it could break in  pitch and/or yaw, if it doesn't start rotation at the 
ame time.  If you initiate all three axis at the same time, rotation WILL start 
t the same instant, and that is specifically NOT permitted.  READ THE RULE!  
he judge MUST determine if the fuselage broke and separated from the flight 
ath first, BEFORE the rotation started.  If it didn't, he MUST severely 
owngrade.

 Jon Lowe

 -----Original Message-----
 From: Woodward, Jim (US SSA) <jim.woodward at baesystems.com>
 To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
 Sent: Mon, 16 Jun 2008 12:37 pm
 Subject: Re: [NSRCA-discussion] Snap entry in FAI

 Jon,

 I’m shocked - you are totally wrong here.  Do not equate “fuselage” to “pitch” 
n the reading of this definition.  As a judge you should NOT apply a 
pitch-assessment” pass/fail criteria to judging FAI snap rolls.  It is 
ompletely rejected.  The plane and therefore “fuselage” must autorotate about 
he flight axis, which means that the nose and tail of the plane will move in a 
onical fashion.  The pilot can initiate with all 3 axis at one time. 

 It is the responsibility of the judge to determine if autorotation occurred, 
nd not determine how or in what order the pilot did it.  

 Thanks,

 Jim

 From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] 
n Behalf Of Jon Lowe
 Sent: Monday, June 16, 2008 1:21 PM
 To: nsrca-discussion at lists.nsrca.org
 Subject: Re: [NSRCA-discussion] Snap entry in FAI

 You are correct, as long as there is no roll induced at the same instant.  I 
verlooked that possibility.  Not sure how rudder alone will induce the 
supposed to be in a stalled condition" though!!  There are many attitudes (e.g. 
5 down on center) where a judge could not likely see a rudder departure alone 
irst, and thus conclude that departure did not occur before the roll departure 
tarted.  And a judge might also not see a pitch departure first on a end box 
pline snap, but he could see rudder first.  It is VERY clear that simultaneous 
oll with either or both of the other axes departures is NOT allowed as others 
ave tried to state here.    I did say that pitch and yaw departure could happen 
imutaneously, in my original post, as long as roll doesn't occur at the same 
ime.

 Jon Lowe

 -----Original Message-----
 From: JShulman <jshulman at cfl.rr.com>
 To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
 Sent: Mon, 16 Jun 2008 11:22 am
 Subject: Re: [NSRCA-discussion] Snap entry in FAI

 Jon,

 I don't see where it says pitch break? Rudder first will show attitude break 
nd separation from the flight path. So if one uses rudder and elevator first 
his is also correct.

 Regards,
 Jason
 www.jasonshulman.com
 www.shulmanaviation.com
 www.composite-arf.com 

 -----Original Message-----
 From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On 
ehalf Of Jon Lowe
 Sent: Monday, June 16, 2008 12:11 PM
 To: nsrca-discussion at lists.nsrca.org
 Subject: Re: [NSRCA-discussion] Snap entry in FAI

 I suggest people re-read the definition ofsnap-rolls from the FAI sporting 
ode.  I did a few minutes ago.  Here it is:

 "5B.7.5. SNAP-ROLLS

 A snap-roll (or flick roll/rudder roll) is a rapid autorotative roll where the 
odel 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 
top of the rotation, and

 constant flight path through the manoeuvre is concerned.

 At the start of a snap-roll, the fuselage attitude must show a definite break 
nd separation from the

 flight path, before the rotation is started, since the model aircraft is 
upposed to be in a stalled

 condition throughout the manoeuvre, If the stall/break does not occur and the 
odel aircraft barrelrolls

 around, the manoeuvre must be severely downgraded (more than 5 points). 
imilarly, axial

 rolls disguised as snap-rolls must be severely downgraded (more than 5 
oints).

 Snap-rolls can be flown both positive and negative, and the same criteria 
pply. The attitude

 (positive or negative) is at the competitor’s discretion. If the model 
ircraft returns to an unstalled

 condition during the snap-roll, the manoeuvre is severely downgraded using the 
 point/15 degree

 rule."

 Note that "the fuselage attitude must show a definite break and separation 
rom the flight path, before the rotation is started..."   That means that 
imultaneous pitch and rotation is specifically NOT permitted.  I would 
nterpret it as meaning that pitch and yaw could theoretically happen 
imultaneously, as long as no roll is involved.  Sorry Matt, the rules as 
ritten do NOT allow actuation in all three axes simultaneously.  The rule also 
tates that a constant flight path has to be maintained.

 Let's face it, the only way to prevent severe downgrading from EVERY judge, 
ot just some judges, is to have a pitch break first.  Takes any question away.

 Jon Lowe

 -----Original Message-----
 From: rcmaster199 at aol.com
 To: nsrca-discussion at lists.nsrca.org
 Sent: Mon, 16 Jun 2008 10:46 am
 Subject: Re: [NSRCA-discussion] Snap entry in FAI

 A "Flick" and a "Snap" roll are the same roll in full scale aerobatics 
arlance and reference material. 

 Do these mean the same thing in model aerobatics? In my view, they do 

 The latest FAI regs allow actuation of the three main axes 
imultaneously...that is, the regs don't specifically differentiate "Pitch 
reak" from other deviations. I don't think they specifically require that the 
odel must rotate about it's flight path either, I don't believe (.....plane 
ust rotate in a conical fashion about the fight axis....). The model would 
robably present the best if that's done, so pilots may want to consider that 
hen executing the maneuver. 

 In my take, a rapid Pitch is desired to preload the wing. Contrary to popular 
elief, both panels dot not have to stall for a snap to occur. Quite the 
pposite. Upon rudder deflection, the port panel will practically stall (lift 
uch much less than the other panel) but the starboard panel must be lifting to 
reate the autorotation. If both panels stall, the model will fall out of the 
ky for a distance and a snap would not occur at the correct moment in time 

 MattK 

 -----Original Message----- 
 From: Woodward, Jim (US SSA) <jim.woodward at baesystems.com> 
 To: General pattern discussion <nsrca-discussion at lists.nsrca.org> 
 Sent: Mon, 16 Jun 2008 8:47 am 
 Subject: Re: [NSRCA-discussion] Snap entry in FAI 

 Guys, 

 I thought the FAI changes explicitly allowed flick rolls? The rule 
 reads, "... fuselage attitude must show a definite break and separation 
 from the flight path." 

 It does not say, "MUST SHOW PITCH BREAK." Please DO NOT ERROUNIOUSLY 
 APPLY A PASS/FAIL MAJOR DEDUCTION initial assessment to the snap roll. 
 Watch the whole maneuver then render your score. 

 A break and separation from the flight path simply means that the nose 
 and tail of the plane must rotate in a conical fashion about the fight 
 axis. Yaw, roll, and pitch can all break at the same moment if that is 
 how the pilot does it. 

 Hey :) some really handsome smart guy wrote some stuff at this link 
 below about snap rolls to help clarify how they are done in IMAC. 

 http://www.mini-iac.com/DesktopDefault.aspx?tabid=77 

 thanks, 
 Jim 

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