[NSRCA-discussion] Snap entry in FAI

billglaze billglaze at bellsouth.net
Mon Jun 16 14:02:20 AKDT 2008


My original flight instructor would be interested to know that you can't perform a snap roll without aileron.  In fact, aileron input would probably have earned a smack in the back of the head with an aluminum clipboard.  (Don't ask.)
  ----- Original Message ----- 
  From: Nat Penton 
  To: General pattern discussion 
  Sent: Monday, June 16, 2008 5:51 PM
  Subject: Re: [NSRCA-discussion] Snap entry in FAI


  There is nothing in the rule book, FAI or IAC, that says you have to lead with anything to perform a snap.. The manuever cannot be  performed without aileron, elevator and rudder ( Georgie <G> ).

  The judges guide is poorly worded, which explains the misconceptions.
    ----- Original Message ----- 
    From: george w. kennie 
    To: General pattern discussion 
    Sent: Monday, June 16, 2008 3:44 PM
    Subject: Re: [NSRCA-discussion] Snap entry in FAI


    My lip is becoming too painful from biting it, so I think I'm going to stick my nose in here somewhere.

    I think I'm with Jon on this one.

    My logic, however flawed, tells me that if I am flying my plane straight and level and I input rudder, no matter how much, there is no way that this input will induce a stall to the airframe. Therefore, it seems to me, that the necessary force required to stall the main lifting surface must come from the elevator. It would further seem to me that this input must, by it's very nature produce a pitching attitude to the fuselage whether positive or negative. So I would have to conclude that the attitude "break" referenced by the rule can only refer to a "pitch" break and would be impossible to confuse with an attitude change induced by the rudder seeing that the required result is to stall the main wing.

    And yes Jon, I agree that it would be necessary to lead with the elevator in order to bring about this attitude change before rotation is started, however miniscule the interval might be.

    Of course I'm still open to hearing other interpretations and their validations as these observations are strictly opinions.

    G.




      ----- Original Message ----- 
      From: Jon Lowe 
      To: nsrca-discussion at lists.nsrca.org 
      Sent: Monday, June 16, 2008 2:10 PM
      Subject: Re: [NSRCA-discussion] Snap entry in FAI


      Jim,

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



      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” in 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 completely rejected.  The plane and therefore “fuselage” must autorotate about the flight axis, which means that the nose and tail of the plane will move in a conical fashion.  The pilot can initiate with all 3 axis at one time. 

      It is the responsibility of the judge to determine if autorotation occurred, and 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] On 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 overlooked that possibility.  Not sure how rudder alone will induce the "supposed to be in a stalled condition" though!!  There are many attitudes (e.g. 45 down on center) where a judge could not likely see a rudder departure alone first, and thus conclude that departure did not occur before the roll departure started.  And a judge might also not see a pitch departure first on a end box upline snap, but he could see rudder first.  It is VERY clear that simultaneous roll with either or both of the other axes departures is NOT allowed as others have tried to state here.    I did say that pitch and yaw departure could happen simutaneously, in my original post, as long as roll doesn't occur at the same time.
      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 and separation from the flight path. So if one uses rudder and elevator first this 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 Behalf 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 code.  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 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 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 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."

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

        Let's face it, the only way to prevent severe downgrading from EVERY judge, not 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 parlance 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 simultaneously...that is, the regs don't specifically differentiate "Pitch Break" from other deviations. I don't think they specifically require that the model must rotate about it's flight path either, I don't believe (.....plane must rotate in a conical fashion about the fight axis....). The model would probably present the best if that's done, so pilots may want to consider that when executing the maneuver. 
         
        In my take, a rapid Pitch is desired to preload the wing. Contrary to popular belief, both panels dot not have to stall for a snap to occur. Quite the opposite. Upon rudder deflection, the port panel will practically stall (lift much much less than the other panel) but the starboard panel must be lifting to create the autorotation. If both panels stall, the model will fall out of the sky 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 
         
         
        _______________________________________________ 
        NSRCA-discussion mailing list 
        NSRCA-discussion at lists.nsrca.org 
        http://lists.nsrca.org/mailman/listinfo/nsrca-discussion 

------------------------------------------------------------------------

        Get the Moviefone Toolbar. Showtimes, theaters, movie news, & more! 
_______________________________________________NSRCA-discussion mailing listNSRCA-discussion at lists.nsrca.orghttp://lists.nsrca.org/mailman/listinfo/nsrca-discussion
--------------------------------------------------------------------------

      Get the Moviefone Toolbar. Showtimes, theaters, movie news, & more! 
_______________________________________________
NSRCA-discussion mailing list
NSRCA-discussion at lists.nsrca.org
http://lists.nsrca.org/mailman/listinfo/nsrca-discussion

--------------------------------------------------------------------------
      Get the Moviefone Toolbar. Showtimes, theaters, movie news, & more! 


--------------------------------------------------------------------------


      _______________________________________________
      NSRCA-discussion mailing list
      NSRCA-discussion at lists.nsrca.org
      http://lists.nsrca.org/mailman/listinfo/nsrca-discussion


----------------------------------------------------------------------------
    I am using the free version of SPAMfighter for private users.
    It has removed 9842 spam emails to date.
    Paying users do not have this message in their emails.
    Try SPAMfighter for free now!



----------------------------------------------------------------------------


    _______________________________________________
    NSRCA-discussion mailing list
    NSRCA-discussion at lists.nsrca.org
    http://lists.nsrca.org/mailman/listinfo/nsrca-discussion


------------------------------------------------------------------------------


  _______________________________________________
  NSRCA-discussion mailing list
  NSRCA-discussion at lists.nsrca.org
  http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.nsrca.org/pipermail/nsrca-discussion/attachments/20080616/3551e712/attachment-0001.html>


More information about the NSRCA-discussion mailing list