[NSRCA-discussion] Snap entry in FAI

Tue Jun 17 14:07:23 AKDT 2008

Ok.....

What it does say is:
"in a stalled attitude, with a continuous high angle of attack"
"a stalled condition throughout the manoeuvre"

So any rotation prior to the high angle of attack would be downgraded 1
point per 15 degrees, and if the high angle of attack is never visible, then
the downgrade should be more than 5 points.

I'd say losing 6 points on the snap element of a maneuver would be pretty
good incentive to use the elevator in snaps.

Regards,

Dave Lockhart

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
rcmaster199 at aol.com
Sent: Tuesday, June 17, 2008 1:49 PM
To: nsrca-discussion at lists.nsrca.org
Subject: Re: [NSRCA-discussion] Snap entry in FAI

Yes I read it again and still don't see where it is stated that the 
departure in attitude is in pitch axis. Attitude change can be in any 
of the three main axes IF you take the reg literally. Troy Newman made 
this argument to me a year ago and he was / is correct. However, as I 
argued to Troy, departure in pitch causes things to happen correctly in 
a snap / flick roll. I will not restate what I wrote earlier but it 
still holds true

MattK

  -----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) &lt;jim.woodward at baesystems.com&gt; 
To:
  General pattern discussion &lt;nsrca-discussion at lists.nsrca.org&gt; 
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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