[NSRCA-discussion] APPARENT GEOMETRY (PARALLAXED VIEW)

Tue Apr 10 03:09:28 AKDT 2007

Some great points Jim.  One minor correction, it used to be a 75 degree box line in Scale Aerobatics.

Ed
  ----- Original Message ----- 
  From: Jim Woodward 
  To: NSRCA Mailing List 
  Sent: Tuesday, April 10, 2007 5:35 AM
  Subject: Re: [NSRCA-discussion] APPARENT GEOMETRY (PARALLAXED VIEW)

  Guys, this discussion as carried forth on the Flying giants website under two different threads seen here:

    1.. http://www.flyinggiants.com/forums/fg200/14364-rfa-judging-45-lines.html 
    2.. http://www.flyinggiants.com/forums/fg191/14581-clearest-presentation-proper-gemotery-judge.html 

  This discussion was a carry over from the South East IMAC judging seminar which I attended in Augusta, GA this March.  The reason this discussion was not squashed as heresy immediately was that two influential folks were "supporting" a "judge-centered-paradigm" versus a "true-geometry" paradigm.  The language of a guide type of statement regarding "clearest geometry" and the language of the newly passed "airspace control score" were being construed beyond their individual scope and argued for "overriding" other model aerobatic fundamentals like: 1.)  Maneuvers must be wind-corrected and flown in a single vertical plane, 2.) Maneuvers like top-hats or rolling circles must be flown with the horizontal portion in a single horizontal plane.  That is as vanilla as I can describe the 3 + hrs of single debate on this issue (obviously I was on the true-geometry side of the debate).  

  What needs to be understood is that "pattern" has decided to "control" the airspace on every-single-maneuver.  The maneuvers are supposed to be flown on a line parallel to the flight line 150-175 meters in front of the pilot, and not extend past the 60 degree box lines.  If maneuvers are flown out of this box or "controlled" airspace, there are downgrades that should be applied (we all know what they are).  Thus, although the pattern sequence is subject to some amount of parallax effect, end box maneuvers can still be judged quite easily enough.  Parallax is a fact and we have learned to deal with it.  It is taught in the judging seminars, described in the AMA video, and the 'experienced' pilots also train the new pilots about it and how to fly/judge it.  Another fact of Pattern is that we are "top-heavy" with a much higher number of pattern pilots in the Masters and FAI classes, versus Sportsman or Intermediate - IE, folks know the rules.

  Now, compare and contrast this with IMAC:  IMAC has elected "not" to control the airspace.  The only rule seemingly applied is the "dead-line" - a line which is typically just on the far side of the runway.  Pilots have "free-reign" to fly where ever they want.  There is no center line any more.  There is sort-of-left, and sort-of-right maneuvers.  Thus, the majority of IMAC pilots I've seen fly just on the far side of the dead-line and nearly over the runway.  How the hell is any end-box-maneuver going to look good from the pilot or judge perspective if the pilot positions the plane just on the far side of the runway and does a turnaround 400 meters away?  Thus, the degree to which parallax plays a part in the IMAC contest is HUGELY different than a pattern contest, because pattern "describes" the airspace where as IMAC does not.  Add to this that IMAC is bottom-heavy, with most of the contestants hovering in the Basic, Sportsman, and Intermediate classes.  

  In an attempt to reduce the "footprint" of the IMAC sequences, the previously used 80 degree (I think) box lines and center line were done-away with.  Many people will now say that this was a huge mistake.  Replacing "objective" criteria like the box lines may be giving way to new paradigms like, ". well, maybe the pilot doesn't have to keep his wings level on end-box-maneuvers.. Maybe the pilot doesn't need to fly true-geometry. etc., . I thought is looked OK" .  This simply equates to dumbing-down the judging criteria in allow the lowest-common-denominator type of judge to be effective - essentially allowing for individual standards based on every judge.

  Pattern has a VERY good thing going with the 'standardization' of scoring and airspace control used throughout the USA and World.  From a teaching/coaching/mentoring perspective it is clearly better to at least "begin" with a truth-source like "true-geometry" - versus some "infinitely" changing way to fly a maneuver based on its location in the box.  I truly believe IMAC would be best served to re-institute box lines and this time around, "enforce" box violations.  Given the changes in the community regarding sound (now most everyone who competes uses canisters and many 3-bladed props to reduce noise), and the recognition that some fields have been lost due to overfly and such, that the community would enforce the box limitations this time around.  

  It is to my opinion clearly the responsibility of the judge to become educated and the responsibility of the experienced pilots to teach/coach/mentor new folks.  Moving towards a "judge-centered-paradigm" would be a giant step backwards towards impression judging.

  My 0.02 cents,

  Thanks,

  Jim W.

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  From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Keith Black
  Sent: Tuesday, April 10, 2007 3:31 AM
  To: NSRCA Mailing List
  Subject: Re: [NSRCA-discussion] APPARENT GEOMETRY (PARALLAXED VIEW)

  Fred, are you suggesting that a 45 degree angle at the end of the box would appear the same if the plane is five feet in front of the flight line or 500 feet in front of the flight line?  I don't buy it.

  Keith

    ----- Original Message ----- 

    From: Fred Huber 

    To: NSRCA Mailing List 

    Sent: Monday, April 09, 2007 11:41 PM

    Subject: Re: [NSRCA-discussion] APPARENT GEOMETRY (PARALLAXED VIEW)

    Distance in/out has no effect on parallax.  Its the angle relative to the viewed line.

    The judges and pilots will have the same parallax to deal with if the pilot flys a 30 inch model at 85 yards away as they will with a 60 inch model at 170 yards.  You might be hard pressed to tell plane which is which on film...  Thats why 1/4 and 1/2 scale models get used for making movies.  The camera can remove perspective clues that indicate distance and scale.

      ----- Original Message ----- 

      From: Keith Black 

      To: NSRCA Mailing List 

      Sent: Monday, April 09, 2007 11:24 PM

      Subject: Re: [NSRCA-discussion] APPARENT GEOMETRY (PARALLAXED VIEW)

      I tend to agree with Ed. Furthermore, what hard facts could possibly be stated about this in the rule book? Would you want it to say that when observing end maneuvers the judge should downgrade if the angle doesn't look steeper than 45 deg.? IMO this is inappropriate for the rule book, though it's perfectly acceptable to point out in a judges clinic or judging tips document.

      Keep in mind also that the distance in our out will also change the look of the end 45 deg. angle. This means that this discussion also would need to be in the rule book. I think the rule book should just state facts, educating the pilot and judge on how to recognize geometry so they can enforce the rule book is important but ancillary to the official rule book.

      My opinion.

      Keith Black 

      ----- Original Message ----- 

        From: Ed Deaver 

        To: NSRCA Mailing List 

        Sent: Monday, April 09, 2007 11:04 PM

        Subject: Re: [NSRCA-discussion] APPARENT GEOMETRY (PARALLAXED VIEW)

        Have been thinking about this discussion (currently going on elsewhere also) and suddenly had the light bulb go on.

        At some clubs as we enter the driveway that leads to the field, 1/2 mile away or maybe a bit more, or the NATs site for example from site 3 (grass field I think) to site 2, it is very easy to watch the geometry of the plane being flown.  At this distance, there is almost zero vertical parallax due to the distance from the pilot.

        Sooooo, what do we see at this distance.  Loops sure do look round to me when flown by good pilots, 45's look like 45's or maybe 50's (my contention is a slight bit steeper always scores better than a slight bit flatter) and even though the pilot is standing "under" the manuever, the good pilots still keep the geometry when looked at from a distance, Correct.

        At the end of the box, standing this distance away it is easier to see the geometry again, with only a very little parallax and the good pilots, IMO still keep the geometry very close to what it should be.  The 45's may be a slight bit steeper, but from a distance the 1/2 cuban 8 flown well, will still have a round radius, with very close to a 45 degree downline (again depending on what the local teacher states), with the rolling element centered.

        My point is, too much is being made of this parallax issue and think judges will reward the pilot that flies the correct geometry, which again IMO, can be verified by watching a flight from a distance.

        Just my $.02

        Ed

        rcmaster199 at aol.com wrote:

          A question has been posted from an IMAC gentleman (who is trying to write better IMAC rules) as to how Pattern people fly and judge skewed appearance of maneuvers at box ends or in center when tall maneuvers (Hourglass, Vert Sq 8, Rolling Ess, etc) are involved. 

          Some of us have searched the book and found no wording written that describes what the pilots' responsibilities and the judges' responsibilities are in the performance of the skewed apparent geometry. There is a statement in the Judges Training tape in regard to end maneuvers.... that these will appear different even when accurately flown. The oness is essentially on the judges to know how the True Geometry should appear when flown at an angle to the eye, and must not downgrade for Apparent or Parallaxed appearance difference.

          Spoke with Don about this earlier today and we decided to present the question to the group and get some conversation going. We should be explicit in the book regarding how such Apparent Geometry should be treated....ie- what is the pilot's responsibility and what is the judge's. Description improvements could be written over the next couple rule cycles.

          The pilot's responsibility may appear easy.... they simply need to fly precise geometry per the book. True enough, BUT.....consider what is actually flown, especially by the top guys, and what scores well. These are not necessarily as precise as one might think. The better pilots tend to fly purposely flawed maneuvers that give the impression of precision. 

          MattK

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