[NSRCA-discussion] APPARENT GEOMETRY (PARALLAXED VIEW)
Jim Woodward
Jim.Woodward at armorholdings.com
Tue Apr 10 02:44:32 AKDT 2007
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-pro
per-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.
________________________________
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 <mailto:fhhuber at clearwire.net>
To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>
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 <mailto:tkeithblack at gmail.com>
To: NSRCA Mailing List
<mailto:nsrca-discussion at lists.nsrca.org>
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 <mailto:divesplat at yahoo.com>
To: NSRCA Mailing List
<mailto:nsrca-discussion at lists.nsrca.org>
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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