Basic Principles of the Stunt Hemisphere by Keith Renecle

Basic Principles of the Basic Principles of the Stunt HemisphereStunt Hemisphere

by Keith Renecleby Keith Renecle

7th July 20067th July 2006

Belgrade, SerbiaBelgrade, Serbia

C/L Stunt C/L Stunt is is

Precision Aerobatics!Precision Aerobatics!

Basic principleBasic principle

Pilots who perform Pilots who perform closest to the rules closest to the rules should score the should score the

highest pointshighest points

What does this mean?What does this mean?


Pilots and judges and judges must Pilots and judges and judges must have a good understanding of the have a good understanding of the rulesrules


Pilots and judges and judges must Pilots and judges and judges must have a have a good understandinggood understanding of the of the rulesrules



Pilots and judges must have the Pilots and judges must have the same understanding of the rulessame understanding of the rules



Pilots and judges must have the Pilots and judges must have the same understandingsame understanding of the rules of the rules

This is a SUBJECTIVE sport!This is a SUBJECTIVE sport!

This is a SUBJECTIVE sport!This is a SUBJECTIVE sport!

We must ensure that we do not We must ensure that we do not use use SUBJECTIVITYSUBJECTIVITY as an excuse as an excuse for a lack of understanding!for a lack of understanding!

What can we do to help?What can we do to help?

Benefits of using 3-D graphicsBenefits of using 3-D graphicsin C/L Stuntin C/L Stunt


Competitors:Competitors:

A greater correlation between words and A greater correlation between words and illustrationillustration


Competitors:Competitors:A greater correlation between words and A greater correlation between words and illustrationillustration

WORDSWORDS create mental expectation create mental expectation




ILLUSTRATIONSILLUSTRATIONS create visual create visual expectationexpectation




ILLUSTRATIONSILLUSTRATIONS create visual create visual expectationexpectation

ConflictConflict in expectations creates in expectations creates confusionconfusion


Judges:Judges:Understanding of shape of manoeuvre Understanding of shape of manoeuvre on sphere as viewed from outsideon sphere as viewed from outside


Judges:Judges:Understanding of shape of manoeuvre Understanding of shape of manoeuvre on sphere as viewed from outsideon sphere as viewed from outside

Manoeuvres need to be flown accurately Manoeuvres need to be flown accurately from pilot’s view.from pilot’s view.

Judge must therefore correlate what is Judge must therefore correlate what is seen with what the pilot sees.seen with what the pilot sees.

TECHNOLOGYTECHNOLOGYThe present: The present: (Basically no technology!)(Basically no technology!)

TECHNOLOGYTECHNOLOGYThe present: The present: (Basically no technology!)(Basically no technology!)

Competitor expectation conflicts with Competitor expectation conflicts with judging result:- has always existed.judging result:- has always existed.

TECHNOLOGYTECHNOLOGY

The FUTURE!The FUTURE!

TECHNOLOGYTECHNOLOGY

The FUTURE!The FUTURE!Although possible now…..Although possible now…..

Costs will be prohibitive.Costs will be prohibitive.

TECHNOLOGYTECHNOLOGYThe present:The present:

Conflict between mental expectation Conflict between mental expectation created by words, and visual created by words, and visual expectation created by drawing:- expectation created by drawing:-

has always existedhas always existed

TECHNOLOGYTECHNOLOGYThe present:The present:

Conflict between mental expectation Conflict between mental expectation created by words, and visual created by words, and visual expectation created by drawing:- expectation created by drawing:-

has always existedhas always existed

Technology to address this conflict:- Technology to address this conflict:-

Affordable and available todayAffordable and available today

Use this technology effectively Use this technology effectively to minimise conflictto minimise conflict

Create Create consistentconsistent mental & visual mental & visual expectation for judge & competitorexpectation for judge & competitor



Provide Provide consistentconsistent training tool to training tool to judge & competitorjudge & competitor



Provide Provide consistentconsistent training tool to training tool to judge & competitorjudge & competitor

Create Create consistentconsistent understanding of understanding of manoeuvre appearance on spheremanoeuvre appearance on sphere

This presentation This presentation shows what is shows what is possible now!possible now!

With 3-D graphics we can:With 3-D graphics we can:

See how the manoeuvres fit the sphereSee how the manoeuvres fit the sphere

View the manoeuvres from any angle or View the manoeuvres from any angle or position in the virtual worldposition in the virtual world

Watch them being performed in real Watch them being performed in real timetime

Here are a few screenshotsHere are a few screenshotsfrom the CL Sim-1from the CL Sim-1

Basic Principles of our Basic Principles of our Stunt HemisphereStunt Hemisphere

Why do we have Why do we have misconceptions about the misconceptions about the

stunt manoeuvres?stunt manoeuvres?

PitchPitch

Roll & YawRoll & Yaw

It should be dead easy…………. It should be dead easy…………. just like golf!just like golf!

All you basically have to do is hit a All you basically have to do is hit a small white ball into 18 different small white ball into 18 different holes……… holes………

How difficult can that be??How difficult can that be??

How do we go about How do we go about judging the pattern?judging the pattern?

It is obviously important to know It is obviously important to know exactly how the manoeuvre shapes exactly how the manoeuvre shapes look, and how they will appear look, and how they will appear from the various angles.from the various angles.

How do we achieve this??How do we achieve this??

Judges need a good Judges need a good understanding of the understanding of the

principles that govern our principles that govern our stunt hemispherestunt hemisphere

Judges GuideJudges Guide

4B.4 Judging focus4B.4 Judging focus

1.1. ShapeShape2.2. SizeSize3.3. IntersectionsIntersections4.4. BottomsBottoms

Judges GuideJudges Guide

4B.4 Judging focus4B.4 Judging focus

1.1. ShapeShape2.2. SizeSize3.3. IntersectionsIntersections4.4. BottomsBottoms

The flight path of a tethered object The flight path of a tethered object like a C/L modellike a C/L model

C/L Manoeuvre shapesC/L Manoeuvre shapes

They are just shapes drawn on the They are just shapes drawn on the surface of spheressurface of spheres



The shapes are not dependent on how The shapes are not dependent on how we view themwe view them




They are shapes governed by the rules They are shapes governed by the rules of spherical geometryof spherical geometry




They are shapes governed by the rules They are shapes governed by the rules of of spherical geometryspherical geometry

To understand the stunt hemisphere, To understand the stunt hemisphere, we need to understand the following:we need to understand the following:

Basic principles of lines and paths on Basic principles of lines and paths on spheresspheres



How these paths apply to manoeuvre How these paths apply to manoeuvre shapesshapes



How these paths apply to manoeuvre How these paths apply to manoeuvre shapesshapes

How the manoeuvres fit on the surface of How the manoeuvres fit on the surface of the spherethe sphere


How are shapes made up?How are shapes made up?

F2B Rule bookF2B Rule book

How are shapes made up?How are shapes made up?Flat plane geometryFlat plane geometry

Curve Stra ight line

Continuouscurve

Curve

Stra ightline

A

B

3-D Object3-D Object

X

Y

Z

3-D objects can be manipulated3-D objects can be manipulated

Rules of spheresRules of spheres

1.1. All lines on sphere’s surface are circlesAll lines on sphere’s surface are circles

Rules of spheresRules of spheres

1.1. All lines on sphere’s surface are circlesAll lines on sphere’s surface are circles

2.2. There are There are 2 types of circles2 types of circles::

Great CirclesGreat Circles

Minor circlesMinor circles

Mathematical definitionMathematical definition

““Any plane section of a sphere is a circle. Any plane section of a sphere is a circle. That is, slide a plane along in space like a That is, slide a plane along in space like a knife. If you slice off a piece of a spherical knife. If you slice off a piece of a spherical

shell, the edge that is exposed will be a shell, the edge that is exposed will be a circle. If the slicing plane goes through the circle. If the slicing plane goes through the center of the sphere, the exposed edge will center of the sphere, the exposed edge will be a be a great circlegreat circle, otherwise it is called a , otherwise it is called a

minor circleminor circle.”.”

The Great CircleThe Great Circle



The Minor CircleThe Minor Circle



There are There are NO straight linesNO straight lines on the on the surface of spheressurface of spheres



The spherical equivalent of a straight line, The spherical equivalent of a straight line, is the is the great circle pathgreat circle path..


The spherical equivalent of a straight line, The spherical equivalent of a straight line, is the is the great circle pathgreat circle path..

It is the shortest distance between two It is the shortest distance between two points on the surface of the sphere.points on the surface of the sphere.

Great Circle pathGreat Circle path

FAI rule definition ofFAI rule definition of“Straight line”“Straight line”

Means the closest distance between two Means the closest distance between two points as seen in two dimensions. These points as seen in two dimensions. These words are marked with inverted commas words are marked with inverted commas throughout to provide a constant reminder throughout to provide a constant reminder that the requirement (in all the square and that the requirement (in all the square and triangular manoeuvres for example), is for triangular manoeuvres for example), is for a number of turns ("corners") which should a number of turns ("corners") which should be joined together with flight paths which be joined together with flight paths which appear to be straight lines when seen by appear to be straight lines when seen by the pilot.the pilot.

The SphericalThe Spherical“Straight line”“Straight line”

The shortest distance between two pointsThe shortest distance between two points



A path with no change in direction or A path with no change in direction or headingheading



A path with no change in direction or A path with no change in direction or headingheading

QuestionQuestion::

Is flying around parallel to the ground at Is flying around parallel to the ground at

45 degrees a straight line?45 degrees a straight line?

Why do we need to understand Why do we need to understand this point so well?this point so well?


These These two distinct pathstwo distinct paths will will project very different shapes from project very different shapes from almost any point of view.almost any point of view.


These These two distinct pathstwo distinct paths will will project very different shapes from project very different shapes from almost any point of view.almost any point of view.

These These two distinct paths two distinct paths are not are not interchangeableinterchangeable..

Interesting Sphere factsInteresting Sphere factsThere are NO parallel great circlesThere are NO parallel great circles

Interesting Sphere factsInteresting Sphere facts

There are NO parallel great circlesThere are NO parallel great circles

Minor circles can be parallelMinor circles can be parallel


There are NO parallel great circlesThere are NO parallel great circles

Minor circles can be parallelMinor circles can be parallel

In plane geometry, there are no interesting In plane geometry, there are no interesting polygons with only 2 straight sidespolygons with only 2 straight sides

PolygonsPolygons


On the sphere surface, a polygon can be On the sphere surface, a polygon can be formed by 2 great circles ie. 2 straight formed by 2 great circles ie. 2 straight sidessides

Global mappingGlobal mapping

How does all this apply to How does all this apply to our stunt pattern?our stunt pattern?

Minor circle paths = ConeMinor circle paths = Cone

Loops are conesLoops are cones

Figure eights = 2 conesFigure eights = 2 cones

The “straight side” shapesThe “straight side” shapes

How do they look on the sphere?How do they look on the sphere?

The “straight side” shapesThe “straight side” shapes

The hourglassThe hourglass

FAI rule definition ofFAI rule definition of“Straight line”“Straight line”

Means the closest distance between two Means the closest distance between two points as seen in points as seen in two dimensionstwo dimensions. These . These words are marked with inverted commas words are marked with inverted commas throughout to provide a constant reminder throughout to provide a constant reminder that the requirement (in all the square and that the requirement (in all the square and triangular manoeuvres for example), is for triangular manoeuvres for example), is for a number of turns ("corners") which should a number of turns ("corners") which should be joined together with flight paths which be joined together with flight paths which appear to be straight lines when seen appear to be straight lines when seen by the pilot.by the pilot.

The present FAI rules are written The present FAI rules are written from the pilot’s viewpointfrom the pilot’s viewpoint


Some good reasons:Some good reasons:

The pilot is at a constant distance from the The pilot is at a constant distance from the sphere’s surface. (sphere’s surface. (fixed by line lengthfixed by line length))




The pilot sees the manoeuvres with the The pilot sees the manoeuvres with the least spherical distortion.least spherical distortion.




The pilot sees the manoeuvres with the The pilot sees the manoeuvres with the least spherical distortion.least spherical distortion.

““Vertical” always looks vertical to the pilot.Vertical” always looks vertical to the pilot.

Seeing things in perspectiveSeeing things in perspective


There are various drawing views:There are various drawing views:


There are various drawing views:There are various drawing views:

Plan or orthographic viewsPlan or orthographic views

Isometric viewsIsometric views

Perspective viewsPerspective views

Plan or orthographic viewPlan or orthographic view

Isometric viewIsometric view

Perspective viewPerspective view

Perspective viewPerspective view

Orthographic versus PerspectiveOrthographic versus Perspective

Orthographic Vertical 8Orthographic Vertical 8

Perspective view of Vertical 8Perspective view of Vertical 8

Charles Mackey’s Charles Mackey’s Stunt judging machineStunt judging machine

What’s the big deal?What’s the big deal?

Does it really make any difference?Does it really make any difference?

What do you think?What do you think?

How do we see things?How do we see things?


Peripheral vision:Peripheral vision:

120 to 140 degrees wide120 to 140 degrees wide


Peripheral vision:Peripheral vision:

120 to 140 degrees wide120 to 140 degrees wide

Peripheral perception:Peripheral perception:

What we do with the info that we seeWhat we do with the info that we see

Eye/hand co-ordinationEye/hand co-ordination

e.g. Tennis players, racing drivers etc.e.g. Tennis players, racing drivers etc.


What is the Pilot’s view?What is the Pilot’s view?


It is close to a view from the geometric It is close to a view from the geometric centre of the spherecentre of the sphere



Depends where the pilot holds the handleDepends where the pilot holds the handle



Depends where the pilot holds the handleDepends where the pilot holds the handle

Viewing distance is fixed by the length of Viewing distance is fixed by the length of the lines, and is the lines, and is almostalmost like viewing a flat like viewing a flat planeplane

CAUTION!!CAUTION!!The surface of the sphere from the pilot’s The surface of the sphere from the pilot’s view is view is NOTNOT the same as a flat surface! the same as a flat surface!


The rules of spheres still apply.The rules of spheres still apply.Minor circles remain minor circlesMinor circles remain minor circles

Great circles remain great circlesGreat circles remain great circles


The rules of spheres still apply.The rules of spheres still apply.Minor circles remain minor circlesMinor circles remain minor circles

Great circles remain great circlesGreat circles remain great circles

The pilot’s view is still a perspective viewThe pilot’s view is still a perspective view

The orange testThe orange test

The orange testThe orange test

The Pilot’s viewThe Pilot’s view



The Square manoeuvres!!The Square manoeuvres!!

The Square manoeuvres!!The Square manoeuvres!!

Judges SquareJudges Square





Judges Square 8Judges Square 8

Great Circle SquareGreat Circle Square



Great Circle Square 8?Great Circle Square 8?

GC & MC SquareGC & MC Square

GC & MC Square Vertical 8GC & MC Square Vertical 8





FAI squareFAI square

FAI square 8FAI square 8

FAI square 8FAI square 8

FAI square judges viewFAI square judges view

FAI square 5 ft. cornersFAI square 5 ft. corners

Can our models turn a 5ft. Can our models turn a 5ft. radius corner?radius corner?

Loren NellLoren Nell



FAI square 16 ft. cornersFAI square 16 ft. corners

How close to the rulebook How close to the rulebook shapes are the top fliers flying??shapes are the top fliers flying??

Ted FancherTed Fancher

Ted FancherTed Fancher

Billy WerwageBilly Werwage

Billy WerwageBilly Werwage

Serge DelabardeSerge Delabarde



SummarySummary

All our manoeuvre shapes are sphericalAll our manoeuvre shapes are spherical

SummarySummary


The shapes are independent of of how we The shapes are independent of of how we view themview them

SummarySummary


The shapes are independent of of how we The shapes are independent of of how we view themview them

We need to learn to understand these We need to learn to understand these principlesprinciples

SummarySummary


The shapes are independent of how we The shapes are independent of how we view themview them

We need to learn to understand these We need to learn to understand these principlesprinciples

This 3-D software shown here can help This 3-D software shown here can help to enhance our training methods, and to enhance our training methods, and is freely available.is freely available.

Where to from here?Where to from here?


Work together to ensure a common Work together to ensure a common understanding of the manoeuvre shapesunderstanding of the manoeuvre shapes



Correct the basic problems in the rulesCorrect the basic problems in the rules



Correct the basic problems in the rulesCorrect the basic problems in the rules

Develop a judges training systemDevelop a judges training system

Thank you for attending Thank you for attending this workshopthis workshop

Documents

Basic Principles of the Stunt Hemisphere by Keith Renecle