Boomerang Ing

8/14/2019 Boomerang Ing

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The arm on the left (with hand) is the dingle arm. The arm on the right is the lead arm.Left handed boomerangs would be the opposite.

The bottom of the boomerang (unpainted side) should be against your palm. The top(painted side) should be against your thumb. Remember, spin is more critical than a

hard or forceful throw.Your grip should allow the boomerang to begin to spin (rotate)as it leaves your hand. Use what works best for you, and remember spin is king!


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NEVER THROW SIDEARM!!

Throw no more than 45 degrees from vertical. Too laid over (sidearm) and the

boomerang will climb too high and slide back towards the ground!! Proper layover

will create a lower, more controlled flight. Not enough layover, see Effects of

Layover. Each model requires a different degree of layover. A good rule of

thumb is as the wind increases come up closer to vertical.

Release the boomerang at a slight upward angle (in relation to the horizon). Distant

treetops are usually a good rule of thumb. Keep it off the ground, but don't put it in theclouds!! Too low of a release angle creates a high-climbing end of the flight. A touchmore release height will create a level, more consistent flight. degrees


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#1. Determine wind direction and velocity.

#2. Depending on the model throw 40-60 degrees off the wind.

If the boomerang lands in front of you, throw more into the wind. If it lands behind

you, throw more off the wind.You must know wind speed and direction prior to eachthrow. Right handed: throw right of the wind. Left handed: throw left of the wind. As you

become more proficient you will be able to handle more and more wind.

In a calm wind use a little more layover. The flight will be more elliptical with less wind.

In a wind, throw with less power and less layover. The flight will be more round with the

wind.


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When thrown too hard the flight will look like this.

When thrown too soft the boomerang will not make it back to you.

When thrown too much into the wind the boomerang will land behind you...throw

more off the wind. Remember righties throw right of the wind, and lefties throw left

of the wind.

When thrown too far off the wind the boomerang will land in front of you... throw

more into the wind. Remember righties throw right of the wind, and lefties throw

left of the wind.


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This is what happens when you use too much layover. Too close to a sidearm throw.

This is what happens when you do not use enough layover. The layover was too

vertical.

To check for warp while out throwing, hold from the

lead arm (righties). Sight straight down the edge of the

'rang. If the 'rang is warped you will see the profile (or

partial profiles) of the far arm. Check both arms of the

boomerang. Slight warp can have significant effects on

the flights. Bend the boomerang accordingly to correct

the warp. Slight tips up warp is ok (if painted side is

top).


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Lay the boomerang on a

perfectly flat surface,

painted side up. Slightclicking just at the tips is

what you want. Be sure to

check both arms.

When your boomerang consistently sinks on the outbound part of the flight... Check

warp, bend the tips up.

When your boomerang climbs too high, too fast... check the warp. Try bending the

tips down so the boomerang is flat.

Because competition is never stopped for very windy conditions, weighting and tuningboomerangs has become an art. In addition, as throwers have become more sophisticated

they have developed innovative tuning techniques to adjust and fine tune the flights oftheir boomerangs.

Proper weighting can be used to gain more control in a strong wind, get more distance

from your boomerang, increase the hover, shorten the hover or adjust the trajectory ofreturn. Some people like to weight every one of their boomerangs in the same spot toaccommodate their own throw. And others like to have identical boomerangs weighted in

different ways to accommodate different tournament events and wind conditions.


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Generally speaking:1)Weights at one or both tips increase the distance and give you a certain

degree of wind control.

2)Weights on the wings nearer the elbow (center of gravity), increase wind

control without increasing distance.

3)A weight on one wing (usually trailing wing) near the elbow can shorten the

hover.

4)A weight at the elbow can increase the hover of some 'rangs.

5)Return trajectory can be adjusted by weighting near the elbow (try severaldifferent positions).

6)A tape spoiler on the wing is a terrific way to slow the spin and fight a wind.Creating drag provides great wind control.

7)Another tape trick is a half inch trailer of tape flowing behind either wing.

8)Boomerangs with holes drilled in them make great wind rangs. The holescreate drag and can be drilled anywhere from the tips to the elbow. The holes

create a tremendous amount of turbulence and drag.

Experimentation is the only way to learn the art of weighting and tuning. Every

different boomerang style has its own specific flight characteristics due to its

aerodynamics, wood density, and weight balancing built into the 'rang. And like our

fingerprints, each tree in a stand can be different (ie. less or more dense) than the

tree growing right next to it.

There are too many variables of design for weighting rules to be iron-clad so don't be

afraid to experiment. Sometimes combined ideas produce the desired effect.

Weighting can be used to adjust the flight of a particular boomerang to your particularthrowing style. Once you are getting consistently accurate returns - begin moving a

weight, or weights, around the boomerang to see what the results are. Some people like toweight every rang they own on the lift arm near the elbow.

Things used for weighting are coins, lead tape or flattened lead pieces of different size.

They can be attached with electricians tape or colored plastic tape available at hardwarestores in the hobby section.

Attaching the weights to the bottom of the wing decreases the lift which is desirable in a

strong wind. But weights attached to the top of the wing work very well, too. Experimentto find out which method produces the desired results.


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I used to always tape the weight in such a way that the tape was smoothly attached to theboomerang surface with the weight not protruding beyond the tapes edge. This produced

an aerodynamically smooth surface. But, creating drag works extremely well in fightinga strong wind and is not necessarily a bad thing even in light wind. Creating drag can be

accomplished by numerous methods, drilling holes in the wing or using anything that

stands up a bit off the wing. It could be an abrupt transition from wing to coin or even asmall piece of weather stripping. Or even a folded piece of tape that forms a spoiler (orwind flap) on top of the wing. It can stand up from 1/8" to 3/8". In other words, anything

that creates drag. If you have taken the time to study aerodynamics you know that flightis achieved through a delicate balance of controlling lift and drag. Drag is also an

excellent way to slow the spin down during return, which reduces hover time and makesit easier to catch. Drag is desirable even in calm winds.

For boomerangs with holes drilled in the wings, I like to tape over the holes on the

bottom of the boomerang with small pieces of tape. As the wind increases remove onepiece of tape at a time to fully expose a hole. If you need more drag, expose another hole,

etc. Different flights can be achieved by exposing different combinations of holes. Whenthe wind is blowing hard and all the holes are fully exposed and you need more drag, try

a tape spoiler on top or a trailer of tape off the back of one wing. A great technique whenyou have two holes drilled near each other is to use garbage bag ties. Loop a tie through

the holes and let it stick straight up or down. If you need more distance and the wind isblowing hard don't be afraid to tape 2 nickels or 2 quarters near the lift arm tip. One on

top and one on the bottom.

Triple bladers can be weighted in numerous places. At one or all of the tips, in the verycenter or along one or all of the wings. A good trick with a tri-blader to keep the flight

low, is to have a trailer of tape flapping in the breeze behind one wing. This is very

effective in a wind. The tape should stick out about 1/2 inch behind the wing. Remember,weights near the tip of a boomerang increase the distance.

Adjusting the trajectory of return is usually for short distance 'rangs, such as a Fast Catch

competition I rang. By moving the weight(s) around the boomerang, usually near theelbow, you can adjust where the 'rang is returning. Some turn so tight that no matter how

you adjust to the wind, it's always coming around in front of you, or they may come inbehind you every time. So move the weight around to get it to come in where you are

comfortable with the catch. (Careful flex-tuning down is sometimes necessary to keep theflight low, especially with an aggressive Fast Catch boomerang.)

FLEX-TUNING YOUR BOOMERANG

Check your boomerangs periodically to maintain flatness. Refer to the Warping section in

the instruction booklet for general flex-tuning tips. You want most boomerangs to beperfectly flat, or slightly clicking tips when tested on a FLAT surface. For some longer

distance 'rangs, try a special warp. Basically flat, but with an up TWIST on the lead armand a down TWIST on the trailing arm. The up twist is called a positive angle of attack

and the down twist is called a negative angle of attack. That will result in a more elliptical


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flight path. For a flat round flight, try a gentle down warp of either tip. With someboomerangs, flex-tuning the lead tip down and an up TWIST on the trailing arm can

produce a low flight.

If any boomerang is climbing too high, you may be throwing with too much lay-over

(sidearm) or you may have an up-warp on one or both wings. Carefully flex-tune to flat,or possibly down warp one tip.

If a particular boomerang is just not flying the way you think it should, check it verycarefully for a subtle warp. A slight warp that you can't see at a quick glance can

dramatically effect the flight. Larger rounded elbow boomerangs like the Delicate Arch,Kilimanjaro, Adirondack, etc. can develop a subtle warp that dramatically effects the

flight. Check them often.

I prefer throwing every boomerang (except the Kilimanjaro and Mirage) from the dingle

arm. The dingle arm makes a better handle and the balance feels better. It also has more

distance that way and fights a wind better. A dead vertical release gives you a flatterflight and a release with a bit of layover gives you a climbing flight. I throw almost allboomerangs with a slight degree of layover. In a dead calm throw with a more laid over

release and as the wind increases stand the boomerang up to a more vertical position andcloser to 90 degrees "off" the wind.

Remember, EXPERIMENTATION is the only way to really learn about

Weighting and Tuning.

To fully understand what makes a boomerang work, it is necessary to understand the

basic principles of lift and flight as well as two other laws of physics. Lift is importantbecause a boomerang is simply two airplane wings joined in the middle. The other two

principles involve the spinning of the boomerang and how that spinning creates thereturn.

Aborigines are credited with the invention of the returning boomerang and the oldest one

found in Australia is around 14,000 years old. The best theories surrounding the subjectare that returning boomerangs accidentally evolved from the non-retuming hunting throw

sticks. Returning boomerangs were most likely use for sport and recreation, but a largereturner could easily injure a small animal, take out a bird in flight (with an incredibly

lucky throw) or be used as a decoy to draw in birds and then net them.

Boomerangs are a wonderful fusion of Stone Age man and Space Age Technology.

MAIN FORCES OF FLIGHT:

LIFT - THRUST - DRAG


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lst law governing lift is NEWTONS 3RD LAW OF MOTION:

For every action

there is an equal and

opposite reaction.

This law implies that a wing is just an incline plane. So when you give it thrust, that

deflects the air down, which in turn deflects the wing up. The air hitting the

underside of the wing creates 30% of the lift of a wing. In the case of an airplane the

thrust is obviously produced by the engines. In the case of boomerang the throw

produces the thrust.

2nd law governing lift is BERNOULLI'S LAW:

An increase in

air speed

reduces the

static pressure.

Hold a strip of paper in your hand, let it hang down then blow over the top. Airproduces roughly 14 pounds of pressure on every object from every direction. The

paper rises, because the air pressure on top is reduced and the air pressure pushing

up on the bottom is the same.

As the air moves across the wing of a plane it has farther to go over its curved surface

than it does it's flatter underside. The air needs to meet at the same time on the other side,

so it speeds up over the top. As it moves faster over the top than it does on the bottom itcreates less downward air pressure. Bernoulli's law produces 70% of the lift of a wing.

You may be asking why the air needs to reach the back of the airfoil at the same time. Air

is a fluid and occupies space - if you push a basketball down into a tub of water, the waterlevel throughout the tub rises because the ball is taking up space. An airfoil is creating asimilar effect in the air.

The preceding laws plus gyroscopic stability and gyroscopic precession complete the

science of a returning boomerang.

Gyroscopic stability is something everyone has experienced. Try balancing on a bicyclewithout rolling forward and you understand the stability of spinning wheels. We have all

spun a gyroscope or top, the simple act of spinning it creates stability. That gyroscopicmotion keeps rockets on course and bicycles upright. It is the same spinning motion that

gives the boomerang stability in the air.

Gyroscopic precession is definitely more involved and the short version (without any

math) is: As the boomerang spins, the wing going over the top creates more lift.


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This increased lift at the top of the circle begins turning the boomerang and it begins itsreturn. As the speed of the flight decreases these forces decrease which result in finally

laying the boomerang flat as it hovers in for an easy catch. For a quick simple exampletake a bicycle wheel off your bike and hold it by the axle while spinning the wheel. Turn

it slightly and feel the force.

The very thing that creates lift, also creates drag. Flying an airplane especially landingand taking off, is a delicate balance of controlling lift and drag. At boomerang

tournaments you will see boomerangs with holes drilled in them, rubber bands wrappedaround the wings, spoiler flaps and coins taped on the wings. These things create drag to

produce different effects in the flight like reducing the hover or keeping the flight lower.Controlling the lift using drag on a boomerang is also a delicate balance and something of

an art. To boomerang fanatics DRAG is not a four letter word, it's a necessity.

The throw of a boomerang is an overhand throw exactly like throwing a football and at

the moment of release the boomerang should be more or less straight up and down. Therate of spin of the boomerang is much more important to a good flight than a hard toss.

To create lots of spin think of the action as an exaggerated knock on a door, or cracking awhip. The uninitiated thrower always thinks it's a sidearm toss, but because of the physics

principles we just discussed, a boomerangs flight is perpendicular to the plane of theboomerang so it must be an overhand throw to produce the round returning flight. A

sidearm throw will produce a straight up flight with a crashing return, usually resulting ina broken boomerang.

So why does a boomerang boomerang?The throw produces the thrust. Wings produce lift. The spinning produces gyroscopic

stability. The lift and the spinning create gyroscopic precession that turns it until it

is gently hovering in.

So next time you are throwing boomerangs and making momentary sculptures in

the sky, consider the science involved, and envision Stone Age man working through

technology that wouldn't be fully understood for thousands of years.

There are 3 types of Drag at work during flight - Profile, Induced & Parasite. In aircraftflight it is a delicate balance of lift and drag, in boomerang flight it is a matter of creating

the amount of drag desired.


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Profile Drag:is caused by the airfoil itself. The layer of air closest to thewing creates friction and travels slower over the wing. Slots and deflectors

are two methods of controlling this boundary friction.

Induced Drag:is created at the back of the airfoil. The air moving over thetop hits the air flowing underneath and drives it downward, interrupting the

smooth flow of air.

Parasite Drag:is resistance from the rest of the aircraft.

Airplane wings are attached at a slight angle to the longitudinal axis of the airplane

to take advantage of Newtons's 3rd Law of Motion.

As the speed of an aircraft is increased due to more powerful engines and other

technological advances - that angle as well as the airfoil are changed to produce a more

neutral (lower) lift coefficient. This lower coefficient makes the aircraft more stable andeasier to fly.

Aircraft airfoils

Traditional

A less pronounced leading edge and a rounderunderside tends to produce a more neutral lift.

For lower speed aircraft.This airfoil produces themost lift at the lowest speeds. Subsonic..........................Supersonic

Stealth- very unstable

Boomerang Airfoils - the Basics

Boomerang airfoils can be any of the airfoils found on aircraft. They can also be radically

different to produce various flights.

Boomerangs can be modified by drilling holes in their wings, placing tape spoilers on the

top or the bottom, or tape trailers behind the wing, or rubber bands wrapped around thewing to create drag over the top and along the bottom. Some people use weather stripping

to create a spoiler on the top of a wing, or just a coin to create a raised area.


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Taping weights to boomerangs is a very effective way to increase the distance as welladjust certain aspects of the flight, such as the trajectory or hover time and flight path.

Because of the different shapes of boomerangs and the wide ranging density of woods

(even from the same mill and the same specifications) there are no hard fast rules

governing the flights of boomerangs.

Undercut produces more spin and makes for a

more stable and more accurate flight.Traditional boomerang airfoil

A lower flight path can be produced by building the boomerang with a very laid back

leading edge (subsonic or supersonic airfoil) or by using any of a number of drag

creating methods.

The top choices of throwers to control the flight; whether for wind, distance, or

trajectory, are weights in various positions and/or holes, tape are other materials attachedto the wing to create drag.

Tape Spoilerscreates drag to keep the flight low and reduce the speed of the spin. Aspoiler near the leading edge creates more drag than near the trailing edge. For short

distance boomerangs like a Competition Fast Catch the spoiler near the front keeps theflight lower than a spoiler at the back. Spoilers are also a very effective way to fight a

strong wind.

A trailer of tape creates muchthe same effects as the

spoiler

but not as pronounced.

......

Blunt leading edge

creates a slower spin

&a shorter hover.

.....

Blunt leading edge and a

shorttrailing edge creates a

rounderflight as well as a slower spin

& a short hover.

Special concave undercut creates turbulence

which holds the flight low

Holescreate turbulence and tremendous amounts of drag. They force the flight to stay

low and fight strong winds. They can be various sizes. The closer to the tip, the greatereffect they have.


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Concaves carved into the underside of the wing also create turbulence and help keep theflight low. The Colorado Boomerangs Condor Comp has a very special concave cut into

the underside. These concaves keep the flight low throughout the flight and really helpput the brakes on as it is coming in.

Because of the different shapes of boomerangs and the wide ranging density andthicknesses of woods (even from the same mill and the same specifications) there are nohard fast rules governing the flights of boomerangs.

Field testing and experimentation is the only way to truly determine

flights

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Boomerang Ing