Editing Boomerang (section)

==Aerodynamics==
[[File:Cross Boomerang Oc1933,0403.10.jpg|thumb|A cross-shaped toy boomerang at the [[British Museum]]]]
A boomerang is a [[throwing stick]] with [[Aerodynamics|aerodynamic]] properties, traditionally made of wood, which returns to the thrower after an elliptical flight. "Classic" boomerangs usually follow a circular trajectory, or sometimes in the shape of a teardrop. Its range varies from {{cvt|3-60|m}}. Hunting, or non-returning, boomerangs, fly in a straight line, usually {{cvt|40-90|m}}. There are also long-range boomerangs, which differ in design and fly in an S-shape. Wind affects the flight paths of all types of boomerang.<ref name=how>{{cite web | title=How the boomerang flies | website= Decoboomerangs | url=https://decoboomerangs.com/en/article/how-a-boomerang-flies | access-date=16 May 2025}}</ref>

A returning boomerang is a rotating wing. It consists of two or more arms, or wings, connected at an angle; each wing is shaped as an [[airfoil]] section. Although it is not a requirement that a boomerang be in its traditional shape, it is usually flat. Boomerangs can be made for right- or left-handed throwers. The difference between right and left is subtle, the planform is the same but the leading edges of the aerofoil sections are reversed. A right-handed boomerang makes a counter-clockwise, circular flight to the left while a left-handed boomerang flies clockwise to the right. Most sport boomerangs weigh between {{convert|70|and|110|g|abbr=on}}, have a {{convert|250|–|300|mm|abbr=on}} wingspan, and a {{convert|20|–|40|m|abbr=on}} range.

A falling boomerang starts spinning, and most then fall in a spiral. When the boomerang is thrown with high spin, a boomerang flies in a curved rather than a straight line. When thrown correctly, a boomerang returns to its starting point. As the wing rotates and the boomerang moves through the air, the airflow over the wings creates lift on both "wings". However, during one-half of each blade's rotation, it sees a higher airspeed, because the rotation tip speed and the forward speed add, and when it is in the other half of the rotation, the tip speed subtracts from the forward speed. Thus if thrown nearly upright, each blade generates more lift at the top than the bottom.<ref name=hyper>{{cite web |url= http://hyperphysics.phy-astr.gsu.edu/hbase/brng.html |title= Boomerang |work= gsu.edu |access-date= 8 May 2012 |archive-url= https://web.archive.org/web/20120614185310/http://hyperphysics.phy-astr.gsu.edu/hbase/brng.html |archive-date= 14 June 2012 |url-status= live}}</ref> While it might be expected that this would cause the boomerang to tilt around the axis of travel, because the boomerang has significant angular momentum, the [[gyroscopic precession]] causes the plane of rotation to tilt about an axis that is 90 degrees to the direction of flight, causing it to turn.<ref name=hyper/> When thrown in the horizontal plane, as with a [[Flying disc|Frisbee]], instead of in the vertical, the same gyroscopic precession will cause the boomerang to fly violently, straight up into the air and then crash.

Fast Catch boomerangs usually have three or more symmetrical wings (seen from above), whereas a Long Distance boomerang is most often shaped similar to a question mark.<ref>{{cite web |url= http://www.baggressive.com/copper/thumbnails.php?album=6 |title= baggressive.com |publisher= Baggressive.com |date= 19 April 2005 |access-date= 3 March 2010 |archive-url= https://web.archive.org/web/20081224082313/http://www.baggressive.com/copper/thumbnails.php?album=6 |archive-date= 24 December 2008 |url-status= dead}}</ref> Maximum Time Aloft boomerangs mostly have one wing considerably longer than the other. This feature, along with carefully executed bends and twists in the wings help to set up an "auto-rotation" effect to maximise the boomerang's hover time in descending from the highest point in its flight.

Some boomerangs have [[turbulator]]s — bumps or pits on the top surface that act to increase the lift as boundary layer transition activators (to keep attached turbulent flow instead of laminar separation).

In 1992, German astronaut [[Ulf Merbold]] performed an experiment aboard [[Spacelab]] that established that boomerangs function in [[Weightlessness|zero gravity]] as they do on Earth. French Astronaut [[Jean-François Clervoy]] aboard Mir repeated this in 1997.<ref>{{cite web |url= http://www.flight-toys.com/boomerang/boomnews/spacebooms.html |title= Boomerangs in Space |publisher= Flight-toys.com |date= 18 March 2008 |access-date= 3 March 2010 |archive-url= https://web.archive.org/web/20100524160448/http://www.flight-toys.com/boomerang/boomnews/spacebooms.html |archive-date= 24 May 2010 |url-status= live}}</ref> In 2008, Japanese astronaut [[Takao Doi]] again repeated the experiment on board the [[International Space Station]].<ref>{{cite news|url=http://www.news.com.au/couriermail/story/0,23739,23411383-952,00.html |archive-url=https://web.archive.org/web/20080324172123/http://www.news.com.au/couriermail/story/0%2C23739%2C23411383-952%2C00.html |archive-date= 24 March 2008 |title= Boomerang works in space, says astronaut |publisher= News.com.au |date= 21 March 2008 |access-date=3 March 2010 |url-status=dead}}</ref><ref>{{cite news |url= http://www.universetoday.com/2008/03/24/does-a-boomerang-work-in-space/ |title= Does a Boomerang Work in Space? |work= Universetoday.com |date= 24 March 2008 |access-date= 3 March 2010 |archive-url= https://web.archive.org/web/20081201030529/http://www.universetoday.com/2008/03/24/does-a-boomerang-work-in-space/ |archive-date= 1 December 2008 |url-status= live}}</ref>