What causes a boomerang to flatten out in flight

[sarm2005]

I understand why it turns to travel in a circular path. But why does it flatten out from vertical when you throw it.

 

[rcgldr]

First you have the combination of a rotating airfoil with more air speed on the "leading" edge of the air foil and less air speed on the trailing edge of the air foil. Depending on the airfoil shape, this could cause a direct rolling torque, that would result in a pitch reaction.

In addition, the boomerang may produce more lift at the "front" than at the "back" (or vice versa) and the pitch torque would result in a roll reaction.

Depending on the design, and given enough altitude, a boomerang will fly in a figure 8 pattern, although if through from the ground, many designs will land before making the transition to the second half of the figure 8 pattern.

The Aerobie flying ring is a special case. There's very little different in lift between the left and right side, or the front and back side, allowing an Aerobie to fly without the normal precession effects you get from boomerangs or frisbees. An Aerobie is best thrown with no perceptible angle of attack, relying on the airfoil's special shape to generate lift. It will actually climb without changing pitch if thrown horizontally with sufficient air speed, most noticable if it flies into a gusting headwind.

Link to boomerang website (earlier chapters have some generic stuff about aerodynamics):
http://www.researchsupporttechnologies.com/boomerang_site/boomerang5.htm

Aerobie physics:

http://www.aerobie.com/Products/Details/RingScientificPaper.htm

 

[astrokreng]

The flattening out of a boomerang in flight is due to the principles of aerodynamics. When a boomerang is thrown, it experiences a force called lift, which is created by the interaction between the shape of the boomerang and the air it travels through. This force is perpendicular to the direction of the boomerang's motion and causes it to rise and turn in a circular path.

As the boomerang moves through the air, its curved shape creates an area of low pressure on the top surface and an area of high pressure on the bottom surface. This pressure difference causes the boomerang to rotate and creates a lift force. However, as the boomerang gains speed and rotational motion, the angle of attack (the angle at which the boomerang meets the air) changes, causing the lift force to decrease.

As the lift force decreases, the boomerang's upward motion slows down and it begins to flatten out. This is because the force of gravity is acting on the boomerang and pulling it down towards the ground. Eventually, the lift force and the force of gravity reach a balance, causing the boomerang to maintain a stable, flattened trajectory.

In summary, the flattening out of a boomerang in flight is a result of the balance between lift force and gravity, which is influenced by the boomerang's shape, speed, and angle of attack.