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Boomerang Gyroscope Demonstration Device
Team members: Chuanyue Xia, Akinari Ohashi, Steven Teixeira
, Kangchun Wang
Sponsor: Prasad Gudem
CAD Model:
Final Design Hardware:
Background
The motivation for this project was to build a device that would model boomerang flight
dynamics. Prasad Gudem, Ph.d, Vice President of Engineering at Qualcomm, is fascinated with boomerangs and has invested countless hours into learning how boomerangs work. He hoped to be able to present the complex dynamics of boomerang flight in an easy to understand method by using a gyroscope as a model. This gyroscope would be used as a presentation tool in front of large audi
ences in various scholastic environment. Prasad additionally will use this gyroscope to help demonstrate boomerang dynamics when he presents at this year’s boomerang convention in Albuquerque.
Project Overview
A boomerang is a simple device invented thousands of
years ago and was originally used by
ancient civilizations for hunting and killing. However, despite the simple structure of the
boomerang, the dynamics behind boomerang flight are actually very complex. With that being
said, there are three primary phenomena that are present during boomerang flight and are
responsible for a thrown boomerang returning: aerodynamic lift, gyroscopic precession, and
nutation.
1. Aerodynamic Lift
Aerodynamic lift is a force that is created when geometries traveling through the air create
pressure differentials. For example, an airplane wing’s teardrop-shaped cross-section reduces air pressure on top and increases air pressure under the wing which creates a net force pushing up. Similarly, a vertically thrown boomerang generates a lift force that acts in the direction pointing toward the center of the boomerang’s flight path.
2. Gyroscopic Precession
A boomerang thrown through the air possesses linear and rotational velocity. The trailing arm has a higher velocity because its linear and rotational velocities add
together, while the leading arm travels slower because its linear and rotational velocity are in opposition. Since lift is greater for great velocity, this means a net force is created on the top of the boomerang which creates a net torque that acts in the direction opposing the boomerangs linear motion. Additionally, the boomerang possesses angular momentum, J. For planar bodies rotating around a perpendicular axis, (such as a boomerang in flight) the angular momentum vector points in the same direction as the angular momentum, which in this case is toward the center of the boomerang’s flight path. It is the relationship between torque and angular momentum that causes the boomerang to precess. Torque is equal to the rate of change of angular momentum, which means that for a rotating object the angular momentum
3. Nutation
Nutation is the tilting of a body, and describes the act of the boomerang laying over. In general, a boomerang tha
t is thrown vertically will nutate, or “lay over”, throughout the course of its flight and return rotating horizontally. This is a current area of study, but today the main theory for the cause of boomerang nutation is that the asymmetry of the boomerang causes it to lay over as it precesses.
Objectives:
The objective of this project is to build a gyroscope that effectively models the precession and nutation of a boomerang in flight. Additionally, a method of applying a measurable torque is desired to simulate aerodynamic lift. The gyroscope is also to be mounted on a base with wheels. These wheels are to be fixed at specific angles to allow for linear motion of the gyroscope with turning diameters up to 10 meters. These wheels are d
esigned in such a way so as to simulate the linear motion of the boomerang as it curves along its flight path. The Boomerang Gyroscope must also be large so that it can be effectively used as a presentation tool in front of large audiences to help teach t
he dynamics of boomerang flight. It must also be possible to take apart and reassemble the Boomerang Gyroscope so that it can be carried on a suitcase on international flights for presentation purposes. Lastly, the Boomerang Gyroscope also needs to be equipped with sensors to track the motion of each rotating part to aid in the analysis of gyroscope dynamics, with the end goal of using conclusions from this to learn more about precession and nutation in boomerang flight.
Final Design Performance:
Performance Results:
This projects requires construc
vector will continuously move to point more in the direction of the torque. As the angular momentum changes direction, so does the boomerang, and the boomerang will precess.
tion of a large gyroscope capable of modeling boomerang flight dynamics. The innermost gyrowheel simulates the rotation of the boomerang in flight. The gyrowheel is attached to a frame that tilts to simulate nutation of the boomerang. The n
utating frame is attached to a frame that can turn to simulate precession of the gyroscope. The gyroscope is attached to a base with wheels so that linear motion of the boomerang in flight can be simulated. The wheels of the base can be fixed at various angles to simulate different path sizes of the boomerang. Additionally, the gyroscope is equipped with sensors to measure the speed of each rotating component. A motor is used to drive the motion of the innermost gyrowheel.
Design Solution:
