ABOUT THE X-ZYLO
WHAT MAKES PLANES FLY?Planes fly because of their aerodynamics. Aerodynamics is the study of air as it moves around objects. A wing flies because of its cross sectional shape. In order to understand why a wing's shape is important we have to understand Bernoulli's Principle. Bernoulli's principle says that an increase in the velocity (speed) of air decreases the air pressure. Likewise, a decrease in flow velocity causes an increase in air pressure. A wing is curved on the top and flat on the bottom, as shown in the diagram below?
To demonstrate the Bernoulli Principle try this simple experiment:
Try another experiment. Observe the model airplane. Does its wings have a dihedral shape? Throw it and note its flight characteristics. Does it have lift? How far does it fly? Does it fly straight? Do you think Bernoulli's principle applies here? Now fly X-zyLo. Does its' surface have the same shape as a
plane's wing? Does it have lift? How far does it fly? Does it fly straight? Why
is its performance in terms of both distance and accuracy far superior to that
of an airplane wing with the same weight and surface area? We will address this
later. First, we need to consider not only why objects have lift but also what
keeps them stable in flight and prevents them from just tumbling all over the
place.
CENTER OF GRAVITY AND CENTER OF PRESSUREEvery flying object has what is called a center of gravity and center of pressure. The center of gravity and center of pressure must be in close proximity to one another in order for a wing to have a stable flight. The normal center of gravity is a fixed point on the object where it is balanced by gravitational forces. To find the center of gravity on X-zyLo, take a pen or pencil and move the tip up and down the underside of the top surface of the cylinder until you reach the point where the X-zyLo is balanced on the tip. This is X-zyLo's approximate center of gravity. One of the purposes of X-zyLo's heavy front ring is to place its center of gravity near its center of pressure. The center of pressure on a wing is the point through which the most lifting pressure passes due to air flowing over it. Just as the center of gravity on a wing is where gravity focuses its pull, the center of pressure is where the air pressure focuses its lift on a wing. Why must the curve of an airplane wing bulge in front rather than the middle or back of the wing? The reason is because the bulge in the front causes the center of air pressure to be near or over the wings center of gravity. In this way, the two forces hold the plane in place as it glides through the air. If the center of pressure is not over the center of gravity, but at some other point of the wing, it would push the plane over and cause it to tumble. Can you guess where the center of pressure is on the X-zyLo? It's where you located the center of gravity - in the first 1/3 of the body. The weight of the ring causes the center of pressure be near the center of gravity? Why does X-zyLo fly with a stable, straight, flight whereas the model plane does not? The answer lies in the fact that forces other than strictly aerodynamics are interacting with X-zyLo. Contrary to traditional planes, X-zyLo spins in flight and this spinning creates gyroscopic forces as we will next see. Before we talk about gyroscopic forces, lets look more closely at X-zyLo's flight characteristics.
WHAT IS A GYROSCOPEA gyroscope is a spinning wheel or ring often mounted on a movable frame. When rapidly spun it stands straight up. When it is not spinning it is captured by gravity and falls down. Bicycles act as gyroscopes when they keep the bicycle straight up when the wheels are spinning. Also, tops act as gyroscopes when they stand straight up while rapidly spinning. Gyroscopes seem to defy the laws of gravity. By simply spinning, gyroscopes resist the forces of gravity. Gyroscopic forces probably were first recorded by Isaac Newton in the 17th century. Try this experiment with a gyroscope if you have one.
As you can see, by spinning, gyroscopes produce a force that resists gravity, or any other force that tries to change its direction, and that keeps it stable. X-zyLo is really a spinning gyroscope with wings. Its spinning allows it to fly stably and straight in flight without nosing down. That's why it flys much straighter and farther than the model plane. To demonstrate this point another way, try the following:
To understand reasons behind gyrosopic forces we need to know about angular momentum and precession. ANGULAR MOMENTUMThe concept of "momentum" states that if any object is in motion it will continue to stay in motion in the direction it is moving unless another force acts upon it. Momentum equals the object's mass times its velocity or speed. "Angular momentum" applies to objects that are moving in circles or spinning. In other words, they are moving "angularly" as opposed to a straight line. All spinning bodies exhibit angular momentum which is the measure of how fast the body is spinning, how much mass the body has, and how that mass is distributed. The equation for angular momentum is: H=MR2 where M is the mass, R is the radius of the rim, and W is the spin velocity. To make the point, angular momentum is what keeps gyroscopes spinning in place and X-zyLo flying straight and stably through the air. The force that it creates is called centrifugal force. It resists any other force that tries to change the gravity, wind, a collision with another object, etc. Let's try another experiment.
GYROSCOPIC PRECESSIONYou have observed that X-zyLo curves left at the end of its flight. This is because its spinning momentum slowed which caused the strength of its centrifugal force to weaken. When this happens gravity pulls the nose of X-zyLo down and it moves to the left in a direction opposite to its spin. Now throw the X-zyLo with it spinning the opposite way (either have a left-hander throw it or throw it under hand). Does it curve? Does it curve the same way at the end, or does it curve the other way? The curving of X-zyLo at the end of its flight demonstrates gyroscopic precession. Gyroscopic precession states that a spinning body
tends to react to a disturbing force by rotating in a direction at right angles
to the direction of the torque. The equation for gyroscopic precession
is P=T/H where P is the rate of precession, T is the
applied torque and H is the angular momentum.
WHAT MAKES X-zylo FLY?You have seen that (1) planes fly because of their aerodynamic characteristics and that (2) gyroscopes resist gravity and stand straight up because they efficiently spin. The technology that enables the spectacular flight performance of X-zyLo utilizes both aerodynamic and gyroscopic phenomena. The top and bottom of the cylinder give X-zyLo lift similar to that of a bi-winged plane and the rapid spinning of the heavy ring gives it stability and prevents it from nosing down to the ground. However, it is unclear exactly how the two interact. The interactions are very complex and there are different and conflicting theories as to what goes on. How does X-zyLo fly straight when the principle of gyroscopic precession states that rapidly spinning bodies should turn right angles when outside forces, such as gravity, are applied against them? Some observers say that certain aerodynamic forces affect the right angle turning tendency of gyroscopic characteristics. Others are not so sure. What do you think? If you have any insights or theories into this matter, please contact the William Mark Corporation at: Research and Development Dept. |
A special thanks to VASTfor hosting our web site. |