XDISC is the most versatile flying disc on the planet.
A patented gull-wing profile provides super accurate and stable flight. Advanced aerodynamics means it's easier for beginners of all ages.
The concave flight plate provides an ergonomic grip for a more natural
throwing position that results in less hooks and slices. XDISC has
endless potential for freestyle invention and creativity!
Spin it! XDISC is more than a flying disc!
Pass it on
Because the base of the pyramid in the XDISC is depressed into the disc, the aerodynamic property referred to as the “Coanda” effect occurs which stabilizes the boundary layer. The Coanda effect occurs because, when the stream lines of the flow across the top surface of the XDISC bend, a radial pressure gradient is induced in the flow so that the pressure field just overcomes the centrifugal force of the curved flow. As a result, additional lift is generated in the XDISC. Since this additional lift occurs at any speed, this feature of the XDISC is a particular advantage at low speeds. The turning or bending of the stream line of the flow also helps to stabilize the boundary layer of the front half of the disc without resorting to a high drag turbulent boundary layer.
The pyramid acts as a rudder to stabilize the lateral directional flying characteristics of XDISC. The pyramid performs this function because, as the XDISC flies through the air the pyramid is rotated approx. ten degrees to the rear of the flight path. The rotation of the pyramid at this angle of attack during flight places the aerodynamic center of the pyramid behind the center of gravity of the entire XDISC. This causes the pyramid to generate aerodynamic yawing moments which stabilize the turning tendency of XDISC through the air.
As a result of the flat edge surfaces of the pyramid, the pyramid contributes substantially to the structural integrity of the XDISC. As is generally known, triangular shapes provide extremely strong support for compressional loads. By placing the triangular pyramid’s axis normal to the bending plane of the XDISC, the bending moment is taken as a compressive or tension load on each face of the pyramid. Not only does this reduce the structural weight needed to stiffen the disc in bending, but it also enhances the structural integrity of the XDISC in the early stages of flight, that is, upon launching, when the compressional loads are the greatest. As a result, the XDISC maintains its aerodynamic shape throughout the flight path which in turn enables the XDISC to perform other utilitarian features mentioned, throughout the flight.
Again, because of the flat edge surfaces of the pyramid, the pyramid acts as a roll stabilizer immediately upon launch. This is accomplished by inertial coupling of the pitching moment caused by drag and the gyroscopic precession caused by the rotation of the XDISC. For example, when a right-handed person launches the XDISC in a normal manner, the rotation is positive about the yaw axis. The pyramid induces a moment which is positive (nose up) about the pitched axis. This moment causes a precession about the roll axis. Since the XDISC is essentially a flattened gyroscope, its moment of inertia characteristics induce retrograde precession which in turn induces a negative roll about the negative roll axis. This tends to immediately flatten the XDISC flight path upon launching.
All the XDISC tricks and moves are made possible by the rotational inertia of the spinning XDISC. Rotational inertia is a term that refers to the fact that a rotating rigid body maintains its state of uniform rotational motion. Its angular momentum is unchanged, unless an external torque is applied; this static state is also called conservation of angular momentum. Rotational inertia depends on the object remaining structurally intact as a rigid body, and also has practical consequences. For example, a gyroscope uses the property that it resists any change in the axis of rotation, until external torque is applied (finger on trick deck), which creates the angular movement that makes XDISC turn upside down while spinning.
So, applying torque (with your fingernail of index finger) on the XDISC trick deck changes the angular momentum of the gyroscopic balance of XDISC, making it rotate perpendicular to its plane of rotation. From this effect all the spinning, turnover, and balance tricks of XDISC are possible. Remember, XDISC only turns over as long as you apply pressure to the trick deck. As soon as you stop pushing down on the trick deck, the XDISC will stop its angular motion in relation to the axis of rotation. Now go practice your turnover and make some up some new moves all your own!