Flying disc

A flying disc is a round object with a flat shape and a thick rim. The rim helps with gripping and throwing the disc, and it also prevents it from flipping over while in the air. To throw the disc, the goal is to make it spin while it's in flight.
There is another type of flying object called a flying ring, which is sold under the brand name Aerobie. Although they have different designs, both flying discs and flying rings rely on air resistance to fly.
Flying discs are used in two popular sports, Ultimate Frisbee and Disc Golf. The Frisbee brand of flying disc is not commonly used in official competitions for these sports. In fact, the team sport of Ultimate Frisbee is officially known as "Ultimate." However, the term "Frisbee" is still widely used to refer to any flying disc, just like "Kleenex" was once used to mean "facial tissue."
The Aerobie
The Aerobie Superdisk is an alternative design of flying disc that, although somewhat differently shaped, still has very similar properties to the conventional disc. It has less air resistance. Because there is less resistance to motion, the Aerobie discs can fly farther than the conventional disc. The Aerobie flying ring has minimal drag and holds the world record for the longest flight by a human-thrown projectile. However, due to the lack of a rim, the Aerobie is less suited to angled, curved flights and air-bouncing.
Spin of the disc
The spin of the disc helps to keep the disc stable in flight and prevent unplanned tilting. This is because a large angular momentum stabilises the disc in the same way that it keeps a gyroscope steady, with the angular force forcing the mass of the disc away from the centre of mass, perpendicular to the axis of rotation. Any unequal force acting on a particular area of the disc is quickly redirected to be equal over the circumference of the disc.
As the disc spins faster, it becomes more stable due to the rapidity of the equalisation of forces.
Mass of the disc
The force required to accelerate the disc is directly proportional to the mass of the disc. This decreases the acceleration of the disc, assuming that the force of projection is constant. Therefore, discs come in a variety of weights, although those used for Ultimate are mainly 175 g in mass, heavier than the majority of discs and considerably heavier than an aerobie.
Flying discs (including Frisbees) can be thrown in many ways. All involve spinning the disc to give it gyroscopic stability, and accelerating its mass to a certain velocity. Without spin, a disc will wobble and fall; without velocity, the disc will not go anywhere. Using these two guidelines, any number of throws are possible. Most discs are designed to create lift when thrown with the flat side up.
Techniques
Right-side up
Right-side up throws are all similar in that they react the same way to the tilt of the disc when it is released. A disc thrown right-side up will accelerate in the direction of the low end of the disc. A disc tilted leading-edge up will lose speed at the end of the throw and make a gentle landing; if tilted sideways (known in aeronautics terms as roll), it can curve around objects.
There is a language for describing throws that curve. Both descriptions are relative to the direction the person is facing and intends to throw. This axis is marked in red in the picture.
Inside-out (i-o) throws (green paths) occur when the thrower releases the disc in such a way that it initially comes towards the throwing axis (inside-). However, the disc is tilted with the side closest to the body highest, which causes the disc to curve away from the thrower (-out).
Outside-in (o-i) throws (blue paths, sometimes also called a bender) follow the opposite path. The thrower releases the disc moving away from the throwing axis (outside-), but with the side of the disc closest to the body lowest. This tilt causes the disc to bend back towards the thrower (-in).
Backhand
This is probably the most commonly learned throw, and also one of the most powerful.
Grip: Fingers are curled under the disc's rim, and the thumb is placed on top of the disc to hold it in place. The index finger may either be on the edge of the disc (to help aim), or four fingers may be tucked underneath the rim (to aid power).
Throw: The thrower draws the throwing arm across the body to build velocity for the disc. During this movement, the arm straightens out. As the arm becomes straight, the wrist is flicked, to impart spin.
Variations
The High Release: Used to get around an object (or a person), the High Release is thrown above the thrower's shoulder, and relies more heavily on the flick of the wrist to impart power.
The Air Bounce: This throw is released at a downward angle, but with a high angle of attack. This throw will move toward the ground at first before downwash causes it to rise, giving the visual effect of the disc "bouncing" in the air. This is done by pressing down with the thumb, which lowers the trailing edge at the instant of release.
The Beach Backhand: Rather than reaching and throwing the disc across the body, the arm is curled and the disc is cocked next to the hip on the same side of the body as the throwing arm. The disc is released by extending the arm straight ahead and snapping the wrist. The term "beach backhand" is considered pejorative, as this release technique is uniformly inferior to a standard backhand.
Forehand
This throw is also known as the flick, two-finger, or the side-arm. Focused in the wrist, this throw takes little time to execute. Along with the backhand, it is one of the two most common throws used in Ultimate.
Grip: The middle finger is extended and laid along the rim of the disc. The index finger is placed against the middle finger for power, or pressed on the bottom of the disc pointing towards the center for stability. The thumb is pressed against the top of the disc. The wrist is cocked back, and the arm is extended out from the body.
Throw: A snap of the wrist imparts spin as the disc releases off the middle finger, as well as some forward velocity. Extension of the lower arm provides additional power, as does shoulder and upper body rotation.
Variations
The forehand is a versatile throw, and can be adapted to many different situations.
Different wrist or arm angles on release can allow for inside-out or outside-in curves.
Most upside-down throws (see below) use the forehand grip and use the same wrist snap and release, and are therefore variants of the forehand in some sense.
The High Release: Used to get around an object (or a person), the High Release is thrown above the thrower's shoulder, and is powered by the flick of the wrist as well as the rising action of the arm on release.
Push Pass
The Push Pass: A relatively little-used throw, it is thrown with a grip similar to a backhand (index finger on the outer rim of the disc, thumb on top, other fingers curled underneath) but is released on the forehand side from a forehand stance. A pronating wrist snap similar to a forehand release pushes the disc forward, while spin is imparted "backwards" by rolling the disc off the index finger. A final flick of the index finger finishes the release. It is difficult to impart as much spin to the push pass as one can typically impart to a forehand or backhand, resulting in a less stable throw. It is useful in Ultimate for very short throws released to the forehand side.
Thumber forehand
The thumber forehand is also known as a The Beach Thumber, Peach, or in the sport of guts, simply as a thumber. Its primary advantage is that it can be thrown quite hard and with a great amount of spin, and is relatively easy to learn. It is often seen used in a game of Guts due to its power and velocity. It is unpopular in Ultimate due to several disadvantages when compared to the standard forehand. It is relatively difficult to impart different curves or release angles to, it is harder to release extended away from the thrower's body, and it makes for slow grip transitions to a backhand or hammer.
Grip: The thumber derives its name from the grip: it is thrown on the forehand side with the thumb under the rim and the rest of the hand against the outside of the disc. The arm should also be tucked against the side, and the elbow bent. The disc is kept parallel to the ground and the wrist is cocked back.
Throw: To release, the wrist is snapped forward. Spin is imparted off the flat part of the thumb; power can be gained by rotating the arm at the shoulder or the body at the hips. A flat release is critical to a successful thumber forehand.
Overhand
The Overhand (also known as Hungarian, flamingo, dragonwing, windmill, waffle, discus, wrist-hook, chicken wing, or biscuit) is rarely used among ultimate players, because the alternative, the traditional forehand, allows greater sideways arm extension, useful in moving the disc around defenders. The Overhand is most useful when the disc is caught above the head and must be thrown quickly without changing grips, such as during a Greatest attempt.
Grip: The fingers of the hand are spread out over the top, with the thumb under the disc and perpendicular to the rim. For greater control, extend the index finger along the rim, as in the control grip for the forehand.
Throw: The arm is held horizontal and behind the thrower, then quickly brought forward, and the wrist is snapped laterally as the disc is released. Typically, release occurs at or above shoulder height, although it is possible to release at waist height or lower. The whole body and arm can be allowed to rotate, and the forearm must move very quickly to impart enough momentum to send the disc a significant distance. For maximum power, the entire body rotates, as in the ancient discus throw seen in track and field events; for a right-hander, the torso starts leaning right, and ends leaning left. Wrist snap is especially important, as the throw has no stability without a strong spin.
Duck
The Duck (also known as a bear claw, a duder, or a useless) is thrown with a similar grip to the Overhand, except it is the backward version of it. While the Overhand is thrown with counter-clockwise spin (for right-handers), the duck is thrown with clockwise spin. It is usually thrown with the arm out to the side or above the head. It is called the duck due to the shape of the gripping hand during the throw, as if making a duck shadow puppet. This throw is used in attempts at The Greatest (jumping out of bounds and throwing the Frisbee back in to play while in the air).
Upside-down
A disc thrown upside-down has a very different flight path than one thrown right-side up. The lift force does not enforce stable flight as it does on a right-side up disc, resulting in a more of a parabolic arc in flight. As with a right-side up throw, however, the flight path of the disc will curve toward the lower edge. This banking effect is most pronounced when the disc is at a 45 degree angle, and less pronounced when it is near-vertical, or near-horizontal.
Gyroscopic precession causes the disc to rotate toward horizontal through its flight path. Unlike a right-side up throw, however, an upside-down disc will not precess toward a stable flat state, and will in stead oscillate past horizontal and begin to bank in the opposite direction. This shuttlecock-like effect is known as "helixing", and is generally avoided due to the difficulty in controlling a helixing flight path. For this reason, an upside down throw is typically released with either clockwise rotation and the left edge up, or counterclockwise rotation and the right edge up. The longer the disc is expected to remain in the air, the closer to vertical it must be at release to avoid the helixing effect.
Hammer
The Hammer is gripped just like a normal forehand throw, and is generally a mid-range, high and arching throw.
Grip: Identical to the forehand.
Throw: From an open stance, the throwing arm is swung over the head in a similar motion to an overhand throw or volleyball spike. The disc is released using a wrist snap identical to that of a forehand. The angle of the disc on release can be anywhere between vertical and nearly upside-down, depending on the flight path desired.
A hammer, when thrown by a right-handed thrower, will arc up and to the left as it moves away from the thrower, and will bank towards the right in flight. The banking effect will be more pronounced if the disc is thrown higher and spends more flight time near a 45 degree angle.
Scoober
Another upside-down variant of the forehand, the scoober (also known as the "Spoon pass" or Hiawatha) is similar to a hammer, but released away from the body from a backhand stance, instead of over the head from a forehand stance. The scoober travels in a path similar to the hammer, although the initial release is typically more flat than a hammer release. Although it is more difficult to impart power to a scoober than a hammer, a scoober can be an effective short-range (10 to 20 yards/meters) throw and is used in Ultimate for breaking the mark and to throw over defenders in a zone defense.
Grip: Identical to a forehand or hammer.
Throw: The thrower steps towards the backhand side, holding the disc upside down and bringing the throwing arm across the body. Leading with the elbow, the throwing arm is swung forward, and the disc is flicked off the middle finger (as in a forehand), releasing the disc upside down.
Thumber
The Thumber (not to be confused with the thumber forehand) is a throw that is rarely used in competitive play, compared to the Hammer or standard forehand. It has a flight path that is the mirror-image of the Hammer (arcing high and to the right for a right-handed thrower). It can be useful when the disc needs to drop quickly and fly with an opposite curve to a Hammer in order to avoid defenders.
Grip: The thumber derives its name from the grip: the disc is held with the thumb tightly against the rim and the rest of the hand against the outside of the disc. The wrist is cocked back in a similar fashion to a forehand.
Throw: Cock the arm backwards, then bring it forward in a similar motion to a baseball pitch. The disc is released by a forward wrist snap.
Table of basic disc throws
This table represents the fundamental disc throws with classic technique in the foreword form, in fact exist many variations of throws and grips that make the number of pitches quite infinite.
The natural path is the trajectory the disc takes without pre-release tilt.
The hyzer path is the trajectory the disc takes when the outside edge of the disc is tilted downward.
The anhyzer path is the trajectory the disc takes when the outside edge of the disc is tilted upward.
The spin is the rotation of the disc.
Every throw can be done with the right hand or the left hand and this is shown in the hand column.
RH=right hand, LH=left hand, R=the path tends to the right of the thrower, L=the path tends to the left of the thrower, 0 means that the path is quite linear.
So R with RH and L with LH are outside-in (OI) paths; R with LH and L with RH are inside-out (IO) paths.
In spin column numbers represent the sign of the angular momentum relative to the upside of the disc (+1=positive (counter-clockwise rotation), -1=negative (clockwise rotation)).
Throws may be signed as follows: hand acronym+throw acronym+tilt acronym. For example LHBHIO is an inside out backhand throw pitched with the left hand; RHFH0 is a linear forehand throw pitched with the right hand. To have linear paths the disc must be released with a light opposite tilt than his natural path.