What is "transonic"

a. 1 just below, or just above the speed of sound (0.8 < Ma < 1.2 approximately) 2 passing from subsonic to supersonic, or vice versa

adj. (of speed) having or caused by speed approximately equal to that of sound in air at sea level; "a sonic boom" [syn: sonic] [ant: subsonic, supersonic]

In aeronautics, transonic refers to the condition of flight in which a range of velocities of airflow exist surrounding and flowing past an air vehicle or an airfoil that are concurrently below, at, and above the speed of sound in the range of Mach 0.8 to 1.0, i.e. at sea level. This condition depends not only on the travel speed of the craft, but also on the temperature of the airflow in the vehicle's local environment. It is formally defined as the range of speeds between the critical Mach number, when some parts of the airflow over an air vehicle or airfoil are supersonic, and a higher speed, typically near Mach 1.2, when most of the airflow is supersonic. Between these speeds some of the airflow is supersonic, but a significant fraction is not.

Most modern jet powered aircraft are engineered to operate at transonic air speeds. Transonic airspeeds see a rapid increase in drag from about Mach 0.8, and it is the fuel costs of the drag that typically limits the airspeed. Attempts to reduce wave drag can be seen on all high-speed aircraft. Most notable is the use of swept wings, but another common form is a wasp-waist fuselage as a side effect of the Whitcomb area rule.

Severe instability can occur at transonic speeds. Shock waves move through the air at the speed of sound. When an object such as an aircraft also moves at the speed of sound, these shock waves build up in front of it to form a single, very large shock wave. During transonic flight, the plane must pass through this large shock wave, as well as contend with the instability caused by air moving faster than sound over parts of the wing and slower in other parts.

Transonic speeds can also occur at the tips of rotor blades of helicopters and aircraft. This puts severe, unequal stresses on the rotor blade and may lead to accidents if it occurs. It is one of the limiting factors of the size of rotors and the forward speeds of helicopters (as this speed is added to the forward-sweeping [leading] side of the rotor, possibly causing localized transonics).

Transonic (Laurie Tromette) is a fictional comic book superhero appearing in books published by Marvel Comics. The character first appeared in Uncanny X-Men #526, in the first chapter of the "Five Lights" storyline, and was created by Matt Fraction and Kieron Gillen. She is one of the "Five Lights"—a group of mutants who manifested their abilities after the events of "Second Coming".

Transonic is the debut album by American jazz drummer Whit Dickey, which was recorded in 1997 and released on AUM Fidelity. For his first record as leader, Dickey went into the studio with long-time associate, saxophonist Rob Brown, and then relative newcomer to the scene, bassist Chris Lightcap. He notes that many of the cuts were inspired by two Thelonious Monk compositions, "Off Minor" & "Criss Cross", along with the magic of tenor saxophonist David S. Ware.