Bell X-2

The Bell X-2 (nicknamed "Starbuster") was an X-plane research aircraft built to investigate flight characteristics in the Mach 2–3 range. (The term "Starbuster" is seldom, if ever, found in contemporary accounts.) The X-2 was a rocket-powered, swept-wing research aircraft developed jointly in 1945 by Bell Aircraft Corporation, the U.S. Air Force and the National Advisory Committee for Aeronautics (NACA) to explore aerodynamic problems of supersonic flight and to expand the speed and altitude regimes obtained with the earlier X-1 series of research aircraft.

Design and development

The Bell X-2 was developed to provide a vehicle for researching flight characteristics in excess of the limits of the Bell X-1 and D-558 II, while investigating aerodynamic heating problems in what was then called the "thermal thicket".

The Bell X-2 had a prolonged development period due to the advances needed in aerodynamic design, control systems, high-temperature resistant materials to be used, and other technologies that had to be developed. Not only did the X-2 push the envelope of manned flight to speeds, altitudes and temperatures beyond any other aircraft at the time, it pioneered throttleable rocket motors in U.S. aircraft (previously demonstrated on the Me 163B during World War II) and digital flight simulation. The XLR25 rocket engine, built by Curtiss-Wright, was based on the smoothly variable-thrust JATO engine built by Robert Goddard in 1942 for the Navy.

X2

X2 may refer to:

Mathematics

Films

Video games

Transport

X2 (film)

X2 (often promoted as X2: X-Men United, or internationally as X-Men 2) is a 2003 American superhero film, based on the X-Men superhero team appearing in Marvel Comics, distributed by 20th Century Fox. It is the sequel to 2000's X-Men and the second installment in the X-Men film series. The film was directed by Bryan Singer, written by Michael Dougherty, Dan Harris, and David Hayter, and features an ensemble cast including Patrick Stewart, Hugh Jackman, Ian McKellen, Halle Berry, Famke Janssen, James Marsden, Rebecca Romijn-Stamos, Brian Cox, Alan Cumming, Bruce Davison, Shawn Ashmore, Aaron Stanford, Kelly Hu, and Anna Paquin. The plot, inspired by the graphic novel God Loves, Man Kills, pits the X-Men and their enemies, the Brotherhood, against the genocidal Colonel William Stryker (Brian Cox). He leads an assault on Professor Xavier's school to build his own version of Xavier's mutant-tracking computer Cerebro, in order to destroy every mutant on Earth.

Development on X2 began shortly after X-Men (2000). David Hayter and Zak Penn wrote separate scripts, combining what they felt to be the best elements of both scripts into one screenplay. Michael Dougherty and Dan Harris were eventually hired to rewrite the work, and changed the characterizations of Beast, Angel, and Lady Deathstrike. Sentinels and the Danger Room were set to appear before being deleted because of budget concerns. Filming began in June 2002 and ended that November. Most of the filming took place at Vancouver Film Studios, the largest North American production facility outside of Los Angeles. Production designer Guy Hendrix Dyas adapted similar designs by John Myhre from the previous film.

Square (algebra)

In mathematics, a square is the result of multiplying a number by itself. The verb "to square" is used to denote this operation. Squaring is the same as raising to the power 2, and is denoted by a superscript 2; for instance, the square of 3 may be written as 3², which is the number 9. In some cases when superscripts are not available, as for instance in programming languages or plain text files, the notations x^2 or x**2 may be used in place of x².

The adjective which corresponds to squaring is quadratic.

The square of an integer may also be called a square number or a perfect square. In algebra, the operation of squaring is often generalized to polynomials, other expressions, or values in systems of mathematical values other than the numbers. For instance, the square of the linear polynomial x + 1 is the quadratic polynomial x² + 2x + 1.

One of the important properties of squaring, for numbers as well as in many other mathematical systems, is that (for all numbers x), the square of x is the same as the square of its additive inverse −x. That is, the square function satisfies the identity x² = (−x)². This can also be expressed by saying that the squaring function is an even function.