Ultraman Chuck was one of three Ultra-heroes sent to Earth from the planet
Ultarra, to combat a race of Sorkan monsters newly arrived on Earth. The
Sorkan were part of a race of monsters from a planet near the star M78 (note
that, this time, the monsters, not the Ultra-heroes, come from M78). They were
trapped in a meteroid, until the meteroid broke up in Earth's atmosphere,
releasing 4 different monsters across the globe.
The three Ultra-heroes, called "The Ultra Force" on Earth, merged with three Air Force pilots while they were putting on an air show. The merger caused a great flash of light, and the three planes crashed. Miraculously, the three pilots, including the leader, Captain Chuck Gavin, seem to have survived. (Actually, they were killed, but were revived by the Ultra-heroes, much as Hayata was revived by Ultraman.) Due to the mysterious nature of the accident, however, the three "Flying Angels" were grounded indefinitely. While the Air Force may not have discovered what happened, Chuck and his compatriots, Lt. Beth O'Brian and Lt. Scott Masterson, found out about their shared existences through an Ultra-agent on Earth. We never find out if this agent had an Ultra-hero identity or not; all we see is a semi-elderly golf club greenskeeper named Walter Freeman. Walter explains what happened, and how the Ultra-heroes resuscitated them by merging with them.
The three Ultra-heroes do battle with the 4 Sorkan monsters, and get mixed reviews from the people whom they are defending. Finally, all 3 defeat the fiercest Sorkan, and gain at least some popularity with the people of Earth. The Ultra-Force are allowed to stay on Earth.
The Ultra-Force's base is housed inside Mount Rushmore. They have the use of 3 high-tech high-speed aircraft, which can be remotely controlled if necessary. The craft can be launched from the ground, or from a mother ship also provided for support. Assisting the Ultra-Force are three androids: Andy, the small but stable "leader" of the androids; Samson, the big burly android; and Ulysses, a tall and slender android who loves to argue with Samson about which one is better.
Ultraman Chuck (the term is used loosely, as he was never referred to by any other name than "Chuck," even in his Ultra form) possessed the standard Specium Beam-style energy beam, emitted from crossed hands. He also had the unique ability to create a "space bubble" around anything; he encased one docile Sorkan monster in a bubble to protect it on its long journey to another planet where it could live, and he encased another in a bubble to attempt to contain it. The bubble normally could not be penetrated, although the fourth Sorkan was able to pierce it by reuniting a severed limb still outside the bubble with its stump inside the bubble. Like the other members of the Ultra-Force, Ultraman Chuck could communicate telepathically with the others and the support ship.
Ultraman Chuck and his compatriots appear only once, in a movie jointly produced by Hanna-Barbara (creators of the Flintstones, Yogi Bear, Huckleberry Hound, and a host of other popular cartoons) and Tsuburaya Productions. The movie features the voices of Chad Everett, Stacy Keach, Sr., and Adrienne Barbeau, among others. The movie, entitled Ultraman: The Adventure Begins, appears to be a pilot for an ongoing TV series. Sadly, no such series was ever produced.
This Ultra-Force was never officially connected with the majority of the Ultra-mythos, although live stage shows in Japan have featured these three (obviously in costumes made from the drawings) along with the rest of the Ultraman family.
The Japanese transliteration of Ultraman Chuck's name is Shiyakutu, or simply Shiyak.