here for discussion of the relationship between sf and superheroes.
Superheroes are of two kinds: those who are physically strong, fast, able to fly etc and those whose powers derive from something that they wear, a ring, suit etc.
Poul Anderson's Jack Havig is of the first kind. He time travels by an act of will - and thus can fight several opponents simultaneously by jumping backward and forward in time.
John C. Wright's Phaeton is of the second kind:
"The armor had a truly astonishing number of control interfaces, servo-minds, and operator hierarchies... Phaeton, with the armor, was able to use these control-interfaces to dominate the local thoughtspace."
-John C. Wright, The Golden Age (New York, 2003), p. 122.
Wearing the armor, Phaeton is able to move upward at several times the speed of sound. Thus, not Superman but Iron Man, so to say.