Machine Head

Machine Head was a member of the Freefall Warriors, a team of spacecraft racers and stunt fliers. His teammates were Bruce, Cool Breeze and Big Cat.

The Freefall Warriors encountered the Fourth Doctor at the Festival of Five Planets. Machine Head took Dr. Ivan Asimoff and him on a ride in his spacecraft, but during the flight they ran into a party of raiders from the sixth planet and were shot down over an asteroid. While the Doctor repaired the damage, Machine Head contacted the other Warriors and warned them of the raiders. They set off to battle the raiders, destroying them before they could cause major damage to the Festival, and were greeted as heroes upon their return. (DWM: The Free-Fall Warriors)

The Freefall Warriors attended Bonjaxx's birthday party on Maruthea. (DWM: Party Animals)

When a Vortex parasite attacked the Doctor's TARDIS, the Eighth Doctor summoned images of his allies, including the Freefall Warriors, in his battle against it. (DWM: A Life of Matter and Death)

Behind the scenes
The Freefall Warriors also appeared in back-up stories in Captain Britain #1-4, which gave their origins.