The F-100 had an interesting ground starting option, a large chamber that received a large gas generating cartridge. When ignited by electrical current, the expanding gas from the black powder-like pyrotechnic cartridge drove a starter turbine which brought the engine up to a self-sustaining rpm via a drive system. This eliminated the need for heavy and bulky ground starting units, but the starter cartridge spewed out a characteristic dense cloud of choking black smoke, which was often mistaken by inexperienced ground crews for an engine fire.
The powder charge for the ground start came in a big sealed can, and on opening and extracting the cartridge, you'd find two small metal tabs on the bottom of the cartridge. These tabs were the electrical contact that fired the cartridge when the pilot moved the throttle outboard on start, before bringing the throttle forward. As soon as a tiny RPM registered on the tach, you brought the throttle around the horn to feed fuel and engine ignition to the rapidly-building engine speed.
Sometimes the big metal receptacle that held the gas generator cartridge would get so dirty from repeated use that the metal tabs wouldn't make contact. Then the cartridge would refuse to fire, and the crew chief would give the starter receptacle a good healthy whack with a chock, usually curing the powder charge of any reluctance to fire. We'd often take a can holding a starter cartridge with us as an alternative starting means on cross-country.
The story is told, one of few that I didn't witness, of John Green going into Memphis, Millington NAS or MCAS, in an F-100 back in the very early seventies. He was met by a couple of young Marine ground crewmen, who asked what kind of plane he was flying. "F-100 Super Sabre" in reply only got him further puzzled looks. One of the ground crew said, "Sir, I don't think we have tech data on this bird. What do you need for start, a huf fer or just electrical"?
"Neither one", John came back. "If I can get, oh, about six guys to give me a push to start me rolling, I'll just pop the clutch and get the engine started that way." More and more doubtful looks! "Yessir" was the comeback. What else would a young Marine say?
The Hun was pretty finely balanced on the two main gear struts. When you tapped the brakes, the nose strut compressed so much that the nose took a dip, just like the hood of a car used to when being clutch-started. So now six Marines are standing at the ready, still doubtful but not about to question an Officer on procedure. "Just get me going at about a fast walk", John instructed. "I'll wave you all clear when we're fast enough, pop the clutch and be on my way. Thanks for the good turnaround!"
Six Marines pushing, they quickly get the bird up to a brisk-stepping speed. John waves his arms, and the Marines warily stand well clear. The nose dips as John "pops the clutch", there is a big cloud of choking smoke as the engine whines to life, and off goes Captain Green to the takeoff end of the runway, leaving six puzzled Marines in his wake.