I see that SH engines, and maybe others, offer new gasoline powered engines without an external battery source for the spark plug.  How is this possible, when old “spark ignition” engines had a battery pack and timer?

   Search the forums for information on this. It's not new, and I think some one has actually tried one on a sport stunt model. I don't think the results were satisfactory because gasoline burns hot. That is the reason most don't use gasoline for old ignition model engines, and another reason that alcohol is used for glow engines and other larger,  high performance engines. You have to run almost twice the amount of alcohol to get the same BTU release as gasoline, but it does it at a lower temperature and is easier to control. Even if there is never another Glow Devil R/C Long or Thunderbolt glow plug produced, I don't think gasoline will ever replace what we have become used to using since the 1950s.
  Type at you later,
  Dan McEntee