G'day all. I first saw Thunder Tiger 15 engines back in the mid 1970s. I think they were made in Taiwan. They looked very much like Enya engines at that time. They were selling for less than AU$20 if I remember correctly. An OS or Enya 15 would have been about AU$30 at the time. There were also Fuji engines that looked similar but I think they were made in Japan. At the time I was too busy playing with Super Tigre G20 15 diesels and G15 glow engines. These cost about AU$40 to 45 at the time. The very elegant Super Tigre G15 RVD was about $90. They could be made to go really hard but tended to break crank pins. The Thunder Tigers of the time were very much entry level engines. They have improved out of sight in more recent times.