Biplane et al,
An article written by Dan Santich on this subject appeared in the Octobrer '85 issue of Model Airplane News concerning this topic. Dan, later on, (unfortunately I do not have the date) again wrote in MAN on this subject piping a BIG HOTS for tip smoke. He used brass tubing and high temperature nylon fittings for the job. MAN can probably dig out the article upon request
John (MAAC - 13304L)