ORIGINAL: ELTIGRE
there are commercial smoke bombs availible that work just fine to give smoke trails , so lighting a fuse will work. can also be done electrically. rocket motorsmounted under the C/G have been used in the past for JATO take offs. you will be violating the AMA safety code however.
While the Roman Candles are still 'verboten', the new 2005 AMA Safety Code now is better written and DOES allow those devices that burn producing smoke, plus rockets up to G size that are firmly attached to the airplane during flight.