This has probably been discussed before, but please forgive mew if I overlooked it.
Many people use fuel rich charcoal spilling propellants to create strong tails.
Since I had great success with nozzleless BP and whistle, and new techniques seem to allow
hotter fuels even with nozzled engines, burdening my fuel with technically useless additives is out of the question.
Yes I know - use external comets - but I prefer an internal solution.
Ideally something that can be riced/granulated like BP for convenient handling.
A lot of mixtures seem to have the habit to produce slag/droplets that like
to cling to the tube, or if one is present, build up at the nozzle and stay there.
Especially after the core is consumed and the pressure drops.
-> no visible tail
What delay mixtures do you prefer?
W39j seems to be the answer, but maybe there's something else / something better I dont know yet.