Flame Blanket Knowledge
Flame blankets must be used whenever there is a deployment charge. They prevent the hot debris from the charge from reaching the shock cord or parachute, which can be melted or burned. They are generally made of a flame retardant material like NOMEX.
Flame blankets are usually constrained on the shock cord, free to move up and down.
Flame blankets are generally squares, but some are available in circles. They are generally sized by their width, which should be around 3 times the diameter of the body tube. For example, a 6 inch rocket should have at least an 18 by 18 inch square flame blanket.
Flame blankets should fully envelop the bottom and sides of the shock cord and parachute, so that there is as little of the recovery system exposed to the charge as possible.