Delay Grain

[north boy]

Hi everyone I have a Gorilla 38mm motor and was wondering if anyone has any knowledge of where I can find info on the build up and physics of building a delay grain to work with the motor and how its seperate from the motor chamber but still ignited by the chamber during the burn. Im going to order a RRC2 altimeter from atxcple when I have the money in a week or so but would like to do some ground tests for delay grain also. Im not bothered about what the chemical build up is but just the general how the hell does the chamber pressure get seperated from the grain but manages to ignite it ......

[COrocket]

Delay grains are not "separate" from the motor chamber. They are in an endburning configuration and the end facing the motor chamber is ignited when the motor is lit on the pad. If it is a tracking smoke grain like you see in 75/98MM commercial reloads, they are inhibited on one end so both ends don't ignite. Delay grains use O-ring sealing. From what I've seen most experimental people don't make delay grains, and some make tracking smoke. Delays are very hard to make regarding timing accuracy, even by commercial manufacturers. Going with an altimeter is a better option for rockets powered by homemade motors.

[north boy]

Delay grains are not "separate" from the motor chamber. They are in an endburning configuration and the end facing the motor chamber is ignited when the motor is lit on the pad. If it is a tracking smoke grain like you see in 75/98MM commercial reloads, they are inhibited on one end so both ends don't ignite. Delay grains use O-ring sealing. From what I've seen most experimental people don't make delay grains, and some make tracking smoke. Delays are very hard to make regarding timing accuracy, even by commercial manufacturers. Going with an altimeter is a better option for rockets powered by homemade motors.

Thanks for reply, I think I've got it now. The altimeter is a must and I am going to get it.