Question: Do your pages always have to start with a long, preachy narrative?Problem 1: No smoke trail. When I first launched my Sugar Rush with the Loki 54mm motor, it simply vanished. I was thrilled by that act a couple of times, then though it might be nice to track the rocket to apogee. Someone suggested a smoke trail, so I started thinking about it.
|Solution 3: The Clock grain.
At first I placed a divider inside the smoke grain, a small chunk
of 1/4 inch plywood
(Click the small picture or here for a better description)
Problem 3a: It didn't work. In my one static test, the smoke grain did not make smoke. At least not after the propellant grains had fired. I assumed that the flame had "leaked" through past the top inhibitor or maybe somewhere else and burned the smoke stuff along with the propellant stuff. Not bad for thrust, not good for its intended purpose.
And yes, there is plenty of safety margin in this motor casing to burn the smoke grain simultaneously, no significantly increased danger of CATO.
||Note that the illustration is "upside down."
Meaning that the propellant grains and nozzle will be to the top
of the illustration, the head-end closure will be to the bottom.
I drew it this way because this represents the view while assembling the grain.
A short section of inhibitor tube is cut, in this case one inch in depth.
A solid plywood disk is epoxied into the bottom end.
Topside of the solid disk is coated with epoxy, as well as the inside of the inhibitor tube. 5-minute epoxy works fine, as long as I work quickly.
A blob of warm, uncatalyzed rcandy is pressed into the tube, enough to almost half-fill it.
The first perforated disk is pressed firmly onto the propellant. It had been coated with epoxy first. Enough pressure is applied to remove any bubbles around the edges, and to extrude propellant slightly through the perforation.
The process is repeated with another layer of rcandy, this time catalyzed with a little red iron oxide. I find that catalyzed propellant does not extinguish easily when the case pressure drops, uncatalyzed propellant sometimes goes out.
As before, all surfaces are coated with epoxy, to fill any air gaps and to ensure that the propellant sticks to the surfaces well.