So, I've undertaken to modify a Quest Terrier-Orion into a two stager, representing its namesake.
Quest Terrier-Orion
NASA Terrier-Orion
I started with thinking and designing, thinking, redesigning, procrastinating, more thinking, and more redesigning over a couple of years. And now I've finally begun building. And then I got more than half done before I thought to take some pictures for a build thread, so here's the best I can do.
The basic concept is to use rear ejection in the booster, propelled by the ignition charge while the sustainer is being lit. To accomplish this, I've left the motor mount floating in the aft end of the booster, and lengthened it to meet a fixed extension tube that ends about 1/2 inch short of the sustainer motor. This extension is held in position by two vented centering rings, which will allow gas to progress down into the main volume of the booster. The booster airframe is not vented; the role usually played by venting is played instead by the expanding volume inside the airframe as the motor mount slides out. The fixed extension includes about 2-1/2 inches of coupler on its aft end; thus, contact is maintained between the mobile motor mount and the extension for some time as the motor mount begins its exit.
I was compelled to make a couple of on-the-fly modifications during the build so far; once I have updated my RockSim design accordingly I'll post it.
Quest Terrier-Orion
NASA Terrier-Orion
I started with thinking and designing, thinking, redesigning, procrastinating, more thinking, and more redesigning over a couple of years. And now I've finally begun building. And then I got more than half done before I thought to take some pictures for a build thread, so here's the best I can do.
The basic concept is to use rear ejection in the booster, propelled by the ignition charge while the sustainer is being lit. To accomplish this, I've left the motor mount floating in the aft end of the booster, and lengthened it to meet a fixed extension tube that ends about 1/2 inch short of the sustainer motor. This extension is held in position by two vented centering rings, which will allow gas to progress down into the main volume of the booster. The booster airframe is not vented; the role usually played by venting is played instead by the expanding volume inside the airframe as the motor mount slides out. The fixed extension includes about 2-1/2 inches of coupler on its aft end; thus, contact is maintained between the mobile motor mount and the extension for some time as the motor mount begins its exit.
I was compelled to make a couple of on-the-fly modifications during the build so far; once I have updated my RockSim design accordingly I'll post it.