Some Close-Up Details of the Pack 412 Space Derby System
FRONT OF LAUNCH TOWER
The yellow launcher (with the dowels and the numbers) rotates on the blue frame. The vertical dowels hold the rockets in place (and keeps the rockets from spinning on the fishing line before launch). The dowels sticking out the front (above the number) keep the propellors from spinning before launch.
The screen door spring roates the yellow launcher (and releases the rockets) when the firing pin is pulled (see next picture).
The white spacers (look like drinking straws) ensure that all rockets start from the same position. The white carriers are standard Space Derby rocket carriers.
REAR OF LAUCH TOWER
The firing pin (on top of the yellow block on the blue crossbar) is pulled to release the yellow launch assembly, which is now free to be pulled down by the screen door spring on the other side.
When the launch assembly rotates, it triggers some electronics near the top of the right-hand blue tower leg. The electronics send a signal to the computer (somewhat visible in the center background) to start the timer.