Issue link: https://www.e-digitaleditions.com/i/1520252
to the right-hand switch at all, so turning the right-hand switch before the le-hand switch is turned one click does nothing. All the LEDs, the buzzer, and the continuity check are powered by a 3 volt circuit that acts independently of the other 9 volts from the "second DC power supply" (DCPS2). It is only when both keys are turned all the way to the right against spring tension that the 9 volts from the second set of batteries travels through the firing leads to fire the igniter (IGN). Launch Sequence Callouts e text of each lighted callout on my panel is taken directly from the Titan II system, though modified in meaning for my model launch sequence: BATTERIES ACTIVATED. For the Ti- tan II missile, this confirmed that electro- lyte solution was being pumped into bat- teries on board the missile, which sat dry as the missile awaited launch. In my system, this illuminates upon turning the le-hand key to Center position. ADVANCE TO READY. is callout was part of the guidance system of Titan II. In my sequence, it lets me know that only the le-hand key is turned to Center, and that the readiness check depends on the right-hand key being turned one click. DC PWR SUP 2 ON READINESS. For the Titan II missile, this showed that a backup power supply was online. My model sequence, this illuminates when the right-hand key is turned, and it implies that the second bank of batteries is ready to boost the current up to the level needed for ignition (although it doesn't actually check those batteries). READY TO LAUNCH. When the right- hand key is turned to Center position, and if there is continuity to the igniter, the Ready to Launch callout illuminates and the buzzer sounds. Turning both keys simultaneously to the their far right positions sends the 9 volts from the second set of batteries down to the line to the rocket to achieve ignition. e text callouts are manufactured parts called Roto-Tellites. ese were used ex- tensively in missile systems and NASA launch control centers, in addition to other industries where automation assisted with old-school electromechanical equipment. SPORT ROCKETRY MAY/JUNE 2024 33 Figure 6. Front of launch controller showing text callouts between the launch key switches. Is your launch rod/rail Is your launch rod/rail angled away from angled away from the flight line? the flight line? SAFETY SAFETY CHECK: CHECK: Don't Fly Over the Flight Line! Don't Fly Over the Flight Line! Don't Fly Over the Flight Line! Don't Fly Over the Flight Line!