Flight Sequence Controller

The prototype Flight Sequence Controller

The Flight Sequence Controller (FSC) shown above is not intended to be flown. It is a bench test version and is far to big and heavy to be installed in a model. The D-9 connector is used to program the BS-2 STAMP at the heart of the FSC and also to transfer flight parameters to and from the FSC. The 32 kHz watch crystal and 4060 oscillator/divider are mounted to the right of the STAMP and provide an accurate time base to the control program. The TO-220 package to the right of the clock circuit is a BUZ11 power MOSFET that controls the power supplied to the servo. In order to minimise battery drain the servo is only powered up when it is to execute a sequence of movements.

The machined component below the prototype system is a M&K tow hook with factory fitted reed switches that sense hook position (forward or back) and whether the latch is open or closed. It is shown in its forward position relative to its mounting and with the latch open. All flight control is achieved by moving a standard RC servo, visible above the prototype system, through a timed series of movements. Both the timing and the distance of the movements are configurable.

The FSC is started by pulling the tow hook forward. It can detect towline breaks (the hook remains back with the latch closed for a configurable time) and starts the flight control sequence when the model is released from its towline. Release is recognised when the hook moves back with the latch open. After the preset flight time is ended, the FSC dethermalises the model and turns itself off.