I reverse engineered the flap circuit of the Columbia and modified it for my ESP. Advantage: pure electro-mechanical, no microprocessor or timing circuitry involved. Disadvantage: you need to figure out a way for the flaps to activate some switches
600 hours -> so far, so good
It requires 4 roller switches:
- The "Full UP" switch opens when flaps move above full up position, is closed when flaps are below full up
- "TOE" snaps when moving from full up and arriving at and below takeoff position
- "TOR" switches when moving from landing and arriving at and above takeoff position
- The "Full Down" switch snaps when the flaps arrive at and below landing position
The roller switches are driven by plastic rings from McMaster-Carr into which I machined cam lobes. I used two rings -- each ring drives two switches. The cams are clamped to the flap torque tube.
It's not my best work, but here are the installed cams and (upgraded) flap relays under the rear seat (you can see some profiling on the cams):
I have a four position switch on my panel indicating "up", "takeoff", "landing", and "off". "Off" drops power to the command lines and stops the flaps wherever they are:
The circuit provides indicators for "flap in motion" and each command position....but I never bothered to use the indicators because I just look out the window. I've attached the schematic, the arrows indicate whether the signal is going into or out of the circuit.
-isaac
ESP N7842K