N546RV
Well Known Member
Planning, planning, planning...such is my life these days. This must be that last 90% everyone talks about. This has surfaced a couple questions about installing/packaging the CPI2 components.
#1: How accessible should the ECU and backup battery units be? Both these units have fuses that might require service at some point. I have no expectation of making them accessible in-flight, but I'm also not sure that burying them behind the panel is smart either.
My first inclination was to package the ECU alongside my fuse blocks, which I intend to place on a hinged mount behind the panel for on-ground accessibility, but getting the ECU on there alongside the fuse blocks and associated stuff is pretty tight. Moving the ECU to my upper avionics shelf - which will only be accessible by removing the center of the panel - would make things a good bit roomier.
I figure in a general sense if these fuses are blowing on any regular basis, I've got obvious issues, so I suppose this mostly comes down to possibly dealing with teething problems early on. I still feel like overall, having these units somewhat buried wouldn't be a bad thing.
#2: I'm interested in the "switchology" for the CPI2. I'll be full electronic, and thus running a dual ECU unit. I intend to use toggle switches, not a key switch, for ignition control. My current schematic iteration has two DPST switches, one for each ECU. Each switch controls power to the ECU and coil (purple and red wires) for that ECU.
What I'm wondering is whether I should also provide a way to kill the coils with a dedicated switch or switches, either for the purpose of killing the engine quickly, or for killing the coil packs individual (as with a traditional mag check). I know all the preflight stuff can be done from the controller - is there any benefit to using the controller in lieu of external switches for the runup procedure?
One thing I thought about was to replace those DPST switches with ON-OFF-(ON) DPDT switches for this purpose. The center position would of course have everything powered off, up would be the normal "on" position in-flight, and down would be the momentary position, and could activate the external kill function for the connected ECU. This would enable both traditional "mag checks" as well as the ability for a quick engine kill.
The other alternative would be to simply have a third switch that killed both ECUs, and was used only for an emergency shutdown, and all runup operations could just run through the controller.
This is definitely the more fun question, and I'm very interested in people's thoughts here. Thanks!
#1: How accessible should the ECU and backup battery units be? Both these units have fuses that might require service at some point. I have no expectation of making them accessible in-flight, but I'm also not sure that burying them behind the panel is smart either.
My first inclination was to package the ECU alongside my fuse blocks, which I intend to place on a hinged mount behind the panel for on-ground accessibility, but getting the ECU on there alongside the fuse blocks and associated stuff is pretty tight. Moving the ECU to my upper avionics shelf - which will only be accessible by removing the center of the panel - would make things a good bit roomier.
I figure in a general sense if these fuses are blowing on any regular basis, I've got obvious issues, so I suppose this mostly comes down to possibly dealing with teething problems early on. I still feel like overall, having these units somewhat buried wouldn't be a bad thing.
#2: I'm interested in the "switchology" for the CPI2. I'll be full electronic, and thus running a dual ECU unit. I intend to use toggle switches, not a key switch, for ignition control. My current schematic iteration has two DPST switches, one for each ECU. Each switch controls power to the ECU and coil (purple and red wires) for that ECU.
What I'm wondering is whether I should also provide a way to kill the coils with a dedicated switch or switches, either for the purpose of killing the engine quickly, or for killing the coil packs individual (as with a traditional mag check). I know all the preflight stuff can be done from the controller - is there any benefit to using the controller in lieu of external switches for the runup procedure?
One thing I thought about was to replace those DPST switches with ON-OFF-(ON) DPDT switches for this purpose. The center position would of course have everything powered off, up would be the normal "on" position in-flight, and down would be the momentary position, and could activate the external kill function for the connected ECU. This would enable both traditional "mag checks" as well as the ability for a quick engine kill.
The other alternative would be to simply have a third switch that killed both ECUs, and was used only for an emergency shutdown, and all runup operations could just run through the controller.
This is definitely the more fun question, and I'm very interested in people's thoughts here. Thanks!