I'm still here Steve (waiting for the Suwannee river to flood),

   The FBW is installed and working (kind of) in the RV-8 but I decided not to make it a product after two very scary failures.  One was on the ground which caused the engine to go to full throttle.   That was caused by a heat shrink insulated wire connection shorting to ground where it was tie-wrapped to the fuel rail.   Watch out for this cold flow failure if you use heat shrink insulated wire splices!  Also, know what switches you need to turn off in a panic to kill the engine.

The second failure was a software glitch in the primary controller which communicated with the EC3 on the serial bus in order to do things like Hold constant RPM, MP, Fuel Flow, etc.  This one happened on final approach and the engine stopped responding to the throttle quadrant.  I was only 300 ft AGL at the time and would not have made the runway (I know, bad landing habits)    I regained control by switching to the backup (it has a redundant controller like the EC2/3).   The backup did not have the serial communication links like the primary and it still worked.   I eliminated the Hold functions and the serial connection to EC3 on primary FBW to eliminate the failure on it.  Now all the FBW does is mirror the movement of the throttle quadrant at the RX-8 throttle body.

These things could be fixed but the idea of trying to debug customer problems in the field with this much digital systems complexity made me decide that it was not a good idea.

I'll share the schematic & software files if anyone wants to DIY one.  You will need the development tools I use to use them though.

Schematic & PC Board files are in DipTrace,  software is in Microchip MPLAB and uses some PIC BASIC PRO compiler routines as well .  MPLAB is free from Microchip BTW.

Tracy

On Mon, Mar 4, 2013 at 9:22 AM, Stephen Izett <steveizett@me.com> wrote:

Tracy, are you there?

I seem to remember you set up your Rv8/20B originally with the Rx8 fly by wire throttle.
Did you end up using it and developing a controller for it?
If so:
1.  Are you willing to share the hardware and code you used?
2. Current consumption?
3. Most importantly our thoughts on the value or otherwise of fbw? (true single lever/pot! or perhaps just another failure mode)

Cheers

Steve Izett
Perth Western Australia


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