RPM Sensor with Futaba 16SZ

  • I’m Trying to use the SparkSwitch Pro with a Kolm EZ77 and Futaba 16SZ. I have it outputting data to the transmitter but it is incorrect. I am showing 250 at idle and 650 at full throttle. Even if that were 2,500 and 6,500, the numbers do not match what I get with an optical tach. I have read the post about setting up with Futaba, but the 18MZ is different than the 16 SZ. Any suggestions?

  • It is set up per the instructions on the post. Digging into the telemetry settings, there is a "gear ratio" setting that is set to 8.0 by default. I'm not sure what this does, and there is no mention of its application in the tx manual. I have not had a chance to re-test, but multiplying the figures I am currently receiving by 8 yields a number very close to where I should be. Could this be the culprit?

  • Thank you! I thought that may be the problem, but have not had a chance to try it out yet. My manual does not say what the gear ratio is for, or how to set it. However, that’s not surprising for Futaba. Their manual is not always the easiest to follow. I’m assuming that the gear ratio is for a heli.


    Thanks again to both of you for your prompt replies!