I am in Phase I flight testing with my ELSA RV-12 and am having a problem I need some help with.
The SkyView (conversion harness, software version 7.1) shows reliable and steady RPM information for the Rotax only until it hits around 5000 RPM. As soon as it hits the "limit" (and the limit varies, sometimes it is down to 4800 but never below that) the RPM readings jump all over the place and never settle.With jumpy I mean vast jumps of +-500 and more RPMs from one moment to the next.
At low cruise of 4500 - 4800 everything is steady and persistent but on take-off or climb, I cannot get a reasonable or reliable reading from the SV. The engine runs smooth, with low vibrations and the carbs have been balanced. The prop is still set at the initial pitch setting that Van's requested for first engine run which is a fairly high pitch to avoid over-speeding the engine.
The RPM sensor in the Rotax is a two-wire cable(white and blue) that is just hooked up to the FW forward harness(white/green and black) with a plastic plug, so no modifications or crimping had to be done to make this connection and it runs straight to the EMS.
I suspected some resonant vibration at a certain RPM affecting the connection in the plug and cable-tied the connector to a hose ensuring it could not move. That didn't change the behavior one little bit.
I am pretty much at a loss as to what to do or try to identify the issue.
Any thoughts or suggestions?
The SkyView (conversion harness, software version 7.1) shows reliable and steady RPM information for the Rotax only until it hits around 5000 RPM. As soon as it hits the "limit" (and the limit varies, sometimes it is down to 4800 but never below that) the RPM readings jump all over the place and never settle.With jumpy I mean vast jumps of +-500 and more RPMs from one moment to the next.
At low cruise of 4500 - 4800 everything is steady and persistent but on take-off or climb, I cannot get a reasonable or reliable reading from the SV. The engine runs smooth, with low vibrations and the carbs have been balanced. The prop is still set at the initial pitch setting that Van's requested for first engine run which is a fairly high pitch to avoid over-speeding the engine.
The RPM sensor in the Rotax is a two-wire cable(white and blue) that is just hooked up to the FW forward harness(white/green and black) with a plastic plug, so no modifications or crimping had to be done to make this connection and it runs straight to the EMS.
I suspected some resonant vibration at a certain RPM affecting the connection in the plug and cable-tied the connector to a hose ensuring it could not move. That didn't change the behavior one little bit.
I am pretty much at a loss as to what to do or try to identify the issue.
Any thoughts or suggestions?
