RV7A Flyer

RV7A Flyer

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The configuration:
IO-360-M1B
Red Cube circa 2012 (older style connections, I think)
Skyview w/ EMS, etc.

No issues with fuel flow, ever, until today...saw fuel flow rates that dropped several gph, then a lot, then a few, then to 0 gph, then back up to normal, etc. Started about 10 minutes into the flight, did it intermittently while I checked various things en route back to the field, then quit doing it and behaved perfectly fine in the descent and landing (about 10 minutes). On the ground, static run-up to 2500 RPM and all looked normal.

Decowled, looked over entire fuel system...no evidence of any leaks, no blue staining anywhere, etc.

Downloaded data...no change to any other engine data during "dropouts", so as I suspected, it's instrumentation.

My thinking is that the impeller may have had an issue; alternatively, a buddy suggests the connectors might need cleaning.

Anyone have a similar experience? I plan to demate/mate the connectors a few times (and check for any contamination/corrosion) and test fly it before diving into pulling out the red cube...

Thanks!
 
You might take off the cube at the connections and ensure there is no debris in there, before concluding there is a sensor issue.

Where, and what position, is the cube located? Is it possible that air got in the line and gurgled in the cube? If not the cube, maybe it is an indication of something more subtle.

Good luck, keep us posted.
 
The cube is mounted on a bracket attached to the sump, vertically (this was validated as acceptable with the manufacturer, btw). Straight fittings into and out of the cube.

If cleaning connectors doesn't fix it, then yes, I'll remove the cube and inspect it...will keep you guys advised!
 
My first guess would be that some physical contamination passed through the cube. Second guess would be an intermittently failing cube or wiring/ground.

Larry
 
Demated/mated the connectors a few times, buttoned 'er up and went flying. Everything is nominal.

I'll chalk it up to either connector corrosion or a transient bit of "stuff" which impeded the impeller briefly. Hopefully, I've seen the last of this gremlin.
 
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