Fuel Flow Transducer

K

KinzuaBearhawk

Bearhawk QB Companion
I need guidance on how to plumb the gold cube fuel flow transducer. Installation guideline recommends 5 inches of straight tubing for inlet and outlet. I’m building a Bearhawk Companion with Lycoming o-360A1A engine and there is little room. Any suggestions or pictures would be appreciated.
 
I routed the fuel line forward from the gascolator over on the left side of the tunnel, and there was room for it between the floorboard and the bottom of the boot cowl. That's a nice straight run, and the sensor can fit in the middle of it.
 
Here's a photo of where I mounted it, though I was mostly documenting the leak, which was a separate problem.
 

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Jared, I only have an engine-driven fuel pump that feeds the carburetor, so the transducer needs to be mounted downstream from the pump, which places it in the FWF area. That area has limited space.
 
Many folks who have an engine driven pump also have an electric boost pump, in case the engine driven pump fails in such a way that it would otherwise block the flow. When I had that configuration, I put the fuel flow sensor and the boost pump in the area described above. Is this an injected engine? I'm wondering why you would need the pump?
If you really want to install the transducer fwf and really want a pump, can you put the cube in the line between the pump and the carb and wrap firesleeve around it? Seems like that line would be at least 10" but I know the Companion engine sits a lot closer to the firewall.
But it seems like the parts count is getting unneccessarily high.
 
At least with a Garmin system, If you don't have a straight section on each side of the transducer, your fuel flow indication will fluctuate a lot. I have mine on the FWF side, near the bottom of the firewall, more or less in the middle, but my fuel system is the standard gravity feed, no fuel pumps.
 
I understand. So either I remove engine-driven pump and plumb directly to carburetor or I install backup boost pump. I was surprised when my engine arrived with the engine-driven pump since I was planning on gravity fed system. I prefer the simpler route and will need to ensure my fuel flow testing passes 150% max flow of approximately 25 gph. Thanks for the advice.
 
KinzuaBearhawk said:
I need guidance on how to plumb the gold cube fuel flow transducer. Installation guideline recommends 5 inches of straight tubing for inlet and outlet. I’m building a Bearhawk Companion with Lycoming o-360A1A engine and there is little room. Any suggestions or pictures would be appreciated.
Click to expand...
That requirement for a 5-in section of straight line isn't mandatory, but it's probably more important upstream. I think try and avoid anything immediately upstream which creates heavy turbulence, like fittings or sharp bends, in that 5-in section. Mine has a gentle U-bend upstream, then a fuel pump connection fitting immediately downstream, and it works well.
 
Keep it simple.

I am quite confindent your fuel system with 3/8"lines will flow +25 gph. If it fails, then upgrading the tubing to 1/2" from the gasoclator to the carb will drive up the flow.

BTW, I have an injected Patrol with a 180 hp PV IO-360. So I have two fuel pumps, and a red cube downstream of the gascolator & it flows +25 gph up to the engine driven pump. I highly value the simplicity of your Carb.
 
Bcone1381 said:
Keep it simple.

I am quite confindent your fuel system with 3/8"lines will flow +25 gph. If it fails, then upgrading the tubing to 1/2" from the gasoclator to the carb will drive up the flow.

BTW, I have an injected Patrol with a 180 hp PV IO-360. So I have two fuel pumps, and a red cube downstream of the gascolator & it flows +25 gph up to the engine driven pump. I highly value the simplicity of your Carb.
Click to expand...
Thanks for the advice.
 
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