Tip: VM-1000 Fuel Flow Transducer

[Rick6a]

Many builders are puzzled on how to install the fuel flow transducer for a VM-1000 engine monitor. The mounting problem is exacerbated because the transducer has a definite up and down, fuel in, fuel out orientation. Also, it should be mounted at generally the same level as the engine driven fuel pump, and finally, at least 5" of bend free fuel line must enter into the transducer from the fuel pump to minimize errors. With those parameters in mind, this is how I installed mine. I fabricated a simple shelf out of angle stock to which the transducer is bolted in the correct orientation and the assembly was then bolted to the firewall. Of course, this location dictated that I had to make up custom length fuel hoses to complete the fluid connections in from the engine driven fuel pump and out to the carburetor.



Fuel flow is an especially informative reading. As you advance or retard the throttle and/or adjust the mixture, you see instantly how much fuel per hour you are consuming at that specific setting. For instance, wide open my O-320 consumes 11.5 GPH. At times in flight, I find myself adjusting the throttle for a specific fuel flow since an increased fuel flow of an additional 1, 2, 3, etc. GPH may only yield a relatively minor increase in speed. It's up to the pilot to decide if the extra fuel burn is worth the expense. Working in tandem with the fuel computer inside the VM-1000, the data is constantly updated and displayed on the (optional) EC-100 unit showing exactly how much endurance you can expect at a given throttle/mixture setting. Neat stuff.

Rick Galati RV-6A "Darla" 66 hours