Matt's RV-8 Project



Matt Dralle's RV-8 Project
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Date:  4-4-2010
Number of Hours:  1.00
Manual Reference:  
Brief Description:  Calibrating Princeton Capacitive Probes - Part 1

You may recall that I had some trouble with the Princeton Capacitive Fuel Level Probes initially. When I went to go through the calibration procedure, I found that they BOTH errored out (three flashing leds) on the first set point after the Empty level. Needless to say, I was pretty irked at that point, considering that I had already ProSealed them to the fuel tanks AND I had permanently mounted the wings to the fuselage. Nether of which lend themselves to removing the probes at this point in the game.

I got under the airplane and noticed that there was significantly more room to work from underneath compared to access from above. I bought a right-angle electric screw driver attachment and backed out the five long screws that hold the sender on. Three of the four came out alright, but two stripped the Phillips head. I had to slowly back them out using a pliers, which took for ever.

My plan was to just remove the Princeton Probes and replace them with the standard resistive Stewart Warner probes that Van's sells. But, as I was pulling the Princeton probe away from the tank, I noticed that it seemed like the tip of the probe was hitting the bottom the fuel tank. I recalled that the tip of the probe was metal and figured at this point that maybe it was shorting the probe out and that's what was causing the error lights. So, I carefully twisted the probe just enough to bend the tip up off the tank about 1/8" or so and then put the probe back into the tank with a couple of screws.

I reconnected the power to the probe and initiated the calibration sequence and found that it now went from the Empty set point to the 1/4 set point without an error!! Yahoo. I tried the same twisty trick with the other tank and found the same positive results! I mixed up a fresh batch of ProSeal and found ten new screws and reattached the senders to the tank.

Cont Next Log...
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RV-LFT-5S and RV-RHT-5S Princeton Capacitive Probes

RV-LFT-5S and RV-RHT-5S Princeton Capacitive Probes

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5.25 Gallons X 4 Containers

5.25 Gallons X 4 Containers

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RV-8 In Flight Position

RV-8 In Flight Position

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