My RV-12 is the early design with the fuel tank behind the co-pilot seat. Checking fuel level is very important and I do it before every flight. My original fuel measuring stick was a 5/16 wooden dowel extremely warped, (Home Depot stocks lots of the warped ones). The curve is necessary to fit down the filler neck. I drained the tank and filled it 1 gallon at a time and calibrated the dowel with a sharpie to mark it. These marks were also transferred onto the computer to create a full size drawing so I could reproduce the fuel stick.
One day I had no projects so I decided to make the ultimate fuel stick out of carbon fiber with the exact curve to navigate the filler neck of the -12.
Making a curved composite rod was harder than I thought. I used carbon fiber tow and epoxy, then grooved the gallon marks and painted them in with white paint. The stick is sanded with 220 grit for a matte finish to contrast with the wet fuel.
I made 2 sticks with different curves that are required for the different gas caps, standard and locking, the pictures are labeled. The difference is the curve that makes it drop through the neck easy.
Download and print the picture on 3 pages, use landscape mode, and print in default image size. Tape the 3 pages together at the arrow marks and confirm it is the correct size with the 24” scale line.