No picture, but I know I've seen it somewhere on a plane. Something from the 1940, probably. It's a floating cork gauge in the fill cap, but instead of just a wire poking through the cap, the cork (constrained from rotating) slides on a spiral shaft that turns a cylindrical pointer on the top of the cap, and it's all covered by a clear plastic cap.
The reason I'm interested is that my Parrakeet's fuel gauge wire length is constrained by the top wing, which is under. It just about hits the underside of the wing when full, and touches the cap when there's still 4½ gallons left. On the Taylorcraft (this Parrakeet has a T-Craft tank), the wire touched the cap when there was 2 gallons, or a half hour, left.
A rotary gauge would allow full indication from empty to full. It wouldn't be that difficult to build, I suppose, but if it's available off the shelf that saves a lot of time.
I've also seen a similar gauge on top of the tank, separate from the cap, but I'm pretty sure I've seen one in the cap, too.
The reason I'm interested is that my Parrakeet's fuel gauge wire length is constrained by the top wing, which is under. It just about hits the underside of the wing when full, and touches the cap when there's still 4½ gallons left. On the Taylorcraft (this Parrakeet has a T-Craft tank), the wire touched the cap when there was 2 gallons, or a half hour, left.
A rotary gauge would allow full indication from empty to full. It wouldn't be that difficult to build, I suppose, but if it's available off the shelf that saves a lot of time.
I've also seen a similar gauge on top of the tank, separate from the cap, but I'm pretty sure I've seen one in the cap, too.