Cessna 172 (R-S)

We’ve been selling these internal tip tanks since 1967. They carry 24 gallons total, 23 usable. They are fiberglass tanks that fit inside the outermost two bays of the wing. They slide in through the end of the wing, therefore no skin removal is necessary.

To begin installation, the close-out rib is removed and a hole is cut in the second rib that is large enough for our tank to slide through. This can be done with a nibbler or a saw. There’s no loss of strength because our tank has a rib built into it. There are anti-abrasion strips bonded onto our tank to prevent chaffing. The tank is a tight fit because we wanted to get the maximum number of gallons in. There is a locating strap that goes around the tank.

A 4″ hole is cut over the filler cap and a flush fitting door is fitted. A CamLoc is used to hold the door closed. A small hole is cut below the quick drain valve. Under the fuel outlet, an access cover is installed.

The next step is to run the fuel line inboard to the part of the wing where the strut attaches. The transfer pump is mounted here along with two check valves. The fuel line is then run inboard to the main tank. For rubber cell mains, the fuel enters through a tee fitting in the door post into the fuel line that runs from the mains down to the engine. For wet wing tanks, a bulk head fitting is installed in the side of the main tank.

Gauge(s) and lighted rocker switches are then mounted on the panel, pedestal or over the doors. Apply the placards, fill out the 337 and you’re finished.

The kit is quite complete including tanks, caps, mounting and plumbing hardware, transfer pumps, check valves, fuel line, wire, switches, gauges, fuses, installation drawings and STC. You supply some PRC sealant for the main tank connection.

Local installers complete the job in 45 hours but if you have someone do it that has never done one before it will probably take longer. It’s not an exotic installation but, done right, it takes some time.