STC Showcase: High Visibility Sight Gauges

It’s been said gas gauges are only required to be accurate when the tanks are empty.  We prefer our gas gauges to be accurate all the time, and moreover, to be reliable and readable.

Dakota Cub gauge on right, original design on left—notice that the original design is impossible to read from a side angle

Like many parts on these classic aircraft, the design of the fuel gauges is, well, classic, and not in a good way.  The orientation of the original Piper sight gauges makes them impossible to read from any side angle (e.g., the back seat of a Super Cub).  Additionally, the gauge is susceptible to leaking by design.  Anyone who has assembled a Piper sight gauge can tell you the finagling to get the fittings to align properly is a sure headache.  Above and beyond the hassle, though, is a design flaw that leaves many Pipers with leaky gauges.  There are two cork rings, one at each end of the gauge, which provide a seal against fuel.  As you install the tank line fittings, you are compressing the cork rings to create a seal.  Not enough pressure, and the fuel will slip past the ring.  Too much, and the cork ring is destroyed and ineffectual.

Original gauge with cork ring exploded view

Our high-visibility sight gauges address all of these common problems.  As you can see in the photos included, our gauge uses o-rings which won’t break down due to fuel exposure or pressure.  One o-ring seals each end of the Pyrex tube while two more seal the top and bottom hex plugs.  The tank line fittings screw straight in to the side of the assembly—no need to fiddle to get the two lined up!

Dakota Cub gauge with greater visibility and leak-resistant design, exploded view

As can be seen in the photos, our gauges are easily readable from any point in the aircraft, compared to an original Piper design which is impossible to read from a side angle.  This safety improvement, combined with the increased quality of the o-ring system, makes our sight gauges an excellent option for any Piper equipped with sight gauges.  Installation time is similar to the original gauges and cleaning is a cinch due to bottom hex plug which gives access to the tube.

Can I Use It?

Our high-visibility sight gauges are approved for the following models:

  • Piper PA-18 all models, PA-19 all models
  • PA-18A (Restricted), PA-18A “135” (Restricted), PA-18A “150” (Restricted)
  • PA-11 all models
  • PA-12, 12S

For more information, contact us at or give us a call at (605) 757-6628!



About dakotacub

Dakota Cub is the manufacturer of the Super 18 family of aircraft. We are also a supplier of FAA PMA'd parts for various Piper aircraft models no longer supported by the factory. We have numerous STCs for improved parts and other upgrades as well.
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