The International Cessna 170 Association

Does anyone know where I can get a set of wingtip
Nav lights reflectors. I’m not sure what the actual name of the part is but it’s the clear piece of plastic that sits between the wing tip and the nav light to allow you to see if the nav light is functioning from inside the cockpit

Mark,
Cessna calls these "position light detectors". They come in two styles, the second is much more aesthetically pleasing in my opinion. Both styles can be found in fig. 1 of the 56-62 C-172 IPC. The flat acrylic plate, p/n 0523119, is shown in fig. 1-29A (it's p/n 0623101 on the L-19) and the acrylic rod, p/n 0523702-3 and -4, is shown below that in fig. 1-29B.You'll find the flat plate available here or here. This style is also available from Aircraft Spruce. If you have wingtip strobes be aware of Whelen's advice regarding these position light detectors:

PILOT AND CREW INTERFERENCE: ... The Navigation Light Detector will be a source of reflection and should be reduced in size, or masked as necessary. ...

The acrylic rod is also available as p/n 1221201-3 and -4 on the Cessna Cardinal. Matt Perry makes a non-PMAed version of these. His uses 5/16” rod, original was 1/4”. For $5 it looks like you could make your own using clear acrylic rod.

Hey that’s great, thank you very much for the information.

Most welcome Mark. I've added a couple of Accessory Kit instructions on this topic, AK150-53G and AK177-47, to the Maintenance Library here.