Thorp Air Command - T18.net

It appears that the float for my fuel sender has stopped floating so it is time for me to put in a new one. Unfortunately, the original building did not install an access panel for the fuel sender. It appears to me based on prior forum threads that cutting a hole and putting in a new access panel over the fuel sender will be the easiest way to fix this issue. Unfortunately, I do not have the original plans for my plane. Does anyone have any recommendations for how I can find the location of the fuel sender to accurately locate my access panel?

Thank you

Use a borescope. Go behind the instrument panel over the top, on the left side of center. There are three “longerons” running from the firewall to the dash panel behind the instrument panel. You should be in between the center and left one.
Cubes

Thanks Cubes! Obviously I will have to use blind rivets for this. Is there a recommended way to cut the hole for the access panel in the skin?

Once you locate it, take as good of measurements as you can. Then drill a hole big enough for the borescope. Go in and see where you are relative to the sending unit diameter. Then you can slowly enlarge the hole with snips.
If you have enough room, you may get away with a rivet squeezer.
Cubes

When I did mine after the fact I used a Bi Metal hole saw and used a hand rivet squeezer to attach the nut plates . I have used the access hole several times (over the last 14 years) to adjust the Westach capacitance sender . Hint...practice on some scrap aluminum BEFORE you drill on the A/C !!!

RB

NX115RX
2011

i used a fly cutter in my hand drill to cut the hole.

I drilled a 1/2” hole where the sender sort of was and then just shifted the hole as I enlarged it. This way the hole got centered over the sender. I used rivnuts to secure the cover plate.

Jim

This was all super helpful. Thank you guys. I have parts on order and will be tackling this soon.