Fairchild Club Forum

The Fairchild 24 is new to me. I am having trouble with fuel gauges. The previous owner said that gauges weren't hooked back up when wings were recovered. Removed wing root fairings and they appear to be connected. There are blade connectors that I can undo and I assume go to senders. When I ohm them out, I get a -1 on left wing and about 7 ohms on right wing. My left wing gauge reads Empty and my right wing gauge reads Full, no matter how much fuel.
Question 1: Where can I find resistance range (assuming I have original senders?).
Question 2: I have FUEL knob on instrument panel. Seems to power the gauges when pulled out. Why? Why not always on with Master On?
Question 3: Are senders attached to inboard or outboard sides of tanks?
Thanks,
Zeke

Zeke,
See attached drawing.

From what I can tell, the modern equivalent for the original is Stewart Warner p/n F385-C, and the gauge S/W p/n 82211. I do not know for sure. I just ordered a pair to try and get my fuel gauges working. The info on Stewart Warner's website says 240-33.5 ohms. The sending units have to be modified to work.

By the way, you can purchase a CD with most of the Fairchild drawings on it through the Fairchild Club. It's well worth it.

Thanks, Cameron!
I have CD on the way.
It's easy to pull and get gauge P/Ns. Will do so soon.
-Zeke

I just installed one of the new fuel sending units. Seemed to work fine with the original gauges, at least during ground testing. Flight test today.

Cameron wrote: ↑Fri Jul 22, 2022 1:27 pm I just installed one of the new fuel sending units. Seemed to work fine with the original gauges, at least during ground testing. Flight test today.

How did they work out?

Worked well.

Cameron:
Can you point me to the source for new fuel sending units?
Thanks!
-Zeke

Sure,
https://www.aircraftspruce.com/catalog/ ... kkey=21002

I bought p/n 10-01101. ISS Gauge is just reselling Stewart Warner sending units.

You have to bend the float wire to work in the F24 fuel tanks. One thing that I found to watch for is to make sure that when you hold the sending unit in the in flight attitude, that the float will fall down to the empty position under gravity's pull, all on it's own. My RH unit is marginal in this respect and it doesn't transition from full to empty smoothly. The fuel has to slosh around a little bit before the float falls down. I also set mine up to where there is a couple gallons or so of fuel left in the tank when the gauge reads dead empty.

Use thread sealant on the sending unit screws.

Thanks, Cameron.
My wings were re-covered in 2018 (before I owned it). I now need to figure out best way to get to senders.
I have used Stits Poly system on non-structural parts of an experimental, but will seek help in cutting into these.
I have some un-cut inspection holes that may be close, but I doubt large enough for swapping sending units.
-Zeke

If the inspection holes were placed properly, there should be one on each wing, that is right over the sending unit. A regular inspection hole was large enough for me to replace my sending units. Wasn't too bad at all after I got the fuel drained.