Capacitance Fuel Senders

[GeeBee]

I was in KUCY over the weekend and met Justin Wright owner of Red Avionics that manufactures a capacitance fuel probe and gauges. Right now he is making them for the experimental market but said he is moving toward certified. Interestingly his first project is a Mooney M22 that he plans on getting field approval. From there he plans to move on. He says his FSDO is being very cooperative towards this end. He makes everything there at KUCY, even the circuit boards. He says his units are compatible with most major avionics including JPI and Garmin. It looks to be very exciting as they are highly accurate and have zero moving parts, no float, no float arm. We will see, but it looks really interesting and exciting. 

https://www.redavionics.com/s/shop

https://www.redavionics.com/buyers-guide

 

[Pinecone]

I talked to the owner/engineer of Cies at Mooney Max last year about this.  

For those that don't know, they are used extensively in jets and are stupidly accurate.

He said he tried to go that route, but AVGAS is not held to a tight standard, so the capacitance/conductivity varies too much.

Based on threads about G100UL over on BeechTalk, AVGAS is not AVGAS.  It can vary greatly  in many ways.  G100UL may be a good thing for capacitance sensors as it is held to a tighter standard than 100LL.

Maybe Red Avionics figured out a way to deal with the variances with 100LL.   But I hope he tests it with fuel from different refineries over the course of a year.

[GeeBee]

Agree but that sensitivity has an upside. Fuel contamination shows up quickly. I was saved by it once in a 737 when a sweater of a worker who worked inside the tank truck was left in the tank before it was filled.

That all said, I also have a capacitance sender in my boat and the difference in fuel level between straight unleaded gas and unleaded gas with ethanol is unreadable on the gauge.

[dkkim73]

Thanks for sharing, @GeeBee, I'd wondered if something like this existed. Capacitance, or some kind of resonance probes. Reading the instructions makes me wonder how flexible the filling curves are for the G1000-tied EIS and various other units. I would imagine it wouldn't be hard to have implemented it as an arbitrary curve, but maybe some of the specifics are already baked-in to at least the type-certificated installations.