Electrical vs mechanical gauges

[Bob Turner]

I was going to do that to eliminate the stainless tube full of high pressure gas. I think I got a $100 Mitchell - I shall look. I did not install it because it still requires a stainless line - the sender cannot be mounted on the engine due to vibration issues.

Getting to those gauges is fairly easy - take the glare shield off, and you can almost crawl in there with them.

 

[Big Ed]

I was going to do that to eliminate the stainless tube full of high pressure gas. I think I got a $100 Mitchell - I shall look. I did not install it because it still requires a stainless line - the sender cannot be mounted on the engine due to vibration issues.

Getting to those gauges is fairly easy - take the glare shield off, and you can almost crawl in there with them.

I think you can use a flexible line with firesleeve. Regardless, at least the line terminates forward of the firewall.

I want to use the $100 Mitchell, but it does not meet the spec requirements in the AFM. The Mitchell gauge reads up to 30 PSI, and the AFM requires a range arc from 15 to 45 PSI. This UMA gauge and sender combo would meet the requirement:

UMA 2-1/4" Electronic Fuel Pressure Gauges TSO | Aircraft Spruce ®

UMA 2-1/4" Electronic Fuel Pressure Gauges TSO 2-1/4 inch Electronic Fuel Pressure Gauge TSO'd.

www.aircraftspruce.com

UMA Pressure Senders | Aircraft Spruce ®

UMA Pressure Senders UMA's pressure senders offer high reliability and accuracy at an affordable cost. They use precision solid state sensors and are designed for rugged use in just about any environment.

www.aircraftspruce.com

Gauge $250, arc marking $125, sender $150. If I'm going to spend $550 on a mechanical FP gauge, why not spend $850 instead and get FP and FF with the EI FP-5?

And if you keep going with that logic, pretty soon you are spending $5K on a JPI engine monitor to replace ALL your gauges.

 

[Big Ed]

Ed- I did not install the electric gauge. It was pointless, since my goal was to get rid of the stainless line. I’d sell it for half price.

Hey Bob, I missed this offer a while back. Do you still have the gauge? Do you have a picture or a part number?

 

[Bob Turner]

Sure. Let me look today - remind me tomorrow.

 

[Big Ed]

Circling back to this. I am going to resolve this while I have my aircraft in pieces. Definitely not going to reassemble my aircraft with that stupid stainless fuel line through the firewall.

Right now am leaning towards the UMA. I talked to them today and they can drop ship a gauge with the correct range and markings in 3 weeks. Cost is a bit steep at $550. But it stops the slippery logic slope that leads to an EMS at 10x that price. And it gets me reassembling my aircraft with the minimum amount of research and fuss.

 

[Bob Turner]

At that price do they eliminate the stainless line entirely? I suspect the place where these lines fail is at the terminal that vibrates most - the engine.

We had one break on taxi out - brand new engine. Lucked out - just a teeny fire! Broke at the engine fitting.

Check out the Piper twin Comanche - the one close to me has Aeroquip lines, I think. Why not - the input is all Aeroquip.

 

[Big Ed]

Yes. Sender is connected to engine with aeroquip fire shielded hose, same as fuel lines.

 

[Hygenisis]

7KCab io-320
My SW fuel pressure gauge fluctuates wildly. Is there and easy source to replace it. I like the idea of going electronic. I'm definately not a mechanic but any guidance would be appreciated. Thanks in advance.

 

[Big Ed]

Start by getting the snubber from ACA. That fixed it for me. Only about 35 bucks.

There aren't many good choices to replace the SW gauge. I could not find a TSO mechanical gauge. UMA makes a TSO electric gauge and sender, but it is pricey.

Most folks these days seem to be going to engine monitors.

 

[Hygenisis]

Thanks Ed. I'll call tomorrow and order a snubber.

 

[Big Ed]

Following up on this. Received my UMA gauge and sender this week. Seems straight forward to install.

 

[Bob Turner]

That is the way God intended aircraft gauges to look. Very nice. Where does the sender mount?

 

[Big Ed]

That is the way God intended aircraft gauges to look. Very nice. Where does the sender mount?

I must admit a fondness for old school dial faces. Am pleased I went this way instead of blowing a ton of $$ on a primary EM.

Sender is clamped to engine mount or firewall, and connected to sensor port on fuel servo with a hose. The air box cable attach bracket will work well for that purpose, especially since the wet line is clamped there now.