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-   -   Thoughts on dual senders in each tank (https://vansairforce.net/community/showthread.php?t=150449)

PilotjohnS 06-14-2017 07:02 AM

Thoughts on dual senders in each tank
 
I am curious what y'all think about using dual senders in each tank? I was thinking of installing another sender in the outer bay. Seems really easy to do before the baffle is installed.
1) can the G3x calibrate with a resistance range from 64 to 480 ohm? If not I guess i could put a resistor in parallel.
2) is it worth the trouble?

Thanks in advance.

Sam Buchanan 06-14-2017 07:15 AM

What is the rational for two senders?

rvsxer 06-14-2017 07:46 AM

So the fuel gauge comes off of full sooner. A friend of mine has a Bonanza that has 2 float-type senders in each tank for just that reason. A non-issue for me with the advent of accurate fuel totalizers but it could be done.

Sam Buchanan 06-14-2017 07:56 AM

Just wondering about the value of the added complexity just to know the tank is nearly full......

If the second sender ever needed service the tank would have to be removed.

PilotjohnS 06-14-2017 08:38 AM

Reason? We dont need no stinking reasons.....
 
I was thinking of using two senders so that i would start reading the fuel usage and true gallons remaining earlier. This would give me a more accurate range reading as I finish climb out and start cruise. So as soon as i get lean, i could have a accurate range reading.

I guess if I use enough fuel in climb to start dropping the stock fuel senders, it wouldnt matter because until I set the cruise fuel flow, any range calcualted based on fuel flow and galoons remaining wouldnt be accurate anyway.

Maybe i am over thinking this; maybe pre flight planning would tell me when I would start seeing the gauges come off the pegs?

Ironflight 06-14-2017 08:47 AM

Quote:

Originally Posted by PilotjohnS (Post 1180408)
I was thinking of using two senders so that i would start reading the fuel usage and true gallons remaining earlier. This would give me a more accurate range reading as I finish climb out and start cruise. So as soon as i get lean, i could have a accurate range reading.

I guess if I use enough fuel in climb to start dropping the stock fuel senders, it wouldnt matter because until I set the cruise fuel flow, any range calcualted based on fuel flow and galoons remaining wouldnt be accurate anyway.

Maybe i am over thinking this; maybe pre flight planning would tell me when I would start seeing the gauges come off the pegs?

Everything you are trying to accomplish is good - full knowledge of your fuel state relative to your trip plan is a huge comfort, and takes a lot of worry of the pilot's shoulders. Which is why fuel flow gauges and totalizers have become pretty much standard in today's digital environment. Even the simplest engine monitoring part of any EFIS (or a standalone EMS) will have a totalizer. And they work great, for not very much money. Rather than reinventing the wheel with a double gauge system that might take a lot of tweaking, you might look at how such a system would serve your purpose.

From your signature, you've got a ways to go - and when people have completed their aircraft, and are looking back at what they thought were significant expenses in the early days, they wonder why they were worried about a couple of hundred bucks. A drop in the bucket when looking at the final big picture.

PilotjohnS 06-14-2017 08:56 AM

Recommendation?
 
Paul,
Thanks for the very thoughtful answer. So if you were me, would you put dual senders in, or just rely on fuel totalizer?

Mel 06-14-2017 09:23 AM

I am not Paul, and would never pretend to be. BUT, I have inspected many, many fuel system modifications and I would NOT recommend this mod. It adds unnecessary complexity, cost, and weight to a system that has been proven over decades with literally thousands of flying aircraft.

vic syracuse 06-14-2017 09:31 AM

Don't get fooled
 
So at the end of the day the question will always remain: do you trust the fuel gauges? Regardless of how many ways we try to measure the fuel, the best indicator is your watch.

You can fool the indications by parking on a ramp with a slope that is ever so slight that you think both tanks have an equal amount of fuel in them. Even when you check them visually, they can look the same. The reality is that one tank can be much lower than you think.

I just had a friend loose his airplane to this scenario. The tank ran dry much earlier than anticipated due to reliance on an indication.

As Mel said, don't mess with the fuel system. It's proven itself over many flying RV's. The other thing that has been proven is that the resistive floats do fail and need replacing. MUCH easier to just do the one at the wing root.

Vic

PilotjohnS 06-14-2017 09:44 AM

Thanks all
 
Ok thanks everyone for the quick and thoughtful repsonses.

So I have decided no mods on the fuel senders, I will stick with what is tried and proven.

You are all right, what was I thinking?


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