The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!
I haven’t tried this, so take it for what it’s worth. If you can get a small enough boroscope through the fuel drain, and if the fuel pickup isn’t covering the hole, you might be able to see up in there. This might give you a clue.
We measured the resistance from the sender terminal to ground and got 426 ohms no matter the amount of fuel in the tank. A full tank of fuel gives 17 ohms from sender terminal to ground. While trying to calibrate in the Dynon system, we get 5 volts no matter the fuel quantity.
I am not at the hangar with my documents but perhaps someone else can chime in.
My dislexia croppong up again. Resistance was 246 full, 17 empty.
Well, that’s good, or bad depending on how you look at it. I will tell you from experience, as crappy as it is to pull the sender when the wings are attached, it really isn’t that hard of a job. Sounds like you’re headed that way….
What instructions did Vans send out to "fix the problem"? Since the 10 has the same wing and same senders is this airframe effected? I have 650 hrs. on my 14 and 50 hrs. on my 10 and to date never had an issue with the fuel senders.
I am not at the hangar now but I believe In the revised plans from Vans it says bend the fuel gauge rod. Which was done and still a stuck indicator. Moving on to a different unit.
So Pro Seal results in a "thinner" spacing than the gasket and decreases the baffle clearance? This would result in the tanks getting stuck ~ half full? Appreciate the input.
If the resistance is not changing with fuel level either the float is stuck, the wiper arm on the sender is not making contact, or the float itself is no longer properly physically connected to the sender unit. In any event it will require draining and removing the tank to make a repair. I don't understand your statement above (even though you revised it later) because you are indicating it is always one fixed resistance no matter the fuel level and then it another resistance when full. It can't be both ways?
I helped a builder (no names…) who built his entire tank before bending up his senders. I suspect it is common.
^^^^^ This! ^^^^^
Since the 14 has a return fuel line put the borescope in and look around. Better yet place a string in through this access hole and lift the float before pro-sealing the sender in place.
There is a way. I used a string through one of the screw holes to pull the arm up and down for interference testing. Had to make a few tweaks to the bends to get good clearance.
Sure but all that does is verify it doesn’t catch. It does nothing to make sure you aren’t 1/2” off the top of the bottom at each extreme.
I could distinctly hear the float hit the upper and lower skin. I also measured the mechanism outside of the tank and knew exactly how many ohms would be read at the top and bottom positions of the float. So did measurements in the tank to confirm. So, yes, it is possible to get this right on assembled tanks.
But they aren’t supposed to hit the skin.
I ordered the Cies units. Are they plug and play with Dynon avionics? I know they need power, but is there anything else?
Even more lame to get rid of the wings dihedral just so you could see readings above 20 IMHO. Vans designed these planes to be affordable. Specifying a $500 sender instead of a $20 version is counter to that goal. We should accept these planes for what they are.
So, you are going with 2 units per tank? That's the only way I know of to see the full 0-25 vs the 0 - 21 you should get now with properly installed and bent floats. If 4 are used now you are up to 4 * $ 665.00 plus shipping and tax.
I've never missed the top 4 gals as others have noted fuel totalizer works great. Once they start reading accurately (at 21 gals a side) you have 4 hours to contemplate what to do. Normally I stop for a bladder break at 3 to 4 hours anyway.
Yeah, but maybe there’s a solution between $20 and $660 that would not cause so much consternation? I just think poorboying something like fuel level output considering overall cost and time invested in a project like this is ill conceived. Just my $0.02.
Wow! I see this is a sensitive issue. Sorry I unwittingly poked the hornets nest.So, you are going with 2 units per tank? That's the only way I know of to see the full 0-25 vs the 0 - 21 you should get now with properly installed and bent floats. If 4 are used now you are up to 4 * $ 665.00 plus shipping and tax.
BTW since one can set gals used vs time as a reminder to switch tanks, I set my switch reminder at 5 gals that way I perform one switch per side and now can accurately see exactly fuel remaining in my tanks for the next 8 tank switches.
Understood. On the flip side, most of us have fuel totalizers and know with good accuracy how much fuel we have remaining. Honestly in 1800 hours across two rv’s, i have never found a situation where it bothered me that I couldn’t see the fuel level with mostly fuel tanks. I really only cared about individual tank level once down to around 5 gallons in a tank. We are all different and want for different things I suppose.
Interested to hear of your endeavors here. While this thread is related to a sender failure, i do not believe that is very common. Been here a while and don’t see too many posts about this. Sure, they pop up occasionally like all sorts ot other stuff, but this not on the scale of pp alternators. On balance, they are pretty reliable and I am not sure the ones you are looking at are going to be more so. Some parts are just more prone to failure. This is just a wiper sliding across a thin carbon patch bathed in gasoline. They are not going to have insanely low failure rates. They fail just as often in cars that use the exact same thing. None that i know of have moved to elaborate tech to avoid it.
Let us know what you find out and what you decide to switch to.
Actually, you are sending either 5 or 12 volts into that fuel sender sitting inside a bath of gasoline every time you turn your plane on. And most borescopes are not fiber optic. They have a camera/light chip on the end very similar to the one on your phone.Let us know what you find out and what you decide to switch to.
Did it freak you out to stick a boroscope in a tank with fuel still in it? I know it's a fiber-optic and the light/power source is outside the tank but.........
...unless you're using CiES senders
Exactly. There are tens if not hundreds of millions of them in service and have been for decades. We reap the benefit of the massive economies of scale to have a well tested, reliable, accurate and cheap sender.
Not that I think a properly installed kit-supplied sender won't work fine; I'd be interested in knowing about the capacitive option. I've heard of RV-14s using it, but never can find the details.
Check out:
