Intermittent fuel reading Dynon skyview. (RV-9A)

ron sterba · #1 10-10-2016, 09:56 PM

Five hours on just finished RV9A. I have float senders in tanks. Right tank sends intermittent readings of fuel capacity. Figured I had a high resistance open on grounding between frame and fuel tank plate and wing frame. Every screw showed a good short between fuselage/wing ground and large plate ground. fuel float plate (center of plate has screw for sender lead wire) assembly bolts up to the larger plate on tank. This larger plate has good grounding but NOT THE SMALLER plate. I used pro seal on ALL screws on both plates but I figure after testing that smaller plate ,it has HIGH RESISTANCE OPEN TO GROUND. The screws on the small plate are pretty much covered with pro seal that trying to remove one might be impossible. Now my friend helped me come to this conclusion on the high resistant OPEN when he grounded a test lead to the aircraft frame and used the other probe wire pin to scratch a mark into the plating coat of that smaller plate. It was at this point the tank level reading started to read correctly on the Dynon Skyview display. ( same reading as dip stick in tank). Conclusion is I need a ground to the small plate of sending unit. I don't think I want to remove tank from wing. At this point I don't understand why a small angle plate wasn't spot welded to small plate when it was made. Now I grant you I know more about grounding than I did when I made this assembly several years back. So what are your thoughts on making a connection for a ground to this smaller plate????. I can remove the fuel from this tank. I thought of drilling but I would not be able to contain metal fragments in tank from hole drilled. Can a ring terminal be soldered to smaller plate???. Or maybe a spot weld of a angle piece???

OPEN FOR YOUR THOUGHTS😜😜😜😜😜 Always appreciated 👍👍👍👍👍👍

Thanks,Ron in Oregon RV9A

lr172 · #2 10-11-2016, 11:53 AM

Is that plate bronze or steel? I vaguely remember it being bronze. If it is bronze, you could consider soldering on a spade terminal or even just a wire. Be sure to research and assess the risk of this procedure (shops that do gas tank / radiator repair could advise), but it would seem the heat produced should be low enough to not create an issue if the fuel level is low and the cap removed (thinking soldering iron, not a torch).

You could also pull one of the four screws, clean the threads and use a dielectric sealant. I don't know of one off hand, but I am sure they must exist.

I did not use proseal on the sender plate. I made a gasket and used anaerobic sealant on the gasket and screw heads. I have no issues with conductivity.

Larry

airguy · #3 10-11-2016, 02:15 PM

I have float senders in my outboard tanks, capacitive on the inboard. My outboard end plates are prosealed and screwed down (no cork gasket) just like the Vans-standard method (no grounding wire). I have had no problems with the level senders there, 80 hours flying so far, about half of that with fuel in those tanks.

ron sterba · #4 10-11-2016, 02:27 PM

Thanks Larry and Greg. I'll call Vans today to find out the plate material and coating. I haven't taught myself to post a picture on VAF. If either of you wants to send me your email on a PRIVATE EMAIL I'll send you a picture of the tank plates and repost them here in this thread.

Thanks always appreciated

Ron in Oregon

ron sterba · #5 10-11-2016, 05:03 PM

I called Vans today about the material. It's steel with a anti corrosive coating. One of the suggestions was to remove the fuel from the tank, remove the pro-seal around that one screw that you are removing. Take a ring terminal and crimp on a wire. Then place the ring terminal on the screw and then "STAR WASHER" . The teeth of the washer SHOULD dig into the plate,SHOULD. It's your game here, you do now have a pig tail wire to test the potential for continuity. Don't forget to ground the other end to the fuselage frame.

Since iam doing a Honey-do painting roof job here at home my results may take a couple of days to post.

Feel free to still weigh in on the thread. This item is for any newbie or post newbie or correct builder or anyone contemplating

Thanks Ron in Oregon

az_gila · #6 10-11-2016, 05:59 PM

Quote:

Originally Posted by ron sterba

I called Vans today about the material. It's steel with a anti corrosive coating. One of the suggestions was to remove the fuel from the tank, remove the pro-seal around that one screw that you are removing. Take a ring terminal and crimp on a wire. Then place the ring terminal on the screw and then "STAR WASHER" . The teeth of the washer SHOULD dig into the plate,SHOULD. It's your game here, you do now have a pig tail wire to test the potential for continuity. Don't forget to ground the other end to the fuselage frame.

Since iam doing a Honey-do painting roof job here at home my results may take a couple of days to post.

Feel free to still weigh in on the thread. This item is for any newbie or post newbie or correct builder or anyone contemplating

Thanks Ron in Oregon

Interesting, I just wasn't sure about the "no ground" bit, so I did exactly what was described above.

Ring terminal and a star washer under it. After it's all tightened up, a blob of proseal over it will seal it equal to all of the other four screws...

I took the ground wire into the fuselage alongside the sender wire and will ground it tone of the screws holding on the fuel valve selector structure.

It just seemed a cleaner way of doing it and very little extra work.

ron sterba · #7 10-11-2016, 08:52 PM

Good point Gil on the screw grounded up at the valve. I to have my wire bundle close also. I firmly believe Doug Reeves should OPEN a school of engineering. Resources are plentiful here. Here's a name for the school. " BRAIN CELLS ON THE EDGE "... what do you think Gil?

Ron in Oregon, RV9A now flying, thanks to everyone!!! Dual Dynon ( touch ) Skyviews with Auto pilot. Garmin radio, Oregon Aero & Classic aero round out the many great vendors of excellent hardware..!!