Filling Fuel Tanks First Time

I am getting ready to add fuel to the tanks for the first time. I blew the tanks out with compressed air, and had all openings sealed for the last few years. Now when I go to add 100LL what steps should I follow to make sure the tank is clean and the system is working normally?

- I was thinking about taking the CAV-110 drain off, and letting some fuel slosh around and drain out through a coffee filter. If I do that two or three times, maybe any little bits in the tanks will just drain out.

- Next I was thinking about putting two gallons in each tank, and running the fuel pump and the fuel tank switch valve to make sure the switch is working properly. I have a length of tubing with an AN fitting that I plan to hook to the firewall and run to a gas can.

- Last step would be to secure all fittings and run the fuel pump with the engine off for a system pressure test.

These are my plans. Comments or other ideas would be appreciated. Thanks.

Pretty much what I did, more or less. If you have any filters, remove them or work around them, then reinstall for the final fuel flow check. While you are dealing with this you might as well check your fuel flow.

Yep, good plan.

You won't have any problem Peter. You worked clean and did it right using proseal heavily on gaskets and screws http://www.myrv9.com/wng/Wings_5.html#11 I didn't and got a bit of seepage on initial fill up. An RV driver I know emptied tanks and hasn't flown for several months. After filling up tanks leaked rubber seals dried out.

That's about what I did ...

.... A couple gallons of mogas in each, rocked the wings up and down to get some sloshin' going, and then drained thru a fine mesh paint filter. Got essentially no debris out of either tank. (Used that gas in my lawn mower.) when I filled my tanks with avgas after that, I put in one gallon at a time and got the float readings from the EIS 4000 to calibrate the tanks. I did the fuel pump flo rate tests after that.

I don't agree that a single rinse on mounted tanks is best.
It is easy to add fuel to the tanks while they are not mounted to the wings.
It is very easy to add a couple of gallons and shake.
I built cleanly but it took multiple rinses to get the gas to come out clean.
YMMV

Air up as well

Suggest you check tire pressure before you fill up; I had a "who'da thunk it?" moment when I looked at my sidewalls after filling up my tanks. MUCH easier to roll in and out of the hangar as well (forehead slap.)

Interesting how the weight of 36 gallons will compress a "full" tire.

Great plan, BTW; REALLY wish I'd read it before my first fillup...

Hi Peter,

You've pretty much got it nailed. One thing to remember is to not just check the tanks but everything from the tanks to the fuel servo or carb. As Jon Jay alluded to, checking all the filters and / or gascolator screens is important. If you have a servo, check that small screen at the inlet. I pulled this filter after my first engine run.

It is very easy to have aluminum debris get in the fuel tubing and hoses as they lay around while we work on other parts of the airplane. So as the other guys have said, flush it all by running 5 gallons or so through each tank and the entire system.

I tried to cap all of hoses and lines that were not assembled immediately and still flushed some junk out. Hoses have been known to have liner issues from nicks during assembly. This can cause obstruction or particles to come dislodged. If you haven't already done so, I suggest checking every single B' nut and fuel fitting torque one last time and marking them with torque seal and then when you are through have someone else check your work.

One more thing. Check to make certain your tank vents are unobstructed. Ask me how I know this:

http://www.vansairforce.com/community/showthread.php?t=16771

Overkill? Fuel system issues cause many accidents. It's a good place to be a little paranoid. Good job asking the question!

Joe

Thanks to all for the quick response. I will follow my plan, after double the torque on each fitting. Feels great to finally be at the end of the project. Flying soon!!!!!!

Results

- I was thinking about taking the CAV-110 drain off, and letting some fuel slosh around and drain out through a coffee filter. If I do that two or three times, maybe any little bits in the tanks will just drain out.

- Next I was thinking about putting two gallons in each tank, and running the fuel pump and the fuel tank switch valve to make sure the switch is working properly. I have a length of tubing with an AN fitting that I plan to hook to the firewall and run to a gas can.

- Last step would be to secure all fittings and run the fuel pump with the engine off for a system pressure test.

Click to expand...

#1 - I ended up going to my big box aircraft supply store (Blue), and buying a fine mesh paint strainer. With that in hand I added 4 gal of fuel to each tank, sloshed it around and drained it out. After 4 or 5 goes at each tank, the filter was clean. The first couple of times it had small bits of proseal and what looked like sand. Anyway, clean now.

#2 - Connected a hose to the firewall leading back to my gas can. With that in place I tried the fuel pump. NO GO!.... Just then Robert Paisley of EFII walked by, yes I am at Cable Airport. He said to pour a cup of fuel down the hose I had secured to the firewall. After doing that, the EFII fuel pump quickly started sucking fuel out of both the left and right tank. Managed to test the Andair fuel selection knob as well.

#3 - Pressure test. First try... leak in the cockpit. A connection that was properly torqued was dripping. Drained the lines, removed the connection, added a dab of fuel lube, reattached making sure it was perfectly straight before tightening the fitting, torqued, tested, perfect.... opps, one more on the engine side was leaking. Same procedure to fix. After getting the two bad connections fixed, the fuel pump ran and I was showing fuel pressure on the TruTrak EFIS.

Pete - one more thing to check are the screws that hold the fittings in the Andair valve. I left them out for some reason when I initially installed the valve, only to have one of the fittings come off when I double checked the torque on the fittings - it was the only time in my whole build where I really got the "chills" thinking what if.

You may very well have installed and checked them already, but thought I'd mention it just to be sure.

Good luck,
Jason

Don't forget proper grounding

Looks good Pete.

Just a reminder, since I didn't see the words "grounded the airplane" anywhere in the posts, make sure the aircraft is well grounded when messing around with fuel. You'll be using gas cans fairly often for the next couple of months as you get the fuel level calibration just right.

I liked to ground the aircraft, and then make sure I always had skin touching the airframe AND the fuel can when pouring fuel. I also attached a ground to the fuel can, even if it might seem useless with a plastic container like you show in the picture. I would pull the plane completly out of the hangar. I also followed all these precautions when pouring fuel from one container to another, and when draining fuel from a wing.

You can't be too cautious.

With an A model, is the attitude of the plane on its tricycle gear close enough to in-flight cruise attitude to do optimal fuel level calibrations?

Thanks,
Russ

Pete - one more thing to check are the screws that hold the fittings in the Andair valve. I left them out for some reason when I initially installed the valve, only to have one of the fittings come off when I double checked the torque on the fittings - it was the only time in my whole build where I really got the "chills" thinking what if.

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I did check the screws, but now that you point it out.... I am going to look yet again. I recall Iron Flight had an issue during his RV3 flight testing. Worth the time to check again. Thanks.

Just a reminder, since I didn't see the words "grounded the airplane" anywhere in the posts, make sure the aircraft is well grounded when messing around with fuel. You'll be using gas cans fairly often for the next couple of months as you get the fuel level calibration just right.

Click to expand...

You are correct. I didn't mention grounding, as I did not do that. What are you using for a grounding strap for the plane?

With an A model, is the attitude of the plane on its tricycle gear close enough to in-flight cruise attitude to do optimal fuel level calibrations?

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Yes. After running the fuel system tests, I sent the caps off to Aircraft Specialty to get engraved. When they come back, I will add one gallon at a time while setting each calibration step on my TruTrak EFIS. It allows for 15 set points. I was thinking of setting the first 'empty' set point at 2 gallons, and they counting up one gallon at a time from there.