Filling the fuel system the first time ...

Rupester · #1 05-12-2012, 11:28 AM

I'm now ready to connect all the fuel lines that connect the tanks, AFP pump/filter assembly, Andair valve, and the IO-320. I have blown out all the individual lines with compressed air and either plugged or connected them to prevent contaminants. The tanks were pressure tested before the wings went on. I plan to disconnect the FF line from the FI servo and energize the boost pump to pump a volume of fuel into a container, checking both pump rate and for contaminants.
Are there any other things I should do/worry about/attend to at this stage??

Cfrisella · #2 05-12-2012, 12:34 PM

You might want to rinse a little gas through the tanks and let it drain freely without the drains installed. There's probably some dirt or whatever from construction that can cause the drain plugs to drip.

thinkn9a · #3 05-12-2012, 01:58 PM

Blow gently in the vent....as in by mouth.... NOT with compressed air. This will keep pump from trying to burn out.

RickWoodall · #4 05-12-2012, 03:10 PM

In Canada we have to do a fuel flow test. Like you are talking, remove a hose at servo, have tub marked to a gallon and time exactly how long the boost pump takes to fill it..do the math and verify the fuel flow per hour. I did that a couple times and, I also suggest when put fuel in your tanks, on occassion, undue the drains and let if flow back into a container. Then when putting back in, ensure you use a fine mesh filter to so **** gets back in. You will likely find a few bits of stuff and some little proseal tags show up. I have done that a couple times. Easy and fast and well worth it. I know of a guy that accidentally used teflon tape of threads, some got into the system and plugged up some pretty important stuff.

Get that thing flying Terry.

Lars · #5 05-12-2012, 07:39 PM

Quote:

Originally Posted by Rupester

I'm now ready to connect all the fuel lines that connect the tanks, AFP pump/filter assembly, Andair valve, and the IO-320. I have blown out all the individual lines with compressed air and either plugged or connected them to prevent contaminants. The tanks were pressure tested before the wings went on. I plan to disconnect the FF line from the FI servo and energize the boost pump to pump a volume of fuel into a container, checking both pump rate and for contaminants.
Are there any other things I should do/worry about/attend to at this stage??

Just did this, oh, 3 hours ago- same setup. Disconnected the fuel line at the servo, dumped gas into a bucket with a fellow VAF member watching. Drained maybe a half gallon from each side. Then did another all eyes on deck review, pushed it out of the hangar, messed with some controls and switches, and pressed the go button. Started on the second blade. Very satisfying.

We did let the gas drain into a clean bucket. There wasn't much in the way of contaminants, but enough that I was glad we took the trouble. Don't forget to switch tanks during the test!

Bob Axsom · #6 05-12-2012, 08:12 PM

This is probably the only time you will be able to start with completely empty tanks and know such things as how much fuel goes in before there is any fuel indication on the gauges or glass panel or whatever. I think this is a most important task in the final tasks before flight if you are planning to travel in your airplane.

Bob Axsom

DanH · #7 05-13-2012, 06:01 AM

Good time for a reminder......

Flow checking and tank calibration tends to be done with plastic gas cans, in the hangar. It is all too easy to start a fire with static electricity, as falling or flowing fuel builds a charge. The charged fuel is insulated from ground, so the voltage potential can increase until some unfortunate circumstance provides the opportunity for a spark discharge.

Take a moment to ground the airplane and the fuel in the plastic gas container. With both fuel and airplane at the same potential a spark is impossible. The basic plan only requires only two lengths of wire and two alligator clips. Strip a few inches of insulation from the wire submerged in the fuel container.

I keep a large metal funnel with three wires riveted to it.

Rupester · #8 05-13-2012, 06:59 AM

Dan, can I assume the ground wires are unnecessary if I use a metal gas can sitting on a concrete floor?

Rupester · #9 05-13-2012, 07:05 AM

Regarding that last question, clearly the metal gas can still must be grounded to the airplane, but at least one of the three wires could be eliminated.

Mike S · #10 05-13-2012, 12:18 PM

I put a measured 5 gallons in the tank, noted the level was not enough to even get a dip stick wet-----let it sit for five minutes or so, and rocked the plane vigorously. Let it sit for another 5 minutes, and rocked again. Then pulled the drain valve, and let all the fuel flow out, into a funnel with a coffee filter in it, then into the fuel can.

Got back a little under 4 1/2 gallons. That gave me a "unusable" fuel figure of slightly less than a gallon-----I just figure one gallon to give myself a pad, and for simplicity of math.

I got a lot of crud ----alum flakes, dirt, and proseal in the coffee filter.

Repeated procedure for the other wing.

Then, put half of the fuel in each wing, and did the flow test with the fuel line removed at the servo-----again draining into the funnel/coffee filter.

More crud, and a fuel flow of close to 40 GPH IIRC. Way more than minimum.

By doing it this way----wings first, then rest of the system, I insured the fuse plumbing would be supplied by clean fuel, and the fuel filter would not be overloaded at the first run----and the last of the crud should be what came out at the fuel servo. Seems to have worked as planned

Then, I took the used fuel and put it into my motorcycle, lawnmower etc.

When I actually filled the tanks for the first time, I made a dip stick for each 5 gallons added.

I have had no issues with the fuel system, other than a weeping rivet or two.