Fuel Filter Survey

[szicree]

I'm in the early stages of routing fuel lines and would like to know what is being used for filtration. I think my selector valve could pass damned near anything, but the Facet pump should probably get a filter. So I'm thinking tanks to selector to filter to flow meter to Facet pump to? I'm not really sold on the gascolator yet. Also, I've heard differing opinions as to whether my boost pump should have a parallel path around the engine driven pump in case the mech pump fails/vaporlocks. Obviously I've got some things to work out and would sure appreciate some advice.

FYI: On Dan Checkoway's site he describes fabricating fuel tubing as an "iterative" process. If anybody's wondering what iterative means, it means you have to make each part at least three times mostly due to flairing ends of tubes without first putting on sleeves.

[Bob Axsom]

I read the gascolator and filter opinions in the RVator several years ago. With my own experience with gascolators and the information on the filtered fuel systems without gascolators in the RVator I decided to implement the later system. I have four filters, one in each fuel line to the selector valve. I did not want a fuel filter to be a single point of failure so each of my four tanks has its own filter. I researched my Photo album (8 inches thick) builder's log and receipt file for the filter information. On February 24, 2001 I bought 4 Fram G15DP metal bodied gas filters from Kragen Auto Parts. At 17:11 I bought the last one in stock at the Laguna Hills store; at 17:48 I bought the last two in stock at the Mission Viejo store; and finally at 17:58 I bought the fourth and final one at the Lake Forest store. The point here is there are not a lot of these carried in stock. I picked this model because it was one of the ones that was reported as successfully used in earlier RV's fuel systems and it looked good when I inspected it. No problems in my own usage for about 1.5 years and 163 flight hours.

Bob Axsom

[Kevin Horton]

Originally Posted by szicree

Also, I've heard differing opinions as to whether my boost pump should have a parallel path around the engine driven pump in case the mech pump fails/vaporlocks.

If you connect the pumps in parallel, here are a few things to consider:

1. You will almost certainly need some check valves to ensure that the system will function properly when one pump is ON, and the other OFF or failed.

2. You will be doing something that few RVers have done, so there isn't much service history here to rely on.

3. You should find a type certificated design that used parallel pumps, and learn about the service history. If the service history is acceptable then it would be wise to copy all details of the installation.

4. Fuel system problems are supposedly one of the leading causes for engine failures in homebuilt aircraft. Fuel system design is not the best place to demonstrate your creativity.

5. There are probably a bunch of other considerations that no one here will think of (see item 2).

[robertahegy]

I have only the gascolator and plumbed my fuel system per the Van's plans for a carby engine (0-360A1A). I have the facet pump. So far all is well. I do recommend a thorough flush of the sytem prior to first flight, after phase one testing (or 25 hrs), then annually to remove any debris in the system.

I did find some AL shards that would get caught in the tank sump drains initially. They never seemed to get any futher than the tank sumps, as I never found them anywhere else. That cleared up after a while. I had QB tanks and wings. I did flush the tanks before closing up the fuel system, but things have a way of working themselves loose later.

I also do a flow volume test during annuals to check for any restrictions to flow. Just run your boost pump into a container by timing and measuring, then calculate to GPH. It should be close to the rating of your boost pump.

Roberta