Conflicting Information on Fuel Lines

[Flyguytki]

It is very common for me to spend an entire day doing research on a single aspect of the build. Yesterday was Propellers and which would be the best match for an IO-375 and today was on Fuel Pumps. With the new pump introduced by Flyefii.com I went into the mechanics of how they work and what the benefit is over the stock vans set up. During that research I read many posts on people installing andair fuel pumps and running into issues with hard fuel lines running from the tanks to the fuel selectors, or from the fuel selector to the firewall. In the A models the Gear mounts cause huge problems, in the 10, it is a long run from the selector to the firewall where there is not an easy way to secure it to something so it does not flex. After seeing these issues I thought why not use Stainless braided lines that are flexible. Did a little search and came up with a good number of threads on exactly this. Many talk about how they used SS braided lines with standard screw on fittings from a source such as JEGS and have had no issues, Then I came across this thread that had some very good information on ensuring you are using teflon hoses that are conductive so that if any static builds up within the line the conductive coating would immediately ground it making it a non issue, Somewhere along that thread someone asked if this only applies to FWF and there was no response to it. Then the topic of using a hose that has a nylon braid as opposed to a metal braid and again the topic was never answered. After all this what I am trying to get at is to get those 2 questions answered.

1. Does the Conductive Teflon hose only apply to FWF or could you use standard SS Braid inside the Cockpit to run from the Tanks to Selector and then from the Selector to Fuel pump and Firewall.

2. Inside the cockpit could you use the nylon braided hose(such as this) that would not build the static like the SS would.

Sorry for the long thread to get to these two points but I figured I should show I did my research before hand.

Thanks alot

-david

[rv7charlie]

For rigid line replacement, obviously they would be more convenient. But I'd see numerous downsides for me.

#1 (I'm cheap) is cost. #2 is weight. #3 is abrasion; obvious with stainless, but even with the nylon braided once it starts picking up dirt & grit. That third issue might force even more support structure than needed for rigid tubing.

FWIW,

Charlie

[David-aviator]

David,

It is not a big deal to build the airplane as per the plan, lots of guys have done it very successfully.

Getting the fuel lines bent to fit in the A model is somewhat of a challenge but as has been mentioned, the materials are relatively cheap and doing it a couple times may be necessary but it is a good learning experience and when is done, it feels good.

You may surprise yourself and get it right the first time which is a better feeling yet.

[hydroguy2]

Can't answer your specific question, BUT you won't go wrong using hoses from Bonaco

[BSwayze]

Originally Posted by David-aviator

David,

It is not a big deal to build the airplane as per the plan, lots of guys have done it very successfully.

Getting the fuel lines bent to fit in the A model is somewhat of a challenge but as has been mentioned, the materials are relatively cheap and doing it a couple times may be necessary but it is a good learning experience and when is done, it feels good.

You may surprise yourself and get it right the first time which is a better feeling yet.

I agree completely. I stressed myself out about this and fretted for many days about installing the fuel, vent, and brake lines. Especially the fuel lines. I'm building a 7A model, so I was worried about the gear leg weldment, too. But once I finally got into it, it was easier than I ever thought it would be. My fuel lines went in without a hitch, successful on my first attempt. I used the conventional tubing from Vans and built it according to the plans. Thousands of RV's are finished and flying this way. I have lots of pics and discussion, if you care to look at how I did it. It's easy. Here's a link:

Installing Fuel Lines

[9GT]

I too am using the per-plans aluminum tubing for my fuel lines. I had no problems getting them right if not the first, but second attempt. I purchased some good quality benders and flaring tool: http://www.mrostop.com/945thbpd-park...l-p-32480.html Contrary to recent discussion on this forum, if used correctly you will get perfect flares. The only thing I changed out was the bulkhead fitting. I went with a steel fitting, washer, and nut instead of the aluminum one's supplied by Van's.

[scsmith]

Hi,

I can answer the first question. If you use a flex hose where the fuel is running in a non-conductive tube, such as teflon, there does need to be the conductive filements in the liner to disipate static charge. This is true everywhere that fuel runs in a hose, not just FWF.

Obviously, aluminum tubing is plenty conductive and disipates static charge throughout the airframe easily, so hard lines are fine.

I can't help address the nylon-braid hose question, because I don't have any familiarity with it.

[Buggsy2]

Originally Posted by hydroguy2

Can't answer your specific question, BUT you won't go wrong using hoses from Bonaco

I will mention one thing about Bonaco lines, not necessarily a negative but a fact and you guys make your own conclusions.

The Bonaco lines do not use AN fittings. PM if you want more details, my intent is not to disparage anything but I've never seen this mentioned before.

[Walt]

I prefer rigid lines aft of the firewall, this is the same way most certified aircraft are built as well. Simpe, light & reliable. If you want to "upgrade" go with 5052-0 in place of the 3003.

[TS Flightlines]

mentioned, has a "rubber", (probably nitril or neoprene), which is non-conductive.

Originally Posted by scsmith

Hi,

I can answer the first question. If you use a flex hose where the fuel is running in a non-conductive tube, such as teflon, there does need to be the conductive filements in the liner to disipate static charge. This is true everywhere that fuel runs in a hose, not just FWF.

Obviously, aluminum tubing is plenty conductive and disipates static charge throughout the airframe easily, so hard lines are fine.

I can't help address the nylon-braid hose question, because I don't have any familiarity with it.