Fuel Lines & Strainers

[Yadama]

Hi Bearhawkers

I am in the USA at present and planning to go via aircraft spruce before I depart. I don't have access to all my tech data at the moment, can you guys let me know what thickness 3/8 5052 fuel tubing you use for the fuel lines and what size finger strainers I should order, I know the wicks pat number but how does that translate to aircraft spruce?

Does anyone additionally have any tips on fuel fittings, how many etc I should purchase???

Thanks in advance

Yadama

[Mark Moyle]

Oh three five wall. Standard finger strainers


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[Mark Moyle]

Oh three five wall. Standard finger strainers. I bought the imperial roto-lock 3/8" tubing bender, imperial rol-lock 37 degree flaring tool. The spring bender comes in handy for bending the fuel line where it exits the fuselage for the fuel tank hose connection. Where the tubing might rub....I used electrical shrink tube. Where I knew it would rub...two layers.


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[jaredyates]

Yikes, it was tricky to come up with the fittings. It will vary considerably depending on how you do things. As for the cross-reference of part numbers, I wouldn't be afraid to hand the ACS guys the Wicks catalog and say "give me one of these." I've only had one time where they weren't able to do that because they didn't have the part.

As I start at the fuel tanks and move towards the engine, here is what I recall that I used for fittings and such:

SA-18 Quick Drain Valve (one per tank, plus one for Bob's gascolator)
Two finger strainers per tank (double check the number, but start with 05-17700)
Pipe thread to flare fittings to mount at the finger strainers- some were 45 degree AN823-6D and some were straight AN816-6D. Each one also needs a sleeve and a nut.
Fuel quantity sight gauges: AN816-4d at the fuel tank, two per tank (plus a sleeve and a nut for each)
AN838-4d where the sight gauge mounts to the root rib- two per wing, plus a nut and a sleeve for each
Approximately 5 feet of 1/4" tube to connect the above
(starting back with the 3/8 lines)
AN 832-6d (straight) or AN837-6d (45), one for each fuel line at the wing root rib, so two per wing. I don't remember which were straight and which were 45, but you could probably make either work if you plan accordingly. Add about 5 feet of tubing to make these connections, plus two nuts and two sleeves for each, plus one AN924 for each.
From there I used 3/8 lines that were bent. In theory you could make those lines in one piece, but that is not likely to happen. I'd toss in a few AN815-6d unions with corresponding nuts and sleeves, probably half a dozen. I don't know how to tell you how much aluminum line to get, but I'd guess around 20 feet per side, depending on how confident you are with making them right the first time. In some cases I made a single line five times, but surely you can do better than that!
Then those lines connect to AN804-6D fittings, one on the left side of the cabin and one on the right. Don't forget three nuts and three sleeves and one AN924 for each fitting.
Lines exit there for the fuel selector, so add whatever fittings you'll need. I'd recommend the Newton SPRL, which used regular flared fittings. You'll just need to add three nuts and three sleeves.
From there you go to the gascolator, which, if you are using Bob's, will require two AN816-6d fittings plus one nut and sleeve for each. From there, go forward to the engine. I used a fuel flow meter, which required two more AN816-6d fittings plus one nut and sleeve for each.
Now you'll need another AN832 to pass through the firewall. Some folks say you should use steel for that fitting. If you do, be sure to get a steel AN924 also. I used aluminum.
From there you need a flex line that goes to the carburetor. At the carburetor you'll have another AN816-6D, or something similar. I used the straight fitting.

Are you shopping for brake lines too?

[jaredyates]

While I've got the catalogs up, here's what I used for brake lines. The reservoir is forward of the firewall, with a short line (AN816-4d, nut, sleeve, nut sleeve) to a single AN834-4d. From there a flex line goes to each left master cylinder, which has either an 816-4d or 823-4d or AN822-4d, depending on the angle. Then a flex line goes from the bottom of the left-left MC to the top of the right-left MC, plus one from the bottom of the left-right MC to the top of the right-right MC. Then one goes from the bottom of the right-left MC to the parking brake valve, then one from the right-right to the parking brake valve. The brake valve required four AN816-4d fittings, plus two nuts and sleeves. The flex lines do not require nuts and sleeves. From the parking brake valve I ran hard lines to the bulkhead under the control stick, where I switched to an AN832-4d (plus AN924 plus a nut and sleeve for each), one for each side. Then I used a flex line to the landing gear leg. At the landing gear leg I used a bulkhead fitting (it doesn't much matter which one, another AN832 would be fine) and then ran the line down the leg. Don't forget another nut, sleeve, and AN924 for each of those. Then at the bottom I had another AN822 at each brake caliper. If you aren't running a flex line down the whole gear leg, you'll need some other sort of union, unless you are running a hard line all the way to the caliper with a big loop for stress absorption.

[Yadama]

Mark, Jared

Thanks very much for the reply and detailed data, that's a great help cheers..

Jared the shirts have arrived in Perth, Thanks!

Yadama

[bergy]

I just made my own gascolator according to the drawings in Bob's Bearhawk Newsletter that arrived with Patrol plans#129. I cannot determine from the drawing how the SS screen is held in position inside the bowl. It appears that the perimeter might be squeezed in between the bowl and the top section of the gascolator, but the edge of the screen could be kinda rough and of varying thickness. I suspect that I could cut the center hole a bit undersize, then press it into a small conical contour and use the natural tension of the screen to have it grip closely around the center bolt. Anyone know a good way to seal around the edges of the screen?

[BTAZ]

I used a brass screen material and put a bead of solder around the OD of the screen and also around the edge of the center hole. It is fairly soft and compressed so the inner hole as sealed by the center bolt and the outer by the "can".

All looked fine at the first inspection this year.

[Archer39J]

After taking mine apart I can just barely see where the screen has been sandwiched between the housing and cap. Seems pretty secure. The o-ring closes out the center hole. This design has apparently been working well for some years now.

[bergy]

As mentioned in an earlier post, I made my own gascolator similar to a sketch provided by Bob in one of the Bearhawk Newsletters. I debated various ways of making the gascolator's screen fit nicely around the center bolt. I decided to solder a small brass bushing into the center of the screen. I made the hole using a punch fabricated from a scrap of 1/2" EMT. I made the bushing from the small scrap of brass stock I used to make the center-bolt. The bushing is made in two halves (one half fits inside of the other) and it is soldered from both sides. I think it will work out well. I was also worried that a small piece of screen-wire might fray loose from the outer edge of the screen and float downstream and lodge in the needle-valve or some other important spot, so a tinned the outer edge of the screen with a thin layer of solder.

GascolatorScreenBolt.jpgGascolatorScreenOnly.jpg

One thing I still worry about is the long-term reliability of the brass center-bolt. I might add a steel-wire spring-clip of some sort to the gascolator that will serve as a redundant retainer to hold the bowl onto the gascolator and also prevent the bolt from vibrating loose (instead of simple safety-wire).

[bergy]

BTW What is the correct sequence for uploading/posting photos to the forum. I get either double-positings or non-at-all?

[Archer39J]

I use the advanced editor when posting to upload an image to the server then insert in-line in the post. Keeps people from having to click on an image to display it. I've also noticed the slideshow image display will sometimes glitch out when flipping through attached images, so I try not to use that if I can avoid it.

[Archer39J]

Looking at the gascolator provided with the kit I notice the cap is a pretty hefty chunk of aluminum. I'm thinking about boring out some lightening holes on the top, being careful not to break through of course. Though I suppose even if I did, since it's the top of the gascolator, I could just fill with a fuel-safe sealant like pro-seal...