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Little pieces of fuel tubing....

Simon Hitchen

Simon Hitchen

Well Known Member
Dohhh!!!

Just took 12 feet of aluminum fuel tubing, 8 hours and have come up with nothing worthy of installing in an aircraft........just lots of little curvy pieces of aluminum.......not the best building day in the log.....

I did learn alot though, now im off to spruce to buy some more and try again

Just venting!
 
Been there, done that ... and came out frustrated too. Probably the least fun I've had in the bldg process.
 
You might make your bending life a little easier by ordering the aluminum tubing in "o" condition, as in no temper. It is much softer and easier to bend, it will harden at the bends from the bending process. Some bends can be completed by hand without the bender. Beware, there could be reasons to use tempered tubing, but in my application I do not see any problems with it.

RC
 
Flexible fuel lines

I'm working with Bonaco on making a fuel line kit for the 7/9, using stainless steel braided fuel line. Stay tuned, probably early February if you can wait long.
 
For even moderately complex hard tubing bends, I first do a mock-up using 1/16" welding or, even better, brazing rod. I bend it to shape, try all the different configurations and adjustments at my leisure, bending the rod by hand. Then I have the shape pretty well fixed, allowing for the greater bend radius requirements of the tubing. Then I take my mock-up over to the bench and use it as a template to make some of the crazy bends that would otherwise have to be figured out in the confines of the fuselage with the tubing trials.
I kinda' even used this method for the initial bends of the fuel lines through the -A gear weldaments. I never did get complete satisfaction from that process. Oh, the things I would do differently :).
 
Simon Hitchen said:
Dohhh!!!

Just took 12 feet of aluminum fuel tubing, 8 hours and have come up with nothing worthy of installing in an aircraft........just lots of little curvy pieces of aluminum.......not the best building day in the log.....

I did learn alot though, now im off to spruce to buy some more and try again

Just venting!
Click to expand...

I redid mine a couple of times when building my -7A. I did have much better results after I slid the spring-type tubing bender on the tubing, worked the tubing into place while within the bender and slid the the bender off. It really worked pretty well.
 
Craig, I'm very interested in the braided fuel lines. Since I weigh 140 lbs and my wife weighs 120 I can splurge a little and not hurt much. Keep us informed and thanks.
 
braided hoses

FWIW, nitril rubber hoses are life limited and teflon coated hoses are not.
 
Any Pictures?

Ron :

Any pictures of the SS Braided hose installation? I have my tubing installed and could probably live with it, but am thinking of going the SS hose route.
 
Simon Hitchen said:
Thanx for the understanding guys, the braided tubing solution sounds promising, I'll watch with interest.
Click to expand...

You might want to give it a bit more of a try (especially using the welding rod trick - it works great). My first attempts were painful, but by the time I was done I could even get the tubes bent quickly and nicely for the 7A weldaments. Make sure to use the bending springs.

No weight penalty and no concerns about lifespan. I too was about to give up and go with flex hoses, then the whole process 'clicked' and became easy and rewarding.
 
Im interested. Let me know

Craig. Were you planning to have the hoses pre fitted with their couplings or have one end done or no ends done and have the builder attach them? The SS hose has a larger outside diameter than the aluminium tube, any suggestions on the mounting through the four center brackets? The holes for the current snap bushing locations are pre-punched and dont leave alot of room for opening them up much larger without them connecting. The 3/4" hole on the side skin I imagine will allow a hose end fitting to pass through.
 
spring-type tubing bender source?

alcladrv said:
I redid mine a couple of times when building my -7A. I did have much better results after I slid the spring-type tubing bender on the tubing, worked the tubing into place while within the bender and slid the the bender off. It really worked pretty well.
Click to expand...

Where did you find the spring-type benders for 3/8" tubing? I used to use them for model airplane fuel lines and they worked great, but did not know they were available for larger tubing sizes.
 
Can't find any

"Any pictures of the SS Braided hose installation?"

Bruce - I can't find any in my archive. I'll have to snap some next time I have the cover panels off.

To address another question about the hole diameters, i didnt have any problem running the hoses through the largest of these in the brackets. Another mod I made had the brake lines running on the side walls, left one on the left, right one on the right. Having dual brakes let me rework the plumbing to accomplish this. That opened up more of the holes. This also alleviated me from bending and running the brake lines as well. When I give up on something, I give it *all* up ;o)

And for the tubing benders -- top of page 533 in the ACS 2006/2007 catalog. You can get them in sizes all the way to 5/8" O.D.
 
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Bubblehead said:
Where did you find the spring-type benders for 3/8" tubing? I used to use them for model airplane fuel lines and they worked great, but did not know they were available for larger tubing sizes.
Click to expand...

You should be able to get them at any home improvement store.
 
Simon Hitchen said:
Dohhh!!!

Just took 12 feet of aluminum fuel tubing, 8 hours and have come up with nothing worthy of installing in an aircraft........just lots of little curvy pieces of aluminum.......not the best building day in the log.....
Click to expand...

Here is what I learned on my 9A:

1. Do not put the 3/8" grommet in the 1" fuselage hole until you are all done.
2. Start from the outside with a slightly bent tube.
3. Thread the rube through the 1" hole and the middle hole in the weldment.
4. Thread the unmounted F-982- cover support rib onto the tube. Make sure the snap bushing is oriented to clear the mounting bolt hole.
5. Thread the tube through the F-983 rib.
6. Make the verticle bend in the center console in place.
7. Make the "S" bend through the fuselage in place.
8. Install the outer grommet.

Also, I put a 1" grommet with a large center hole into the middle weldment hole.

Hope this helps,
 
Since it seems like we're talking about fuel supply tubing on a -xA, my big suggestion is, if you are doing a standard build, deal with the fuel lines before the forward fuselage, including the gear weldaments, have been riveted in. I think that approach worked well for David Nelson after he saw the pain I suffered working on those lines. With the gear weldaments loose, you have many more opportunities to ease your pain.
 
Stainless Steel

Update:
I just got back from Vans today, picking up my finishing kit. While I was there, I picked up an Andair fuel valve, which I'm replacing my stock valve with. Since I now have both, I'll be able to make sure first-hand that whatever kit we come up with will work for either type valve. I hope to have the prototype worked up within a couple days.

182ppl said:
Craig. Were you planning to have the hoses pre fitted with their couplings or have one end done or no ends done and have the builder attach them? The SS hose has a larger outside diameter than the aluminium tube, any suggestions on the mounting through the four center brackets? The holes for the current snap bushing locations are pre-punched and dont leave alot of room for opening them up much larger without them connecting. The 3/4" hole on the side skin I imagine will allow a hose end fitting to pass through.
Click to expand...

The end of the hose that attaches to the fuel tank will have the connector left off, and will be easily installed by the builder. I'll let you know about hose sizes, etc soon. The guys at Bonaco are really great to work with, and they're very interested in making these to be easy for us RV builders. I'll keep in touch!

 
let us know

Craig the package from Bonaco would likely go over well if prices fairl. A buddy of mine in the hydraulics business, said that getting it all researched, pieced together and the parts would be a great plan. If the hoses had one end not crimped with a fitting, the install would be easy, and folks could do that last crimp with their own kit, or as in my case have a buddy with the mobile industrial crimper, swing by and do a favour. Heavy duty everything and easier install. Sounds like a plan. Looking forward to what you put together. (let us know soon, i have to order another roll of fuel line)
 
SCARD has the right idea fellows. I used # 10 copper elec wire with my little bending hicky thing as a sample and then bent my tubing accordingly. Worked good with only minor adjustments.

Leon
RV7A
 
Install the fuel tank tubing in the open

Yup, I fitted my tank fuel lines while the canoe was still upside down and the forward bottom skin and firewall still off. I made a simple cardboard template of the gear tower webbing (complete with holes) and attached it with duct tape at the appropriate location and angle to match the gear towers. The setup was very easy to work with and all while being able to stand. I think this was one of the best building tips.

Say Craig - on the Bonaco fuel line setup, what provisions (if any) are being made for an AFP fuel purge return line?
 
David_Nelson said:
Say Craig - on the Bonaco fuel line setup, what provisions (if any) are being made for an AFP fuel purge return line?
Click to expand...

Well, since I don't have that setup, I can't say. I'm sure they can make it, since they do custom work. I'd need pictures and lengths to give them, and see what they come up with.
 
captainron said:
Sounds easy, but at what weight penalty?
Click to expand...

-6PF hose @ .150 lbs per Ft.
-6Teflon @ .095 lbs per Ft.
-6Teflon w/anti Chafe @ .125 lbs per Ft
38-AL @ .045 lbs per Ft.
241820354798bad33a32e.jpg



Regards,
Brett
Bonaco, Inc.
 
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What's Up?

Anything new on this? I am looking for a "kit" from Bonaco for the fuel lines from the wing interface to the fuel tank selector valve. I bought their brake line hose kit and it looks great!
 
A couple more days.

I've been working with Bonaco on this. Just a couple fine-tuning details to finish and they'll be ready. It's been a long process getting everything just right, but we're almost done. Brett (from Bonaco) or I will post pics and weights here by the weekend, and he'll have pricing ready, too.

By the way, we've also finished the fuel vent lines and firewall to floor brake lines, as well as the "fuel valve forward" set.
 
This will really help!

I've talked to Craig and Brett from Bonaco about this too, and this is really going to help.

Thanks, Craig!

Greg Marlow
 
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