fuel lines-help!!!

[titanhank]

i have all but given up on the aluminum fuel line supplied with the kit. i have a 7a and i have destroyed the entire roll of tubing and still have not successfully installed a fuel line from the tank to the selector withour major kinks. does anyone have any ideas on how to do this or a replacement type of line? i saw one plane that had another type of fuel line, any info would be greatly appreciated.

thanks


hank

 

[szicree]

I don't know much about -7 fuel routing, but what I did with my -4 was to mock up my lines in coat hangar wire first. Also, what are you bending it with? Getting it to fit properly was a pain, but I didn't really have issues with kinks.

 

[AltonD]

I had the same trouble. After agonizing over the decision, I unbolted the gear leg mounts. After that, no problem. I just let them hang loose, routed the line through them, then bolted them back up.

 

[craigvince]

Bonaco Fuel Lines

Here's the answer to all your problems:

Read this thread

 

[Rivethead]

Here's how I did it

just follow the link.

http://www.rvforge7.com/pg3.htm

 

[Bob Axsom]

Are you using a tube bender?

Like a previous poster I use coat hangar wire to mock up my lines and then bend the tubes with the same orientations segment lengths, etc. I worked in the industry for a long time but never bent tubes professionally. We had drawings for every single tube, and a bare bones structure was created as a "tube & cable mockup" for each airplane or maned flight spacecraft. If done properly you can make these tubes come out like works of art. If you are kinking them you are not using proper tools, processes and procedures. The tube bender for the size of tubing you are using is just as important as the flare tool for creating high quality fuel lines. You need to back off and develop your skill on some practice tubes before creating flight hardware. Fuel problems are not something you want to deal with after your plane is completed.

Bob Axsom

 

[titanhank]

the problem is routing the lines through the 7a gear mounts. i think i will pull the mounts off and build the lines and then reinstall them. the kinks are coming from trying to snake them through the holes while making a double reverse bend.

thanks to all that have helped, i think i have the answer.

hank

 

[N941WR]

SS lines are easy to install but plan on replacing them after around 10 years or so.

To make the hard lines easier to install use bulkhead fitttings next to the fuel selector valve and a 90 degree bulkhead fitting where the lines exit the fuselage. Granted that adds more fitting but my experiance has been that they either leak or they don't. Torque them properly when you install the lines and you should be good for the life of the aircraft.

 

[Jekyll]

Kobioshi Maru solution.

I routed mine around the front of the gear mount. They tucked up nicely and are no more exposed than if through the mounts. Much simpler.

Jekyll

 

[Bob Axsom]

I used bulkhead fittings

I used bulkhead fittings to penetrate the fuselage skin for the brake lines vent lines and all four tanks. Routing a fuel line through a rubber grommet in the skin seemed too primitive. Mostly I used 90 fittings with the 90 degree part outside the fuselage for ease of connection. There is a lot of freedom to do what works for you in these airplanes. If something doesn't seem right you can usually figure out a better way if you think about it long enough. As far as the landing gear towers are concerned, I drilled a hole in the interfering web and wrapped the two fuel fines from each side in sheet rubber for chaffing protection.

Bob Axsom

 

[Rupester]

#$%^& Fuel lines

For me, easily the most frustrating part of the build process to date. I followed Jekkyl's lead and routed around the front of the gear towers .. which made the whole bending/grunting/pushing/cussing exercise only slightly better. I have all the lines in, but may go the Bonaco route yet.

 

[craigvince]

SS lines are easy to install but plan on replacing them after around 10 years or so.

My understanding is that these new Teflon hoses that Bonaco uses should last more like 20 years before needing to be replaced. But even at 10 years, they're a piece of cake to install so I won't mind.