Idea for shorter flared tubing runs with a bend

[John Bickham]

I'm doubtful I have an original idea here. I showed it to my neighbor who is building his 11th plane and he was glad I did. Today I was re-doing my aft tubing runs from the rear of the tank to the fuselage. That is because I got some pretty miserable results on my first attempt. I was having doubts that I was going to get the required flow for need for the 150% fuel flow test. Depending on how you plumb it, there is a lot that has to happen from the tank to the fuselage connection in a small area.

I couldn't get the tubing to turn quick enough when I allowed for the room to flare, have a sleeve on before the bend and get all that to fit in the tubing bender. After making a substantial pile of little pieces of scrap tubing out long piece of good tubing, I tried this and happier with the results.

The pictures are better at explaining the technique but here is the cliff-note version:

• flare the tubing end
• slip sleeve on
• insert round into the tubing end. I used a 9/32" center punch.
• let the rod bear on the stop of the tubing bender and bend the required angle
• slip on coupling nut and trim to required length

DSCF2865[1].JPG
shorter run to bend

DSCF2867[1].JPG
longer run to bend as required


I'm sure this is old news to a lot of the experienced builders out there. Hoping it may be helpful to the other rookie builders like me.

[James]

Gold!
Anyone who hasn't got one, this Imperial tube bender pictured here is a fantastic bit of gear :-)

[svyolo]

I ran into the same issues in a couple of places. That is a great idea.