what's your reasoning on fuel and oil?

Colyn,

 

1. Experience.  Another airplane with aviation grade non-teflon lines that hardened and cracked with age.  Especially a fuel line that sprung a leak on the ground with the cowl off.

2. Manufacturers usually recommend that old style aviation grade lines be replaced every 5 years. An onerous and expensive burden.

3. My SS braided teflon lines are over 10 years in use with no signs of deterioration.

4. Fuel/oil leaks can lead to fire.  An undesirable consequence of lines that may leak.

5. Auto racing folk seem to like them and Earl's has a fine stock of lines and fittings. 

 

You might ask, "Surely there must be some drawbacks?"  I would reply, "Yep."

 

1. Weight.  These line tend to be heavier than the old fashioned ones.  Also, every flex fluid line firewall forward is fire shielded.

2. Cost.  The lines and fittings are more costly.  At least hey were when I built my airplane.

3. The lines do not like to suffer a twist when installed and they can (will) take a set.

4. The SS braid should be treated as though you were installing a saw along its length.  It is not likely to become abraded but, under vibration, it can chew its way thru almost anything if it is not supported properly.

 

Fluid lines have certainly been interesting to me.  If I were building my Lancair 320 today, I would probably install SS/teflon brake lines along with Grove wheels and brakes.  I also used (and I am still using) the hydraulic flex lines supplied by Lancair in 1989 but I would consider others today.  Finally, the Tygon lines originally supplied for fuel runs did not seem substantial enough for me so I replaced them, as I was building, with SS/teflon.  Also, those old Tygon lines were not good for fuel as they hardened over time.  Today, Tygon lines are available especially made for carrying fuel, but I still would use SS/teflon.