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It would appear to me that if you are reaching
temperatures in excess of 325F under you cowl - you likely already have a
fuel fire and so at that point, it may not really matter what
materials you have used. I personally to not think temperature
limitations are a factor at that point - more importantly in my
opinion are fatigue and abrasion resistance to prevent the break in the
first place.
I had an aluminum brake line fatigue and break
spraying hydraulic fluid on the hot rotor resulting in ignition and some
exciting few minutes as the wheel pant/tire etc caught on fire. Fortunately, all
ended well with damaged limited to destroyed wheel pant and
tire/tube.
I then switched to stainless steel braided line with
Teflon liner. While it can also fail - it would probably do so a
bit more gracefully (like a growing leak) rather than a catastrophic failure
like a break.
I also use SS braided line as my fuel lines for over
10 years. My belief was that the likelihood of a under the cowl fuel fire
would like be most possible from a compromised fuel line due to fatigue or
abrasion - so a SS Braided hose would be less likely to fail due to either
of those causes.
All material discussed have been used and all can be made
to work with the proper attention to safe practices - in my case, SS Braided
lines made me feel more comfortable. I must admit I am biased against
aluminum tubing under the cowl - although I do use them in low pressure lines
back of the Firewall.
Ed
Sent: Wednesday, February 02, 2011 9:22 AM
Subject: [FlyRotary] Re: Al Tubing in fuel line...
It melts that high, but has lost most of its strength
significantly before that (400 degrees, depending on your definition of
"significantly").
Dustin
On Wed, Feb 2, 2011 at 1:45 AM, wrjjrs@aol.com <wrjjrs@aol.com> wrote:
Ok guys I can
understand the concern with fatigue in a vibrating section, but even a
stainless steel braided line will at best have a teflon inner tube. That is
good to about 325 degrees. Aluminium melts at what, about 1200-1300 degrees. If you do use
aluminium tubing use the soft annealed stuff and use a flare or compression
fitting on the ends. How well you finish the install would probably be more
important than the material. Bill Jepson Sent via DROID on Verizon
Wireless
-----Original message-----
Well, unfortunately!! :>)
Bill
B
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of
Patrick
Sent: Tuesday, February 01, 2011 6:32 PM
To: Rotary motors in
aircraft
Subject: [FlyRotary] Re: Al Tubing in fuel line...
Yeah,
I try to avoid rubber fuel lines too. Stainless braid, silicone,
fire-sleeved line; call me picky.
And hopefully your firewall is
not plastic...!
Ernest Christley wrote:
> Patrick
wrote:
>> Bill,
>> I would suggest taking a propane torch
to a piece of scrap aluminum
>> (beer can) and a piece of
stainless. It may affect your comfort
>> level about aluminum in
the engine compartment.
>>
>> Personally, I would never
use aluminum fuel line in front of the
>>
firewall.
>>
>> Patrick
> If you're going to do
that, you might as well include those rubbery
> pieces of fuel line
in the test. And remember, you're telling that to
> a guy who has the
engine mounted to a plastic airplane 8*)
>
> --
>
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