From: "Steven W. Boese" <flyrotary@lancaironline.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: SS braided fuel lines
Thread-Topic: SS braided fuel lines
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Date: Wed, 29 Oct 2014 15:51:30 +0000
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There has been a good discussion of the relative merits of rubber fuel line=
s vs rubber lines covered by a SS braid with the SS braid possibly consider=
ed overkill with respect to pressure, stiff, heavy, and expensive.  There m=
ay be some value in considering Teflon lined SS braided lines due to the ch=
emical compatibility with nearly everything, high temperature stability, an=
d long lifetime.  They are still heavy, even stiffer than the rubber SS ver=
sion, and expensive.  They are certainly more than adequate since they are =
often used as brake lines with pressure response comparable to steel tubing=
 (very little volume change with increasing pressure).
My system evolved into a system with the fuel pressure regulator located ne=
ar the fuel pumps and outside of the engine compartment.  The leak prone fu=
el pulsation damper on the fuel rail was also eliminated.  The single fuel =
line to the fuel injectors (there is no fuel return line in the engine comp=
artment) consists of aluminum tubing to the firewall, SS braided Teflon lin=
e to the water pump area of the engine, and steel lines to the fuel rails. =
 There was essentially no elasticity in that system which dead ended at the=
 fuel injectors.  I didn't like the probability of high pressure spikes whe=
n all the injectors close simultaneously at substantial fuel flow rates.  S=
o I installed a 2 ft length of firesleeved rubber fuel injection line at th=
e end of the fuel rails as a shock absorber.  So now my system has the disa=
dvantages of both the rubber and the SS braided lines.

Steve Boese
RV6A, 1986 13B NA, EC2, RD1A=