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To: flyrotary@lancaironline.net
Date: Sat, 17 Feb 2007 09:31:15 -0800
Subject: Re: [FlyRotary] Cowling and engine installation RV 7A
Message-ID: <20070217.093120.2628.6.alwick@juno.com>
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From: al p wick <alwick@juno.com>

Absolutely NOT ok. So glad you asked the question. You can prove this to
yourself by shining adjustable strobe on the plumbing while the engine is
running. You will find the tubing bends significantly in response to
various engine rpm. This will fatigue the tubing. This is called hard
line plumbing. It increases your risk significantly. Ironically a lot of
guys will get away with it, some for a few years. It all depends on
whether your plumbing length corresponds to natural frequency of the
system. If you placed one or two supports on tubing, then that would
limit which frequencies it responds to. Greatly reduce risk. Flexible
line also dramatically reduces risk. I had a $million warranty issue once
where the engineer did the same thing you did. I use strobe at the
science museum I work at to show patrons how things bend. It's so
educational. I can rub my hand on metal bowl and it causes water to
splash out of bowl onto patron's face. Just by controlling the rubbing
frequency. I use strobe so they can see the metal deform from vibration.
My bowl has cracks in it now from fatigue.

BTW, just excellent job on wiring. Lot's of wire ties control that same
vibration. Looks attractive.

I'm a little puzzled by your plumbing routing. Why do you send that line
back to the other one?


-al wick
Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam
timing. 
Artificial intelligence in cockpit, N9032U 240+ hours from Portland,
Oregon
Glass panel design, Subaru install, Prop construct, Risk assessment info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html


On Sat, 17 Feb 2007 10:16:36 -0600 Dennis Haverlah
<clouduster@austin.rr.com> writes:
> 
> Here is one photo of the pressure regulator and bypass plumbing 
> showing 
> the aluminum tubing used - question - is the al. tubing  OK on the 
> firewall or should I replace it with flexable line?
> 
> Also incluced are pictures of the installed James Rotary cowl with 
> most 
> of the painting finished!!
> 
> Dennis H.
> 


-al wick
Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam
timing. 
Artificial intelligence in cockpit, N9032U 240+ hours from Portland,
Oregon
Glass panel design, Subaru install, Prop construct, Risk assessment info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html