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Ok, thanks, Bernie
It may be similar to what Van found
when he had a study done of the effects of anodizing the wing spar web.
Apparently this process stiffens the metal to some extend thereby making it more
subject to fatigue. Well, his study assumed aerobatics time on each flight
and it showed that while the fatigue life was lessened, it still would have
taken 20,000 hours (as best I recall) of flying to approach the fatigue life of
the spar - clearly not something one has to lose sleep over at
night.
No, have not flown it yet. Got it installed and
finished the control wiring yesterday, but still need to attach heat shield as
well as few other things. I estimate I should be airborne early next
week. Intend to do ground run-ups this weekend.
Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
Sent: Thursday, March 04, 2004 10:06
PM
Subject: [FlyRotary] Re: Aluminum AN
fittings - Safety (was Re: [FlyRotary] Re: ready to start?
Ed,
Van used to recommend only steel AN fittings on the lycomings until it
was pointed out that the brand new engines were shipped from the factory with
some flight critical aluminum at which time Van backed away from his
recommendation.
Did the DIE variable length fly yet?
Bernie
----- Original Message -----
Sent: Thursday, March 04, 2004 4:00
PM
Subject: [FlyRotary] Re: Aluminum AN
fittings - Safety (was Re: [FlyRotary] Re: ready to start?
----- Original Message -----
From: "David Carter"
<dcarter@datarecall.net>
To:
"Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent:
Thursday, March 04, 2004 12:26 PM
Subject: [FlyRotary] Aluminum AN
fittings - Safety (was Re: [FlyRotary] Re:
ready to
start?
> Paul,
>
> You mentioned "aluminum 1/4 NPT
to -6AN adapter". It is my understanding
> that there is a real
risk in using aluminum fittings on engines due to
lack
> of
"fatigue life" robustness of aluminum, compared to steel AN
fittings.
> There have been cases of these aluminum fittings
eventually breaking off
> where they are threaded into the engine
block.
>
> It is my understanding, from reading the "lists" and
articles in Kitplanes
&
> Sport Aviation, that steel fittings
are preferred over aluminum - that
> aluminum can actually be
considered a safety hazard.
>
> David
I suspect that in
case of an engine with lots of vibration such as an
Lycoming that steel
AN fittings are a prudent option. Most folks I know
flying rotaries
use Aluminum fittings and as yet, I have not hear of one
failing.
But then that might be because only Tracy has any considerable
number of
hours yet. In some cases - like fittings to radiators - there
is
little choice but to use aluminum fittings. Something to keep
our ears open
to anyone who has had bad experience with aluminum
fittings. Needless to
say any fitting whether steel or aluminum
should have minimum stress from
hose/tubing attached to the
fitting.
Ed Anderson
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