Return-Path: <13brv3@bellsouth.net> Received: from imf21aec.mail.bellsouth.net ([205.152.59.69] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 375860 for flyrotary@lancaironline.net; Mon, 23 Aug 2004 22:31:52 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.69; envelope-from=13brv3@bellsouth.net Received: from rd ([65.6.194.9]) by imf21aec.mail.bellsouth.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040824023122.JFTE1791.imf21aec.mail.bellsouth.net@rd> for ; Mon, 23 Aug 2004 22:31:22 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Sorry Rusty - no bind Date: Mon, 23 Aug 2004 21:31:25 -0500 Message-ID: <012501c48982$73ff1ff0$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0126_01C48958.8B2917F0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 This is a multi-part message in MIME format. ------=_NextPart_000_0126_01C48958.8B2917F0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable please don't take this as being critical, I'm just asking - is it true = or not that engine fittings should be steel, not aluminum? or is that just = a myth? does aluminum fatigue faster than steel? what do certified piston planes use? Kevin Lane Portland, OR =20 =20 This is sort of a controversial subject. There is probably an official = FAA rule, or at least rule of thumb about only using steel fittings when = there's relative motion on the two ends of a hose. Of course screwing steel fittings, into an aluminum gear drive would also violate some dissimilar metal rules, so damned if you do, damned if you don't. =20 =20 Since I was schooled at the Van's Aircraft institute, I follow the more common sense rules. If it's a small fitting, that isn't very strong, = it's best to use steel. If it's a fairly large fitting, then aluminum is = plenty strong. AN-6 is about the dividing line, and it comes down to whether there's much motion. In the case of the drain fitting you see in the = pic, there's no relative motion, so I feel aluminum is fine. =20 =20 Cheers, Rusty (not an A&P, and don't even play one on TV) =20 ------=_NextPart_000_0126_01C48958.8B2917F0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
please don't = take this as=20 being critical, I'm just asking - is it true or not that engine fittings = should=20 be steel, not aluminum?  or is that just a myth? does aluminum = fatigue=20 faster than steel?  what do certified piston planes = use?
Kevin Lane  Portland, OR
 
 
This=20 is sort of a controversial subject.  There is probably an = official FAA=20 rule, or at least rule of thumb about only using steel fittings = when=20 there's relative motion on the two ends of a = hose.  Of course=20 screwing steel fittings, into an aluminum gear drive would also = violate=20 some dissimilar metal rules, so damned if you do, damned if you = don't. =20
 
Since=20 I was schooled at the Van's Aircraft institute, I follow the = more=20 common sense rules.  If it's a small fitting, that isn't very = strong, it's=20 best to use steel.  If it's a fairly large fitting, then = aluminum is=20 plenty strong.  AN-6 is about the dividing line, and it comes down = to=20 whether there's much motion.  In the case of the drain fitting you = see in=20 the pic, there's no relative motion, so I feel aluminum is=20 fine.  
 
Cheers,
Rusty (not an=20 A&P, and don't even play one on=20 TV)  
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