X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail24.syd.optusnet.com.au ([211.29.133.165] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTPS id 1035878 for flyrotary@lancaironline.net; Thu, 16 Mar 2006 01:59:49 -0500 Received-SPF: none receiver=logan.com; client-ip=211.29.133.165; envelope-from=lendich@optusnet.com.au Received: from george (d58-104-167-235.dsl.nsw.optusnet.com.au [58.104.167.235]) by mail24.syd.optusnet.com.au (8.12.11/8.12.11) with SMTP id k2G6wxjT021451 for ; Thu, 16 Mar 2006 17:58:59 +1100 Message-ID: <004401c648c7$1b0ce700$eba7683a@george> From: "george lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Motor teardown results Date: Thu, 16 Mar 2006 16:59:01 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0041_01C6491A.EC64E390" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_0041_01C6491A.EC64E390 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message - Chuck have you thought to go to 3mm? George ( down under) I finally got time to get my failed 13b apart. The rear rotor was = missing one apex seal, the other 2 were intact but jammed due to the = fragments of the broken one. The rotor housing has the classic chatter = marks all around. Doing a Google of "13B apex seal chatter" results in = plenty of examples of this failure mode. Apparently the chatter is from = the natural resonant frequency of the seal, it eventually fatigues the = seal causing failure. The front rotor was in good shape, but the housing had the same = chatter marks, but not as severe as the rear rotor. The front rotor = housing was brand new 150 hours ago when I rebuilt this motor after the = Grand Canyon forced landing. At that time the good rotor housing had = slight chatter marks but I reused it. The front rotor was destroyed at = that time due to foreign object entering the rotor. Both rotors were missing the corner seal rubber plugs on the side = with the short apex seal segment. Perhaps the small segment vibrated = more, disintegrating the rubber seals? The first 260 hours of flying my rotary bird was with stock 3-piece = seals, and I never saw any chatter marks. The last 250 hours has been = flown with 2 piece seals and now I have chatter marks . I now have Tracy's 2 piece apex seals and I wonder how they will = perform, it appears that the heavier weight of the 2 piece seals puts = the resonant frequency in the cruising range of 6000RPM? Chuck Dunlap RV6 13B -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_0041_01C6491A.EC64E390 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
 
- Chuck have you thought to go to = 3mm?
George ( down under)
 
 
I = finally got time=20 to get my failed 13b apart. The rear rotor was missing one apex seal, = the=20 other 2 were intact but jammed due to the fragments of the broken one. = The=20 rotor housing has the classic chatter marks all around. Doing a Google = of "13B=20 apex seal chatter" results in plenty of examples of this failure mode. = Apparently the chatter is from the natural resonant frequency of the = seal, it=20 eventually fatigues the seal causing failure.
The = front rotor=20 was in good shape, but the housing had the same chatter marks, but not = as=20 severe as the rear rotor. The front rotor housing was brand new 150 = hours ago=20 when I rebuilt this motor after the Grand Canyon forced landing. At = that time=20 the good rotor housing had slight chatter marks but I reused it. The = front=20 rotor was destroyed at that time due to foreign object entering the=20 rotor.
Both = rotors were=20 missing the  corner seal rubber plugs on the side with the short = apex=20 seal segment. Perhaps the small segment vibrated more, disintegrating = the=20 rubber seals?
The = first 260=20 hours of flying my rotary bird was with stock 3-piece seals, and I = never saw=20 any chatter marks. The last 250 hours has been flown with 2 piece = seals and=20 now I have chatter marks .
I = now have Tracy's=20 2 piece apex seals and I wonder how they will perform, it appears that = the=20 heavier weight of the 2 piece seals puts the resonant frequency in the = cruising range of 6000RPM?
 
Chuck=20 Dunlap
RV6=20 13B

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Homepage:  http://www.flyrotary.com/
Archive and=20 UnSub:  =20 http://mail.lancaironline.net/lists/flyrotary/
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