Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Fri, 12 Mar 2004 20:50:48 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m24.mx.aol.com ([64.12.137.5] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3076479 for lml@lancaironline.net; Fri, 12 Mar 2004 18:36:56 -0500 Received: from Sky2high@aol.com by imo-m24.mx.aol.com (mail_out_v37.4.) id q.89.5a37643 (3964) for ; Fri, 12 Mar 2004 18:36:51 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <89.5a37643.2d83a393@aol.com> X-Original-Date: Fri, 12 Mar 2004 18:36:51 EST Subject: LNC2 Fan Fans: weird vibrations are gone! X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1079134611" X-Mailer: 9.0 for Windows sub 720 -------------------------------1079134611 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Some time back I had problems with my Hartzell prop made of actual 84 inch diameter cut down to the 70 inch diameter with no taper to the blade (thick tips). I had vibration at various rpms. Well, unfortunately I have changed two things and the odd vibrations are gone. 1. I found the forward bulkhead for my aluminum spinner was not quite round and "fill" tape had gathered on the slight gap side. So, after creating a new mounting flange for the lathe and cutting a new bulkhead out of nylon to the exact required roundness, size and taper, this new firmer bulkhead was installed. 2. In the spirit of Appendix D and while the spinner was off, I thought I would lubricate the hub as recommended by the Hartzell prop maintenance manual - especially since I had 150 hours on the prop (probably the longest any hub had not been serviced for blade replacement). Surprisingly, both hubs took an enormous amount of Aeroshell #6 grease (40 strokes) to finally eject some old grease. So, I was flying without enough greasy kid stuff. Anyway, the funny vibrations are gone. PS: This post was repeated on the Lancair Forum Site: _http://www.lancair-builders.com/forum/index.php?s_ (http://www.lancair-builders.com/forum/index.php?s) = Go there and sign up. Scott Krueger AKA Grayhawk Sky2high@aol.com II-P N92EX IO320 Aurora, IL (KARR) "...as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns - the ones we don't know we don't know." D. Rumsfeld -------------------------------1079134611 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Some time back I had problems with my Hartzell prop made of actual 84 i= nch=20 diameter cut down to the 70 inch diameter with no taper to the blade (thick=20 tips).  I had vibration at various rpms.  Well, unfortunately I ha= ve=20 changed two things and the odd vibrations are gone.
 
1.  I found the forward bulkhead for my aluminum spinner was not q= uite=20 round and "fill" tape had gathered on the slight gap side.  So, after=20 creating a new mounting flange for the lathe and cutting a new bulkhead out=20= of=20 nylon to the exact required roundness, size and taper, this new firmer bulkh= ead=20 was installed.
 
2. In the spirit of Appendix D and while the spinner was off, I thought= I=20 would lubricate the hub as recommended by the Hartzell prop maintenance manu= al -=20 especially since I had 150 hours on the prop (probably the longest any hub h= ad=20 not been serviced for blade replacement).  Surprisingly, both hubs took= an=20 enormous amount of Aeroshell #6 grease (40 strokes) to finally eject some ol= d=20 grease.  So, I was flying without enough greasy kid stuff.
 
Anyway, the funny vibrations are gone.
 
PS: This post was repeated on the Lancair Forum Site:
 
http://www.lancai= r-builders.com/forum/index.php?s=3D
 
Go there and sign up.=20
 
Scott Krueger=20 AKA Grayhawk
Sky2high@aol.com
II-P N92EX IO320 Aurora, IL=20 (KARR)

"...as we know, there are known knowns; there are things we kn= ow=20 we know. We also know there are known unknowns; that is to say we know there= are=20 some things we do not know. But there are also unknown unknowns - the ones w= e=20 don't know we don't know." D. Rumsfeld
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