X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 14 Dec 2009 22:52:25 -0500 Message-ID: X-Original-Return-Path: Received: from elasmtp-spurfowl.atl.sa.earthlink.net ([209.86.89.66] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTP id 4020528 for lml@lancaironline.net; Mon, 14 Dec 2009 18:35:02 -0500 Received-SPF: none receiver=logan.com; client-ip=209.86.89.66; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=ZUjswidGhw2ehK9Dlj07+ongv1klTcMliZx6F1K1hvFkMYc7To+xxk0YAu/ikLrv; h=Received:Message-ID:From:To:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:X-ELNK-Trace:X-Originating-IP; Received: from [216.57.118.33] (helo=ccaselt3) by elasmtp-spurfowl.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1NKKQr-00076W-H6 for lml@lancaironline.net; Mon, 14 Dec 2009 18:34:25 -0500 X-Original-Message-ID: <5EADEA21A61B4A3BAA854A9E29E1A5CA@nvidia.com> From: "Colyn Case at earthlink" X-Original-To: Subject: feathering props X-Original-Date: Mon, 14 Dec 2009 18:34:25 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0369_01CA7CEC.0FA88970" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da940d3bcd812fe831a6b1090ae4e93eee43c350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 216.57.118.33 This is a multi-part message in MIME format. ------=_NextPart_000_0369_01CA7CEC.0FA88970 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I have a full feathering prop on my IVP. ....but there are some holes in my understanding I wonder if someone has = a definitive understanding of. I believe the following are true: - on this prop oil pressure pushes it to fine pitch and springs push to = coarse pitch - if you lose oil pressure, it will go to feather - if you pull the prop control all the way out it will go to feather - if you do an air start from feather and you have a strong battery and = starter, you can get it out of feather in about 25 seconds. - it has prop locks which prevent it from going to coarse on a normal = shut down. Here's what I dont' understand: - EXACTLY how do the prop locks work? It seems that if you get rpm = below 1200 but haven't lost oil pressure, somehow the prop locks will = keep it from going to full feather when you finally lose all pressure. - If the engine were at 1100 rpm when you lost power, what would happen? = I assume the prop locks keep it from feathering. - If the prop is windmilling, you have oil pressure. If you slowly pull = the prop back til it's below 1200rpm and then continue all the way back, = how is this different than a normal shut down, as far as the prop is = concerned? In other words, are there scenarios where the prop locks can bite you in = the air and what are they? Colyn ------=_NextPart_000_0369_01CA7CEC.0FA88970 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I have a full feathering prop on my=20 IVP.
....but there are some holes in my = understanding I=20 wonder if someone has a definitive understanding of.
 
I believe the following are = true:
- on this prop oil pressure pushes it = to fine pitch=20 and springs push to coarse pitch
- if you lose oil pressure, it will go = to=20 feather
- if you pull the prop control all the = way out it=20 will go to feather
- if you do an air start from feather = and you have=20 a strong battery and starter, you can get it out of feather in about 25=20 seconds.
- it has prop locks which prevent it = from going to=20 coarse on a normal shut down.
 
 
Here's what I dont' = understand:
- EXACTLY how do the prop locks = work?  It=20 seems that if you get rpm below 1200 but haven't lost oil pressure, = somehow the=20 prop locks will keep it from going to full feather when you finally lose = all=20 pressure.
- If the engine were at 1100 rpm when = you lost=20 power, what would happen?   I assume the prop locks keep it = from=20 feathering.
- If the prop is windmilling, you have = oil=20 pressure.  If you slowly pull the prop back til it's below 1200rpm = and then=20 continue all the way back, how is this different than a normal shut = down, as far=20 as the prop is concerned?
 
In other words, are there scenarios = where the prop=20 locks can bite you in the air and what are they?
 
Colyn
 
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