X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao103.cox.net ([68.230.241.43] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4551122 for flyrotary@lancaironline.net; Mon, 01 Nov 2010 18:10:52 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.43; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao103.cox.net (InterMail vM.8.01.03.00 201-2260-125-20100507) with ESMTP id <20101101221016.RQRP22411.fed1rmmtao103.cox.net@fed1rmimpo03.cox.net> for ; Mon, 1 Nov 2010 18:10:16 -0400 Received: from BigAl ([72.199.216.236]) by fed1rmimpo03.cox.net with bizsmtp id RyAG1f00d56cS2o04yAG7f; Mon, 01 Nov 2010 18:10:16 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.1 cv=dbaSwxnuHrR0yVADEcRPA4YIn3BZCWHRWI2DPCFObtA= c=1 sm=1 a=22k-QPOfQZ8A:10 a=lN8H/RjlhkCyIsyuOn2r7w==:17 a=gpnzF8MYGw6fClgJlRMA:9 a=qbWGfT5py1rPI8rO-14U5fLSxU0A:4 a=CjuIK1q_8ugA:10 a=tQD2ueJG1glGnE5O5Q4A:9 a=uyug62EfnIt0Qk_zF44A:7 a=Y6qVUb2SC7h0BoSvDrFSvEem980A:4 a=lN8H/RjlhkCyIsyuOn2r7w==:117 X-CM-Score: 0.00 Authentication-Results: cox.net; none From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Vne is the question was Re: How fast is it safe to turn a Prop. Opinion Poll Date: Mon, 1 Nov 2010 15:11:57 -0800 Message-ID: <1211C2FB7FC74174B3091DCFE1753BC9@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_003C_01CB79D7.20244AD0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6863 In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5994 Thread-Index: Act6BrSv+Vx8YRzYSKCn9Zu85+rp9wAEfX0g Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_003C_01CB79D7.20244AD0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit I have read articles on both sides of the IAS and TAS issue; probably most were triggered when the RV article first appeared. The accepted practice for certified aircraft seems to be IAS. So, Vne issues asside, what say you about the prop speed issue? I'd say keep the tips subsonic; beyond that your power is not producing speed anyway. On my Catto prop (very similar to yours) the max rpm of 3000 is included on the label on the prop hub. Probably somewhat arbitrary, but keeps you comfortably below mach 1 tip speed. Al * David Leonard ------=_NextPart_000_003C_01CB79D7.20244AD0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I have read articles on both = sides of the IAS and TAS issue; probably most were triggered when the RV article = first appeared.  The accepted practice for certified aircraft seems to be = IAS.

 

So, Vne issues asside, what say you about the = prop speed issue?

I’d say keep the tips = subsonic; beyond that your power is not producing speed anyway.  On my Catto = prop (very similar to yours) the max rpm of 3000 is included on the label on = the prop hub. Probably somewhat arbitrary, but keeps you comfortably below = mach 1 tip speed.

 

Al

n    
David Leonard

 

 

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