X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-da03.mx.aol.com ([205.188.105.145] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4499456 for flyrotary@lancaironline.net; Sat, 09 Oct 2010 09:54:02 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.145; envelope-from=Lehanover@aol.com Received: from imo-ma03.mx.aol.com (imo-ma03.mx.aol.com [64.12.78.138]) by imr-da03.mx.aol.com (8.14.1/8.14.1) with ESMTP id o99DrKh2006704 for ; Sat, 9 Oct 2010 09:53:20 -0400 Received: from Lehanover@aol.com by imo-ma03.mx.aol.com (mail_out_v42.9.) id q.d08.7d0e0b64 (43989) for ; Sat, 9 Oct 2010 09:53:19 -0400 (EDT) Received: from magic-m25.mail.aol.com (magic-m25.mail.aol.com [172.20.22.198]) by cia-dd05.mx.aol.com (v129.5) with ESMTP id MAILCIADD056-abd54cb073ce326; Sat, 09 Oct 2010 09:53:18 -0400 From: Lehanover@aol.com Message-ID: <1620f2.255e67ac.39e1cdce@aol.com> Date: Sat, 9 Oct 2010 09:53:18 EDT Subject: Propeller design. To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_1620f2.255e67ac.39e1cdce_boundary" X-Mailer: 9.0 Security Edition for Windows sub 5381 X-AOL-IP: 173.88.9.178 X-Spam-Flag:NO X-AOL-SENDER: Lehanover@aol.com --part1_1620f2.255e67ac.39e1cdce_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit _http://www.eaa.org/experimenter/articles/2009-02_elippse.asp_ (http://www.eaa.org/experimenter/articles/2009-02_elippse.asp) I sat through a talk by Paul Lipps at Gene Nevada at the alternative engine seminar put on by Contact Magazine several years ago. He flew in his home built, with his propeller. Its outer blades were the size of a 12" ruler. Imagine model sail plane wings, or bread knife blades. He placed split tennis balls on the tips so guests did not stab themselves on the blades. Later, he helped a guy design new wings for a biplane racer, and those wings looked just like his propeller blades. It had a 4 bladed Lipps propeller as well. Not mentioned was the low wetted area of the blades would allow greater span with less drag. The high angle of attack at the root allowed playing card sized cooling inlets. In the event of failed engine his prop has less than a 3rd of the frontal area of a conventional prop. Not exactly full feathering, but better than anything else. So, if the blade has less drag for each unit of lift, then you could add span until you get close to the ground, and then add blade count until you have accounted for all of the available HP. Then you port the rotary to get more HP. Warning, looking at a Lipps propeller blade may hurt your mind...................... _http://www.eaa.org/experimenter/articles/2009-02_elippse.asp_ (http://www.eaa.org/experimenter/articles/2009-02_elippse.asp) Lynn E. Hanover --part1_1620f2.255e67ac.39e1cdce_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

http://www.eaa.org/experimenter/articles/2009-02_elippse.asp

I sat through a talk by Paul Lipps at Gene Nevada at the alternative= engine=20 seminar put on by Contact Magazine several years ago.

He flew in his home built, with his propeller. Its outer blades= were=20 the size of a 12" ruler. Imagine model sail plane wings, or bread knife bl= ades.=20 He placed split tennis balls on the tips so guests did not stab themselves= on=20 the blades.

Later, he helped a guy design new wings for a biplane racer, and thos= e=20 wings looked just like his propeller

blades. It had a 4 bladed Lipps propeller as well.

Not mentioned was the low wetted area of the blades would allow great= er=20 span with less drag. The high angle of attack at the root allowed playing= card=20 sized cooling inlets.

In the event of failed engine his prop has less than a 3rd of the fro= ntal=20 area of a conventional prop.

Not exactly full feathering, but better than anything else.

So, if the blade has less drag for each unit of lift, then you could= add=20 span until you get close to the ground, and then add blade count until you= have=20 accounted for all of the available HP. Then you port the rotary to get mor= e=20 HP.

Warning, looking at a Lipps propeller blade may hurt your=20 mind......................

http://www.eaa.org/experimenter/articles/2009-02_elippse.asp

Lynn E. Hanover

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