X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from omr-d03.mx.aol.com ([205.188.109.200] verified) by logan.com (CommuniGate Pro SMTP 6.0.4) with ESMTP id 6228815 for lml@lancaironline.net; Fri, 26 Apr 2013 19:22:38 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.109.200; envelope-from=Sky2high@aol.com Received: from mtaomg-db04.r1000.mx.aol.com (mtaomg-db04.r1000.mx.aol.com [172.29.51.202]) by omr-d03.mx.aol.com (Outbound Mail Relay) with ESMTP id BA26E7000009C for ; Fri, 26 Apr 2013 19:22:03 -0400 (EDT) Received: from core-mtd003a.r1000.mail.aol.com (core-mtd003.r1000.mail.aol.com [172.29.235.201]) by mtaomg-db04.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 8F757E000082 for ; Fri, 26 Apr 2013 19:22:03 -0400 (EDT) From: Sky2high@aol.com Full-name: Sky2high Message-ID: <104d68.125891fb.3eac661b@aol.com> Date: Fri, 26 Apr 2013 19:22:03 -0400 (EDT) Subject: Re: [LML] Re: Prop overspeed??? To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_104d68.125891fb.3eac661b_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [67.175.156.123] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20121107; t=1367018523; bh=JUKucfSJ5axVDO6sA0PzmaM/Fs0ES4ZGBEF3j89Ga8c=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=Rr2Zq73m9pVoEuaHFzGn+T87PgODVASnbzkCG0BPP05BW6Qkh32tMEpQiFqixY8gM qLpkuY6UWsSIeL8dKAx4V3mcaLE65F2n4xf1qIzZZg0qTifyd2sQJxLX4EcU47arTb wdDbi5rlzTsPYLv0l7nLB2MKhlTv52bF5DmmVy2c= X-AOL-SCOLL-SCORE: 0:2:420256704:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d33ca517b0c1b2d82 --part1_104d68.125891fb.3eac661b_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Angier, For self interest purposes I upped the hi speed limit on the governor to 2770 and I routinely saw 2740 to 2770 on takeoff and climb to 700 AGL. 3000 RPM seems to have been a reasonable limit for certified props. I xcntry raced at 2660 often with no debilitating results. Calculate tip speed and anything over .8 Mach is troublesome. Hmmmm 70 inches equal a radius of 35 inches - say 3 feet. 2800 rpm equal 3 x pi x 2800 = 26390 ft/min = 5 mpm = 300 mph = .394 Mach tip speed. No Problem. Prop balance is another story. The "wing" chord and twist in a prop usually provides max lift abut 2/3 of the way towards the tip. Additional speed on the designed prop has lift vs drag limits. Oh, that's right - if you have a Hartzell prop on a 360 it is only 68 inches as a result of vibration analysis............... Scott In a message dated 4/26/2013 6:05:33 P.M. Central Daylight Time, N4ZQ@VERIZON.NET writes: Scott, I think I may have acknowledged the warning and triggered a reset. For an IO360 180hp, what high RPM would be a serious cause for concern? I routinely see 2660/70 for sea level takeoff so not sure I need to tweak the gov. Angier N4ZQ -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html --part1_104d68.125891fb.3eac661b_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Angier,

For self interest purposes I upped the hi speed limit on the governor = to=20 2770 and I routinely saw 2740 to 2770 on takeoff and climb to 700 = ;=20 AGL. 3000 RPM seems to have been a reasonable limit for certified=20 props. I xcntry raced at 2660 often with no=20 debilitating results.

Calculate tip speed and anything over .8 Mach is troublesome. =20 Hmmmm 70 inches equal a radius of 35 inches - say 3 feet. = 2800=20 rpm equal 3 x pi x 2800 =3D 26390 ft/min =3D 5 mpm =3D 300 mph =3D .39= 4 Mach tip=20 speed. No Problem.

Prop balance is another story.

The "wing" chord and twist in a prop usually provides max lift abut 2/= 3 of=20 the way towards the tip. Additional speed on the designed prop has li= ft vs=20 drag limits. Oh, that's right - if you have a Hartzell prop on a 360 = it is=20 only 68 inches as a result of vibration analysis...............

Scott

In a message dated 4/26/2013 6:05:33 P.M. Central Daylight Time,=20 N4ZQ@VERIZON.NET writes:

= Scott, I=20 think I may have acknowledged the warning and triggered a reset.

F= or an=20 IO360 180hp, what high RPM would be a serious cause for concern?
I=20 routinely see 2660/70 for sea level takeoff so not sure I need to tweak t= he=20 gov.

Angier
N4ZQ

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