X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from omr-m04.mx.aol.com ([64.12.143.78] verified) by logan.com (CommuniGate Pro SMTP 6.0.4) with ESMTP id 6228835 for lml@lancaironline.net; Fri, 26 Apr 2013 19:49:49 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.143.78; envelope-from=Sky2high@aol.com Received: from mtaomg-ma01.r1000.mx.aol.com (mtaomg-ma01.r1000.mx.aol.com [172.29.41.8]) by omr-m04.mx.aol.com (Outbound Mail Relay) with ESMTP id AE0BD700126CE for ; Fri, 26 Apr 2013 19:29:30 -0400 (EDT) Received: from core-mtd003a.r1000.mail.aol.com (core-mtd003.r1000.mail.aol.com [172.29.235.201]) by mtaomg-ma01.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 7167EE000087 for ; Fri, 26 Apr 2013 19:29:30 -0400 (EDT) From: Sky2high@aol.com Full-name: Sky2high Message-ID: <104f2d.37928a85.3eac67da@aol.com> Date: Fri, 26 Apr 2013 19:29:30 -0400 (EDT) Subject: Re: [LML] Re: Prop overspeed??? To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_104f2d.37928a85.3eac67da_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=1367018970; bh=jcI/gNBxmd+GUrozru4crYnfhY32vEeuTtkJEjXxnDU=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=qebHQosiHmSSRh42Fc19gd3pgTY90HteEW2cka7/SugYA6D2YycEBb3joqcja6Quv 08l+zluDtqmX4BpQw2UbYKN27j4/JMPSnb37MijzXxC6qRpDrsMZeQYMcjrXQITBQQ VowXrNuwkzhbc/2pHVOXn/vI12TKNPmWIobNC9wc= X-AOL-SCOLL-SCORE: 0:2:461125536:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d2908517b0dda4dcc --part1_104f2d.37928a85.3eac67da_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Uh, I also forgot. Higher RPM = higher HP and higher HP = higher fuel consumption. If one runs the engine above the documented power and speed of the engine fuel delivery system design, one might have to have the throttle body adjusted for a greater fuel flow at those higher rpms (power). In a message dated 4/26/2013 6:22:45 P.M. Central Daylight Time, Sky2high@aol.com writes: 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_104f2d.37928a85.3eac67da_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Uh, I also forgot. Higher RPM =3D higher HP and higher HP =3D hi= gher fuel=20 consumption. If one runs the engine above the documented p= ower=20 and speed of the engine fuel delivery system design, one might have to have= the=20 throttle body adjusted for a greater fuel flow at those higher rpms=20 (power).

In a message dated 4/26/2013 6:22:45 P.M. Central Daylight Time,=20 Sky2high@aol.com writes:

=

Angier,

For self interest purposes I upped the hi speed limit on the governo= r to=20 2770 and I routinely saw 2740 to 2770 on takeoff and climb to 700&nb= sp;=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.&nbs= p;=20 2800 rpm equal 3 x pi x 2800 =3D 26390 ft/min =3D 5 mpm =3D 300 mph = =3D .394 Mach=20 tip speed. No Problem.

Prop balance is another story.

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

Scott

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

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

For an IO360 180hp, what high RPM would be a serious caus= e for=20 concern?
I routinely see 2660/70 for sea level takeoff so not sure I= need=20 to tweak the gov.

Angier
N4ZQ

--
For archiv= es=20 and unsub=20 http://mail.lancaironline.net:81/lists/lml/List.html<= /DIV>

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