X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from omr-d02.mx.aol.com ([205.188.109.194] verified) by logan.com (CommuniGate Pro SMTP 6.0.4) with ESMTP id 6228830 for lml@lancaironline.net; Fri, 26 Apr 2013 19:30:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.109.194; envelope-from=Sky2high@aol.com Received: from mtaomg-ma05.r1000.mx.aol.com (mtaomg-ma05.r1000.mx.aol.com [172.29.41.12]) by omr-d02.mx.aol.com (Outbound Mail Relay) with ESMTP id B77657001F900 for ; Fri, 26 Apr 2013 19:26:05 -0400 (EDT) Received: from core-mtd003a.r1000.mail.aol.com (core-mtd003.r1000.mail.aol.com [172.29.235.201]) by mtaomg-ma05.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 9191BE000082 for ; Fri, 26 Apr 2013 19:26:05 -0400 (EDT) From: Sky2high@aol.com Full-name: Sky2high Message-ID: <104e5b.4c172ad3.3eac670d@aol.com> Date: Fri, 26 Apr 2013 19:26:05 -0400 (EDT) Subject: Re: [LML] Re: Prop overspeed??? To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_104e5b.4c172ad3.3eac670d_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=1367018765; bh=25DM7GmiGw16m9QEJ+7V4ZiPJ/Er7iXSGU4npI5s4oM=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=LNUNJp4v5lfI4lhjByD0lbSybcZv7ZYnY5lmzP7LBk1SfLVAwrwXpeq98KpBndI7S Muf0o+9lfdAaj7wZ/OO7lRDdnTl3r8o99KEYqPPDrVR/MlDQ1O0jkwtJNqWECGjDTX vc14FcR/J1AYAturrOiD+PgyJrymT1zxdljlJCBg= X-AOL-SCOLL-SCORE: 0:2:416464288:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d290c517b0d0d5bc6 --part1_104e5b.4c172ad3.3eac670d_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Also, sometimes people want to include the spiral speed (taking into account forward speed along with rotational speed - I leave that additional calculation as an exercise for the interested. 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_104e5b.4c172ad3.3eac670d_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Also, sometimes people want to include the spiral speed (taking into= =20 account forward speed along with rotational speed - I leave that additional= =20 calculation as an exercise for the interested.

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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