X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [64.12.143.101] (HELO imo-m13.mail.aol.com) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3748729 for flyrotary@lancaironline.net; Tue, 07 Jul 2009 21:46:22 -0400 Received-SPF: none receiver=logan.com; client-ip=64.12.143.101; envelope-from=Berniehb7448@wmconnect.com Received: from imo-ma01.mx.aol.com (imo-ma01.mx.aol.com [64.12.78.136]) by imo-m13.mail.aol.com (v107.10) with ESMTP id RELAYIN1-24a53fa257; Tue, 07 Jul 2009 21:45:09 -0400 Received: from Berniehb7448@wmconnect.com by imo-ma01.mx.aol.com (mail_out_v40_r1.5.) id q.c75.5527da5a (32913) for ; Tue, 7 Jul 2009 21:45:29 -0400 (EDT) From: Berniehb7448@wmconnect.com Message-ID: Date: Tue, 7 Jul 2009 21:45:29 EDT Subject: Re: [FlyRotary] Re: INJECTION OIL IN FUEL To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_c75.5527da5a.37855439_boundary" X-Mailer: 6.0 for Windows XP sub 11501 X-Spam-Flag:NO X-AOL-IP: 64.12.78.136 --part1_c75.5527da5a.37855439_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit This is what I figured out as my "formula": Max Prop RPM & Speed of Sound 1 Mile = 5,280 Feet Speed of Sound = 768 mph (I think this is at sea level barometric pressure, I haven't figured out what happens with altitude.) pi = 3.1429 6 FT (72") D (Diameter) Prop CIRCUMFERENCE = pi X D = 3.1429 X 6 ft = 18.857 ft Circumference 1 RPM = 18.857 ft/Minute at prop tip With 2:1 PSRU Reduction, calculate by prop RPM and Circumference: Prop RPM 3,000 (Engine RPM 6,000) = 56,571 ft/Minute = 10.714 miles/minute = 642.84 MPH (768 MPH - 642.84 MPH = 125.16 MPH under Speed of Sound) Prop RPM 3,500 (Engine RPM 7,000) = 66,000 ft/Minute = 12.5 miles/minute = 750 MPH (768 MPH - 750 MPH = 18 MPH under Speed of Sound) ================================================ I paid enough attention in my math classes to think I've got it right. Here's one for you: Does a cogbelt PSRU's powerlimit increase with a wider belt? Like, for example, if a two incher can handle 150 HP, then you might need a four inch belt to handle 300 HP. Something like that? Here's another: One maker put an engine RPM limit on the PSRU, and I'm thinking it has to do with the capability of the bearing at the input end. Maybe because these bearings are sealed - they don't run in an oil bath. Thank you, Bernie. --part1_c75.5527da5a.37855439_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable This is wha= t I figured out as my "formula":

Max Prop RPM & Speed of Sound

1 Mile =3D 5,280 Feet

Speed of Sound =3D  768 mph (I think this is at sea level baromet= ric pressure, I haven't figured out what happens with altitude.)

pi =3D 3.1429

6 FT (72") D (Diameter) Prop

CIRCUMFERENCE =3D  pi X D =3D   3.1429  X  6= ft  =3D 18.857 ft Circumference

1 RPM =3D 18.857 ft/Minute at prop tip

With 2:1 PSRU Reduction, calculate by prop RPM and Circumference:
Prop RPM 3,000 (Engine RPM 6,000) =3D  56,571 ft/Minute =3D 10.71= 4 miles/minute =3D 642.84 MPH
(768 MPH - 642.84 MPH  =3D 125.16 MPH under Speed of Sound)
Prop RPM 3,500 (Engine RPM 7,000) =3D  66,000 ft/Minute =3D 12.5= miles/minute =3D 750 MPH
(768 MPH - 750 MPH  =3D 18 MPH under Speed of Sound)
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D
I paid enough attention in my math classes to think I've got it right.=

Here's one for you: Does a cogbelt PSRU's powerlimit increase with a= wider belt? Like, for example, if a two incher can handle 150 HP, then yo= u might need a four inch belt to handle 300 HP. Something like that?
Here's another: One maker put an engine RPM limit on the PSRU, and I'm= thinking it has to do with the capability of the bearing at the input end= . Maybe because these bearings are sealed - they don't run in an oil bath.
Thank you, Bernie. --part1_c75.5527da5a.37855439_boundary--