X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from smtp103.sbc.mail.gq1.yahoo.com ([67.195.15.62] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with SMTP id 3748775 for flyrotary@lancaironline.net; Tue, 07 Jul 2009 22:42:37 -0400 Received-SPF: neutral receiver=logan.com; client-ip=67.195.15.62; envelope-from=bryanwinberry@bellsouth.net Received: (qmail 7941 invoked from network); 8 Jul 2009 02:42:00 -0000 Received: from unknown (HELO acer7fbfa7e2f7) (bryanwinberry@69.84.247.131 with login) by smtp103.sbc.mail.gq1.yahoo.com with SMTP; 8 Jul 2009 02:41:59 -0000 X-Yahoo-SMTP: ypistUSswBAcKOUYA2cBKjVRQmDkl.Ngk4wGghEgQapiJJN8eY7N2A-- X-YMail-OSG: vw1k5Q8VM1kD.sQVBDqWtF4fEBJ7ZR5g0VKBiDVu4MTelot7hU2yy9MoYFqRwzNgFZp6bMzg82Yq2kkX5RndhLk.RgGN807DUyMuItwsUmtw6bdOBccnWAz.DLxdNh4ueGT1R2fGIpgyvYlUF0rE86tq4qZmtjuN5JjQmR8RgNcmLYZ3WnZVlEv4Ej6uvdhuz1.fRJJ_GZI4fa69gc5MXn_3ByaFeHjs80gT7Ssl9odBvpGsxVXofmyVX0Pw81RmZulBjD7U8asz2epNUWOlPOyxEZ3MVM700JXwK9e3xzT_mA7xBBQ1pXMtQv4- X-Yahoo-Newman-Property: ymail-3 From: "Bryan Winberry" To: "'Rotary motors in aircraft'" References: Subject: RE: [FlyRotary] Re: INJECTION OIL IN FUEL Date: Tue, 7 Jul 2009 22:42:00 -0400 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005C_01C9FF54.241AC640" X-Mailer: Microsoft Office Outlook 11 Thread-Index: Acn/beZ5ATcn5OFpRHeu4DshnS1f+gAB3/6w In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_005C_01C9FF54.241AC640 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Bernie, Here's another formula if you want a crosscheck: PropTipSpeed = Sqrt (Radius2 X AngularVelocity2 + TAS2) where: Angular Velocity in radians per second TAS in feet per second Radius in feet PropTipSpeed will come out in feet per second This was taken from the Avweb site. One of John Deakins articles that someone mentioned here a while back. Bryan _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Berniehb7448@wmconnect.com Sent: Tuesday, July 07, 2009 9:45 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: INJECTION OIL IN FUEL 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. ------=_NextPart_000_005C_01C9FF54.241AC640 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Bernie,

=

Here’s another formula if you = want a crosscheck:

 

PropTipSpeed =3D Sqrt = (Radius2 X = AngularVelocity2 + TAS2)

where:

Angular = Velocity in radians per second

TAS in feet per = second

Radius in = feet

PropTipSpeed = will come out in feet per second

 

This was taken from the Avweb site. =  One of John Deakins articles that someone mentioned here a while = back.

 

Bryan

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Berniehb7448@wmconnect.com
Sent: Tuesday, July 07, = 2009 9:45 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = INJECTION OIL IN FUEL

 

This is what 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 = barometric 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 10.714 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 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.

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