X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3751849 for flyrotary@lancaironline.net; Fri, 10 Jul 2009 03:21:31 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (sv1-1.per.aanet.com.au [203.24.100.68]) by poplet2.per.eftel.com (Postfix) with ESMTP id 91FC1173746 for ; Fri, 10 Jul 2009 15:20:48 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id EEA63BEC01C for ; Fri, 10 Jul 2009 15:20:47 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Interested in cog-belt PRSUs? Date: Fri, 10 Jul 2009 17:20:48 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0022_01CA0182.C415CDE0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 090709-0, 07/09/2009), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0022_01CA0182.C415CDE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Bernie, The calculations for ratio of this kind is (ring gear divided by sun = gear). Using teeth numbers on the ring gear divided by the teeth numbers = on the sun gear; If you had 81 teeth on the ring gear and 45 teeth on = the sun gear i.e. (81/45=3D1.8). Now if there were an intermediate gear as on the planetary i.e. = planetary gear - then the calculation for the planetary gear teeth. is; = ring gear minus sun gear divided by two i.e.( 81- 45)/2 =3D 18. As a = planetary runs with 3 gears, the prop runs the same way if the planetary = is held (in place) by the ring gear, the calculations are 1.85 +1 =3D = 2.85:1 Ratio. As the rotary runs anti-clockwise in out orientation ( from the rear of = the motor forward ) we have a clockwise prop direction when using a = planetary PSRU, with ring gear held. With the planet housing held it = would run anti-clockwise and would be 1.8:1=20 =20 However we only have two gears (sprockets) in this belt PSRU so ir must = run in the direction the motor runs i.e. anti-clockwise. The ratio is = similar to the Ford planetary which is 1.85:1. I don't really know the numbers of the teeth on the belt PSRU sprockets = but used the numbers abovementioned as demonstration only. Hope that's clearer!?=20 George (down under) "With the rotary, that would mean an anti-clockwise prop rotation, = view from=20 the cockpit, 1.8:1 is right on the mark as compared to the Ford = planetary=20 reduction which is 2.85:1 with clockwise rotation i.e. 1.85+1.=20 George (down under)."=20 I am totally confused about having two different ratios going from = clockwise prop rotation to anti-clockwise for the same engine speed and = prop speed. I am way out of my depth here. HELP!!! Bernie ------=_NextPart_000_0022_01CA0182.C415CDE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Bernie,

The calculations for ratio of this kind = is (ring=20 gear divided by sun gear). Using teeth numbers on the ring=20 gear divided by the teeth numbers on the sun gear; If you had 81 = teeth on=20 the ring gear and 45 teeth on the sun gear i.e. = (81/45=3D1.8).

Now if there were an intermediate gear = as on the=20 planetary i.e. planetary gear - then the calculation for the planetary = gear=20 teeth. is; ring gear minus sun gear divided by two i.e.( 81- 45)/2 = =3D 18. As=20 a planetary runs with 3 gears, the prop runs the same way if the = planetary=20 is held (in place) by the ring gear, the calculations are 1.85 +1 = =3D 2.85:1=20 Ratio.

As the rotary runs anti-clockwise in = out=20 orientation ( from the rear of the motor forward ) we have a clockwise = prop=20 direction when using a planetary PSRU, with ring gear held. With the = planet=20 housing held it would run anti-clockwise and would be 1.8:1 =

However we only have two gears = (sprockets) in this=20 belt PSRU so ir must run in the = direction=20 the motor runs i.e. anti-clockwise. The ratio is similar to the Ford = planetary=20 which is 1.85:1.

I don't really know the numbers of the = teeth on the=20 belt PSRU sprockets but used the numbers abovementioned as demonstration = only.

Hope that's = clearer!?

George (down under)

"With the rotary, = that would=20 mean an anti-clockwise prop rotation, view from
the cockpit, 1.8:1 = is=20 right on the mark as compared to the Ford planetary
reduction = which is=20 2.85:1 with clockwise rotation i.e. 1.85+1.
George (down under)."=20

I am totally confused about having two different ratios going = from=20 clockwise prop rotation to anti-clockwise for the same engine speed = and prop=20 speed. I am way out of my depth here. HELP!!!=20 Bernie=20 ------=_NextPart_000_0022_01CA0182.C415CDE0--