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 3752931 for flyrotary@lancaironline.net; Fri, 10 Jul 2009 17:53:38 -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 54E6A173954 for ; Sat, 11 Jul 2009 05:53:00 +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 AB076BEC013 for ; Sat, 11 Jul 2009 05:52:58 +0800 (WST) Message-ID: <3526C213E83A4A9A96D2132E64638AB7@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Interested in cog-belt PRSUs? Date: Sat, 11 Jul 2009 07:53:00 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001B_01CA01FC.9C6A77D0" 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 090710-0, 07/10/2009), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_001B_01CA01FC.9C6A77D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Bryan, I understand your confusion, as I had to get my head around this stuff a = long time ago. That's 85 minus 45 =3D 36 divided by 2 =3D18 which is the number of = planet teeth. I see what you have done, you have divided 85 by 45 - = that's the overall ratio 1.8 then divided by 2 to get .9.=20 There are 4 major components of the planetary the ring gear, the planet = gear housing, the planet gear itself and the sun gear.I threw the = calculations for planet teeth as a bonus for those unfamiliar with the = process, thinking it may be confusing, but for the overall picture it's = a necessary part of a planetary system, as is the difference between = holding the planet housing as compared to holding the ring gear, the = difference here is + 1. The + 1 is when you run the planetary opposite = to the crank. In our case we hold the ring gear to attain the +1. Showing the reason for the +1 was necessary to show the comparison = between a 3 gear system (like the planetary 2.85) and the 2 gear system = ( 1.8) like the belt and pulleys/ sprockets.- which are very similar in = ratio but turn the opposite direction. Hope that helps!? George ( down under)=20 George you lost me with (81-45)/2=3D1.8 I get .9 Bryan =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of George Lendich Sent: Friday, July 10, 2009 3:21 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Interested in cog-belt PRSUs? =20 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). =20 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. =20 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=20 ------=_NextPart_000_001B_01CA01FC.9C6A77D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
Bryan,
I understand your confusion, as I had = to get my=20 head around this stuff a long time ago.
 
That's 85 minus 45 =3D 36 divided by 2 = =3D18 which is=20 the number of planet teeth. I see what you have done, you have = divided 85=20 by 45 - that's the overall ratio 1.8 then divided by 2 to get .9. =
 
There are 4 major components = of the=20 planetary the ring gear, the planet gear=20 housing, the planet gear itself and the = sun=20 gear.I threw the = calculations for planet=20 teeth as a bonus for those unfamiliar with the process, thinking it may = be=20 confusing, but for the overall picture it's a necessary part of a = planetary=20 system, as is the difference between holding the planet housing as = compared to=20 holding the ring gear, the difference here is + 1.  The + 1 is when = you run=20 the planetary opposite to the crank. In our case we hold the ring gear = to attain=20 the +1.
 
Showing the reason for the +1 was = necessary to show=20 the comparison between a 3 gear system (like the planetary 2.85) and the = 2 gear=20 system ( 1.8) like the belt and pulleys/ sprockets.- which are very = similar in=20 ratio but turn the opposite direction.
Hope that helps!?
 
George ( down under) 
 
George you = lost me with=20 (81-45)/2=3D1.8

I get=20 .9

Bryan

 

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of George Lendich
Sent: Friday, July 10, 2009 = 3:21=20 AM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: = Interested in=20 cog-belt PRSUs?

 

Bernie,

The calculations for = ratio of this=20 kind is (ring 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.=20 (81/45=3D1.8).

 

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

 

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

 

However we only have two = gears=20 (sprockets) in this 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=20 the teeth on the belt PSRU sprockets but used the numbers = abovementioned as=20 demonstration only.

Hope that's=20 clearer!? 

George (down=20 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 =

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