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 3752986 for flyrotary@lancaironline.net; Fri, 10 Jul 2009 18:53:51 -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 1BD1C173490 for ; Sat, 11 Jul 2009 06:53:12 +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 2A502BEC00A for ; Sat, 11 Jul 2009 06:53:11 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Interested in cog-belt PRSUs? Date: Sat, 11 Jul 2009 08:53:13 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0005_01CA0205.06254BC0" 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_0005_01CA0205.06254BC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Bryan, I know it's sometimes hard, but something's you have to take things ( = like the +1) as a given. I think I remember seeing it explained = somewhere on the Net, but can't remember how it was explained.=20 It's a bit like trying to explain how to find a square root of a very = large number (with pencil and paper) it can be done but everyone uses a = calculator. But your right, as long as it does the job. George (down under) Thanks George, I caught my math error, but that +1 thing still evades me a little. = There's some good animation out there on the internet. I'll need a = little time to wrap my head around it. All I really care about is that my RD-1C makes me go fast in the = forward direction :>) BW =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of George Lendich Sent: Friday, July 10, 2009 5:53 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Interested in cog-belt PRSUs? =20 =20 Bryan, I understand your confusion, as I had to get my head around this stuff = a long time ago. =20 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 =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. =20 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!? =20 George ( down under)=20 =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_0005_01CA0205.06254BC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Bryan,
I know it's sometimes hard, but = something's you=20 have to take things ( like the +1) as a given. I think I remember seeing = it=20 explained somewhere on the Net, but can't remember how it was explained. =
 
It's a bit like trying to explain how = to find a=20 square root of a very large number (with pencil and paper) it can be = done but=20 everyone uses a calculator.
 
But your right, as long as it does the=20 job.
George (down under)

Thanks=20 George,

I caught my = math=20 error, but that +1 thing still evades me a little.  There=92s = some good=20 animation out there on the internet.  I=92ll need a little time = to wrap my=20 head around it.

All I = really care=20 about is that my RD-1C makes me go fast in the forward direction=20 :>)

BW

 

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of George Lendich
Sent: Friday, July 10, 2009 = 5:53=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: = Interested in=20 cog-belt PRSUs?

 

 

Bryan,

I understand your = confusion, as I=20 had to get my head around this stuff a long time=20 ago.

 

That's 85 minus 45 =3D = 36 divided by=20 2 =3D18 which is the number of planet teeth. I see what you have = done, you=20 have divided 85 by 45 - that's the overall ratio 1.8 then divided by 2 = to get=20 .9.

 

There are 4=20 major components of the planetary the ring gear, the = planet gear=20 housing, the planet gear = itself and=20 the sun=20 gear.I threw the calculations for planet = teeth as a=20 bonus for those unfamiliar with the process, thinking it may be = confusing, but=20 for the overall picture it's a necessary part of a planetary system, = as is the=20 difference between holding the planet housing as compared to holding = the ring=20 gear, the difference here is + 1.  The + 1 is when you run the = planetary=20 opposite to the crank. In our case we hold the ring gear to attain the = +1.

 

Showing the reason for = the +1 was=20 necessary to show the comparison between a 3 gear system (like the = planetary=20 2.85) and the 2 gear system ( 1.8) like the belt and pulleys/ = sprockets.-=20 which are very similar in ratio but turn the opposite=20 direction.

Hope that=20 helps!?

 

George ( down=20 under) 

 

George you = lost me=20 with (81-45)/2=3D1.8

I get=20 .9

Bryan

 

From:=20 Rotary motors in = aircraft=20 [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=20 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=20 had 81 teeth on the ring gear and 45 teeth on the sun gear i.e.=20 (81/45=3D1.8).

 

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

 

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

 

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

I don't really know = the numbers=20 of the teeth on the belt PSRU sprockets but used the numbers = abovementioned=20 as 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=20 prop speed. I am way out of my depth here. HELP!!!=20       Bernie=20 =

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