Received-SPF: none
 receiver=logan.com; client-ip=211.29.133.168; envelope-from=lendich@optusnet.com.au
Message-ID: <005f01c57200$d3ccada0$be00ecdc@george>
From: "George Lendich" <lendich@optusnet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-1002866@logan.com>
Subject: Re: [FlyRotary] Re: planetary gear ratios
Date: Thu, 16 Jun 2005 09:20:32 +1000
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

Ernest,
Sorry to be confusing!
Yours is a 3.17 with the ring hear held and both the sun gear and the planet
housing turning clockwise.
This is usually called the 2.17 and has the planet housing help in place.

The 2.85 also has the ring gear held, with both the sun gear and planet
housing turning clockwise.

Both 6 planet units come from the EDO4 Ford gearbox the 2.85
( or 1.85) is the front one and the 2.17/3.17 is the rear one.

I believe the 3 or 4 planet units from the C6 have the same ratios but
different tooth profile- but not real sure on that.

To add to the confusion there is a third planet set - the overdrive. I can't
remember the ratios of that one - sorry!
George

> George Lendich wrote:
>
> >Ernest,
> >If it turns counter clockwise it's the 2.17 ( you don't add the one in
the
> >calculations).
> >If it turns clockwise it's 3.17.
> >The 2.17 turns counter clockwise.
> >The 2.85 turns clockwise ( looking at it from the pilots seat)
> >George ( down under)
> >
> >
>
> George, if you meant to confuse me then you have done a spectacular job
8*)
>
> Let's back up just a second.  The ring gear is locked.  The output is
> taken from a splined shaft that is driven by the planet gear carrier.
> When I turn the sun gear clockwise, the output shaft turns clockwise.
> It takes *about* 3 turns of the sun gear to get one turn on the output
> shaft.  You've said (or at least I read it that way) that this is both a
> 2.85 and 3.17.  Was there a typo in there somewhere?
>
> Kelly, I was thinking more along the lines of 8000RPM redline, with a
> 7000 cruise.  That would put the prop revs at 2208, which I *think* is a
> good number.  The problem I'm having is trusting the 3-pinion planet set
> I have.  I took the gearbox to a transmission shop.  The technician said
> I was wasting money to replace it.  They use that same gearset to drive
> busses.  But I can't help but to be swayed by advertisements like item
> number #9X on this site:
>
> http://www.transmissioncenter.net/C4_C6.htm
>
> That's a lot of reassurance for $218 that follows all the laws of
> physics I know.  I would have switched it out already, I'm just not
> positive about which gearset I have exactly.  Does anyone know for
> certain the teeth count on the different gearsets?
>
> --
>          ,|"|"|,                                    |
> ----===<{{(oQo)}}>===----        Dyke Delta         |
>         o|  d  |o          www.ernest.isa-geek.org  |
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>