Interesting info Ken.
I would agree completely with you that the Ford gears are the wrong
choice for a 3.xx to 1 ratio drive. The reason is that they require you to
modify the gear set from fixed planet to fixed ring gear. It can
be done but the challenge is not worth it when a gear set designed to work that
way already exists ( Dodge). I also agree that you are flying one of
the few planes that actually need a 3+ ratio drive.
I am not familiar with the Dodge transmission but an overdrive gear with a
ratio of 3.17 : 1 is astounding! Every other OD gear I've come across has
a ratio something like .707 to 1. Are you sure about that
gear's use? I'm always up for learning a new wrinkle.
Tracy
----- Original Message -----
Sent: Thursday, January 05, 2006 12:45
AM
Subject: [FlyRotary] Dodge vs Ford
Here is is an email that was sent to me
to forward to you all from a friend of mine that talked me out of building a
C-6 based 3.17 ratio gearbox and talked me into using the 3.21 Dodge
gears.
He is not on this list but you may have heard
of him as he is on the rotary roster as he is building a Coot with a rotary
and he is using one of my 2.95 belt drives and he should be flying it this
summer.
He thinks I am nuts going away from the belt
drive that I have put 900 trouble free hrs on and says he will stick with the
belt even though works on transmissions for a living.
Ken Welter
Date: Wed, 04 Jan 2006 06:47:42 -0800
(PST)
From: Arnold <vwsandndirt@yahoo.com>
Subject: Re: Fwd Re:
[FlyRotary]Soapbox Warning! PSRU Ratios
X-Originating-IP:
[66.218.79.59]
To: Ken Welter
<rotary.coot@verizon.net>
One thing I can tell you is that
in the last 15 plus years that I have dealt with planetaries, I still
see Ford sun gears coming apart in 80% of units I take apart and I have yet
to find a bad Dodge sun gear with the exception on total planet meltdown due
to a plugged trans cooler. I am not an engineer, just an observer and
a very qualified transmission expert.
Another thing I can tell you is that it was
not the amount of pinion gears that were put into the Ford planets that made
it better, it was the change from aluminum to steel to keep the splines from
stripping out. Also, the Ford planets are only being used (loaded)
during up shifts and the Dodge planet set in question is being used during
the long period of time the truck is towing the trailer down the highway in
overdrive.
Good luck with your ratio debate and I hope
this info is of help.
Arnold Norton ASE
certified
American
Transmissions