Received-SPF: pass
 receiver=logan.com; client-ip=199.185.220.220; envelope-from=haywire@telus.net
Message-ID: <1115279609.4279d0f953c0f@webmail.telus.net>
Date: Thu,  5 May 2005 00:53:29 -0700
From: Todd Bartrim <haywire@telus.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: re; CVT (continuously variable transmission)
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
User-Agent: Internet Messaging Program (IMP) 3.1-cvs

Has anyone heard of any research toward using these for PSRU's?  I have no 
idea how heavy they are, or if they could be dumbed down from the factory 
computers, or if they could be made to survive.  Sure would be a nice option 
if they could work.  
 
Rusty
 
 As mentioned in the article, these are used in very succesfully in 
snowmobiles (the pulley type). In the old days they would eat belts, but 
they've come along ways since then. The sled I currently ride pushes 130hp and 
has never blown a belt in 5 seasons of riding. I did change it after the first 
2 seasons, but still carry it as a spare. Mountain riding is very demanding on 
the clutches, much more than I'd expect in an aircraft application so I think 
reliabilty should be good. My peak power is at 8400 rpm so the primary engages 
at 4000rpm and begins the upshift untill 8400 is reached at which time the 
secondary limits this and controlls the backshift as load demands. When not 
heavily loaded (like cruising down a trail) it will not downshift, allowing 
lower rpm cruise for fuel efficiency, but will instantly respond to an 
increased load (climbing a hill).
  However I always wondered why they're not used with Rotax engines in ultra 
lights? Since the Rotax is the power for Ski-Doo, I'd have expected that 
someone would have used the combination in an UL aircraft. But since it didn't 
apply to my needs I didn't think about it for long.
   I'd never heard of the torroidial CVT before, but the article was very 
interesting and I can certainly invision one of these as a PSRU. It's an 
interesting concept that I'd like to see pursued, but right now my old brain 
is running out of RAM so I've got to reserve that for school right now. 
  Why don't you try a pulley type CVT on one of your multitude of planes? How 
many do you have now? And does your wife know? How many actually fly? :-)

Todd Bartrim    (big ole' EC2, EM2 & planetary geared RD2)

C-FSTB RV-9endurance
13B Turbo