<VV> alternate fans

[Joel McGregor]

A variable belt drive has to have a variable pulley on both ends and it would miss-align the belt and cause more belts to come off.  There would also be problems getting the signals & power to your electrically variable pulley system.  All that mess make a hydraulic setup look like a better option.
A more efficient stock replacement fan with an aluminum hub and titanium pulley would be a better place to shoot for.  There are probably some modern plastics that would handle the heat.  They might also be a good choice for hub material.
Joel McGregor 

-----Original Message-----
From: virtualvairs-bounces at corvair.org [mailto:virtualvairs-bounces at corvair.org] On Behalf Of Dale Dewald
Subject: Re: <VV> alternate fans
This is done all the time on heavy equipment (dozers, loaders, graders,
etc) using hydraulic drive.  Of course, all of these machines have large hydraulic pumps and systems already in place from which to tap hydraulic flow to run a fan drive.  I would not want to add the complexity of an additional hydraulic system to my Corvair, however.

On the other hand, I think Jay may have an idea with some merit. How about a compact CVT (variable diameter pulley perhaps?) that is adjusted by servo (stepper) motor to maintain a set RPM based on head temperature.  It could use  engine RPM and the motor position/pulley ratio function to keep the fan speed at the desired setpoint. It might be desirable for this mechanism to adjust quickly to account for engine speed changes when shifting gears (for belt life), but I don't think it would be necessary.  The system would just need to maintain a time-weighted average fan speed based on head temperature.

Dale Dewald
Hancock, MI