# UFO & G60

Bernie Benz b.benz at charter.net
Tue Feb 1 18:56:12 EST 2005

```Dan,

Good job!  I knew you'd make good with that lead.

Bernie

> From: Dan Cordon <cord4530 at uidaho.edu>
> Date: Tue, 01 Feb 2005 15:48:43 -0800
> To: Bernie Benz <b.benz at charter.net>
> Cc: 200q20V mailing list <200q20v at audifans.com>
> Subject: Re: UFO & G60
>
> Bernie Benz wrote:
>
>>> However, in the last two years, it's seen frequent trips down a few
>>> miles of washboarded gravel roads. That's got to be like 10 years of
>>> potholes right?
>>
>> Dan,  Here's a topic for your thesis.  A formula for the optimum speed at
>> which to transverse pot holes of varying diameters and depths.  When is
>> flying across better than dropping in?
>
> <snip>
>
> A simple mathematical model wouldn't be too bad (just a mass, spring,
> damper system). Of course, to make it hard, we could incorporate the
> non-linear damping, and how compression and rebound damp differently.
> Then the suspension geometry and relative mass-in-motion would have to
> come in to play. Chances are the rear suspension likes a speed that's
> different from the front, so we'd have to consider the MSD system of the
> car's unit body in all its vibrational modes. And of course there's
> sensitivity issues...how sensitive is the model to wear in the
> components. Don't forget the statistical analysis to determine average
> washboard dimensions...which could be a thesis in itself.
>
> Maybe I should do another thesis. It wasn't *that* bad the first time :o)
>
> Oh, my bad. I read 'washboard' when you clearly typed 'potholes.' This
> is looking more and more like a dissertation. <grin>
>
> As much as I hate to admit it, I really like driving my Land Cruiser
> over washboards. The dimensions created by average car/truck tires
> aren't even noticeable with the 39" tires on the Cruiser. Of course, it
> stinks to drive anywhere else :o)
>
> For the washboards here, and my worn shocks/bushings, 25-30 mph seems to
> be the worst. Anything over 55 and you can't even tell the difference
> between the road bumps and a passenger passing gas. I guess eventually
> you'd smell one case....but you get the idea.
>
> --
> Dan Cordon
> Mechanical Engineer - Engine Research Facility
> University of Idaho
>

```