OK--everybody get your tomatoes ready to throw--- engineering stuff incoming:
I'd be inclined to be a little careful about rigid mounts unless you have some
experience and know what you're doing. You don't want to overconstrain things
and end up distorting something that shouldn't be or worse yet putting an
unnecessary load on a bearing somewhere in the drive train. You need to deal
with things like thermal expansion, chassis flex and just plain realistic
levels of accuracy in building the car. A three point rubber mount for an
engine/trans takes care of a lot of this as does your driveshaft universals.
The vibration isolation of the rubber comes as a bonus.
There's an old concept in mechanical engineering getting some new play under
the name "Minimum Constraint Design" A Google search on this subject will
bring up a good engineering book on the subject and some lofty discussions.
It's probably more for engineering types than us racer-builders. Still, if
you're into something pretty ambitious like a +300 mph car with the attendant
innovative design that inevitably happens it wouldn't hurt to have a good
understanding of this subject.
Bottom line is that a 4 legged chair won't sit right on the floor unless all
four legs are the same length AND THE FLOOR STAYS FLAT.
Ed Weldon
|