re: chassis stiffeners

[<dawnanddan@domain.elided>]

Greetings alfisti !

Chris Prael wrote :
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I have never tried one of these, nor would I!  They are a shuck.

If you much about structures, it should be obvious that any "bolt-on"
device will add a lot of weight and do very little stiffening.  

It is simply a matter of leverage.  Alfa already built extra weight
into the floor of the 105/115 chassis to stiffen the Spider.  Any
structure that you bolt to the floor pan will have an even worse
strength-to-weight ratio.  

You can produce a useful improvement in torsional stiffness by careful
design of a roll cage that is welded to the car. But the car will be a 
single seat race car, not a street machine.

These chassis stiffeners probably make great ballast, but that will not
improve the car's performance.

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Although my Duetto doesn't have it's stiffener yet ( heck it doesn't even 
run yet ! ),  this is how it was explained to me my a fellow AROSC member 
and owner of an aircraft engineering company ( ie: somebody familiar with 
metallurgy and bracing ):

As a Spider body twists, the chassis will stretch slightly ( try twisting 
something soft and you'll see what I mean ).  The stiffener resists this 
stretching since it is attached to the steering box/idler arm box at the 
front and the control arm attachments at the rear.  

Quite simple, really !

Ciao all !!

Dan Walker
68 Euro Duetto
87 Milano Gold

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