NC crank prep/lightening for a DIY'r?

[Geoff Richards]

Ross Corrigan mailto:zxv at istar.ca     wrote
Any good
>before/after pics anywhere for knife edging etc?


A read from the step-by-step guide to Engine Blueprinting 
states that  *quote*
To our knowledge,no-one has ever tested whether sharpening
the counterweights provides any real benefits (aside from the 
obvious advantage of lightening the rotating assembly).On the 
face of it ,it seems doubtful.As any textbook on aerodynamics
will point out,it is the TRAILING edge of an object not the leading edge
that accounts for most of the drag.In fact,the "perfect" counterweight
shape would be from an aerodynamic standpoint would be a teardrop,
with a blunt leding edge and a long,tapering tail.So if you want to spend
time shaping the counterweights for a racing engine,it might be wiser to
concentrate on the back ends of the counterweights
*end quote*
I realise not everything that's printed is true,the message just jogged my
memory so I thought I'd post what I'd read
Leave ya to it
Cheers
Geoff