<VV> Corvair Fan

[John Dozsa]

In the late seventies I attended a technical Colloquium in which the
invited guest speaker was the then head of GM Research Labs.  My
employer, a university sponsored, DoD national lab was having difficulty
justifying the cost of it's in-house research labs.  The speakers topic
was the cost effectiveness of GM research.  One of the many examples he
cited as a huge return on investment involved the Corvair cast magnesium
fan.  Apparently the production line was having great difficulty dynamic
balancing the fan.  He stated initial attempts provided more scrap than
useful product.  GM Research Lab engineers where called in to solve the
problem.  They designed a fan production process that would create only
balanced fans.  Every wonder why there are no balance weights or weigh
balance holes on the Corvair fan?  It was done by first spin balancing
the fan before any fan bearing mounting holes were drilled.  Then the
production machine moved the casting to the exact balance center.  The
casting was then drilled and bored.  Apparently the process was so good
that a dynamic re-balance check was not needed.  As a result of GM
Research Labs' examples and others the government continued to fund my
employers applied research lab.  Somewhere I have an old SAE paper on
dynamic balancing that has a photo of the Corvair fan production
balancing machine.

John Dozsa