Flat spiral or helical primary?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Parpp807-at-aol-dot-com>

Can someone please 'splain me the relative merits
of a primary wound as a flat Archimedes spiral and
a primary wound as a helical solenoid?

I have seen a few coils use a solenoid primary. A few 
wound with strap, but it seems that these are usually
large coils. The flat, Archimedes spiral is almost
always used by coilers. Why?

I am in the process now of converting one of my 
24 inch secondaries from the twin bipolar into a 
1/4 wave coil. I have many solenoids of various
configurations that I will at least try with the
1/4 wave TC before making a flat coil. 

Happy day,
Ralph Zekelman