Jim -

I'll hazard a guess here that the 6" prop was a MAX diameter.  I'm sure that for lack
of any other guesses on what the power of a "1/2E" might be, and since this is for
a 1/2A contest, it was Jim Renkar's way of keeping things even - since glow 1/2A's
are pretty much limited by their power band to 6 in. props, then he is also limiting
the electrics to 6" props.

Mike A