Posted for mquinns@aol.com:

 Peter,
 ?I think I remember a Lancair 360 fly off some years ago (10+) between a 68"
and a 70" prop. It was a post to this site but I can't find it in the
archives. The same aircraft flew the 68' and then switched and flew
the?70'?(under the same conditions). I don't remember the numbers but the
general results were the 68" prop was faster but didn't climb as well. The 70"
prop climbed better but was slower. Maybe somebody remembers the test and can
find the results.?
 
 Mark Quinn
 Lancair 360
 Daytona Beach