That said, the Whirlwind seems to be the lightest, fastest C/S prop for the buck out there.... It is also lighter than any C/S prop, and less expensive.
Actually, Lary isn't the ONLY one who has done direct prop comparisons - you can also find Randy Lervold's work on his RV-8 Web Site:
http://www.romeolima.com/RV8/Prop.htm
I switched from a Blended airfoil to a 200RV and was surprised at the performance deference.
Lighter yes, which is a big advantage. Faster and cheaper, no. Larry Vetterman did what seems to be the only direct comparison of the Whirlwind with the Hartzell blended airfoil on the same airplane under the same conditions, and the results are a wash in terms of performance:
http://www.vansairforce.net/vetterman/vettermanexhaust.htm#prop
The price shown on WW's website for the 200RV is two thousand dollars higher than Van's OEM price for the Hartzell.
Brings up a good point on CG. Most RV7's end up more tail heavy than not empty (unless you take drastic measures to prevent it) and this can impact your baggage carrying capability...I would not want a lighter prop on my nose.
Not the only comparison - see this RV-8 prop comparison. EDIT - hehe, Ironflight beat me to it! /EDIT That is the study I was referring to, and in that the 200RV edged out Hartzell on the same plane. Different planes or slight differences in testing technique may account for the difference in results. Don't know how much difference the blended airfoil makes.
Randy's comparison was between the 200RV and a Hartzell with the older 7666 blades. The 200RV came out 1 to 2 mph faster than the Hartzell. Van's suggested in an Rvator article that the blended airfoil blades are about 3 mph faster than the 7666 blades. Bob Axsom and I both recently switched from the 7666 to the 7496 (blended airfoil) prop, and both of us saw about 3 mph gain. So, in my mind this is all consistent with Larry Vetterman's conclusion that there is little if any difference in speed between the two props. I'm not sure what the final price for the group buy was for the 200RV but I think it was still a few hundred higher than Van's Hartzell price.
As far as I can tell the 200RV is a great choice, particularly for weight savings. This could make for a big difference in flying qualities of the RV-8.