Dave S wrote:
snip snip
One person who was running a Mazda rotary/wankel conversion in an RV 4
had a speed penalty incurred by using the product. He had a benefit at
low speed with regards to performance, but broke even with a fixed pitch
cruise prop around 140-150mph (that was installed later) and he had a
signigicant penalty on the high end with the IVO top speed being about
187 mph and with the cruise prop getting him about 210-215 mph. Some of
this is from his website (www.rotaryaviation.com) and some of this is
from telephone conversations with him.

On the Ivoprop website, it says that the prop can be adjusted between
30-90" or 45-105". See http://www.ivoprop.com/inflightmagnumodel.htm

I take this to mean that one has a choice of the baseline pitch
during installation. From that it would follow that you have a
choice of optimising between climb and cruise.

I wonder if the fellow in this example chose the lower pitch range,
and if he would see top speed improvement (and some loss of takeoff
and climb performance) if he had chosen the higher pitch range.

Just my guess...