Design Improvements for the Zenith 601 HDS:
The Zenith kit
had a 3-bladed GSC propeller. We used it for many years.
It runs very smoothly, requires little maintenance, and after 1200 hrs
was still in excellent condition. But the propeller is not so
efficient. For mountain flying with takeoffs at high density
altitude, it had to be repitched such that
cruise performance was dismal.
In 2009, we switched to the Sensenich 2-blade composite propeller,
which is light-weight, strong, and very efficient.
A simple yet effective method for setting blade pitch
of the propeller is described in the blog post
Setting Blade Pitch for Sensenich Composite
Both cruise and climb performance are excellent.