"Ebby" wrote in message
...
I have to decide between a climb prop and a cruise prop for my Hatz
biplane. I am looking for a primer on propellor choice. For climb I was
thinkng Sensenich W74EM-54 and for climb Sensenich W74EM-58. Propellor
experts educate me please.

Contact a reputable prop maker, tell him/her your specs and desires and they
will match a prop to your use. For rough calculations, go to
http://www.greatplainsas.com/ed.html and enter your numbers. This will give
you an answer for this type of prop, but will be in the ballpark for others.

If you specify the diameter and pitch - and it's not right - don't expect
the prop maker to give you modify it for free.
Tell them your intended use and leave it up to them to supply the proper
fan. Then if it's not right, it's their problem. You are paying for their
expertise.

Rich S.