Roger Halstead wrote:

Why less RPM? Speed maybe, but why more fuel consumtion?

To get less noise with a particular prop you have to reduce the RPM.

Yes, but we talked about changing the prop.

To go with more blades to reduce the noise is reduced efficiency,

This needn't to be so.

The noise from the 2 blade prop is on take off.

The noise which causes most problems is the take off noise. En route
noise can be reduced by flying high and avoiding populated areas. Of
course a quiet plane is a nice thing en route, too.


To me, working on the muffler(s) is like trying to keep
the mouse from squeaking while the lion is roaring.

Nobody prevents one to work on both.

Stefan