I am new to this forum - I am from Austria Europe.
We design ice protection systems for propellers and used several 3 blade MT propellers on Mooney M20K´s for the development. We did over 2000 hours on those Propellors so far in all kind of conditions. No problems at all - they work great and run smooth.
Besides replacement de-icer pads our main focus was to implement the de-icer into the propeller blade for improved aerodynamics (glued on de-icer pads decrease airplane performance measurably).
I do not know the performance of the Hartzell 3 blades Propellers in comparison - however with the clean MT 3 blade (with internal de-icers) a Mooney M20K does 180 TAS on 10-11 gph in FL 180 running ROP and in the temp limits (CHT < 400, TIT < 1550) . The airplane is equipped with intercooler and Merlyn waste gate. This should give you an idea about the performance which we think is very good.
If you fly an MT prop without Propeller de-icing and want to get an additional bit more performance out of it then rip off the black rubber erosion strips on the inside of the propeller blades - it will give you some extra performance - enough that you should be able to measure it.
If interested here is a link to some of the work we do with Propellers http://www.villinger.com/index.php?lang=2&hID=24
