After entertaining several ideas for alternative engines, and rejecting each of them for a variety of reasons, I believe I've settled on a Rotax 912iS. Once the applause dies down, we can move to choosing a prop.

One of the props I'm considering is the IVOPROP IFA. I've spent several hours reading through many of the threads in this section of the forum, and it seems that most of the folks using an IVOPROP IFA are pretty pleased with the performance/price of the system.

For those of you using an IVOPROP Medium IFA on a Rotax 912 or 914, I have several questions:

Q1: Are you using a 2-blade or 3-blade prop?

Q2: What prop length are you using?

This thread from 2012 seems to indicate that a 3-blade IVOPROP Medium IFA exceeds the 6,000kgcm2 maximum limit for mass moment of inertia on a 9-series engine. I'm leery of putting one on a brand new engine and having gearbox problems (followed immediately by warranty problems!).

Q3: For those running 3-blade props, what's been your experience WRT gearbox wear, vibration, jerkiness during start or shutdown, etc.?

Q4: Has anyone independently confirmed the test result in that 2012 thread, or gotten a MMoI value from IVOPROP?

Thinking ahead to engine mods in the future, I'd like to get a prop that's approved for >100 hp but the IVOPROP website contradicts itself on that point. At the bottom of the landing page it says the Medium is good for 150 hp. On the Medium IFA product page it says 100 hp in one place and 150 hp in another. An apparently older version of that page confuses things even further; it says 100 hp and 140 hp.

Q5: Does anyone know the correct maximum horsepower rating for this prop?

Thanks!