Prop Pitch

I think there was a thread on this topic but I can't find it. What are the optimum parameters for prop pitch? Such as Static RPM, desired climb RPM, desired cruise RPM?

Also how do we calculate % power at different altitudes? The only document I can find is in the Rotax literature that says 50% is 4800 rpm and 75% is 5000 rpm. It seems to me that can't be true at sea level AND at 8500 feet. Is it possible to use manifold pressure to figure that out? We have it displayed and there must be some utility. I have never had one on other that a variable pitch aircraft.

The pitch settings are very close together and it is difficult to make "small" changes. I had it at what I thought was OK but then needed to take the prop off and now I am trying to get it back to where it was.

If we get wheel pants option is this going to change and how?

Rotax is saying the take off RPM should be 5200.

You can adjust your prop?? Mine came with an internal stop holding it in one pitch setting......apparently the position Van's wants it set at. Any one else have an adjustable prop that isn't "fixed" at one setting?
Paul Shepard 120007

pmshep said:

You can adjust your prop?? Mine came with an internal stop holding it in one pitch setting......apparently the position Van's wants it set at. Any one else have an adjustable prop that isn't "fixed" at one setting?
Paul Shepard 120007

Click to expand...

Paul, you can rotate the prop about 1 1/2 "marks" on the hub. This is plenty to give you too much or too little prop for the -12.

Hey Paul

You will want to set the blades with a prop protractor also. They don't cost much. The limiter block is fairly decent, but still allows each blade to move a little from the other. You'll have a balance problem if you don't get them set pretty close to each other.

John Bender

Richard,

Here is the post you are looking for.

http://www.vansairforce.com/community/showthread.php?t=50447&highlight=prop+protractor

My adjustments are detailed there. I still have to do it again, once the weather warms. I do not get the recommended 5200 rpm per the Rotax service bulletin (Operation at High Manifold Pressures) on the take-off roll. With my current prop adjustment I am between 5000-5100 rpm.

For power settings, all I have seen is the small chart in the POH.

Hope that helps.

John, Larry, Marty

Thanks for the info, I just ordered a prop protractor.....Looks like it will be of great value in the near future!
The RPM numbers will also be quite helpfull.....I'm a LYC guy and this Rotax is all new.....
Paul