Pills & propellers

Bob,

Thanks for one more entertaining text and valuable lesson.
Hoping the question's not too stupid: while you mention diameter and
pitch and some parameters I don't really understand, why do you never
discuss the number of blades on the prop?

It seems obvious that a two-bladed prop is by far the easiest to make.
But at my home airfield I see a lot of 3-bladed, and one ultralight even
sports a 4-blade on a Rotax 912. Why? What's the importance?

On Nov 22, 7:27*am, jan olieslagers
wrote:


It seems obvious that a two-bladed prop is by far the easiest to make.
But at my home airfield I see a lot of 3-bladed, and one ultralight even
sports a 4-blade on a Rotax 912. Why? What's the importance?
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Dear Jan,

Most of my messages are directed toward people using converted VW
engines. The fellow with the Rotax 912 is far outside our field of
interest. But as a point of interest, the number of blades is
normally dictated by the ground clearance and the amount of power that
must be converted to thrust.

-R.S.Hoover