Brian Whatcott wrote:

I an unfamiliar with the autoprop.If it turns its blades' angle of
attack to the near zero angle (actually slightly negative angle) that
minimizes drag, then this is said to be a feathering prop.
[one realises that a blade's angle varies with distance from the hub,
so that the idea of a fixed angle of attack is a slight abstraction]

If a prop system allows the blades to fold at the hub in order to
minimize drag this is usually described as a folding prop.

If a prop system allows the prop blades' angle of attack to vary so as
to maximize power transfer at the present water speed, this is said to
be a variable pitch prop system.

This may be a description for some. However, in my world, a "variable
pitch" prop starts at "zero" pitch (blades 90 deg to a "feathered"
position) and to increase speed, pitch is increased. These are also
called controllable pitch props and they ( normally ) can not be
"feathered".
However, it appears from the literature on the autoprop/maxprop, there
may be a degree of "variable" to these props ..... I'm mentioning this
here, as it does appear there is room for confusion.

otn


Let me ask Jim specifically (in order to avoid interjections from the
lunatic fringe) which of these three types of prop system he would
call the Autoprop?

Regards

Brian Whatcott Altus OK