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Shen44
 
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ubject: What are the pros and cons of a folding prop?
From: "Jeff Morris"


If you insist on calling the Autoprop "feathering" then you have to admit its
a
pretty poor one, having 5 to 10 times the drag of other feathering props.
For
example, in the MIT/Practical Sailor test, at about 7 knots the Autoprop had
10
pounds of drag, while the 2 and 3 blade Maxprop feathering props had about 1
and
2 pounds respectively. The folding props were so low they weren't shown. 10
pounds of drag is pretty good, compared to the 25 to 35 pounds for many of
the
props in the test, but it isn't the same as feathering. The Autoprop has
some
interesting properties, like very good performance in reverse, if you rev


From this, and looking at diagrams of both the "maxprop" and "autoprop", it
appears that both designs can rightly call themselves "feathering".
However, it appears that the design of the hub of the autoprop is such that it
still creates a marked amount of drag which has little to do with the
shape/curvature of the blades.
Agree/disagree/comments?

Shen