X-Mozilla-Keys:                                                                                 
Bill Freeman wrote:

Paul,

Several of the faster Long EZs have been using pure
carbon (no core left) prop tips for many years.  The
procedure has been to remove about 1/16" of wood from
the flat side of the blade over the outboard 6".  Then
apply about 1/16" of carbon fiber with the fibers 30 deg
from the hub-to-tip line, alternating +30 deg and -30 deg.
cure, and trim.  Then remove all the wood for the first
2-3 inches of the tip and gradually taper the wood back
to 1/16" under the original contour about 6" from the
tip.  Apply 1/16" of carbon on the top, same +30/-30 ply
orientation for proper torsional stiffness, lapping over the
leading edge slightly.  Cure and trim, vacuum bagging is
a plus.  Sand the tip to a 6% symmetrical airfoil by eyeball
and go to town.  The carbon is stiff enough to avoid
tip flutter at this extremely thin airfoil, which works much
better than a 12-15% typical Clark Y used in most wood
props.  If you try to thin the wood tip it will flutter off
and destroy (at minimum) the prop.  Y'all be careful out
there.

Bill

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