Graupner 50mm 4-Blade prop for 4mm threaded
shaft. Looks good in the pack.
Take a saw of your choice and slice a slot
for the drive dog on the front of the prop to match the stock nylon prop's
Saw off the rear tip of the prop and the end
cap of the threaded brass insert. Saw carefully and sand square. Don't let
the brass heat up enough to melt the plastic prop. I left the 4mm threads
alone. They just slipped over the 6-32 shaft threads and centered the prop
The prop looks pretty good mounted. 50mm is
the maximum size prop I would try. It just fit by less than 1/16"
from the skeg and the hull.
This side view shows you why this prop did
not perform as well as the cheap, er...eh...inexpensive stock prop. It
doesn't have much pitch to start with and looses much of that near the
tips of the blades. Since it didn't do as well as the stock prop, no
further tests were performed. This may be a great prop with other motors