X-Mozilla-Keys:                                                                                 
Vance and Emily Jaqua wrote:

 Paul and Perry and others
Sorry,I don't have any real coordinates for fan
blades, but I agree fully that a 15 percent Clark
Y or similar is probably not the way to go. Classic
fan blades are generally metal (often titanium) and
have foils well under 10 percent. The Rare Bear
prop is operating in a similar environment and is
reputed to be 2% and looking at it "I believe"

Max thickness is well back from Clark Y location,
and with flat backside and low pcnt thk there is
very little camber. When working on early fans
at GE the darn aero guys were always asking us to
retwist the blades (which was a bear decause many
of these early configurations had "ears" to carry
a tip shroud to minimize recirculation and provide
damping - most long ones now have midspan dampers)

The reason for this random ranting is to further
reinforce the desirability of ground adjustible
pitch. The Warp drive blades also have a foil that
seems to fit that earlier description quite well.

Pushy Galore runs a Warp for their "drag" races
about 54 in dia to about 4000 rpm with a bit over
200 nitrous fed horses. I think that 3 cut down
Warp blades set at equiv of about 38 in pitch
would be a good starting point. If you are pulling
a bit over 100 shaft power at static you should see
close to 300 lb thrust - probably about 2/3 of
what a bogged down 235 makes there - but enough
for safe take off power. I think you said that
Judy Saber made an adapter to SAE 2 for you, so that
would be a simple bolt on for the Warp. I would
still vote to leave off the shroud - I think the
 noise would be high but tolerable

 
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