Here's some interesting propeller developments from a company called Bica
mber Technology. They claim to have a new airfoil design thats much
more efficient=2C using a concave section behind the maximum camber point
on both sides of the blade.
http://www.bicambertechnology.com/
But in a recent test between a two blade Bicamber shaped foil and the Paul
Lipps designed 3 blade Ellipse=2C the Lipps prop proved significantly more
efficient. Reposted from the Rotary Eng list: Hi Paul and group. I brought
the subject of bicamber tech. So with a little research I got theses data
for the group to share. Please note that Paul Lipps is working with Catto a
nd Bicamber tech as specified on this link. This Jim Smith was introduced t
o me by Paul Lipps. http://www.biplaneaerobatics.com/elippse
Marc Joseph Hi Marc=2CI have been flying an Elippse 3 blade propeller (Desi
gned by Paul Lipps) on my 150hp RV-6 forone year now.Last June I tested a 2
blade propeller (Designed and built by Fred Felix) that had the same tip s
hapeas my Elippse and also incorporated the Bi-Camber Technology.Below are
the flight test numbers at 4=2C000 Palt and 10=2C000 Palt for both props. 4
=2C000 Palt RPM IAS(mph) TAS(mph) Effective pitchBi-Camber 2=2C778 170.8 18
3.5 69.7"Elippse 2=2C740 180.8 193 74.4 " 18% more efficient 10=2C000 Palt
Bi-Camber 2=2C695 149 177.5 69.5"Elippse 2=2C655 157.6 184.4 73.3" 14% more
efficient Rate of Climb 2=2C000 to 10=2C000 PaltBi-Camber Avg. 774 fpmElip
pse Avg 916 fpmThe above numbers are an average of several test flights. Hi
gher speeds with fewer RPM anda better rate of climb for the Elippse prop.
Gross T.O. Weight for all flights 1=2C440 lbs. I am marketing the Elippse p
ropeller (for Paul) for the Experimental aircraft. If I can be of any furth
er help=2Cplease get back with me. Thanks for the inquiry and intrest=2CJim
Smith
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