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Old 03-15-2005, 05:10 AM
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David Staten David Staten is offline
Rotary Powered Velocity
 
Join Date: Jul 2004
Location: KEFD, Houston Area, Texas
Posts: 441
Default You can buy one...

Quote:
Originally Posted by JonC
So, why not add small winglets to the tips of a prop since they are just twisted airfoils.. .
They are already on the market. Hartzell sells the "Q-tip" propeller.

The following is a paste from the AOPA website regarding the Q-tip props they put on the "Win A Twin" sweepstakes of recent

Quote:
Originally Posted by AOPA
What about those Q-tips, you ask? Are they purely cosmetic? Hartzell says there are two advantages. One is that the propellers' normal diameters are reduced by one inch. This keeps dirt and small stones farther from the blade tips, and keeps tip erosion during ground operations to a minimum. Noise reduction is another plus. The curl of the Q-tip acts much like a winglet, smoothing out the vortices — and therefore the noise — caused by low-pressure air moving to high as the propeller tips reach the supersonic speeds of high power settings.

But the Q-tips do have an undeniable ramp appeal. They get the looks, get the comments, and it's difficult to resist touching them. And how many times do we hear the wisecracks about landing gear-up? Always. They invoke the story about a hapless flight standards district office official who, upon spotting his first Q-tip propeller, began writing up its pilot for a violation. "Honest, they're supposed to be that way!" came the defense. The report was allegedly filed, and the case was heard. In the hearing, the propeller manufacturer gave a presentation about its line of Q-tip props, and the ticket-happy official received his comeuppance.
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Also, from the Hartzell Website..

Quote:
Originally Posted by http://www.hartzellprop.com/product_support/support_faqs.htm
What is a Q-Tip propeller? What are its advantages?
Q-tip propeller blades are formed by bending the tip section of the blade 90° toward the face side.

Aerodynamic improvements include a reduced diameter and decreased tip speeds. This results in quieter operation and reduced tip vortices. The 90° bend reduces the vortices that, on traditional blades, pick up debris that can contact the blades and cause nicks, gouges and scratches.
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Dave
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