flyrotary@lancaironline.net Mailing List Archive

Ed,

Thanks, I thought we were discussing bell shaped ducts, I must have confused myself, however that info on wedge shaped and streamlined wedge shaped ducts is extremely interesting - a picture says a thousand words. I can see instantly why there is a bump in the design.

Although I do like the bell shaped duct and I'm sure it's the best, for ease of construction, I might look at the streamlined wedge shaped duct.

Thanks for that info - it's much appreciated.

George ( down under)

George, here are two figures from K&W – one could be described as a “Wedge” figure 12-6 and the other one a “streamline” wedge figure 12-12.

Always dangerous for me to try to interpret what K&W are really saying, but from what I get from these two figures, it would appear that the “streamline” wedge permits you to use a smaller inlet (Ai = 0.30 Ab) for the same performance (same losses) that you get with a larger opening Ai = 0.44 Ab for the pure Wedge. But, that is just my take on it.

The slight bump (where the 64 deg angle is annotated) of the Streamline wedge may be to increase the boundary layer velocity to delay separation of the boundary layer in that far corner where duct meets core.

Ed

Ed Anderson

Rv-6A N494BW Rotary Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.rotaryaviation.com/Rotorhead%20Truth.htm

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