Jim,

I certainly don't mean to undermine your knowledge, however at the WC, Christophe had his canalizer in a different position on his Osmose than he had initially, and said that the longitudinal placement made a big difference. I also have heard Don Szczur talk somewhat along the lines of noting the difference in the performance of his Brio with the canalizer, and he said, interestingly enough, that stall turns required more rudder. Also, when you refer to a dorsal fin, I'm assuming that you're referring to literally a fin, and not a 'T' canalizer. Similar to what I saw on Dave Lockhart's Prestiges at the Nats this past year. Does the addition of the wing on top of the canalizer fin change anything?

I would think that the placement of it would be very critical. From what I understand, it is used to straighten the slipstream. Every diagram that I've seen in my entire life shows a slipstream as a very loose spiral that encircles the fuselage a few times and ends up hitting the side of the vertical fin. Is this a simplified depiction to show the general concept of what it is, or is the spiral really compact, almost like a spring? If that's the case, I can see where the placement wouldn't be as critical as you're hitting that spiraling mass several times, but something is making me think that the slipstream is in direct correlation to the RPMs the motor is turning. Am I correct, or is that something that is understood when talking about it? It's been a while since I really studied aerodynamics, so I'm more than likely quite rusty. Also, I would imagine that prop size has something to do with the performance of the canalizer or dorsal fin. Did you experiment with props to see the difference it made? Does a higher pitch prop cause the "spacing" of the P-factor to be greater?

I apologize if I'm completely off base here, or if I'm over analyzing anything. Any insight would be much appreciated. Take care.