I have been working on this project for about a month, and finally got them done this morning. My apologizes to George Roland for not answering his questions via e-mail. Sorry George I accidentally deleted your e-mail before I could answer it. I hope this thread will explain how to do this. A few here have done a 300 Hz version of this horn with excellent results. Jorden (jorjen) for one was inspirational to me to proceed with this project. JWCullison was working on this exact 225 Hz horn that I built, but I don't think he finished due to many irons in the fire, not to mention a new bundle of joy, and building a new home. I don't know how you do what you have done already JC ;) This project was more difficult and time consuming than I anticipated ( aren't they always!) I learned alot of things along the way that I would do differently next time. There are lots of pics to follow and I will try to answer any questions that I can, but be warned, I am only a hobbiest wood worker and only slightly knowledgeable of the science behind the tractrix horn. Enjoy,
The 1st pic is of the printout of the tractrix horn calculator that I used to determine the flare. I found this spread sheet program on the volvotretter web site, which has alot of useful information. There were alot of points to layout, I'm sure I could have used alot less points (about 10 fold) and still been plenty accurate enough for this project.