Hi all,
thanks for the feedback, I will try to answer all the questions:
1) Ohma2 : I have left on purpose enough width on the feather because as you know you can always cut off more but can't put it back. I will produce another arrow with the same two fledge design but with the difference of mounting a field point so I can comfortably shoot it without having to worry of busting the gorgeous obsidian point made by Steve Allely. I do suspect that with the tips of the tail feathers still intact the arrow should not be too noisy because they are free to move and hopefully will dampen any vortices generated.
2) JEB: as answered above I have not yet shot the arrow and wanted to make an equivalent with a field point first before I shoot it with the obsidian point. I do use the Veritas down maker for making the shafts and it worked really well. The table that listed the adjustments for the sizing of the dowels did for some reason not work for me and I had to make a few adjustments beyond the listed settings until I had the arrow size I was after. I have settled on the 5/16 size. If I can maintain a consistent spine on the arrows I think they will be fast and hard hitting. I had a bit of trouble controlling the speed of the feed through the dowel maker and on a few of them when I tried to slow down the feed it pulled the arrow off the socket supplied for the drill to drive the dowel. I then settled to just let the dowel maker determine the speed of the feed and not try to slow it down and the arrows turned out pretty consistently thereafter. I would be happy from others that are using it for any feedback on how to better control the speed.
I have shot my three feather fledged white ash arrows made with the tool and they performed just as well in comparison to my purchased arrow blanks. I actually achieved a bit more distance and had a nice smooth release without wobble.
3) Hawkdancer: the twist is exactly the way it is shown in the Encyclopedia of Native American Bows, Arrows & Quivers (Volume 1) written by Steve Allely and Jim Hamm except I don't have as wide a gap to the shaft in the midsection of the fledging. A good example of it is on page 50 where it depicts a Seneca hardwood shaft with hawk tail feathers. On page 92 it also shows similar fledging with a turkey tail feather but in that case there is a wider gap to the shaft from each side of the feather mounted on the shaft. It will be interesting to see what impact that has on the aerodynamic behaviour of the arrow. I have mounted it a bit differently for the reasons listed in my post (I wanted to preserve the tips of the turkey feathers) but the twist is the same.