I commented on this awhile back but I'll try again. This is just my thinking so it is probably wrong. Straight fletchings will contact fewer whiskers than curved. All of the fletching on a straight vane or feather will go through the same "channel" in the biscut where as a curved vane or feather has to contact more whiskers becasue it is curved. If you look at the shaft from the nock end a straight vane or feather is at noon four and eight o'clock or 0, 120 and 240 degrees. A curved vane or feather starts at the same clock or degree position but ends 6 dgrees beyond (0-6, 120-126 and 240-246 degrees) where the vane or feather starts. This curve contacts more whiskers because it can't cut one channel through the whiskers. I think this will cause more drag and slow you arrow down. How much? If sombody has a chronometer we could run some tests. As far as stabilizing the arrow, I use straight vanes and feathers. I have taken deer with them, so I guess it works.
If I'm off on this PLEASE correct me. It won't be the first time I've been wrong.
The 'Bonker