Dr Ashby,
Thanks for chiming in on this one. I am recently returned to the trad fold after a 20 year hiatus. I am an engineer by trade and have found your research very helpful in my quest for finding what will hopefully be a perfect arrow set up for the hunting that I do. my next steps are to try the 2.25 and 2.5 inch fletchings, I also plan to try a 2 - 3 " and 2 - 2" fletch set up set at 90 degrees with the 2 and 3 inch fletches alternating.
I am shooting Axis FMJ 500 shafts at 31 inches long with 175 grain grizzly broadhead with 100 grain brass inserts. I am using the factory nocks with a 5 inch tape and 4 - 2 inch fletch right now. I have about 21.4% EFOC. I am shooting them out of a reflex / deflex, 68 inch long, 55lb longbow. My draw length is 30.25 inches. I am 6.4" tall and can shoot the bow all day long.
I do have a question for you. If I bump the head up to 200 grains and shorten the arrow to get it to tune to 30.5 inches the FOC increases to roughly 25%, will this improve penetration much or is it money ill spent pursing the extra 3 to 4 % foc?
John and George. Both of you have good points and there is definately a point of diminishing returns. The thing to remember is that diminishing return comes on both ends of the speed and penetration spectrum. What each archer has to decide is what they want from their arrows and then go about pursuing it.
I am presently on a quest for an arrow that I can be confident in shooting. I want the arrow to be reasonably fast ( 160 fps + ) and to have a high or preferably extreme FOC. The FOC is to help me out if an animal spins on me at the shot, or I flub my shot due to buck fever / bad form.
George, I admire anyone who has the experience and abilities that you have. They are hard earned and I enjoy your humor. I do have to say that I, and I bet most other traditional archers have neither your skill level nor confidence in our set ups. I would bet a large sum of money that I am at least 25% more likely to make a bad shot in my shooting comfort zone ( 20 yards ) while hunting than you are. I just don't have that much traditional hunting experience.
The two inch fletching runs are a fun testing process to see if they will work or not for my shooting abilities and style. I would bet a large sum of money that a man with your skill could shoot 2 inch fletchings and not notice a difference in your arrow flight at all.
Having said all of that, if we all just stuck to what works for someone else, we would all still be throwing spears with Atlatals and we would be still be discussing what stone head weight, single or double bevel edge, what shaft weight and materials would work best by smoke signal and scratching on the ground when we got together to chat.
I am all for each archer shooting an arrow and bow that is tuned and matched, which they are fully confident in. Shoot what you want. Just remember that some of us have not had the time to get to that point and really enjoy the quest for knowledge that comes with the trad way of life.